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Since 1983, I have lived, worked and raised a family in a progressive, egalitarian, income-sharing intentional community (or commune) of 100 people in rural Virginia. AMA.
Hello Reddit! My name is Keenan Dakota, I have lived at Twin Oaks, an income-sharing, intentional community in rural Virginia for 36 years, since 1983. I grew up in northern Virginia, my parents worked in government. I went to George Mason University where I studied business management. I joined Twin Oaks when I was 23 because I lost faith in the underpinnings of capitalism and looking for a better model. I have stayed because over time capitalism hasn't looked any better, and its a great place to raise children. While at Twin Oaks, I raised two boys to adulthood, constructed several buildings, managed the building maintenance program, have managed some of the business lines at different times. Proof this is me. A younger photo of me at Twin Oaks.Here is a video interview of me about living at Twin Oaks.Photo of Twin Oaks members at the 50th anniversary. Some things that make life here different from the mainstream:
The labor system - all work is considered equal, whether you are earning income for the community or not. Cooking/cleaning counts the same as planning the annual budget. Also, you don't have to do the same job all week - your day can be a mix of indoor and outdoor work, you have freedom to arrange your day, and you can gain skills in a wide array of tasks and trades.
Non-gender binary, queer and trans people are very welcome at Twin Oaks. People introduce themselves with their pronouns and a significant number of our members go by they/them.
Verbal consent culture is very important here. It is not okay to touch anyone without asking.
Nudity and partial nudity is allowed in some parts of the farm, such as in the sauna, swimming hole, on the hiking trails, etc.
Our social norms prohibit using phones in common areas when other members are present, with the exception of a few cafe-style spaces.
Every day we provide a home-cooked, plant-based lunch and dinner with options for special diets including vegetarian, vegan, gluten-free, and no onions & garlic.
Raising kids here is easier. Some of the time that parents spend raising their children counts towards their labor quota. Many of the kids are home-schooled or "unschooled", and they spend more time outside than in front of a screen. The kids have no problem passing the state's annual standardized test to move onto the next grade level.
We have a shared clothing resource called Commie Clothes, which is like a free thrift store. Borrow something and then return it dirty, and it gets washed and re-hung up.
More about Twin Oaks: Twin Oaks is an intentional community in rural central Virginia, made up of around 90 adult members and 15 children. Since the community's beginning in 1967, our way of life has reflected our values of cooperation, sharing, nonviolence, equality, and ecology. We do not have a group religion; our beliefs are diverse. We do not have a central leader; we govern ourselves by a form of democracy with responsibility shared among various managers, planners, and committees. We are self-supporting economically, and partly self-sufficient. We are income-sharing. Each member works 42 hours a week in the community's business and domestic areas. Each member receives housing, food, healthcare, and personal spending money from the community. We have open-slots and are accepting applications for new members. All prospective new members must participate in a three-week visitor program. Applicants to join must leave for 30 days after their visit while the community decides on their application. We offer a $5 tour on Saturdays of the property, starting in March. More info here. Ask me anything! TL;DR: Opted out of the rat-race and retired at 23 to live in the woods with a bunch of hippies. EDIT: Thanks for all the questions! If you want some photos of the farm, you can check out our instagram. EDIT2: I'm answering new, original questions again today. Sort by new and scroll through the trolls to see more of my responses. EDIT3: We DO have food with onion & garlic! At meals, there is the regular food, PLUS alternative options for vegan/vegetarian/no gluten/no onions & garlic. EDIT4: Some of you have been asking if we are a cult. No, we are not. We don't have a central leader or common religion. Here are characteristics of cults, FYI. Edit: Yikes! Did I mention that I am 60? Reddit is not my native land. I don't understand the hostile, angry and seemingly deliberately obtuse comments on here. And Soooo many people! Anyway, to the angry crowd: Twin Oaks poses no threat to anyone, we are 100 people out of a country of 330 million? Twin Oaks reached its current maximum population about 25 years ago, so not growing fast, or at all. Members come and go from Twin Oaks. There are, my guess is, 800 ex-members of Twin Oaks, so we aren't holding on to everyone who joins—certainly, no one is held against their will. Twin Oaks is in rural Virginia, but we really aren't insular, isolated, gated or scared of the mainstream culture. We have scheduled tours of the whole property. Local government officials, like building inspectors, come to Twin Oaks with some frequency. People at Twin Oaks like to travel and manage to do so. I personally, know lots of people in the area, I am also a runner, so I leave the property probably every day. There are lots of news stories about Twin Oaks over the years. If you are worried about Twin Oaks, maybe you could go read what the mainstream (and alternative) media have to say. Except about equality Twin Oaks is not particularly dogmatic about anything. (I know some people at Twin Oaks will disagree with that statement.) Twin Oaks isn't really hypocritical about Capitalism, Socialism, or Communism, we just don't identify those concepts as something that we are trying to do. Twin Oaks is not trying to DO Communism, we are trying to live a good life with equally empowered citizens—which has led us to try to maintain economic parity among members. Communists also do that. In making decisions in the community I don't remember anyone trying to support or oppose an idea due to excess or insufficient Communism, Socialism, or Capitalism. In most practical senses those words aren't useful and don't mean anything. So, no need to hammer Twin Oaks for being insufficiently pure, or hypocritical. Twin Oaks is very similar to the Kibbutz in Israel. If anyone has concerns or questions about what would happen if places like Twin Oaks suddenly became much larger and more common, read about the history of the Kibbutz, which may have grown to possibly 1% of the population at their largest? There was and is no fight with Capitalism from the kibbutz—or with the State. My point is—not a threat. To the other people who think that the ideas of Twin Oaks are interesting, I want you to know it is possible to live at Twin Oaks (or places like Twin Oaks) and happily live ones entire life. There is no central, critical failing that makes the idea not work. And plenty of upside. But do lots of research first. Twin Oaks maintains a massive web site. (Anyway, it takes a long time to read.) But what I would like to see is more people starting more egalitarian, income-sharing communities. I think that there is a need for a community that is designed and built by families, and who also share income, and provide mutual support with labor and money. If you love this concept, maybe consider gathering together other people and starting your own. Ideologically speaking: -Ecology: the best response to ecological problems is for humans to use fewer resources. The easiest way to use fewer resources is to share resources. Living communally vastly cuts down on resource use without reducing quality of life. -Equality: ideologically speaking, most people accept the idea that all humans have equal rights, but most social structures operate in ways that are fundamentally unequal. If we truly believe in equality then we ought to be willing to put our bodies where our ideology is. In a truly equal world, the issues of sexism and racism and all other forms of discrimination would, essentially, not exist. -Democracy: Twin Oaks uses all manner of decision-making models and tools to try to include everyone and to keep people equally empowered. There is no useful word for this. We do use a majority vote sometimes, as a fallback. But sometimes we use consensus. We sometimes use sociocracy (dynamic governance). The word "Isocracy" (decision-making among equals), would be useful to describe Twin Oaks' decision-making model, but Lev in Australia has written an incomprehensible "definition" on Wikipedia, that he keeps changing back when someone corrects it. -Happiness: The overarching goal of all ideologies is to make people happy, right? I mean, isn't it? Capitalism is based upon the belief that motivation is crucial to human aspiration and success (and therefore more happiness). Under Capitalism, equality is a detriment because it hinders motivation (less fear of failure, or striving for success). Twin Oaks believes that humans are happier when they are equal, and equally empowered. So the place to start up the ladder of happiness is to first make everyone equal. Well, Twin Oaks is mainly still working on that first step. EDIT5: Some have asked about videos - here are links to documentaries about Twin Oaks by BBC, VICE and RT.
Hi everyone, this is my first ever post here. I run a little website called The Thought Experiment where I talk about various issues, some of them Singapore related. And one of my main interests is Singaporean politics. With the GE2020 election results, I thought I should pen down my take on what us as the electorate were trying to say. If you like what I wrote, I also wrote another article on the state of play for GE2020 during the campaigning period, as well as 2 other articles related to GE2015 back when it was taking place. If you don't like what I wrote, that's ok! I think the beauty of freedom of expression is that everyone is entitled to their opinion. I'm always happy to get feedback, because I do think that more public discourse about our local politics helps us to be more politically aware as a whole. Just thought I'll share my article here to see what you guys make of it :D Article Starts Here: During the campaigning period, both sides sought to portray an extreme scenario of what would happen if voters did not vote for them. The Peoples’ Action Party (PAP) warned that Singaporeans that their political opponents “might eventually replace the government after July 10”. Meanwhile, the Worker’s Party (WP) stated that “there was a real risk of a wipeout of elected opposition MPs at the July 10 polls”. Today is July 11th. As we all know, neither of these scenarios came to pass. The PAP comfortably retained its super-majority in Parliament, winning 83 out of 93 elected MP seats. But just as in GE2011, another Group Representation Constituency (GRC) has fallen to the WP. In addition, the PAP saw its vote share drop drastically, down almost 9% to 61.2% from 69.9% in GE2015. Singapore’s electorate is unique in that a significant proportion is comprised of swing voters: Voters who don’t hold any blind allegiance to any political party, but vote based on a variety of factors both micro and macro. The above extreme scenarios were clearly targeted at these swing voters. Well, the swing voters have made their choice, their roar sending 4 more elected opposition MPs into Parliament. This article aims to unpack that roar and what it means for the state of Singaporean politics going forward. 1. The PAP is still the preferred party to form Singapore’s Government Yes, this may come across as blindingly obvious, but it still needs to be said. The swing voter is by its very definition, liable to changes of opinion. And a large factor that determines how a swing voter votes is their perception of how their fellow swing voters are voting. If swing voters perceive that most swing voters are leaning towards voting for the opposition, they might feel compelled to vote for the incumbent. And if the reverse is true, swing voters might feel the need to shore up opposition support. Why is this so? This is because the swing voter is trying to push the vote result into a sweet spot – one that lies between the two extreme scenarios espoused by either side. They don’t want the PAP to sweep all 93 seats in a ‘white tsunami’. Neither do they want the opposition to claim so much territory that the PAP is too weak to form the Government on its own. But because each swing voter only has a binary choice: either they vote for one side or the other (I’m ignoring the third option where they simply spoil their vote), they can’t very well say “I want to vote 0.6 for the PAP and 0.4 for the Opposition with my vote”. And so we can expect the swing voter bloc to continue being a source of uncertainty for both sides in future elections, as long as swing voters are still convinced that the PAP should be the Government. 2. Voters no longer believe that the PAP needs a ‘strong mandate’ to govern. They also don’t buy into the NCMP scheme. Throughout the campaign period, the PAP repeatedly exhorted voters to vote for them alone. Granted, they couldn’t very well give any ground to the opposition without a fight. And therefore there was an attempt to equate voting for the PAP as voting for Singapore’s best interests. However, the main message that voters got was this: PAP will only be able to steer Singapore out of the Covid-19 pandemic if it has a strong mandate from the people. What is a strong mandate, you may ask? While no PAP candidate publicly confirmed it, their incessant harping on the Non-Constituency Member of Parliament (NCMP) scheme as the PAP’s win-win solution for having the PAP in power and a largely de-fanged opposition presence in parliament shows that the PAP truly wanted a parliament where it held every single seat. Clearly, the electorate has different ideas, handing Sengkang GRC to the WP and slashing the PAP’s margins in previous strongholds such as West Coast, Choa Chu Kang and Tanjong Pagar by double digit percentages. There is no doubt from the results that swing voters are convinced that a PAP supermajority is not good for Singapore. They are no longer convinced that to vote for the opposition is a vote against Singapore. They have realized, as members of a maturing democracy surely must, that one can vote for the opposition, yet still be pro-Singapore. 3. Social Media and the Internet are rewriting the electorate’s perception. In the past, there was no way to have an easily accessible record of historical events. With the only information source available being biased mainstream media, Singaporeans could only rely on that to fill in the gaps in their memories. Therefore, Operation Coldstore became a myth of the past, and Chee Soon Juan became a crackpot in the eyes of the people, someone who should never be allowed into Parliament. Fast forward to today. Chee won 45.2% of the votes in Bukit Batok’s Single Member Constituency (SMC). His party-mate, Dr. Paul Tambyah did even better, winning 46.26% of the votes in Bukit Panjang SMC. For someone previously seen as unfit for public office, this is an extremely good result. Chee has been running for elections in Singapore for a long time, and only now is there a significant change in the way he is perceived (and supported) by the electorate. Why? Because of social media and the internet, two things which the PAP does not have absolute control over. With the ability to conduct interviews with social media personalities as well as upload party videos on Youtube, he has been able to display a side of himself to people that the PAP did not want them to see: someone who is merely human just like them, but who is standing up for what he believes in. 4. Reserved Election Shenanigans and Tan Cheng Block: The electorate has not forgotten. Tan Cheng Bock almost became our President in 2011. There are many who say that if Tan Kin Lian and Tan Jee Say had not run, Tony Tan would not have been elected. In March 2016, Tan Cheng Bock publicly declared his interest to run for the next Presidential Election that would be held in 2017. The close result of 2011 and Tan Cheng Bock’s imminent candidacy made the upcoming Presidential Election one that was eagerly anticipated. That is, until the PAP shut down his bid for the presidency just a few months later in September 2016, using its supermajority in Parliament to pass a “reserved election” in which only members of a particular race could take part. Under the new rules that they had drawn up for themselves, it was decreed that only Malays could take part. And not just any Malay. The candidate had to either be a senior executive managing a firm that had S$500 million in shareholders’ equity, or be the Speaker of Parliament or a similarly high post in the public sector (the exact criteria are a bit more in-depth than this, but this is the gist of it. You can find the full criteria here). And who was the Speaker of Parliament at the time? Mdm Halimah, who was conveniently of the right race (Although there was some hooha about her actually being Indian). With the extremely strict private sector criteria and the PAP being able to effectively control who the public sector candidate was, it came as no surprise that Mdm Halimah was declared the only eligible candidate on Nomination Day. A day later, she was Singapore’s President. And all without a single vote cast by any Singaporean. Of course, the PAP denied that this was a move specifically aimed at blocking Tan Cheng Bock’s bid for the presidency. Chan Chun Sing, Singapore’s current Minister of Trade and Industry, stated in 2017 that the Government was prepared to pay the political price over making these changes to the Constitution. We can clearly see from the GE2020 results that a price was indeed paid. A loss of almost 9% of vote share is very significant, although a combination of the first-past-the-post rule and the GRC system ensured that the PAP still won 89.2% of the seats in Parliament despite only garnering 61.2% of the votes. On the whole, it’s naught but a scratch to the PAP’s overwhelming dominance in Parliament. The PAP still retains its supermajority and can make changes to the Constitution anytime that it likes. But the swing voters have sent a clear signal that they have not been persuaded by the PAP’s rationale. 5. Swing Voters do not want Racial Politics. In 2019, Heng Swee Keat, Singapore’s Deputy Prime Minister and the man who is next in line to be Prime Minister (PM) commented that Singapore was not ready to have a non-Chinese PM. He further added that race is an issue that always arises at election-time in Singapore. Let us now consider the GE2015 results. Tharman Shanmugaratnam, Singapore’s Senior Minister and someone whom many have expressed keenness to be Singapore’s next PM, obtained 79.28% of the vote share in Jurong GRC. This was above even the current Prime Minister Lee Hsien Loong, who scored 78.63% in Ang Mo Kio GRC. Tharman’s score was the highest in the entire election. And now let us consider the GE2020 results. Tharman scored 74.62% in Jurong, again the highest scorer of the entire election, while Hsien Loong scored 71.91%. So Tharman beat the current PM again, and by an even bigger margin than the last time. Furthermore, Swee Keat, who made the infamous comments above, scored just 53.41% in East Coast. Yes, I know I’m ignoring a lot of other factors that influenced these results. But don’t these results show conclusively that Heng’s comments were wrong? We have an Indian leading both the current and future PM in both elections, but yet PAP still feels the need to say that Singapore “hasn’t arrived” at a stage where we can vote without race in mind. In fact, this was the same rationale that supposedly led to the reserved presidency as mentioned in my earlier point. The swing voters have spoken, and it is exceedingly clear to me that the electorate does not care what our highest office-holders are in terms of race, whether it be the PM or the President. Our Singapore pledge firmly states “regardless of race”, and I think the results have shown that we as a people have taken it to heart. But has the PAP? 6. Voters will not be so easily manipulated. On one hand, Singaporeans were exhorted to stay home during the Covid-19 pandemic. Contact tracing became mandatory, and groups of more than 5 are prohibited. But on the other hand, we are also told that it’s absolutely necessary to hold an election during this same period, for Singaporeans to wait in long lines and in close proximity to each other as we congregate to cast our vote, all because the PAP needs a strong mandate. On one hand, Heng Swee Keat lambasted the Worker’s Party, claiming that it was “playing games with voters” over their refusal to confirm if they would accept NCMP seats. But on the other hand, Heng Swee Keat was moved to the East Coast GRC at the eleventh hour in a surprise move to secure the constituency. (As mentioned above, he was aptly rewarded for this with a razor-thin margin of just 53.41% of the votes.) On one hand, Masagos Zulkifli, PAP Vice-Chairman stated that “candidates should not be defined by a single moment in time or in their career, but judged instead by their growth throughout their life”. He said this in defense of Ivan Lim, who appears to be the very first candidate in Singaporean politics to have been pushed into retracting his candidacy by the power of non-mainstream media. But on the other hand, the PAP called on the WP to make clear its stand on Raeesah Khan, a WP candidate who ran (and won) in Sengkang GRC for this election, stating that the Police investigation into Raeesah’s comments made on social media was “a serious matter which goes to the fundamental principles on which our country has been built”. On one hand, Chan Chun Sing stated in 2015, referring to SingFirst’s policies about giving allowances to the young and the elderly, “Some of them promised you $300 per month. I say, please don’t insult my residents. You think…. they are here to be bribed?” On the other hand, the PAP Government has just given out several handouts under its many budgets to help Singaporeans cope with the Covid-19 situation. [To be clear, I totally approve of these handouts. What I don’t approve is that the PAP felt the need to lambast similar policies as bribery in the past. Comparing a policy with a crime is a political low blow in my book.] I could go on, but I think I’ve made my point. And so did the electorate in this election, putting their vote where it counted to show their disdain for the heavy-handedness and double standards that the PAP has displayed for this election. Conclusion I don’t say the above to put down the PAP. The PAP would have you believe that to not support them is equivalent to not wanting what’s best for Singapore. This is a false dichotomy that must be stamped out, and I am glad to see our swing voters taking a real stand with this election. No, I say the above as a harsh but ultimately supportive letter to the PAP. As everyone can see from the results, we all still firmly believe that the PAP should be the Government. We still have faith that PAP has the leadership to take us forward and out of the Covid-19 crisis. But we also want to send the PAP a strong signal with this vote, to bring them down from their ivory towers and down to the ground. Enough with the double standards. Enough with the heavy-handedness. Singaporeans have clearly stated their desire for a more mature democracy, and that means more alternative voices in Parliament. The PAP needs to stop acting as the father who knows it all, and to start acting as the bigger brother who can work hand in hand with his alternative younger brother towards what’s best for the entire family: Singapore. There is a real chance that the PAP will not listen, though. As Lee Hsien Loong admitted in a rally in 2006, “if there are 10, 20… opposition members in Parliament… I have to spent my time thinking what is the right way to fix them”. Now, the PAP has POFMA at its disposal. It still has the supermajority in Parliament, making them able to change any law in Singapore, even the Constitution at will. We have already seen them put these tools to use for its own benefit. Let us see if the PAP will continue as it has always done, or will it take this opportunity to change itself for the better. Whatever the case, we will be watching, and we will be waiting to make our roar heard once again five years down the road. Majulah Singapura! Article Ends Here. Here's the link to the actual article: https://thethoughtexperiment.org/2020/07/11/ge2020-the-roar-of-the-swing-vote And here's the link to the other political articles I've written about Singapore: https://thethoughtexperiment.org/2020/07/07/ge2020-the-state-of-play/ https://thethoughtexperiment.org/2015/09/10/ge2015-voting-wisely/ https://thethoughtexperiment.org/2015/09/05/expectations-of-the-opposition/
I think I've figured out how Rask and Rusk are going to work in Kerbal Space Program 2
[WALL OF TEXT INBOUND] Bit of a primer here. Kerbal Space program calculates your ship's trajectory in a vacuum using what is known as patched conics. Each planet or moon has a "sphere of influence" (or SOI) within which it is the only thing in the universe affecting your ship, gravitationally speaking. The game uses Newton's law of gravitation, Gm1m2r-2, to plot out a line your ship will follow when unpowered. When you coast from one SOI to another the game records your velocity, direction, and location as you are leaving the old SOI and patches it into the new one- where the new body is now able to exert a pull on the ship rather than the old one. This is in order to save on computation, and to avoid annoying things like station-keeping lest player's precious space station around Laythe come crashing down into the ocean due to orbital pertubations from Tylo pulling on it. Not to mention that the stock system must exist on rails lest moons start flying everywhere were you to really do the math for everything pulling on everything else. What's new in KSP 2? Well, since the patched conics approximation works better when bodies are similar to distant points from each other it's probably going to remain for the Kerbol system as well as in other systems. As to relative stellar motion I can't say- that may also be on rails. What we do know however, is that there's going to be a binary planetoid pair called Rask and Rusk, so close to each other their interacting tidal forces have melted portions of their surface. Since patched conics relies on only one body pulling on your craft at a time, how will the problem of orbital motion around these bodies be addressed? I believe the answer will be through something called the restricted 3-body problem. This system of analysis involves two massive bodies orbiting a center of mass or barycenter, and a third body whose mass is so small relative to the first two that the force it exerts on them can be completely neglected. These two bodies can of course be on rails. As a result, computation needs for solving the trajectory of the small mass (the ship) is greatly reduced and I predict that this is how flying within Rask and Rusk's SOI will work. So what are the implications for gameplay? Well for starters, orbits are almost guaranteed to look nothing like a standard KSP 1 trajectory (whose basic shape is some combination of circles, ellipses, parabolas, and hyperbolas either alone or patched together). Instead, expect orbits to form chaotic and open continuous spirals ending at some prediction limit like those found in Children of a Dead Earth. This trajectory will likely be presented to the player from an inertial reference frame which is centered on the barycenter of Rask and Rusk, and rotates along with the two planetoids. Normally in KSP the reference frame does not rotate with respect to a target body, but in the case of this binary system it likely will have to because the risk of accidental lithobraking is greatly increased. When a blue line intersects one of the two planetoids the player should immediately know that a collision will eventually result. So now you may be asking yourelf, how the hell is a long term orbit possible if I'm going to zigzag around and in between these lobes? Eventually I'll get ejected or crash. That's where Lagrange Points come in. Exclusively the domain of approximations more accurate than patched conics, Lagrange points are areas in a two body system where a small object can reside in theory indefinitely if no other forces exert on it. These points rotate with the two bodies and any craft placed in them would appear stationary relative to the two bodies. Thus, by introducing the restricted three-body problem it is possible for these areas to exist. In practice there is drift in these areas, but it is likely that there will be some automatic option to station keep while using one unit of monopropellant a year or something. Edit: added bonus, here's a video I found which has this exact type of simulation. Although they have different masses, the pink and purple points in this simulation are analogous to Rask and Rusk while the yellow point represents a spacecraft. TL;DR restricted three-body for inside Rask and Rusk's SOI and patched conics everywhere else.
Ethereum on ARM. Raspberry Pi 4 images release based on Ubuntu 20.04 64 bit. Turn your Raspberry Pi 4 into an Eth 1.0 or Eth 2.0 node just by flashing the MicroSD card. Memory issues solved and new monitoring dashboards. Installation guide.
TL;DR:Flash your Raspberry Pi 4, plug in an ethernet cable, connect the SSD disk and power up the device to turn the Raspberry Pi 4 into a full Ethereum 1.0 node or an Ethereum 2.0 node (beacon chain / validator) Some background first. As you know, we’ve been running into some memory issues  with the Raspberry Pi 4 image as Raspbian OS is still on 32bits  (at least the userland). While we prefer to stick with the official OS we came to the conclusion that, in order to solve these issues, we need to migrate to a native 64 bits OS Besides, Eth 2.0 clients don’t support 32 bits binaries so using Raspbian would exclude the Raspberry Pi 4 from running an Eth 2.0 node (and the possibility of staking). So, after several tests we are now releasing 2 different images based on Ubuntu 20.04 64bit : Eth 1.0 and Eth 2.0 editions. Basically, both are the same image and include the same features of the Raspbian based images. But they are setup for running Eth 1.0 or Eth 2.0 software by default Images take care of all the necessary steps, from setting up the environment and formatting the SSD disk to installing and running the Ethereum software as well as starting the blockchain synchronization.
Based on Ubuntu 20.04 64bit
Automatic USB disk partitioning and formatting
Adds swap memory (ZRAM kernel module + a swap file) based on Armbian work 
Changes the hostname to something like “ethnode-e2a3e6fe” based on MAC hash
Runs software as a systemd service and starts syncing the Blockchain
Includes an APT repository for installing and upgrading Ethereum software
Includes a monitoring dashboard based on Grafana / Prometheus
Both images include the same packages, the only difference between them is that Eth 1.0 runs Geth by default and Eth 2.0 runs Prysm beacon chain by default. Ethereum 1.0 clients
30303 Port forwarding (Eth 1.0) and 13000 port forwarding (Eth 2.0) 
A case with heatsink and fan (Optional but strongly recommended)
USB keyboard, Monitor and HDMI cable (micro-HDMI) (Optional)
You will need and SSD to run the Ethereum clients (without an SSD drive there’s absolutely no chance of syncing the Ethereum blockchain). There are 2 options:
Use a USB portable SSD disk such as the Samsung T5 Portable SSD.
Use a USB 3.0 External Hard Drive Case with a SSD Disk. In our case we used a Inateck 2.5 Hard Drive Enclosure FE2011. Make sure to buy a case with an UAS compliant chip, particularly, one of these: JMicron (JMS567 or JMS578) or ASMedia (ASM1153E).
In both cases, avoid getting low quality SSD disks as it is a key component of you node and it can drastically affect the performance (and sync times) Keep in mind that you need to plug the disk to an USB 3.0 port (blue)
3.- Insert de MicroSD into the Raspberry Pi 4. Connect an Ethernet cable and attach the USB SSD disk (make sure you are using a blue port). 4.- Power on the device The Ubuntu OS will boot up in less than one minute but you will need to wait approximately 10 minutes in order to allow the script to perform the necessary tasks to turn the device into an Ethereum node and reboot the Raspberry. Depending on the image, you will be running:
Eth 1.0: Geth as the default client syncing the blockchain
Eth 2.0: Prysm as default client syncing the beacon chain (Topaz testnet)
5.- Log in You can log in through SSH or using the console (if you have a monitor and keyboard attached)
User: ethereum Password: ethereum
You will be prompted to change the password on first login, so you will need to login twice. 6.- Open 30303 port for Geth and 13000 if you are running Prysm beacon chain. If you don’t know how to do this, google “port forwarding” followed by your router model. 7.- Getting console output You can see what’s happening in the background by typing:
sudo tail -f /valog/syslog
Congratulations. You are now running a full Ethereum node on your Raspberry Pi 4.
Syncing the Blockchain
Now you need to wait for the blockchain to be synced. In the case of Eth 1.0 This will take a few days depending on several factors but you can expect up to about 5-7 days. If you are running the Eth 2.0 Topaz tesnet you can expect 1-2 days of Beacon chain synchronization time. Remember that you will need to setup the validator later in order to start the staking process (see “How to run the Eth 2.0 validator” section below).
For this first release, we included 3 monitoring dashboards based on Prometheus  / Grafana  in order to monitor the node and clients’ data (Geth and Besu). You can access through your web browser:
All clients run as a systemd service. This is important because in case of some problem arises the system will respawn the process automatically. Geth and Prysm beacon chain run by default (depending on what you are synchronizing, Eth 1.0 or Eth 2.0) so, if you want to switch to other clients (from Geth to Nethermind, for instance), you need to stop and disable Geth first, and enable and start the other client:
Clients’ config files are located in the /etc/ethereum/ directory. You can edit these files and restart the systemd service in order for the changes to take effect. The only exception is Nethermind which, additionally, has a mainnet config file located here:
Blockchain clients’ data is stored on the ethereum home account as follows (note the dot before the directory name): Eth 1.0
/home/ethereum/.eth2 /home/ethereum/.eth2validators /home/ethereum/.lighthouse Hyperledger Besu and Nethermind
Nethermind and Hyperledger Besu
These 2 great Eth 1.0 clients have become a great alternative to Geth and Parity. The more diversity in the network, the better, so you may give them a try and contribute to the network health. Both need further testing so feel free to play with them and report back your feedback.
How to run the Eth 2.0 validator (staking)
Once the Topaz testnet beacon chain is synchronized you can run a validator in the same device. You will need to follow the steps described here: https://prylabs.net/participate The first time, you need to create manually an account by running the “validator” binary and setup a password. Once you completed this step you can add the password to /etc/ethereum/prysm-validator.conf and start the validator as a systemd service
We put a lot of work trying to setup the Raspberry Pi 4 as a full Ethereum node as we know the massive user base of this device may have a very positive impact in the network. Please, take into account that this is the first image based on Ubuntu 20.04 so there may be some bugs. If so, open an issue on Github or reach us on twitter (https://twitter.com/EthereumOnARM).
[Table] Asteroid Day AMA – We’re engineers and scientists working on a mission that could, one day, help save humankind from asteroid extinction. Ask us anything!
Source There are several people answering: Paolo Martino is PM, Marco Micheli is MM, Heli Greus is HG, Detlef Koschny is DVK, and Aidan Cowley is AC.
Can we really detect any asteroids in space with accuracy and do we have any real means of destroying it?
Yes, we can detect new asteroids when they are still in space. Every night dozens of new asteroids are found, including a few that can come close to the Earth.
Regarding the second part of the question, the goal would be to deflect them more than destroy them, and it is technologically possible. The Hera/DART mission currently being developed by ESA and NASA will demonstrate exactly this capability.
I always wanted to ask: what is worse for life on Earth - to be hit by a single coalesced asteroid chunk, or to be hit by a multiple smaller pieces of exploded asteroid, aka disrupted rubble pile scenario?
DVK: This is difficult to answer. If the rubble is small (centimetres to meters) it is better to have lots of small ones – they’d create nice bright meteors. If the rubble pieces are tens of meters it doesn’t help.
Let’s say that hypothetically, an asteroid the size of Rhode Island is coming at us, it will be a direct hit - you’ve had the resources and funding you need, your plan is fully in place, everything you’ve wanted you got. The asteroid will hit in 10 years, what do you do?
DVK: I had to look up how big Rhode Island is – a bit larger than the German Bundesland ‘Saarland’. Ok – this would correspond to an object about 60 km in diameter, right? That’s quite big – we would need a lot of rocket launches, this would be extremely difficult. I would pray. The good news is that we are quite convinced that we know all objects larger than just a few kilometers which come close to our planet. None of them is on a collision course, so we are safe.
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Why are you quite convinced that you know all object of that size? And what is your approach in finding new celestial bodies?
DVK: There was a scientific study done over a few years (published in Icarus 2018, search for Granvik) where they modelled how many objects there are out there. They compared this to the observations we have with the telescopic surveys. This gives us the expected numbers shown here on our infographic: https://www.esa.int/ESA_Multimedia/Images/2018/06/Asteroid_danger_explained
There are additional studies to estimate the ‘completeness’ – and we think that we know everything above roughly a few km in size.
Thanks for the answer, that's really interesting! It's also funny that the fist Flyeye deployed is in Sicily, at less than 100km from me, I really had no idea
DVK: Indeed, that's cool. Maybe you can go and visit it one day.
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What about Interstellar objects however, like Oumuamua?
DVK: The two that we have seen - 'Oumuamua and comet Borisov - were much smaller than the Saarland (or Rhode Island ;-) - not sure about Borisov, but 'Oumuamua was a few hundred meters in size. So while they could indeed come as a complete surprise, they are so rare that I wouldn't worry.
Would the public be informed if an impending asteroid event were to happen? And, how would the extinction play out? Bunch of people crushed to death, knocked off our orbit, dust clouds forever?
DVK: We do not keep things secret – all our info is at the web page http://neo.ssa.esa.int. The ‘risky’ objects are in the ‘risk page’. We also put info on really close approaches there. It would also be very difficult to keep things ‘under cover’ – there are many high-quality amateur astronomers out there that would notice.
In 2029 asteroid Apophis will fly really close to Earth, even closer than geostationary satellites. Can we use some of those satellites to observe the asteroid? Is it possible to launch very cheap cube sats to flyby Apophis in 2029?
DVK: Yes an Apophis mission during the flyby in 2029 would be really nice. We even had a special session on that topic at the last Planetary Defense Conference in 2019, and indeed CubeSats were mentioned. This would be a nice university project – get me a close-up of the asteroid with the Earth in the background!
Go to the section 'resolutions'. This is now a statement that scientists can use to present to their funding agencies, demonstrating that it's not just their own idea.
Thanks for doing this AMA! Did we know the Chelyabinsk meteor in 2013 (the one which had some great videos on social media) was coming? Ig not, how comes? Also, as a little side one, have there been any fatalities from impact events in the past 20 years?
Unfortunately, the Chelyabinsk object was not seen in advance, because it came from the direction of the Sun where ground-based telescopes cannot look.
No known fatalities from impacts have happened in the past 20 years, although the Chelyabinsk event did cause many injuries, fortunately mostly minor.
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How often do impacts from that direction happen, compared to impacts from visible trajectories?
In terms of fraction of the sky, the area that cannot be easily scanned from the ground is roughly a circle with a radius of 40°-50° around the current position of the Sun, corresponding to ~15% of the total sky. However, there is a slight enhancement of objects coming from that direction, therefore the fraction of objects that may be missed when heading towards us is a bit higher.
However, this applies only when detecting an asteroid in its "final plunge" towards the Earth. Larger asteroids can be spotted many orbits earlier, when they are farther away and visible in the night side of the sky. Their orbits can then be determined and their possible impacts predicted even years or decades in advance.
There must be a trade-off when targeting asteroids as they get closer to Earth, is there a rule of thumb at what the best time is to reach them, in terms of launch time versus time to reach the asteroid and then distance from Earth?
DVK: Take e.g. a ‘kinetic impactor’ mission, like what DART and Hera are testing. Since we only change the velocity of the asteroid slightly, we need to hit the object early enough so that the object has time to move away from it’s collision course. Finding out when it is possible to launch requires simulations done by our mission analysis team. They take the strength of the launcher into account, also the available fuel for course corrections, and other things. Normally each asteroid has its own best scenario.
Do you also look at protecting the moon from asteroids? Would an impact of a large enough scale potentially have major impacts on the earth?
DVK: There are programmes that monitor the Moon and look for flashes from impacting small asteroids (or meteoroids) - https://neliota.astro.noa.g or the Spanish MIDAS project. We use the data to improve our knowledge about these objects. These programmes just look at what is happening now.
For now we would not do anything if we predicted a lunar impact. I guess this will change once we have a lunar base in place.
Why aren't there an international organisation comprised of countries focused on the asteroid defence? Imagine like the organisation with multi-billion $ budget and program of action on funding new telescopes, asteroid exploration mission, plans for detection of potentially dangerous NEA, protocols on action after the detection - all international, with heads of states discussing these problems?
DVK: There are international entities in place, mandated by the UN: The International Asteroid Warning Network (http://www.iawn.net) and the Space Mission Planning Advisory Group (http://www.smpag.net). These groups advise the United Nations. That is exactly where we come up with plans and protocols on action. But: They don’t have budget – that needs to come from elsewhere. I am expecting that if we have a real threat, we would get the budget. Right now, we don’t have a multi-billion budget.
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There is no actual risk of any sizable asteroids hitting earth in the foreseeable future. Any preparation for it would just be a waste of money.
DVK: Indeed, as mentioned earlier, we do not expect a large object to hit is in the near future. We are mainly worried about those in the size range of 20 m to 40 m, which happen on average every few tens of years to hundreds of years. And where we only know a percent of them or even less.
President Obama wanted to send a crewed spacecraft to an asteroid - in your opinion is this something that should still be done in the future, would there be any usefulness in having a human being walk/float on an asteroid's surface?
DVK: It would definitely be cool. I would maybe even volunteer to go. Our current missions to asteroids are all robotic, the main reason is that it is much cheaper (but still expensive) to get the same science. But humans will expand further into space, I am sure. If we want to test human exploration activities, doing this at an asteroid would be easier than landing on a planet.
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Yes, but I am slightly biased by the fact that I work at the European astronaut centre ;) There exist many similarities to what we currently do for EVA (extra vehicular activities) operations on the International Space Station versus how we would 'float' around an asteroid. Slightly biased again, but using such a mission to test exploration technologies would definitely still have value. Thanks Obama! - AC
I've heard that some asteroids contains large amounts of iron. Is there a possibility that we might have "space mines" in the far away future, if our own supply if iron runs out?
Yes, this is a topic in the field known as space mining, part of what we call Space Resources. In fact, learning how we can process material we might find on asteroids or other planetary bodies is increasingly important, as it opens up the opportunities for sustainable exploration and commercialization. Its a technology we need to master, and asteroids can be a great target for testing how we can create space mines :) - AC
By how much is DART expected to deflect Didymos? Do we have any indication of the largest size of an asteroid we could potentially deflect?
PM: Didymos is a binary asteroid, consisting of a main asteroid Didymos A (~700m) and a smaller asteroid Didymos B (~150m) orbiting around A with a ~12 hours period. DART is expected to impact Didymos B and change its orbital period w.r.t. Didymos A of ~1%. (8 mins)
The size of Didymos B is the most representative of a potential threat to Earth (the highest combination of probability and consequence of impacts), meaning smaller asteroids hit the Earth more often but have less severe consequences, larger asteroids can have catastrophic consequences but their probability of hitting the earth is very very low.
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Why is there less probability of larger asteroids hitting earth?
DVK: There are less large objects out there. The smaller they are, the more there are.
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Is there any chance that your experiment will backfire and send the asteroid towards earth?
PM: Not at all, or we would not do that :) Actually Dimorphos (the Didymos "moon") will not even leave its orbit around Didymos. It will just slightly change its speed.
I'm sure you've been asked this many times but how realistic is the plot of Armageddon? How likely is it that our fate as a species will rely on (either) Bruce Willis / deep sea oil drillers?
Taking into consideration that Bruce Willis is now 65 and by the time HERA is launched he will be 69, I do not think that we can rely on him this time (although I liked the movie).
HERA will investigate what method we could use to deflect asteroid and maybe the results will show that we indeed need to call the deep sea oil drillers.
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So then would it be easier to train oil drillers to become astronauts, or to train astronauts to be oil drillers?
I do not know which one would be easier since I have no training/experience of deep see oil drilling nor becoming an astronaut, but as long as the ones that would go to asteroid have the sufficient skills and training (even Bruce Willis), I would be happy.
If budget was no object, which asteroid would you most like to send a mission to?
Nice question! For me, I'd be looking at an asteroid we know something about, since I would be interested in using it for testing how we could extract resources from it. So for me, I would choose Itokawa (https://en.wikipedia.org/wiki/25143_Itokawa), which was visited by Hayabusa spacecraft. So we already have some solid prospecting carried out for this 'roid! - AC
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Not sure if it counts as an asteroid, but Detlef and myself would probably choose ʻOumuamua, the first discovered interstellar object.
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Do we even have the capability to catch up to something like that screaming through our solar system? That thing has to have a heck of a velocity to just barrel almost straight through like that.
DVK: Correct, that would be a real challenge. We are preparing for a mission called 'Comet Interceptor' that is meant to fly to an interstellar object or at least a fresh comet - but it will not catch up with it, it will only perform a short flyby.
After proving to be able to land on one, could an asteroid serve as a viable means to transport goods and or humans throughout the solar system when the orbit of said asteroid proves beneficial. While it is probably quite problematic to land the payload, it could save fuel or am I mistaken?
Neat idea! Wonder if anyone has done the maths on the amount of fuel you would need/save vs certain targets. - AC
PM: To further complement, the saving is quite marginal indeed because in order to land (softly) on the asteroid you actually need to get into the very same orbit of that asteroid . At that point your orbit remains the same whether you are on the asteroid or not..
can the current anti-ballistic missiles systems intercept a terminal phase earth strike asteroid? or it is better to know beforehand and launch an impacting vehicle into space?
DVK: While I do see presentations on nuclear explosions to deflect asteroids at our professional meetings, I have not seen anybody yet studying how we could use existing missile systems. So it's hard to judge whether existing missiles would do the job. But in general, it is better to know as early as possible about a possible impact and deflect it as early as possible. This will minimize the needed effort.
How much are we prepared against asteroid impacts at this moment?
DVK: 42… :-) Seriously – I am not sure how to quantify ‘preparedness’. We have international working groups in place, mentioned earlier (search for IAWN, SMPAG). We have a Planetary Defence Office at ESA, a Planetary Defense Office at NASA (who spots the difference?), search the sky for asteroids, build space missions… Still we could be doing more. More telescopes to find the object, a space-based telescope to discover those that come from the direction of the Sun. Different test missions would be useful, … So there is always more we could do.
Have you got any data on the NEO coverage? Is there estimations on the percentage of NEOs we have detected and are tracking? How can we improve the coverage? How many times have asteroids been able to enter earths atmosphere without being detected beforehand?
As expected, we are now nearly complete for the large ones, while many of the smaller ones are still unknown.
In order to improve coverage, we need both to continue the current approach, centered on ground-based telescopes, and probably also launch dedicated telescopes to space, to look at the fraction of the sky that cannot be easily observed from the ground (e.g., towards the Sun).
Regarding the last part of your question, small asteroids enter the Earth atmosphere very often (the infographics above gives you some numbers), while larger ones are much rarer.
In the recent past, the largest one to enter our atmosphere was about 20 meters in diameter, and it caused the Chelyabinsk event in 2013. It could not be detected in advance because it came from the direction of the Sun.
We have however detected a few small ones before impact. The first happened in 2008, when a ~4-meter asteroid was found to be on a collision course less than a day before impact, it was predicted to fall in Northern Sudan, and then actually observed falling precisely where (and when) expected.
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DVK: And to add what MM said - Check out http://neo.ssa.esa.int. There is a ‘discovery statistics’ section which provides some of the info you asked about. NASA is providing similar information here https://cneos.jpl.nasa.gov/stats/. To see the sky which is currently covered by the survey telescopes, you need to service of the Minor Planet Center which we all work together with: http://www.minorplanetcenter.org, ‘observers’, ‘sky coverage’. That is a tool we use to plan where we look with our telescopes, so it is a more technical page.
Are there any automatic systems for checking large numbers of asteroids orbits, to see if the asteroid's orbit is coming dangerously close to Earth, or is it done by people individually for every asteroid? I ask it because LSST Rubin is coming online soon and you know it will discover a lot of new asteroids.
Yes, such systems exist, and monitor all known and newly discovered asteroids in order to predict possible future impacts.
It is automatically updated every day once new observational data is processed.
What are your favourite sci-fi series?
DVK: My favorites are ‘The Expanse’, I also liked watching ‘Salvation’. For the first one I even got my family to give me a new subscription to a known internet streaming service so that I can see the latest episodes. I also loved ‘The Jetsons’ and ‘The Flintstones’ as a kid. Not sure the last one counts as sci-fi though. My long-time favorite was ‘Dark Star’.
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Big fan of The Expanse at the moment. Nice, hard sci-fi that has a good impression of being grounded in reality - AC
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When I was a kid I liked The Jetsons, when growing up Star Trek, Star wars and I also used to watch with my sister the 'V'.
When determining the potential threat of a NEA, is the mass of an object a bigger factor or size? I'm asking because I'm curious if a small but massive object (say, with the density of Psyche) could survive atmospheric entry better than a comparatively larger but less massive object.
The mass is indeed what really matters, since it’s directly related with the impact energy.
And as you said composition also matters, a metal object would survive atmospheric entry better, not just because it’s heavier, but also because of its internal strength.
What are your thoughts on asteroid mining as portrayed in sci-fi movies? Is it feasible? If so would governments or private space programs be the first to do so?What type of minerals can be found on asteroids that would merit the costs of extraction?
Certainly there is valuable stuff you can find on asteroids. For example, the likely easiest material you can harvest from an asteroid would be volatiles such as H2O. Then you have industrial metals, things like Iron, Nickel, and Platinum group metals. Going further, you can break apart many of the oxide minerals you would find to get oxygen (getting you closer to producing rocket fuel in-situ!). Its feasible, but still needs alot of testing both here on Earth and eventually needs to be tested on a target. It may be that governments, via agencies like ESA or NASA, may do it first, to prove the principles somewhat, but I know many commercial entities are also aggresively working towards space mining. To show you that its definitely possible, I'd like to plug the work of colleagues who have processed lunar regolith (which is similar to what you may find on asteroids) to extract both oxygen and metals. Check it out here: http://www.esa.int/ESA_Multimedia/Images/2019/10/Oxygen_and_metal_from_lunar_regolith
Will 2020's climax be a really big rock?
DVK: Let's hope not...
Considering NASA, ESA, IAU etc. is working hard to track Earth-grazing asteroids, how come the Chelyabinsk object that airburst over Russia in 2013 came as a total surprise?
The Chelyabinsk object came from the direction of the Sun, where unfortunately ground-based telescopes cannot look at. Therefore, it would not have been possible to discover it in advance with current telescopes. Dedicated space telescopes are needed to detect objects coming from this direction in advance.
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Is this to say that it was within specific solid angles for the entire time that we could have observed it given its size and speed?
Yes, precisely that. We got unlucky in this case.
Have any of you read Lucifer's Hammer by Larry Niven? In your opinion, how realistic is his depiction of an asteroid strike on Earth?
DVK: I have – but really long ago, so I don’t remember the details. But I do remember that I really liked the book, and I remember I always wanted to have a Hot Fudge Sundae when reading it.
I was thinking about the asteroid threat as a teen and came up with this ideas (Hint: they are not equally serious, the level of craziness goes up real quick). Could you please comment on their feasibility? 1. Attaching a rocket engine to an asteroid to make it gradually change trajectory, do that long in advance and it will miss Earth by thousands of km 2. Transporting acid onto asteroid (which are mainly metal), attaching a dome-shaped reaction chamber to it, using heat and pressure to then carry out the chemical reaction to disintegrate asteroids 3. This one is even more terrible than a previous one and totally Dan Brown inspired — transporting antimatter on asteroid, impacting and causing annihilation. Thank you for this AMA and your time!
DVK: Well the first one is not so crazy, I have seen it presented... the difficulty is that all asteroids are rotating in one way or another. So if you continuously fire the engine it would not really help. You'd need to switch the engine on and off. Very complex. And landing on an asteroid is challenging too. Just using the 'kinetic impactor' which we will test with DART/Hera (described elsewhere in this chat) is simpler. Another seriously proposed concept is to put a spacecraft next to an asteroid and use an ion engine (like we have on our Mercury mission BepiColombo) to 'push' the asteroid away.
As for 2 and 3 I think I will not live to see that happening ;-)
What is the process to determine the orbit of a newly discovered asteroid?
The process is mathematically quite complex, but here's a short summary.
Everything starts with observations, in particular with measurements of the position of an asteroid in the sky, what we call "astrometry". Discovery telescopes extract this information from their discovery images, and make it available to everybody.
These datapoints are then used to calculate possible trajectories ("orbits") that pass through them. At first, with very few points, many orbits will be possible.
Using these orbits we can extrapolate where the asteroid will be located during the following nights, use a telescope to observe that part of the sky, and locate the object again.
From these new observations we can extract new "astrometry", add it to the orbit determination, and see that now only some of the possible orbits will be compatible with the new data. As a result, we now know the trajectory better than before, because a few of the possible orbits are not confirmed by the new data.
The cycle can then continue, with new predictions, new observations, and a more accurate determination of the object's orbit, until it can be determined with an extremely high level of accuracy.
What are some asteroids that are on your "watchlist"?
It's called "risk list", and it includes all known asteroids for which we cannot exclude a possible impact over the next century. It is updated every day to include newly discovered asteroids, and remove those that have been excluded as possible impactors thanks to new observations.
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That's quite a list!! Do you guys ever feel stressed or afraid when you have to add another dangerous candidate (and by dangerous I mean those above 200m) is added to this Risk List?
Yes, when new dangerous ones are added it's important that we immediately do our best to gather more data on them, observing them with telescopes in order to get the information we need to improve our knowledge of their orbit.
And then the satisfaction of getting the data needed to remove one from the list is even greater!
What inspired you to go into this field of study?
I was fascinated by astronomy in general since I was a kid, but the actual "trigger" that sparked my interest in NEOs was a wonderful summer course on asteroids organized by a local amateur astronomers association. I immediately decided that I would do my best to turn this passion into my job, and I'm so happy to have been able to make that dream come true.
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DVK: I started observing meteors when I was 14, just by going outside and looking at the night sky. Since then, small bodies in the solar system were always my passion.
As a layperson, I still think using nuclear weapons against asteroids is the coolest method despite better methods generally being available. Do you still consider the nuclear option the cool option, or has your expertise in the field combined with the real-life impracticalities made it into a laughable/silly/cliche option?
DVK: We indeed still study the nuclear option. There are legal aspects though, the ‘outer space treaty’ forbids nuclear explosions in space. But for a large object or one we discover very late it could be useful. That’s why we have to focus on discovering all the objects out there as early as possible – then we have time enough to use more conventional deflection methods, like the kinetic impactor (the DART/Hera scenario).
It seems like doing this well would require international cooperation, particularly with Russia. Have you ever reached out to Russia in your work? Do you have a counterpart organization there that has a similar mission?
DVK: Indeed international cooperation is important - asteroids don't know about our borders! We work with a Russian team to perform follow-up observations of recently discovered NEOs. Russia is also involved in the UN-endorsed working groups that we have, IAWN and SMPAG (explained in another answer).
If multiple videos or pictures, taken from different locations, are available, then it's possible to reconstruct the trajectory, and extrapolate where the object came from.
Regarding the composition, it's a bit more difficult if nothing survives to the ground, but some information can be obtained indirectly from the fireball's color, or its fragmentation behavior. If a spectral analysis of the light can be made, it's then possible to infer the chemical composition in much greater detail.
I've always wanted to know what the best meteorite buying site is and what their average price is??
DVK: Serious dealers will be registered with the 'International Meteorite Collectors Association (IMCA)' - https://www.imca.cc/. They should provide a 'certificate of authenticity' where it says that they are member there. If you are in doubt, you can contact the association and check. Normally there are rough prices for different meteorite types per gram. Rare meteorites will of course be much more expensive than more common ones. Check the IMCA web page to find a dealer close to you.
Just read through Aidans link to the basaltic rock being used as a printing material for lunar habitation. There is a company called Roxul that does stone woven insulation that may be able to shed some light on the research they have done to minimize their similarity to asbestos as potentially carcinogenic materials deemed safe for use in commercial and residential applications. As the interior surfaces will essentially be 3D printed lunar regolith what are the current plans to coat or dampen the affinity for the structure to essentially be death traps for respiratory illness?
At least initially, many of these 3d printed regolith structures would not be facing into pressurised sections, but would rather be elements placed outside and around our pressure vessels. Such structures would be things like radiation shields, landing pads or roadways, etc. In the future, if we move towards forming hermetically sealed structures, then your point is a good one. Looking into terrestrial solutions to this problem would be a great start! - AC
What kind of career path does it take to work in the asteroid hunting field?
It's probably different for each of us, but here's a short summary of my own path.
I became interested in asteroids, and near-Earth objects in particular, thanks to a wonderful summer course organized by a local amateur astronomers association. Amateur astronomers play a great role in introducing people, and young kids in particular, to these topics.
Then I took physics as my undergrad degree (in Italy), followed by a Ph.D. in astronomy in the US (Hawaii in particular, a great place for astronomers thanks to the exceptional telescopes hosted there).
After finishing the Ph.D. I started my current job at ESA's NEO Coordination Centre, which allowed me to realize my dream of working in this field.
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DVK: Almost all of us have a Master's degree either in aerospace engineering, mathematics, physics/astronomy/planetary science, or computer science. Some of us - as MM - have a Ph.D. too. But that's not really a requirement. This is true for our team at ESA, but also for other teams in other countries.
What is the likelihood of an asteroid hitting the Earth In the next 200 years?
Have you played the Earth Defence Force games and if you have, which one is your favourite?
No I have not played the Earth Defence Force games, but I just looked it up and I think I would liked it. Which one would you recommend?
How close is too close to earth? Space is a SUPER vast void so is 1,000,000 miles close, 10,000,000? And if an asteroid is big enough can it throw earth off its orbit?
DVK: Too close for my taste is when we compute an impact probability > 0 for the object. That means the flyby distance is zero :-) Those are the objects on our risk page http://neo.ssa.esa.int/risk-page.
If an object can alter the orbit of another one, we would call it planet. So unless we have a rogue planet coming from another solar system (verrry unlikely) we are safe from that.
Are you aware of any asteroids that are theoretically within our reach, or will be within our reach at some point, that are carrying a large quantity of shungite? If you're not aware, shungite is like a 2 billion year old like, rock stone that protects against frequencies and unwanted frequencies that may be traveling in the air. I bought a whole bunch of the stuff. Put them around the la casa. Little pyramids, stuff like that.
DVK: If I remember my geology properly, Shungite forms in water sedimental deposits. This requires liquid water, i.e. a larger planet. So I don't think there is a high chance to see that on asteroids.
Abstract — I discuss several models for assigning probability to timelines under the assumption that time travel is possible, but paradoxes are absolutely impossible, as is the case in many fictional worlds. The models are mathematically precise, and illuminate issues that have previously confused many people about what sort of timelines are "most likely". I discuss an example due to TimTravel in a old post on /HPMOR, then analyse whether time travel can be used to solve the halting problem. I outline how timeline probability may interact with physical probabilities, often used to justify physics "conspiring" or contriving a certain outcome to prevent paradox. Total length: ~5000 words, or about 15-20 minutes of reading. Edit: commenters have pointed out similarities between this and the Ted Chiang story, What's Expected of Us. The similarity was not intentional, but is undeniable. Note: The text of this post has been revised in response to objections, and some commenters may be reacting to the initial version of my arguments.
Model A: Path Realism
Model B: Local Branch Realism
Model C: Reroll Realism (or, Bayesian Branch Realism)
Model D: Weighted Branch Realism
Which Model is Best?
Example: The Time Thief Puzzle
Alice and Bob
Interlude: TIME FORCE
Back to Alice and Bob
Applications to More Permissive Time Travel Schemes
Bound Time Travel
Free Time Travel
Let's say you're walking down the street one day when a wizard appears in a clap of thunder, and places a strange gray device of buttons and switches into your hands. You're looking down at it, struggling to make heads or tails of it, and then you look up and the wizard is gone. At the top of the device, there is a slider, already set to the leftmost extreme. Below it, two switches: a power switch already set to ON, and an stiff, unlabeled switch, the exact gray of the surface, rising so inconspicuously low off the surface you almost miss it. Below that, two LED buttons, both inactive. Suddenly, the left LED glows blue. Confused, you press the button (it goes in with a satisfying click) and the light flashes off instantly. Furrowing your brow, you decide to press the button again. The blue light quickly comes on while your finger's still moving, and it again winks out immediately as the button is depressed. You try pressing the button again and again, and each time the blue light turn on, seeming to predict or anticipate the button press. Then, the other LED button glows red. You press it, and it turns off; several tries later, you conclude it behaves exactly the same. You decide now to deliberately not press either button, even if the lights were to shine encouragingly. But nothing happens; neither light comes back on. You move your finger closer to a button, determined to arrest its motion at the last possible second. But the light doesn't come on, even when your skin is brushing the cool metal. You forget it and press the button. The light blinks bright blue milliseconds before you've even decided. Now, you (you, dear reader, not the above character) have already read the title of this post. This is strange device sends information backward in time. Specifically, it sends a single bit back in time one second. Or well, you fiddle with the slider, and notice it controls the interval; you can set it to one minute, an hour, or even a day. All that established, it's time to test something. "Red is heads, and blue tails," you say. A coin from your pockets is flipping in the air until you catch it and slap it down on your wrist. The device shines blue. You lift your hand. It's heads. You push the blue button anyway, out of habit, the light flashing off. And then it hits you: you have to commit intently to pressing the right button even when (especially when) the device is wrong. Another test: if the device shines red again, you'll press blue. But if it shines blue, you'll press still blue. There's a noticeable delay before the device tentatively shines a light. It's blue. Call this act forcing. You can force the device to be red or blue. You try the coin flip test just a few more times. Now, the device is always right, even if it seems to pause a random interval before shining a light. The opposite of forcing would be splinting (after 'splinterpoint'). This is, pressing the button for whichever light comes on next, with no tricks and no conditionals. Finally, the last thing you can do — for a broad notion of 'can' — is what we'll call crashing. This is: pressing the button of whichever light doesn't blink on. It's less that you can do this, and more that you can intend this, and reality responds to that. You give it a try right now: you commit to crashing if your next coin toss doesn't come up heads. You flip the coin, anxiously watching it's path through the air, catch it, slap it down on your wrist, spend a few seconds working up the nerve and then lifting your hand. It's tails. You take a deep breath, and look expectantly at the device. No light comes on. You're waiting for a few minutes. And then it hits you; the device isn't binary, it's trinary. Sure, it can shine red or blue — but so too can it not shine at all! And if it either light leads to paradox, why would any light come on? The only winning move is not to play. Is that it, then? Are your dreams of munchkinry doomed to fail? Was it just a coincidence that 'forcing' seemed to work earlier? And then the red light comes on. You grin triumphantly, with not a little dread. You're about to destroy the universe! Before the implications catch up to, you're flinging your hand forward, jabbing it at the device. You don't want to lose your nerve. You look down, and see that you missed, pressing the red button, rather than the blue like you planned. Is this fate? Is the world itself conspiring to prevent paradox, just like in the stories? You want to give crashing another try, but the last thing you want is to wait those long minutes for the light to come on again. You glare down at the device, and then you notice the second switch. You'd almost forgotten about it. You idly flick it, and immediately the blue light comes on. It forces a prediction? Maybe your plans aren't doomed. You consider giving crashes another try, but maybe destroying the whole timeline is not worth the risk. You decide to spare the universe, and press the blue button. You need to understand how this device works before you can really exploit it. And you have just the idea for another experiment. What if you splint, and if the splint comes out blue, you force blue again, but otherwise you just splint again. After two button presses, you turn off the device. It's clear there are three possibilities: blue-blue, red-blue and red-red. But which are most likely? You run this experiment a hundred times, and keep track of the results. Call it the double blue experiment. There are a few ways it could turn out:
Model A: Path Realism
It seems that consistent timelines are the only thing that matters. It's as if the universe has already set aside exactly the number of timelines there needs to be, and you're already in a certain timeline, you just don't know which one yet. In the double blue experiment, there are three possibilities, and every one is equally likely. p(red,red) = p(red,blue) = p(blue,blue) = 1/3 You find it strange, as a follow-up experiment aptly demonstrates: Splint once. If it comes out blue, force blue twenty-nine times. Otherwise, do nothing. Turn off the device. On the face of it, it's crazy that you can even experience the second possibility. It's like winning the lottery half the time. Then again, maybe it's not so crazy? If you were to just force blue twenty-nine times, it's equally unlikely on the face of it; like flipping dozens of coins that all come up heads. There's a weirder consequence, though. If you splint ten times, you can see any combination of reds and blues; red-blue-blue-red-red-red-blue-red-red-red and all the others, with uniform probability. But if you splint ten times, and if and only if every splint came up blue, you splint ten more times, you'll find that the first set of splints come up all blue half the time! This is easy to reconcile with path realism. There are 210 = 1024 through the ten splints. Each is as likely as the other. But if you commit to doing ten more splints if and only if the first set comes up all blues, then there are 211 = ~2048 paths down the time-tree. If each is as likely as the other, then half of them are located under one branch!
Model B: Local Branch Realism
It seems that splints are basically coin tosses; it either comes up blue or it comes up red. The exception is if one of those options always leads to paradox. If you commit to causing paradox when the light shines blue, then it will always shine red. If you commit to splinting then crashing when the first splint comes out blue, then the splint will similarly always shine red. The intermediate is more interesting: if you, as in the original experiment, splint and then splint again and crash if both splints come out blue, then half the time the first splint will come out red, but if the first splint comes out blue, the next one always comes out red. In numbers, the possibilities are p(red,red) = p(red,blue) = 1/4, and p(blue,red) = 1/2. It's like the universe is a savescumming gamer: it saves to a slot to every time a time travel event is about to happen. If a paradox happens, it reloads from its saves on after another, finding newest one that lets it avoid the paradox.
Model C: Reroll Realism (or, Bayesian Branch Realism)
Edit: a commenter pointed out that this resembles Tim's model. You're not sure if paradoxes really don't happen. You've looked at the numbers. What it suggests is that, rather than avoiding paradoxes, paradoxes could simply cause the universe to restart. The stats from the double blue experiment don't lie: p(red) = 2/3, p(blue,blue) = 1/3. Imagine you were simulating the universe. 1/2 the time, red comes up and you're just fine. 1/2 the time, blue comes up. 1/2 the time after that (for a total of 1/4 the time), blue comes again, and you've got a paradox on your hands. What if you just, restarted the universe, and hoped it didn't happen again? Well, there's a 1/4 chance it will. Since you have a 1/4 chance of restarting in the first place, that's 1/16 of the time you'll restart twice. Luckily, it's getting exponentially less likely. Looked at another way, the odds of it coming up red is the limit of the infinite sum: 1/2 + 1/4 * 1/2 + 1/16 * 1/2 + 1/64 * 1/2 + 1/256 * 1/2 ... This series converges on 2/3. But there's another interpretation, with seems less like the work of a lazy programmer and more like something a statistician would come up with. Suppose, as we must, that the timeline is consistent. What is the posterior probability of that timeline being red, given that 100% of red timelines are consistent, and 50% of blue timelines are consistent? Or, in symbols:
Even more intuitively: you have four balls (timelines) you paint half of the balls red and half blue (splinterpoint), and you take away one blue ball (paradox). 2/3 of the remainder is red. You'll recognize this as Bayes' Theorem.
Model D: Weighted Branch Realism
The reality is more subtle than you thought. It seems that, while you've never seen a paradox, if a branch has a path through splinterpoints that ends in paradox, that fact subtracts probability from the branch and gives it to its counterfactual sibling. This happens in Local Branch Realism too, but not to this degree: the very possibility that a time-path has a paradox however many days or years down the line always shaves some degree of probability, if only just a sliver; but naturally, that sliver increases as the paradox gets closer. Thus, the results of the experiment are: p(red, red) = p(red, blue) = 3/8, while p(blue, blue) = 1/4 = 2/8. You can see it clearer with a more involved experiment. Take your device and a sheet of paper and: Splint, call this splint A:
if A is red, write "foo" on the paper
if A is blue, splint and call it splint B
if B is red, write "bar" on the paper
if B is blue, splint and call it C:
if C is red, write "baz" on the paper
if C is blue, crash
According to weighted branch realism, the probabilities look like: P(foo) = 20/32 = 5/8, P(bar) = 9/32, P(baz) = 3/32. To understand this result, we have to define a notion of "static paradox fraction", or spf. If you intend to force blue, then the spf is 1/2. Why? To force blue you must (intend to) cause a paradox in the event that not-blue happens. Despite that fact that paradoxes never happen, static paradox fractions seems be a real quantity in Weighted Branch Realism. It is as if the device is looking at every possible and impossible timeline, and measuring which ones are paradoxical. (Note that static paradox fractions are diminuted by splints. So if you splint and when the splint is blue you then force red, the spf of the first splint is 1/4, even if there is no second splint whenever the first is red. This distinguishes it from simply counting paradoxical timelines; 1/3 of the timelines are paradoxical, but a paradox behind a splinterpoint has lesser weight.) Furthermore, let's have a notion of "intrinsic probability" or ip. The ip of both splint outcomes is 1/2, even if one of them is paradoxical. Thus:
(Note for the pedants: normally, the ip is actually 1/3, and ditto for spf; we're ignoring that the device can not shine a light, because you can just flip a switch and force a light on. Even without the switching, committing to either turning the device off, or splinting endlessly once the the experiment is over means the probability of the device choosing to not shine drops exponentially while the alternatives remain constant.) This model is somewhat unintuitive, because despite the name, it has more in common with Path Realism than the other two _ Branch Realisms. You can't emulate the probability distribution of WBR by running one timeline and restarting (either from the beginning (Bayesian), or from the nearest viable alternate splint (Local)). This is entirely the fault of a phenomena we can call "paradox by association"; in the foo-bar-baz experiment, in a certain sense, just as 1/8 of quasi-timelines are paradoxical because they end in crashing, 1/4 of the quasi-timelines ending in baz are paradoxical just because baz timelines are near to the paradox. This accounts for the numbers: p(foo) is 5/8, 4/8 intrinsic + 1/8 from the paradox. p(bar) is 9/32: 8/32 intrinsic + 1/32 from baz's paradox by association. p(baz), lastly is 3/32 owing to loosing 1/32 from paradox by association. (Why 1/4? Good question. There must be a reason, and it's clear this is the number that comes out of the equations. Alas, I'm not smart enough provide a reason in words and not symbols.)
Which Model is Best?
Path Realism and Local Branch Realism are both pretty wack. Path Realism discards all local information about plausibility, and allows munchkins to blow up the probability of their favorite timelines arbitrarily high. Local Branch Realism does the same thing from the opposite direction; wanton invocation of paradoxes intuitively should be penalized, but Branch Realism simply says I don't mind. Between Weighted Branch Realism and Reroll Realism, I'm inclined to prefer the latter. WBR is the first I thought up, but RR is just more natural. It has two obvious interpretations, both things that anyone would come up with after thinking about it for a little while. WBR, in the other hand, is harder to conceptualize in terms of what mechanism would actually cause the probabilities to look like that (I've tried; the results are not pretty). "Paradox by association", while potential a fresh concept to use in a story, is a truly strange mechanism. Now, how does the connect with TimTravel's ideas? Just as he proposed, it is, in some models the case that the most probable timelines are the ones in which time machines are never invented. In Local Branch Realism, this is not true (unless some bad actor arises in every single timeline and causes paradox. Time Beast, anyone?). In Path Realism, this is again never true without positing a Time Beast. However in WBR and RR, it's more or less true. In general, timelines with fewer instances of retrocausation are more likely, only because instances of retrocausation are a proxy for instances of paradox. Now, if paradoxes are rare, this argument would be weak. (But to be fair, most meaningful uses of time travel require copious paradox; it's the oil in the engine.) That said, I believe it is admissible for a work to posit that the characters find themselves in the (slightly unlikely) timeline where retrocausation happens. After that, though, the principles constrain the probability space.
Suppose Alice has a bag of money with a dollar on it. If anyone steals it, she'll go back in time and see who did it. Bob wants to steal it. He knows she has this policy. He decides he'll give himself the thumbs up just before he leaves the future if all goes well stealing it and she doesn't see him. If these policies are followed then it leads to a paradox, so something must prevent them both from simultaneously following their policies. Either Alice wins because Bob goes to the past without getting an honest thumbs up from himself or Bob wins because Bob sees the honest thumbs up and Alice doesn't go back and check who stole the money for some reason, or some third possibility prevents both. There is no reason to think that either of them automatically wins in this situation. Timelines in which Alice wins should be about equally frequent as timelines in which Bob wins. Numerous characters have implicitly assumed that there is a reason to think one of them automatically wins in such situations.
We'll have to change this scenario a little bit to fit with the schema we've been using so far. (Besides, Tim's example is kind of unclear and it's not even obvious that paradox must occur in all permutations. If Bob doesn't get the thumbs up, wouldn't he not steal? Puzzle solved.)
Alice and Bob
Let's say that in the morning Alice has acquired a bag full of money from sources unknown, and has come to an arrangement with a shadowy individual: leave a dufflebag full of money with a dollar sign on it at a dropoff location, and in exchange, the individual will leave a limited print run of all eleven books of Worth the Candle at the same location. Alice knows people want to steal that money, but part of the arrangement is that she can't be there guarding it when the shadowy individual arrives. On Tuesday morning, the deal is still in its negotiation stage, and there are two places Alice can think of to arrange for dropoffs: atop the looming mountains outside of town, or deep into the mysterious catacombs below it. Both of these hiding places will take two hours to enter and two to leave. (Pretend the mountains have a rogue paramilitary that shoots down helicopters or something.) Due to work obligations, Alice can only make the dropoff in the early morning, and return that evening to pick up the books. Meanwhile, Bob, the thief, knows all this and certainly doesn't want to get caught. He can't go into either location until Alice has left, else he'll be seen. Lucky for him, that leaves a large window for him to do the deed. Both of these characters have the same magical devices from the earlier section, and they'll naturally use them to ensure success; except, for obvious reasons, we'll call their predictions "catacombs" and "mountains". Before she goes to hide the money at 5:00 AM, Alice consults her device for where to hide it. Four hours after he has seen Alice leave, at 9:00, Bob consults his device to determine where she hid it. If the predict is wrong, he forces a paradox. When Alice returns to get the money, at 17:00, if it's there, she confirms the location that the device advised. Otherwise, she presses the opposite button, forcing a crash via paradox. What happens? This requires introducing yet another notion.
Interlude: TIME FORCE
The TIME FORCE is any one in a billion freak accident that happens 100% of the time to prevent a paradox from occurring. TIME FORCE is a quantum fluctuation that causes right neuron to misfire which butterflies into changing your whole decision. TIME FORCE is random air currents that causes a bird to fly by and drop a rock on the right button of the time-device. TIME FORCE is the lightning in the clear blue sky which spells out Do not mess with time in typographically perfect serifs. There are a few things we can say about TIME FORCE. Let's say that the general odds of TIME FORCE acting on a given person in a given second is extremely, astronomically unlikely. One in a billion, or one in a trillion sounds about right. But from that, it follows that the odds of TIME FORCE acting over an interval of time is proportional to the length of that interval. (It's at least monotonic. Difficult/impossible to say how fast it grows.) It also follows that the odds of TIME FORCE acting is increased if an agent is acting in concert with it, and decreased if they are acting in opposition, proportional to the efficacy of that agent. I.e., an agent is defending against TIME FORCE, or attempting to utilize TIME FORCE. (consider: if Bob, after stealing, were to proceed to try to also steal Alice's device or persuade her to cancel her prediction herself (e.g., by faking a dire emergency which requires her foreknowledge to solve), then TIME FORCE would provide some boost to the probability of success.) An obvious corollary to all this is that TIME FORCE is almost never relevant. If you had a bigger device that spat out 32 red/blue pairs at a time, you could predict the lottery without seriously worrying about TIME FORCE. One common confusion which leads people to overstate the importance of TIME FORCE is the fact that parallel universes and timelines aren't necessarily the same thing. Let's say you wanted to force a coin to come up heads. Turn on your device. Then, splint. If the result was blue, flip the coin. If the result was red, splint again. The idea is to have the device spawn as many timelines as possible. Pressing buttons (subtly) alters the configuration of your brain and muscles and the microcurrents of air in the room, and the hope is a certain combination of buttons at a certain rhythm is prod you into the right configuration to flip the coin heads. This is almost certainly true in this specific example, but if the coin is flipped before the device is turned on, time cannot help you. And if you don't have intimate control over the outcome, time cannot save you. E.g., if a meteor is flying towards your town, forcing a paradox if it hits true cannot avert its course. Of course, if you splint long enough, maybe the branches describe a powerful, quickly-createable, meteor-destroying technology in morse code. Or maybe it just spells out "You needed worth opponents," and you give up and let the asteroid take you. (There is one slight exception, and this is where the different formulations of Bayesian Branch Realism and Reroll Realism differ. In BBR, the universe is posited to either A) know before splintering the posterior probabilities of each branch or equivalently, B) have so many timelines that destroy paradoxical ones leaves the distribution looking as it should. However, in RR, paradoxes are posited to cause the universe to restart from the beginning (or when the device was turned on). This means that in RR, simply flipping a coin and forcing a paradox if it's tails is all you need. That is, assuming quantum fluctuations making the coin heads is more likely than quantum making you decide not to crash, or failing to crash. Or dying instantly and having the wizard return to push the button.) There's one last possibility, and that's if you posit that quantum randomness itself are biased by time travel, so each quantum measurement counts as a splinterpoint. I'm reluctant to do such, because the edict I've heard over and over again is that when worldbuilding, Do Not Mess With Physics. I'm going to continue writing this article with the assumption that physical randomness is not biased by timelines. Extreme improbabilities are still extremely improbable, but, to mangle the quote, when you have eliminated the impossible, whatever remains, however improbable, must happen.
Back to Alice and Bob
So, with TIME FORCE in mind, what happens to Alice and Bob? It's 4:50. Alice is sitting beside her bag of money with a dollar sign on it, her device in front of her. If the device shows 'catacombs', she intends to, when she returns from work, press 'mountains' in case her bag was stolen and she doesn't have her book, or otherwise she will confirm 'catacombs' (and vice versa). She waits. And the device doesn't say anything at all! It's well known that sometimes there are random delays before the devices spit out answers. Some users interpret it as an omen, suggesting that whatever you're asking is so likely to lead to paradox, time itself has to work up the nerve to allow it to happen; the theorized mechanism is 'paradox aversion', where in some models, the odds turn against timelines long before the paradox is even nigh. (But as far as Alice knows, no one has never proved which model they live in.) She decides to buck superstition and conjecture, and reaches out to flip the switch which forces an output. Record scratch, freeze frame. What happens next? A) TIME FORCE intervenes before Alice can flip the switch. B) Alice flips the switch, but TIME FORCE subverts the resulting prophecy. (I.e., the bag is stolen, but events contrive to have the incorrect button on the device pressed anyway.) C) Alice flips the switch, and TIME FORCE subverts Bob's prophecy instead, sending him to the wrong location. Her bag is not stolen, and she happily reads the ending of WtC. D) Alice presses the secret button, and TIME FORCE subverts both prophecies. (Stop reading now if you want to try to work out an answer yourself.) The correct answer is B, which is about three times more likely than anything else, barring unspecified details. A requires TIME FORCE to act in the acute interval before Alice presses the button, which is at best a few minutes long. C requires TIME FORCE to act in the four hour interval of 9:00-13:00. D is the conjunction of A and C, and less likely than both. B is the winner, because it only requires the TIME FORCE to act on the long, twelve-hour interval of 5:00-17:00 I think this goes even if timelines nudge physical probabilities. Exercise for the reader, though. (((Now, one may object that this formulation bears little resemblance to Tim's example. My only excuse is that Tim's model was too unclear for me to formalize specifically. When I tried, I got this scenario: First, Alice gets a prediction from the device: stolen, or untouched. Iff it says stolen, she waits to see who the thief is, and gets them. Else, she goes about her day, secure knowing her money is safe. Then, Bob consults his device as to whether his theft would be successful: if it says yes, then either 1) Alice is there, catches him, and he triggers a paradox, or 2) Alice isn't there, he gets away, and she triggers a paradox later. However, if it says no, then he just sighs, and fucks off, no paradox to worry about. Even if I missed something/misinterpreted TimTravel and this situation is paradoxical all four ways, it still follows that Bob will probably win (if not so overwhelmingly so) because he spends less time in temporal limbo where TIME FORCE might fuck with him.)))
It's clear that if one were to disassemble the strange device and hook up a few wires to its circuit boards to a computer, you'd create a hybrid device capable of advanced feats of computation. What is the exact strength of this retrocausal computer? As mathematicians are wont to do, we will dispense with practicalities like having to use at most as much space as actually exists, or needing our computations finish before the heat death of the universe. Given all this, if we have an idealized retrocausal computer, a la the idealized turing machine, what can we do? Let's try the halting problem, a classic test of strength. Say we have a computer program, and we want to know if it's ever stops running. Well, either it does or doesn't. Consider a slightly different device, instead of red/blue leds, it has magic screen which can display any integer. (For models where it matters, the intrinsic probability of an integer n is equal to 2-k, where k is smallest number with 2k > n and k > 0.) It also has a numpad now, which allows the input of any integer. With this device, to determine when a program halts, given that it halts, is as simple and looking at what number comes up on its screen, and running the program for that many steps. If it halts before then, input when it halted (causing paradox). Otherwise, input the number it gave you. Otherwise otherwise, cause a paradox via your preferred means. If the program might run forever, things are trickier. What you can do is interpret the number the screen outputs as the index of a proof of (not) halting. This isn't sufficient, however, as no computably-checkable proof system can prove that any turing machine (never) halts, essentially by definition. But we can use the fact that if a program runs forever it doesn't halt: simply try over and over again until 1) you learn the program does not, or 2) the odds of it halting given that you found no proof is as astronomically low as satisfies you. By construction, the odds of the screen outputing the right halting time decreases exponentially as the halting time increases. If the halting time is in the millions, it takes a several hundred trials before you have even odds of the screen having already spat out the right answer. If the time is in the billions, it takes several hundred thousand. (Model-specific tricks can alleviate this quite a bit. In Path Realism, you can use the path blowup technique to increase the probability of the correct halting time coming up. In Weighted and Reroll, you can inflate the static paradox fraction to arbitrary heights, reducing the odds of false negatives.) From ordinary turing machines, this is a difference in degree (retrocausal machines are better at it), but not kind (retrocausal machines can never decide whether a machine halts or doesn't). Long story short, retrocausation can increase the efficacy of your computers, but you're still stuck at 0.
Applications to More Permissive Time Travel Models
Our device is quite limited, in the world of retrocausation. There are at least two stronger types of models:
Bound Time Travel: our system only sends information back in time, where most extant system allow entire persons to make the journey. While I strongly prefer this "prophecy" scheme to proper time travel (prophecy is simpler and more physically plausible, and opens up less strange cases), the evidence suggests that's not the prevailing taste.
Free Time Travel: In contrast to a Primer-style system where time travel is limited to when and where a machine exists, quite a few just let you pop out at old place and time. Again, this is not preferable to me because it doesn't allows limits to be as clear (a desirable quality for any rational system), but free time travel seems rather common. Cf. HP Time Turners, the very things which started this discussions.
Bound Time Travel
It's clear how our models transfer the bound case; proper time travel is basically sending a whole bunch of information at once. There's another hurdle though: can you tell from when a time travel comes? With our red/blue device, the slider at the top puts an upper bound on how long the device waits for stablization. If the system allows this, then great! It means there's a clean cutoff point after which we know the timeline is stable or not. Otherwise, you probably want to make probability proportional to how far in the future the traveler comes from; if you're uniformly selecting a person that could exist between now and the heat death of the universe (without grandfathering themselves, granted), it's probably not going to be you from two weeks hence, of all people. There's a more interesting question this is avoiding though. What can we say about what will probably step out of the time machine, aside from whence it came? Well, it's helpful to assume that there's an organization controlling and regulating time travel. There's some failure modes that would be cripplingly common. For instance, doppelgangers. Temporal doppelgangers are a variation of the bootstrap paradox (i.e., self-causation), where a mutant version of your steps out of the time machine, finds current you, and forcibly alters your mind to replicate its own (anthropically, it must know how to succeed at this). This seems pretty inevitable from the premise, and it provides a nice, fresh justification for "you can't interact with your past self". Not out of fear that it might cause a paradox, but out of fear that it won't. If your mind is randomly altered repeatedly, even by slight amounts each time, the results are quickly going to not be pretty. Other than that, this scheme of time travel seems somewhat tractable; while the odds of any given arrangement of matter is a specific person with a specific set of memories consistent with the past and future of the extant universe is very very very low, there is some wiggle room, especially depending on the specifics of the time machine. The assumption baked into our models is that, in effect, the time travel mechanism is plucking a random configuration of matter from possibility space. Most arrangements of matter, even restricting to the stable ones, aren't neat blobs of protein and water. And the most of the ones that are, are random goop! Now, requiring that the configurations which arise in the past-time machine are exactly 1-1 equivalent to what enters the future-time machine is very tight requirement. I doubt bodies will be too much worse for wear if a few atoms are a few picometers off. And you can relax the requirement even further, allow what appears in the present to be "close enough" to its future equivalent, and increase the possibilities further. Of course, this will have ramifications; cancer, prions, strange tastes in the mouth. The organization controlling the time machines could require that everyone who walks out of a time machine undergo a medical examination, and make most crippling ailments thereby paradoxical. (And, likewise for the dead bodies which can't walk out anyway).
Free Time Travel
Free Time Travel is the trickiest of all, but it has a few felicities in addition to all the extra warts. There's not necessarily authoritative time travel device (or an immediately plausible time travel agency) that you can stick in to stealthily add in extra conditions and assert nice properties. With FTT, a time traveler could pop up anywhere, and at any time. Unless you add in a time agency that can monitor for new arrivals, there's nothing you can do about doppelgangers, unless you bolt 'no interacty with the past self' into the rules of the system somehow. You probably shouldn't have location be conserved; requiring that you come out exactly where you came tightens probabilities too tightly. Allowing leeway puffs them up a bit. The same goes for concerns about exact molecular matching. All those caveats aside, it seems as tho you can otherwise treat BTT and FTT similary to our toy examples, where they line up, showing the benefits of the simplification.
Well, that turned out much longer than I'd expected (or wanted). It feels like it puttered out here at the end, but I've said everything I set out to say and then some. I hope this served to sharpen your intuitions regard time travel, and make precise things which were previously vague. I would like to thank the nice people on the /rational discord for inspiring this line of thinking and providing the impetus to refine it. Thank you for coming to my TED talk. P.S.: worth mentioning that Tim covered much of the same ground as me in their initial post. My post is less a refutation to theirs than me working out my own solution to the problems they pose, as I didn't understand or believe all of their arguments.
(Under Construction, last updated: 06/06/20) Q: What is Nucleus Co-Op? A: https://www.youtube.com/watch?v=jbituCgu3Bc Nucleus Co-Op is a free and open source tool for Windows that allows split-screen play on many games that do not initially support it. The app was originally created by Lucas Assis, Zerofox later took over and added a ton of new features and improvements to support a lot more games. Ilyaki later joined in and brought multiple keyboards/mice support and more great features to the table. The app is currently being developed and updated by these devs: Lucas Assis, Zerofox and Ilyaki. R-mach too for making and supporting the website that hosts the Nucleus Co-Op scripts. Also the further development of the app wouldn't have been possible without all the amazing contributions and hard work from the SplitScreen Dreams Discord members (which include the devs mentioned above) that made all the new Nucleus Co-Op scripts and continue to make new discoveries and scripts to support even more games, among them: Talos91, PoundlandBacon, dr. old.boi, Pizzo and many more. Q: How does Nucleus Co-Op work? A: Essentially Nucleus Co-Op opens multiple instances of the same game (some games require mutex killing for that or other methods) that will only answer to one specific gamepad (we do this via Nucleus Co-Op custom xinput dlls or xinput plus dlls) and connects those instances via LAN or steamworks online multiplayer emulation (Goldberg Emulator), all while making sure all windows have focus so they can be playable with gamepads or that the instances are playable even in the background. Nucleus then resizes, removes borders and repositions the games windows so you can have synthetic splitscreen to play locally with your friends. Q: Which games can be splitscreened using Nucleus Co-Op? A: There are a lot of supported games, all mentioned in the list above. A ton of games are now supported thanks to the amazing program called Goldberg Emulator, developed by Mr. Goldberg, a big thank you to him. Read the Goldberg FAQ linked too if you want to know more. Q: Where do I download Nucleus Co-Op? A: You can download latest version from Github. Download the compiled .rar release, don't download the source code zip if you just want to use the app. Q: How do I use Nucleus Co-Op? A: Here is a quick video tutorial: https://www.youtube.com/watch?v=hWmvz59i-o0 1.- Download and exctract Nucleus Co-Op (extract using apps like 7-zip or winrar). 2.- Open NucleusCoop.exe. 3.- Click on Download Game Scripts, search for a game in the supported games list and download a script. You can also see all available scripts from the app now by pressing the view all option. 4.- Once the script has finished downloading you will get a prompt asking if you would like to add a game now, press yes if you want to add it now, if you select no proceed to step 6. 5.- Next you need to find where your game's executable is located. If you're not sure, try Googling 'where is (game) installed' and just searching for .exe in the place they tell you to look. For Steam games this is usually something along the lines of 'C:\Program Files\Steam\steamapps\common(game)'. Some games will have their real .exe stashed away in a folder called 'bin' or 'binaries' inside that place. Once you choose the right .exe, add the game. 6.- You can also automatically add games, click 'Auto-Search' and select the drive and path you want to add games from. 7.- Once your game is added, select it in the Nucleus UI and drag the gamepads icons to the splitscreen layout, click on the top-left icon on the layout corner to change the type of splitscreen layout. You can also right click a player in the layout to change the size. 8.- Finally press play and you are ready to go. Q: Where should I place the Nucleus Co-Op folder? A: Nucleus Co-Op can be placed almost anywhere(Documents, Downloads, Desktop, etc...) except inside the game files. Q: How do I play with an uneven amount of players (such as 3 players) without having an empty space? A: Right click on a section of the splitscreen layout Q: Nucleus Co-Op doesn't launch, how do I fix it? A: Here are a few things you can try: 1.- Try updating your Microsoft.net framework, and install/reinstall Visual C++ 2010-2017. 2.- Run Nucleus Co-Op as admin. 3.- Make sure your antivirus program is not blocking Nucleus Co-Op. 4.- Restart your PC, and try again. Q: I wish to help out with the project, how can I get in touch? A: Join the Nucleus Co-Op discord community or contact us here in the subreddit. Q: When support for X game? A: Not all games are easy to splitscreen, if you want to suggest a game make a post with the title [Request] Name of the game and provide useful information like if the game supports LAN or dedicated servers, if it is available on Steam or in other services, if it uses external servers for online etc. Also you can contact any of our experienced Nucleus scripters here or in the Nucleus Co-Op discord and ask if a script is possible. The main scripter is the OP of this post for instance. Remember that Scripters are limited by the games they own and can test on, so if you really want support for a game to be added consider donating the game to the scripter in question. Q: How do I know when a script gets updated? A: Scipt updates are always announced in the Nucleus Co-Op discord server in the channel script updates. Q: How do I create my own splitscreen script for Nucleus Co-Op? A: Here is the documentation, open the .js file with notepad to read it. You can also use the other scripts you download from Nucleus as reference, they get downloaded to the Nucleus scripts folder. If you create a working script or if you have any questions about Nucleus scripting you can ask us in the Nucleus Co-Op discord or here in the subreddit, we can help you improve your script so it is fully working for sharing with the community. Q: Does Nucleus Co-Op work on Linux/Mac? A: Nucleus Co-Op depends on a lot of Windows functions and APIs, at the moment it only works on Windows 7 and Up. If you are interested in porting Nucleus Co-Op to other operating systems please feel free to contact any of the developers. Q: Where can I report a bug/issue? A: Note that Nucleus Co-Op is a tool in development and still in Alpha. Expect bugs, glitches and weird things to happen. Help other people not have these things happen by checking for a solution here and submitting a [BUG REPORT] to the reddit as a new topic or in the comments here, if no-one else has brought it up. A good [BUG REPORT] looks like this: Thread name: [BUG REPORT] Simon falling off horse BUG: Simon falls off his horse. EXPECTED: Simon should not fall off his horse, right? CAUSE: I'm pretty sure it's because I have my computer plugged into an auto-blow. STEPS TO REPRODUCE 1.- Open up Simon Stays On His Horse: The Interactive Video Game of the Movie. 2.- Choose Co-Op and join with another player. 3.- Simon falls off his horse!!! TYPE: Severe! The gameplay can't continue if Simon isn't on his horse! (Alternatively, Minor if the gameplay can continue but it's just annoying) NUCLEUS OPTIONS: I played with 2 players using the vertical splitscreen (left and right) on one tv and 2 famicom controllers. I'm using the latest version SYSTEM: I'm on Windows 3.1 with 4MB of RAM, a 2KHz CPU and no graphics card, playing on a projector. She's a monster. I'd really like this to get fixed please thanks magic man! -Beanboy" Keep in mind most scripts are made and tested using the latest legit steam versions of the game, so provide information about what version of the game you have. Also provide a debug log of the NucleusCoop error, enable the debug log in Nucleus UI settings. You can also ask for support in our discord. Q: Why is Nucleus Co-Op resizing the game instances incorrectly/the instances look stretched? A: Try setting your monitor scale to 100% in your monitoTV resolution settings. It is also highly recommended that you add custom resolutions to all your monitors from your AMD/Nvidia/Intel panel (For example if you are using a monitor resolution of 1920x1080 add custom resolutions like 960x540, 1920x540, 960x1080, ect.) that way most games will be able to see and use those custom resolutions and the splitscreen will not look stretched(Example). Note that not all games support custom or widescreen resolutions. Also try disabling the Nucleus status bar in Nucleus UI settings. Q: Why is Nucleus Co-Op throwing an error message that it can not find a file when launching a script? A: A lot of scripts edit the game's .ini or .cfg files to force windowed and to adjust the game resolution, so make you sure you run your game at least once and change some graphic settings before running it via Nucleus Co-Op, that way you make sure the config files are getting generated first. If you are still getting the error after doing that, select the game in the UI, click on Game Options and select Delete UserProfile Config Path for all players. Also try disabling the Nucleus status bar in Nucleus UI settings. Q: Where are my Nucleus Co-Op save files located? A: Some scripts save to the Nucleus Co-Op enviroment folder located in C:\Users\YourUser\NucleusCoop, you can access each game save file via the Nucleus Co-Op UI too, select a game, click on Game Options and select Open UserProfile Save/Config Path. Other scripts just save in the same file path your regular game saves to. Q: Why are my in-game frames per second low/better in one instance than in the others when using Nucleus Co-Op? A: Remember that Nucleus Co-Op opens multiple instances of a game, so depending on the game this can be quite demanding for your PC, to improve FPS and performance try reducing graphics settings like textures and shadows, limit the FPS or unfocus all the game windows so that they get equal priority and the FPS even out, you can do this by Alt-Tabbing to a different window like the Nucleus app window, the game windows will still remain on top, you can also press the windows key+b in your keyboard to unfocus all instances. Q: My Playstation/generic PC controller isn't working/isn't being detected by Nucleus Co-Op, how do I fix it? A: Most Nucleus Co-Op Scripts only detect Xinput gamepads. Controllers that work best are Xbox 360, Xbox One and Logitech game controllers for minimum hassle. There are a few scripts that also support Direct Input gamepads but Xinput gamepads are generally easier to restrict to a specific game instance than Dinput gamepads. If you are using PS4 gamepads try the app DS4windows, look in the settings for an option called "hide ds4 controller" - make sure it's ticked. To ensure it's definitely running in exclusive mode make sure ds4windows is set to load on windows startup, then turn your controllers on while windows is loading. Download the latest version here - https://ryochan7.github.io/ds4windows-site/ If you are using generic dinput gamepads the app XOutput is also useful to emulate xinput gamepads. The app X360CE version 4 that creates virtual Xbox 360 Controllers inside your Windows operating system is also very useful to emulate xinput gamepads system wide. Remember that some games detect both dinput and xinput gamepads so even if you are emulating a xinput gamepad the input could still not be restricted correctly because the game is now responding to both the emulated xinput gamepad and to the native direct input of your gamepad, that is why some apps like DS4windows have an "exclusive mode". Also do not place x360ce xinput dlls in the Nucleus Co-Op files as this might interfere with Nucleus custom xinput dlls. If you are using steam controllers try this: https://www.youtube.com/watch?v=wy4F2eqTXQ4 Q: Why is my keyboard not showing in the Nucleus Co-Op UI? A: If a script is only showing gamepads and not keyboard icons that means the script only supports gamepads and doesn't support keyboards and mice in splitscreen yet. Q: There are many keyboards and mice icons in the UI, how do I know which ones to use? A: If you press a key in the keyboard you will use or move the mouse their corresponding icons in the Nucleus Co-Op UI will light up yellow. The app can detect keyboard macros that is why sometimes you will get multiple keyboard icons. Q: Can you play splitscreen+LAN in different PCs? A: Yes, if you run the game via Nucleus Co-Op in different PCs you can connect all instances you launch via LAN, for example you can have 2 players playing vertical splitscreen in one PC via Nucleus and connect to 2 others playing Nucleus splitscreen in a different PC via LAN. If the script uses steamworks multiplayer emulation you'll have to change the instances steam ids in the other PCs you'll connect to, otherwise the instances launched by Nucleus will use the same steam ids and won't be able to connect to each other. For that you can open the game script .js file in Nucleus scripts folder in the other PCs and add for example Game.PlayerSteamIDs = [ "76561198134585131","76561198131394153","76561198011792067","76561198043762785" ]; that will change the default ids of the first four instances you open in one PC via Nucleus Co-Op. Q: Does Nucleus Co-Op have any malware? A: Absolutely not. Q: This project is Amazing where can I donate? A: We don't have an unified donation platform yet but you can support the devs individually here: Zerofox, Ilyaki, Lucas Assis. You can also donate to our main scripters that make the game scripts for Nucleus: Talos91/blackman9
Unusually high CPU and GPU usage on YouTube (Firefox Nightly)
TLDR: So the fix for this, in my instance, was two parts. First was to install new drivers onto my computer. Second, and probably something I should have noticed myself, is that I should have set YouTube not to stream at 4K. Not terribly shocking to need 4x the GPU when processing 4x the data for an image compared to 720p Hi all, So, a few days ago I noticed that Firefox was using way more CPU and GPU resources on YouTube especially. On the same video, Vivaldi's GPU usage would hit about 8% then hover at 2.5% or so. Firefox would go to about 20%, and hover at about 5-10%. I wasn't entirely sure as to why this is happening. I tried turning off Hardware Acceleration, which didn't seem to do anything. I used this video from Engineering Explained where Firefox's GPU usage was always over 20% in the first minute, while Vivaldi peaked at 15% for a moment, then went back down to 2.5%. Hardware Specs: Intel i7-8705G 16GB RAM 512GB NVMe SSD Intel HD 630 (This is the GPU that gets used by Firefox) Radeon RX Vega M GL Let me know if there's anything else I can provide! Edit: Here is the about:support from my browser. I should note that I did try to remedy the issue by turning all add ons off, but that didn't do anything either.
Name: Firefox Version: 78.0a1 Build ID: 20200526213752 Distribution ID: Update Channel: nightly User Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:78.0) Gecko/20100101 Firefox/78.0 OS: Windows_NT 10.0 Launcher Process: Enabled Multiprocess Windows: 1/1 Enabled by default Remote Processes: 18 Enterprise Policies: Inactive Google Location Service Key: Found Google Safebrowsing Key: Found Mozilla Location Service Key: Found Safe Mode: false
NSPR Expected minimum version: 4.25 Version in use: 4.25 NSS Expected minimum version: 3.53 Beta Version in use: 3.53 Beta NSSSMIME Expected minimum version: 3.53 Beta Version in use: 3.53 Beta NSSSSL Expected minimum version: 3.53 Beta Version in use: 3.53 Beta NSSUTIL Expected minimum version: 3.53 Beta Version in use: 3.53 Beta
Content Process Sandbox Level: 6 Effective Content Process Sandbox Level: 6
Disk Cache Path: C:\Users\Daniel Chuchra\AppData\Local\Mozilla\Firefox\Profiles\dmz3ad06.default\startupCache\startupCache.8.little Ignore Disk Cache: false Found Disk Cache on Init: true Wrote to Disk Cache: true
Internationalization & Localization
Application Settings Requested Locales: ["en-US"] Available Locales: ["en-US"] App Locales: ["en-US"] Regional Preferences: ["en-US"] Default Locale: "en-US" Operating System System Locales: ["en-US"] Regional Preferences: ["en-US"]
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