8 ms·

Reading through this in detail just cements that we are never leaving this solar system unless we discover some new physics to get around our speed limitations.

kylecordes 1y ago
c appears to be the speed limit of the propagation of information in the universe - never say never, but so far it appears quite unlikely any new physics will overturn this.
- VagabundoP 1y ago
  If we manage to get anywhere near 0.1c and slow biological ageing we can get nearly anywhere with the right engineering.
JumpCrisscross 1y ago
> we are never leaving this solar system unless we discover some new physics to get around our speed limitations The winning proposal coasts at 0.01c. Propulsion systems--not the speed of light--and thus engineering, not phsyics, are the relevant limitors.
- jvanderbot 1y ago
  We're one good new religion away from colonizing the solar system. Cathedrals were built over 100s of years. Imaging just living in a massive one and your whole holy purpose is to survive and thrive and spread. It's entirely reasonable we'd have the will to make it happen, and pretty reasonable we'd be able to build it with planet scale effort, but sadly quite difficult to imagine it surviving even dust impacts for 400 years.
  - JumpCrisscross 1y ago
    > quite difficult to imagine it surviving even dust impacts for 400 years Whipple shields [1]. [1] https://en.wikipedia.org/wiki/Whipple_shield https://en.wikipedia.org/wiki/Whipple_shield
    - jvanderbot 1y ago
      > up to 18km/s Vs > 0.1c Off by quite a bit
      - JumpCrisscross 1y ago
        Where are you getting either of these figures?
        jvanderbot 1y ago
        The up to 18km/s is from the linked shield. Up to 0.1c is from the interstellar spaceship competition "cruise" speeds (also used 0.01c) as presented in their deck. They're a few orders of magnitude difference. Also, there's plenty of resources around on interstellar travel that shows interstellar dust/debris is going to be a huge problem. For example Atomic Rockets, which has a bunch of good reference materials (albeit poorly organized), or the Astronomy Cafe https://sten.astronomycafe.net/at-what-speed-does-the-interstellar-medium-become-lethal-to-high-speed-flight/ https://sten.astronomycafe.net/at-what-speed-does-the-inters...
    - privatelypublic 1y ago
      Whipple shields are consumed by impacts.
      - JumpCrisscross 1y ago
        > Whipple shields are consumed by impacts Everything is consumed on such a voyage. If we can send a generation ship at 0.01c, we can send replacement parts quicker and probes ahead to verify our estimates even faster.
        jvanderbot 1y ago
        Are you just casually handwaving away sending a dockable resupply ship at 0.01c to somewhere in interstellar space, then doing some kind of rendesvous with it at 0.01c with a spaceship measured kilometers in length? There's no free lunch. Every gram of mass that you want to get to interstellar space requires exactly as much fuel to get there as you'd have to add to the original spacecraft to just carry it. (thought experiment - have them fly side by side, then connect them by string, then shorten the string until they touch, then weld them together - the fuel required doesn't change at any point). And a shield + a resupply ship has a lot more grams than just adding the shield to the original thing.
  - Apocryphon 1y ago
    I've played that game: http://irontowerstudio.com/colony-ship-news http://irontowerstudio.com/colony-ship-news
  - teiferer 1y ago
    > It's entirely reasonable we'd have the will to make it happen "We" are not even able to sustainably inhabit our current planet. We have hundreds of millions starving every day, we have wars in many places, the threat of thermonuclear war looming as strong as ever, and are still using natural resources at an unsustainable rate even though we know that that's the case. Settling on other planets has all these problems plus the issue of getting there plus the issue that the environment you find there is more hostile than the most hostile desert areas here on earth. We currently live on paradise planet and can't even make things work well around here. Hard to see how you could make things work on Mars where you can't just go outside pick a leaf to eat and get some water to drink. Or just, you know, breathe.
    - ivan_gammel 1y ago
      We are a life form that triggered major environmental crisis and is trying to adapt to it at unprecedented speed that no other life form achieved in the past. Our base line for being able to make changes isn’t science fiction but couple billions of history of life on this planet. Our goals are ambitious but we are doing surprisingly well. Just not as we want it to happen.
    - jvanderbot 1y ago
      We do not have hundreds of millions starving every day. And if we did, we don't have a large portion of industrialized/militarized missions starving every day anway. We'd send the best of the best, hand picked, with the best tech we can build. It's fine if you believe we should not go (but I disagree), but the state of the world is not evidence of failure of the mission.
      - teiferer 1y ago
        > We do not have hundreds of millions starving every day. Then maybe it's time you stop being ignorant. It's not even hard to google. Start with the WHO, over 700 million people faced hunger and malnutrition in 2023. [1] And I'm not particularly interested in how you will try to nitpick your way out of that. It's so easy in the west and in upper classes of the developing world to close your eyes to this. [1] https://www.who.int/news/item/24-07-2024-hunger-numbers-stubbornly-high-for-three-consecutive-years-as-global-crises-deepen--un-report https://www.who.int/news/item/24-07-2024-hunger-numbers-stub... > And if we did, we don't have a large portion of industrialized/militarized missions starving every day anway. We'd send the best of the best, hand picked, with the best tech we can build. Initially, sure. But that's not what I was talking about. Eventually you want to build a civilization there, right? Eventually you have millions there. And it's hard to see how you will be able to organize a society in large scale in a way that does not have the problems humankind currently has if you can't even fix that here which compared to all other planets is a nature paradise. Even after a thermonuclear war, earth is easier to live on than any other planet in this solar system. Time to leave your scifi bubble if you believe otherwise. > It's fine if you believe we should not go (but I disagree), but the state of the world is not evidence of failure of the mission. The state of the world is evidence of failure of a mission that is much easier than building a civilization on another planet.
  - dotancohen 1y ago
    > your whole holy purpose is to survive and thrive and spread. Religion already covers that. Go forth, and multiply.
  - FuriouslyAdrift 1y ago
    Imperium of Man?
- os2warpman 1y ago
  If you can build and maintain a system capable of sustaining the lives of 1,000 humans for 400 years, why do you care about interstellar travel anymore? “The indefatigable spirit of exploration” isn’t the answer. People, as a mass, only explore to find new resources due to scarcity. There are exceptions, but they tend to be thrill seekers or publicity hounds seeking to capitalize on a measure of fame upon their return and dying on a spacecraft 1/5th of the way through its journey isn’t thrilling and no ticker tape parades await your return. If you can build a spacecraft capable of sustaining 1,000 human lives for multiple centuries, you’ve solved all local resource scarcity problems. You could just mine the solar system and build billions of habitats that lazily circle the sun. Hell, you wouldn’t even care about habitable planets anymore and a likely endpoint for any interstellar efforts would likely be a long-lived star with large orbiting gas giants you could turn into solid materials in order to build trillions of habitats orbiting that star, not an insignificant earth-like boulder. Imagine turning all of the methane in a gas giant into carbon strands, using its hydrogen to do it and building a near-infinite number of habitats, each perfectly suited to human existence. An earth-like planet with its quakes and tsunamis and seasonal cycles would seem pathetic.
  - JumpCrisscross 1y ago
    > People, as a mass, only explore to find new resources due to scarcity Empirically totally untrue as to be trivially disproven by like half of wealthy social media. > thrill seekers or publicity hounds seeking to capitalize on a measure of fame upon their return Everyone on these ships would be a celebrity on Earth. (Ideally, if they so chose.) Again, a simple reading of one-way trip settler-explorers across history similarly rejects this notion. > If you can build a spacecraft capable of sustaining 1,000 human lives for multiple centuries, you’ve solved all local resource scarcity problems The first several of these ships are likely to end in catastrophe. The first to succeed will be breaking down on arrival. If we learn to build luxurious space habitats it will be through these endeavours.
    - os2warpman 1y ago
      > Empirically totally untrue as to be trivially disproven by like half of wealthy social media. A week in Bali is not the same thing as interstellar travel…
- munificent 1y ago
  I am increasingly certain that culture is by far the biggest limiting factor when it comes to large-scale problem solving now and in the future. We couldn't even reliably get people to put a piece of fabric over their face to stop killing their own relatives. Even if we could build a generation ship, it would turn into an Event Horizon hellscape if we don't figure out better cultural, communication, and sociological tools to enable us to get along and work together effectively.
  - deleted 1y ago
    [deleted]
  - JumpCrisscross 1y ago
    > We couldn't even reliably get people to put a piece of fabric over their face Rural Americans couldn’t. But I don’t see anyone proposing we put high school dropouts and polio patients in space. China, India and Japan managed to pass that test just fine. I imagine one of the former two will be the first to colonise deep space.
    - kryogen1c 1y ago
      >> kill their relatives > Rural Americans > high school dropouts Lol HN you really are too much sometimes. Covid went really well in all the intellectual bastions of liberal democracy right? NYC, SF? California famously no downsides from their policy choices at all. And then to top it off, you compare response to China - the government that lied through it's teeth about covid from the beginning, jailed journalists and destroyed evidence. Unreal
      - JumpCrisscross 1y ago
        Oh, nobody managed Covid well. The question was capacity to sacrifice for the common good. New York is a bad example to call out since it was one of the first places to get hit, locked down hard after a delay, and yet came out with lower per-capita deaths and a stronger economy than most red states. (Speaking as someone who lives in one of the reddest states in the union.) > jailed journalists and destroyed evidence Not sure we can call anyone out on this anymore.
- scythe 1y ago
  Relativity isn't the problem. The problem is that hitting a grain of sand at 0.1 c delivers the energy of several tonnes of TNT. My guess is that we will colonize the asteroid belt (Palladium! So much palladium!) and send lots of interstellar probes long before we try to send humans outside the solar system. Right now we're like a village that lives by a river and has never reached the mouth talking about sailing across the ocean. There are a lot of intermediate stages.
  - pmontra 1y ago
    It's not only about palladium or any other kind of ore. It's that you can launch from there to Earth orbit and spare most of the costs of lifting mass from the surface of our planet. Then you build habitats and ships with that stuff because it's much cheaper. Too bad we don't have neither mining nor factories in space yet. Two not trivial technologies to develop. The book Delta V [1] explores that scenario, with an asteroid on an orbit close to Earth to minimize the delta v to ship things back home. [1] https://daniel-suarez.com/Delta-v_synopsis.html https://daniel-suarez.com/Delta-v_synopsis.html
  - Someone 1y ago
    > Right now we're like a village that lives by a river and has never reached the mouth talking about sailing across the ocean And that’s an enormous understatement. Let’s say the villagers have travelled a meager 10 km of the river. Then, the ocean is, ballpark, at most 1,000 times as wide as the distance to the sea. A thousand times the distance between earth and moon (the farthest humans have travelled) gets you, ballpark, to mars. A lightyear is ~50,000 times the distance to mars or 50,000,000 times as far as humans have travelled. And yet, in interstellar travel, a lightyear gets you nowhere.
    - m4rtink 1y ago
      Sure, but the speeds you can realistically reach on the surface of a planet for any lenght of time is also many orders of magnitude less than you can reach in space & you also don't really loose speed by friction. That at least partially compensates for the mindboggling distances in space.
- andrewflnr 1y ago
  I read their comment as saying that current physics doesn't allow the kind of propulsion systems we need, even with optimal engineering and well below the lightspeed limit.
  - JumpCrisscross 1y ago
    > current physics doesn't allow the kind of propulsion systems we need Which is wrong. Direct-drive fusion fits the bill. It’s also easier than terrestrial power-generating fusion since you don’t need to convert to electricity.
- Ekaros 1y ago
  Energy is the limit. If used Wolfram Alpha right for reasonable comparison that is largest cruise ship with mass of 248663000 kg to speed up to 0.01c mentioned the kinetic energy would be 2.9 times the worlds fossil fuel reserves... Then double that to slow down. And remember efficiency and that well you need to spend some to keep people alive... Seems like energy in general is one of the true problems.
  - WithinReason 1y ago
    You wouldn't be burning coal for propulsion, you would fuse atoms: https://en.wikipedia.org/wiki/Project_Orion_(nuclear_propulsion) https://en.wikipedia.org/wiki/Project_Orion_(nuclear_propuls...
    - Ekaros 1y ago
      I didn't coal would be used. Just that involved amount of energy would be truly massive. Even with fusion.
    - m4rtink 1y ago
      Or even better - ride a continuous fission detonation powered by the worlds biggest super-soaker! :) https://en.wikipedia.org/wiki/Nuclear_salt-water_rocket https://en.wikipedia.org/wiki/Nuclear_salt-water_rocket
  - JumpCrisscross 1y ago
    > If used Wolfram Alpha right for reasonable comparison that is largest cruise ship with mass of 248663000 kg to speed up to 0.01c mentioned the kinetic energy would be 2.9 times the worlds fossil fuel reserves This math is wrong. Back of the envelope: accelerating 250 x 10^6 kg to 1% of c over one year is about 310,000 TWh. That’s like half of current annual energy production. Even at like 10g, which would accelerate that mass to 1% c in less than half a day, you’d only use like a tenth of our 10^22 joules of fossil fuel reserves. > double that to slow down Why the asymmetry? 1x to accelerate, 1x to decelerate. (Less if you can aerobrake and/or use gravity assists.) Taking the 310k TWh from earlier and doubling it, and assuming 18 MeV for D-T direct-drive fusion, and you need 6,600 kg fuel for the journey. (Plus propellant.) 100x that to account for inefficiency and cooling and you have 660 metric tonnes of hydrogen. That, if kept in its bastard liquid form, takes up about 3 Olympic-size swimming pools in volume.
qingcharles 1y ago
Adding to the issue that it is relative pointless (IMO) to send meat popsicles all that way when a robot can make the journey about a million times easier and just send us some postcards. I hate to be a Debbie Downer, but it's kinda boring out there. We'd certainly not want to make the trek until the robots had scoured the galaxy looking for a fun place to visit. And by that time we'll all be living in some post-Singularity holodeck and won't give a hoot about some empty rock 600 light years away. Send the bots. I'll watch the highlight reel from my pod.
- philistine 1y ago
  Said like a true citizen of the Culture. And I mean that as a compliment!
- arethuza 1y ago
  My own view is that the most likely form of interstellar travel will be something like that used in Greg Egan's Diaspora - with upload communities sending themselves in relatively small ships and choosing whether to experience the journey or not.
- lanfeust6 1y ago
  I expect a kind of leapfrogging. Scout ahead, build a gate and/or infrastructure/terraforming, then a small fraction will decide it's worth migrating. Repeat. Expansion will only go as quickly as travel time allows. Even the speed of light seems insufficient beyond a certain point. We will want to manipulate space.
WithinReason 1y ago
We had the technology to do it in 44 years 60 years ago: An atomic (fission) Orion can achieve perhaps 9–11% of the speed of light. [...] At 0.1 c, Orion thermonuclear starships would require a flight time of at least 44 years to reach Alpha Centauri, not counting time needed to reach that speed (about 36 days at constant acceleration of 1 g or 9.8 m/s2). https://en.wikipedia.org/wiki/Project_Orion_(nuclear_propulsion) https://en.wikipedia.org/wiki/Project_Orion_(nuclear_propuls...
- notahacker 1y ago
  Tbf we had nuclear [fission] pulsed propulsion technology in the 1960s in roughly the same way we had nuclear fusion in the 1960s: we had an understanding of some basic principles of physics and some calculations that looked broadly plausible The problem with using thermonuclear explosions to produce that level of thrust are more "but can we actually do it safely" than "but can we do it in a way that generates more that it takes to produce", but that's a not inconsiderable problem even without all the international agreements about where we shouldn't be exploding nuclear bombs...
- slightwinder 1y ago
  > We had the technology to do it in 44 years 60 years ago: No, we had not. That was only theoretical work, no real technology, not even a prototype.
  - m4rtink 1y ago
    IIRC there were sub-scale test done with chemical explosives. Also Feynman said it should work. :)
konart 1y ago
Speed is one thing. Surviving space is another.
FuriouslyAdrift 1y ago
Speed isn't the problem... time is. Long term travel in space will destroy the body. Even with artificial gravity, cancer is nearly inevitable. I am ignoring the mental and emotional issues. Astronauts are extremely tough individuals. Now, if we can figure out some form of suspended animation, that fixes many problems for long range travel. I am much more convinced that our best way to leave our solar system will be without our physical bodies. Some form of synthetic or uploaded consciousness would be much easier to move around. After constructing a network, they could even be transmitted instead of shipped. This is obviously in the range of science fiction but if we exist long enough, who knows. The show, Pantheon, did a fairly decent fictional take on the idea.
- zdragnar 1y ago
  > Now, if we can figure out some form of suspended animation You'll still need someone awake to pilot the ship, otherwise you'll end up crash landed on a planet with Riddick running loose.
  - m4rtink 1y ago
    Yep, it is always a good idea to have a flight crew[0] when most of the passengers are in hibernation. It might take them some time but they will always sort thing out in the end! :) [0] https://revelationspace.fandom.com/wiki/Galactic_North_(short_story) https://revelationspace.fandom.com/wiki/Galactic_North_(shor...
  - random_is_rando 1y ago
    Some sort of AI algorithm? Don't think anyone pilots the SpaceX Dragon.
    - m4rtink 1y ago
      Looks like it is x86 + Linux and C++: https://hackaday.com/2024/02/10/the-usage-of-embedded-linux-in-spacecraft/ https://hackaday.com/2024/02/10/the-usage-of-embedded-linux-...

kylecordes 1y ago

c appears to be the speed limit of the propagation of information in the universe - never say never, but so far it appears quite unlikely any new physics will overturn this.

VagabundoP 1y ago
If we manage to get anywhere near 0.1c and slow biological ageing we can get nearly anywhere with the right engineering.

JumpCrisscross 1y ago

> we are never leaving this solar system unless we discover some new physics to get around our speed limitations The winning proposal coasts at 0.01c. Propulsion systems--not the speed of light--and thus engineering, not phsyics, are the relevant limitors.

jvanderbot 1y ago
We're one good new religion away from colonizing the solar system. Cathedrals were built over 100s of years. Imaging just living in a massive one and your whole holy purpose is to survive and thrive and spread. It's entirely reasonable we'd have the will to make it happen, and pretty reasonable we'd be able to build it with planet scale effort, but sadly quite difficult to imagine it surviving even dust impacts for 400 years.
- JumpCrisscross 1y ago
  > quite difficult to imagine it surviving even dust impacts for 400 years Whipple shields [1]. [1] https://en.wikipedia.org/wiki/Whipple_shield https://en.wikipedia.org/wiki/Whipple_shield
  - jvanderbot 1y ago
    > up to 18km/s Vs > 0.1c Off by quite a bit
    - JumpCrisscross 1y ago
      Where are you getting either of these figures?
      - jvanderbot 1y ago
        The up to 18km/s is from the linked shield. Up to 0.1c is from the interstellar spaceship competition "cruise" speeds (also used 0.01c) as presented in their deck. They're a few orders of magnitude difference. Also, there's plenty of resources around on interstellar travel that shows interstellar dust/debris is going to be a huge problem. For example Atomic Rockets, which has a bunch of good reference materials (albeit poorly organized), or the Astronomy Cafe https://sten.astronomycafe.net/at-what-speed-does-the-interstellar-medium-become-lethal-to-high-speed-flight/ https://sten.astronomycafe.net/at-what-speed-does-the-inters...
  - privatelypublic 1y ago
    Whipple shields are consumed by impacts.
    - JumpCrisscross 1y ago
      > Whipple shields are consumed by impacts Everything is consumed on such a voyage. If we can send a generation ship at 0.01c, we can send replacement parts quicker and probes ahead to verify our estimates even faster.
      - jvanderbot 1y ago
        Are you just casually handwaving away sending a dockable resupply ship at 0.01c to somewhere in interstellar space, then doing some kind of rendesvous with it at 0.01c with a spaceship measured kilometers in length? There's no free lunch. Every gram of mass that you want to get to interstellar space requires exactly as much fuel to get there as you'd have to add to the original spacecraft to just carry it. (thought experiment - have them fly side by side, then connect them by string, then shorten the string until they touch, then weld them together - the fuel required doesn't change at any point). And a shield + a resupply ship has a lot more grams than just adding the shield to the original thing.
- Apocryphon 1y ago
  I've played that game: http://irontowerstudio.com/colony-ship-news http://irontowerstudio.com/colony-ship-news
- teiferer 1y ago
  > It's entirely reasonable we'd have the will to make it happen "We" are not even able to sustainably inhabit our current planet. We have hundreds of millions starving every day, we have wars in many places, the threat of thermonuclear war looming as strong as ever, and are still using natural resources at an unsustainable rate even though we know that that's the case. Settling on other planets has all these problems plus the issue of getting there plus the issue that the environment you find there is more hostile than the most hostile desert areas here on earth. We currently live on paradise planet and can't even make things work well around here. Hard to see how you could make things work on Mars where you can't just go outside pick a leaf to eat and get some water to drink. Or just, you know, breathe.
  - ivan_gammel 1y ago
    We are a life form that triggered major environmental crisis and is trying to adapt to it at unprecedented speed that no other life form achieved in the past. Our base line for being able to make changes isn’t science fiction but couple billions of history of life on this planet. Our goals are ambitious but we are doing surprisingly well. Just not as we want it to happen.
  - jvanderbot 1y ago
    We do not have hundreds of millions starving every day. And if we did, we don't have a large portion of industrialized/militarized missions starving every day anway. We'd send the best of the best, hand picked, with the best tech we can build. It's fine if you believe we should not go (but I disagree), but the state of the world is not evidence of failure of the mission.
    - teiferer 1y ago
      > We do not have hundreds of millions starving every day. Then maybe it's time you stop being ignorant. It's not even hard to google. Start with the WHO, over 700 million people faced hunger and malnutrition in 2023. [1] And I'm not particularly interested in how you will try to nitpick your way out of that. It's so easy in the west and in upper classes of the developing world to close your eyes to this. [1] https://www.who.int/news/item/24-07-2024-hunger-numbers-stubbornly-high-for-three-consecutive-years-as-global-crises-deepen--un-report https://www.who.int/news/item/24-07-2024-hunger-numbers-stub... > And if we did, we don't have a large portion of industrialized/militarized missions starving every day anway. We'd send the best of the best, hand picked, with the best tech we can build. Initially, sure. But that's not what I was talking about. Eventually you want to build a civilization there, right? Eventually you have millions there. And it's hard to see how you will be able to organize a society in large scale in a way that does not have the problems humankind currently has if you can't even fix that here which compared to all other planets is a nature paradise. Even after a thermonuclear war, earth is easier to live on than any other planet in this solar system. Time to leave your scifi bubble if you believe otherwise. > It's fine if you believe we should not go (but I disagree), but the state of the world is not evidence of failure of the mission. The state of the world is evidence of failure of a mission that is much easier than building a civilization on another planet.
- dotancohen 1y ago
  > your whole holy purpose is to survive and thrive and spread. Religion already covers that. Go forth, and multiply.
- FuriouslyAdrift 1y ago
  Imperium of Man?
os2warpman 1y ago
If you can build and maintain a system capable of sustaining the lives of 1,000 humans for 400 years, why do you care about interstellar travel anymore? “The indefatigable spirit of exploration” isn’t the answer. People, as a mass, only explore to find new resources due to scarcity. There are exceptions, but they tend to be thrill seekers or publicity hounds seeking to capitalize on a measure of fame upon their return and dying on a spacecraft 1/5th of the way through its journey isn’t thrilling and no ticker tape parades await your return. If you can build a spacecraft capable of sustaining 1,000 human lives for multiple centuries, you’ve solved all local resource scarcity problems. You could just mine the solar system and build billions of habitats that lazily circle the sun. Hell, you wouldn’t even care about habitable planets anymore and a likely endpoint for any interstellar efforts would likely be a long-lived star with large orbiting gas giants you could turn into solid materials in order to build trillions of habitats orbiting that star, not an insignificant earth-like boulder. Imagine turning all of the methane in a gas giant into carbon strands, using its hydrogen to do it and building a near-infinite number of habitats, each perfectly suited to human existence. An earth-like planet with its quakes and tsunamis and seasonal cycles would seem pathetic.
- JumpCrisscross 1y ago
  > People, as a mass, only explore to find new resources due to scarcity Empirically totally untrue as to be trivially disproven by like half of wealthy social media. > thrill seekers or publicity hounds seeking to capitalize on a measure of fame upon their return Everyone on these ships would be a celebrity on Earth. (Ideally, if they so chose.) Again, a simple reading of one-way trip settler-explorers across history similarly rejects this notion. > If you can build a spacecraft capable of sustaining 1,000 human lives for multiple centuries, you’ve solved all local resource scarcity problems The first several of these ships are likely to end in catastrophe. The first to succeed will be breaking down on arrival. If we learn to build luxurious space habitats it will be through these endeavours.
  - os2warpman 1y ago
    > Empirically totally untrue as to be trivially disproven by like half of wealthy social media. A week in Bali is not the same thing as interstellar travel…
munificent 1y ago
I am increasingly certain that culture is by far the biggest limiting factor when it comes to large-scale problem solving now and in the future. We couldn't even reliably get people to put a piece of fabric over their face to stop killing their own relatives. Even if we could build a generation ship, it would turn into an Event Horizon hellscape if we don't figure out better cultural, communication, and sociological tools to enable us to get along and work together effectively.
- deleted 1y ago
  [deleted]
- JumpCrisscross 1y ago
  > We couldn't even reliably get people to put a piece of fabric over their face Rural Americans couldn’t. But I don’t see anyone proposing we put high school dropouts and polio patients in space. China, India and Japan managed to pass that test just fine. I imagine one of the former two will be the first to colonise deep space.
  - kryogen1c 1y ago
    >> kill their relatives > Rural Americans > high school dropouts Lol HN you really are too much sometimes. Covid went really well in all the intellectual bastions of liberal democracy right? NYC, SF? California famously no downsides from their policy choices at all. And then to top it off, you compare response to China - the government that lied through it's teeth about covid from the beginning, jailed journalists and destroyed evidence. Unreal
    - JumpCrisscross 1y ago
      Oh, nobody managed Covid well. The question was capacity to sacrifice for the common good. New York is a bad example to call out since it was one of the first places to get hit, locked down hard after a delay, and yet came out with lower per-capita deaths and a stronger economy than most red states. (Speaking as someone who lives in one of the reddest states in the union.) > jailed journalists and destroyed evidence Not sure we can call anyone out on this anymore.
scythe 1y ago
Relativity isn't the problem. The problem is that hitting a grain of sand at 0.1 c delivers the energy of several tonnes of TNT. My guess is that we will colonize the asteroid belt (Palladium! So much palladium!) and send lots of interstellar probes long before we try to send humans outside the solar system. Right now we're like a village that lives by a river and has never reached the mouth talking about sailing across the ocean. There are a lot of intermediate stages.
- pmontra 1y ago
  It's not only about palladium or any other kind of ore. It's that you can launch from there to Earth orbit and spare most of the costs of lifting mass from the surface of our planet. Then you build habitats and ships with that stuff because it's much cheaper. Too bad we don't have neither mining nor factories in space yet. Two not trivial technologies to develop. The book Delta V [1] explores that scenario, with an asteroid on an orbit close to Earth to minimize the delta v to ship things back home. [1] https://daniel-suarez.com/Delta-v_synopsis.html https://daniel-suarez.com/Delta-v_synopsis.html
- Someone 1y ago
  > Right now we're like a village that lives by a river and has never reached the mouth talking about sailing across the ocean And that’s an enormous understatement. Let’s say the villagers have travelled a meager 10 km of the river. Then, the ocean is, ballpark, at most 1,000 times as wide as the distance to the sea. A thousand times the distance between earth and moon (the farthest humans have travelled) gets you, ballpark, to mars. A lightyear is ~50,000 times the distance to mars or 50,000,000 times as far as humans have travelled. And yet, in interstellar travel, a lightyear gets you nowhere.
  - m4rtink 1y ago
    Sure, but the speeds you can realistically reach on the surface of a planet for any lenght of time is also many orders of magnitude less than you can reach in space & you also don't really loose speed by friction. That at least partially compensates for the mindboggling distances in space.
andrewflnr 1y ago
I read their comment as saying that current physics doesn't allow the kind of propulsion systems we need, even with optimal engineering and well below the lightspeed limit.
- JumpCrisscross 1y ago
  > current physics doesn't allow the kind of propulsion systems we need Which is wrong. Direct-drive fusion fits the bill. It’s also easier than terrestrial power-generating fusion since you don’t need to convert to electricity.
Ekaros 1y ago
Energy is the limit. If used Wolfram Alpha right for reasonable comparison that is largest cruise ship with mass of 248663000 kg to speed up to 0.01c mentioned the kinetic energy would be 2.9 times the worlds fossil fuel reserves... Then double that to slow down. And remember efficiency and that well you need to spend some to keep people alive... Seems like energy in general is one of the true problems.
- WithinReason 1y ago
  You wouldn't be burning coal for propulsion, you would fuse atoms: https://en.wikipedia.org/wiki/Project_Orion_(nuclear_propulsion) https://en.wikipedia.org/wiki/Project_Orion_(nuclear_propuls...
  - Ekaros 1y ago
    I didn't coal would be used. Just that involved amount of energy would be truly massive. Even with fusion.
  - m4rtink 1y ago
    Or even better - ride a continuous fission detonation powered by the worlds biggest super-soaker! :) https://en.wikipedia.org/wiki/Nuclear_salt-water_rocket https://en.wikipedia.org/wiki/Nuclear_salt-water_rocket
- JumpCrisscross 1y ago
  > If used Wolfram Alpha right for reasonable comparison that is largest cruise ship with mass of 248663000 kg to speed up to 0.01c mentioned the kinetic energy would be 2.9 times the worlds fossil fuel reserves This math is wrong. Back of the envelope: accelerating 250 x 10^6 kg to 1% of c over one year is about 310,000 TWh. That’s like half of current annual energy production. Even at like 10g, which would accelerate that mass to 1% c in less than half a day, you’d only use like a tenth of our 10^22 joules of fossil fuel reserves. > double that to slow down Why the asymmetry? 1x to accelerate, 1x to decelerate. (Less if you can aerobrake and/or use gravity assists.) Taking the 310k TWh from earlier and doubling it, and assuming 18 MeV for D-T direct-drive fusion, and you need 6,600 kg fuel for the journey. (Plus propellant.) 100x that to account for inefficiency and cooling and you have 660 metric tonnes of hydrogen. That, if kept in its bastard liquid form, takes up about 3 Olympic-size swimming pools in volume.

qingcharles 1y ago

Adding to the issue that it is relative pointless (IMO) to send meat popsicles all that way when a robot can make the journey about a million times easier and just send us some postcards. I hate to be a Debbie Downer, but it's kinda boring out there. We'd certainly not want to make the trek until the robots had scoured the galaxy looking for a fun place to visit. And by that time we'll all be living in some post-Singularity holodeck and won't give a hoot about some empty rock 600 light years away. Send the bots. I'll watch the highlight reel from my pod.

philistine 1y ago
Said like a true citizen of the Culture. And I mean that as a compliment!
arethuza 1y ago
My own view is that the most likely form of interstellar travel will be something like that used in Greg Egan's Diaspora - with upload communities sending themselves in relatively small ships and choosing whether to experience the journey or not.
lanfeust6 1y ago
I expect a kind of leapfrogging. Scout ahead, build a gate and/or infrastructure/terraforming, then a small fraction will decide it's worth migrating. Repeat. Expansion will only go as quickly as travel time allows. Even the speed of light seems insufficient beyond a certain point. We will want to manipulate space.

WithinReason 1y ago

We had the technology to do it in 44 years 60 years ago: An atomic (fission) Orion can achieve perhaps 9–11% of the speed of light. [...] At 0.1 c, Orion thermonuclear starships would require a flight time of at least 44 years to reach Alpha Centauri, not counting time needed to reach that speed (about 36 days at constant acceleration of 1 g or 9.8 m/s2). https://en.wikipedia.org/wiki/Project_Orion_(nuclear_propulsion) https://en.wikipedia.org/wiki/Project_Orion_(nuclear_propuls...

notahacker 1y ago
Tbf we had nuclear [fission] pulsed propulsion technology in the 1960s in roughly the same way we had nuclear fusion in the 1960s: we had an understanding of some basic principles of physics and some calculations that looked broadly plausible The problem with using thermonuclear explosions to produce that level of thrust are more "but can we actually do it safely" than "but can we do it in a way that generates more that it takes to produce", but that's a not inconsiderable problem even without all the international agreements about where we shouldn't be exploding nuclear bombs...
slightwinder 1y ago
> We had the technology to do it in 44 years 60 years ago: No, we had not. That was only theoretical work, no real technology, not even a prototype.
- m4rtink 1y ago
  IIRC there were sub-scale test done with chemical explosives. Also Feynman said it should work. :)

konart 1y ago

Speed is one thing. Surviving space is another.

FuriouslyAdrift 1y ago

Speed isn't the problem... time is. Long term travel in space will destroy the body. Even with artificial gravity, cancer is nearly inevitable. I am ignoring the mental and emotional issues. Astronauts are extremely tough individuals. Now, if we can figure out some form of suspended animation, that fixes many problems for long range travel. I am much more convinced that our best way to leave our solar system will be without our physical bodies. Some form of synthetic or uploaded consciousness would be much easier to move around. After constructing a network, they could even be transmitted instead of shipped. This is obviously in the range of science fiction but if we exist long enough, who knows. The show, Pantheon, did a fairly decent fictional take on the idea.

zdragnar 1y ago
> Now, if we can figure out some form of suspended animation You'll still need someone awake to pilot the ship, otherwise you'll end up crash landed on a planet with Riddick running loose.
- m4rtink 1y ago
  Yep, it is always a good idea to have a flight crew[0] when most of the passengers are in hibernation. It might take them some time but they will always sort thing out in the end! :) [0] https://revelationspace.fandom.com/wiki/Galactic_North_(short_story) https://revelationspace.fandom.com/wiki/Galactic_North_(shor...
- random_is_rando 1y ago
  Some sort of AI algorithm? Don't think anyone pilots the SpaceX Dragon.
  - m4rtink 1y ago
    Looks like it is x86 + Linux and C++: https://hackaday.com/2024/02/10/the-usage-of-embedded-linux-in-spacecraft/ https://hackaday.com/2024/02/10/the-usage-of-embedded-linux-...