9 ms·

Antimatter production, storage, control, annihilation applications in propulsion

163 points by belter 2y ago

jp57 2y ago
I don't have references in front of me, (EDIT: I do!) but IIRC it takes about a kilogram of mass-energy to accelerate a kilogram mass to about 0.85c. But that kilogram would have to be carrying another kilogram of matter/anti-matter fuel to decelerate again. So there is a kind of relativistic Tsiolkovsky equation for mass-energy propulsion vehicles that carry their own fuel. Zipping around the galaxy at 0.95c, stopping at destinations and then zipping off again will require carrying a lot of antimatter with you. EDIT: Thanks to Wolfram Alpha I was able to see that it the kinetic energy of 1 kg at 0.87c is very close to the mass energy of 1kg of matter.
- m463 2y ago
  If you could avoid accelerating so much and go a little slower, you could get better lypkg.
  - jp57 2y ago
    Sure, and if you want to go at non-relativistic speeds you hardly need to carry much fuel at all.
- api 2y ago
  This is why there’s ideas like the Bussard ramjet, which may not work but try to work around this problem by using in situ mass-energy. Now I have read that it may be possible to use a powerful magnetic field to assist with slowing down by braking against the interstellar medium, which helps. The Avatar films have (in spite of very derivative plots) fairly realistic (at least physics wise) interstellar ships. They accelerate using beamed laser propulsion from the Sun and use antimatter rockets to decelerate, then repeat this in reverse to come home. One assumes they somehow recharge at their destination but this is not shown. Too bad all that cool tech is in service to humans who decided to be the bad guys from War of the Worlds. Still traveling that close to c brings up tons of other problems. Collision with a micrometeorite would be like an atomic explosion, and blue shifting of incident and cosmic background radiation would blast you in the head with x-rays and gamma rays. Those problems would demand more mass for active or passive shielding, and you’re already mass constrained. All things considered it’s way more practical to go slower — which could still be insanely fast e.g. 0.25c — and figure out how to cryosleep or become an AI that can just turn yourself off for the trip. Cryosleep for humans is a brutally hard biomedical problem but way easier than trying to approach the speed of light. There are other multicellular animals that can do it, albeit much simpler ones, so it’s probably possible. 0.25c allowing for acceleration and deceleration gets you to Centauri in around 25 years and to further star systems with promising exoplanets in hundreds of years. Then there’s generation ships, but that’s the kind of thing Mormons would do. :)
  - PaulHoule 2y ago
    I'd imagine interstellar travelers who have mastered D+D fusion could break the journey down into hops of maybe 10,000 or 100,000 AU looking for large comets or plutoid objects which they could use to replenish their supplies. I'd imagine it would take them 10,000 years or so to make it to the next star system but they might not care if they can live a comfortable lifestyle in the great dark.
    - api 2y ago
      Something I didn’t think about: there is debate over how empty the space between stars is or whether there are a lot of rogue planets, comets, asteroids, maybe even exotic objects like asteroid or planet mass primordial black holes (these are a dark matter candidate). If the space between stars is not as empty as we imagine it opens other possibilities like flybys and refueling.
      - giantrobot 2y ago
        Interstellar space can be filled with junk yet still be effectively empty because it's so mind bogglingly large. Comets and rogue planets also aren't helpful unless 1) you can see/chart them ahead of time and 2) they're on the way to your destination. The first problem is a big challenge as they're cold, dark, and small. Just finding them to begin with is a giant problem. Accurately charting them is another order of magnitude increase in difficulty. Even tiny error bars in the measure of their proper motion means your spaceship can miss them by millions of miles. Even missing them by a dozen miles is the difference between life and death. Even with a huge catalog of extremely accurate interstellar fuel-capable objects they don't do you any good if they're not on the way to where you want to go. A meandering route to a destination in order to visit refueling stops adds tons of extra complexity and points of failure.
    - RajT88 2y ago
      Might I humbly recommend the disaster of a TV show "The Starlost".
      - 2y ago
- thechao 2y ago
  Even at .99c, everything interesting is years, decades, centuries, and millennia apart. All interstellar solutions include maintenance over millennia. Once you're doing that, relativistic velocity is just a hazard, not a boon. If we do conquer interstellar travel it'll probably be at 1% c. The factor of 10-20x scale won't matter to such long lived civilizations.
  - weberer 2y ago
    From the perspective of someone on the ground, yes. But due to time dilation, it could be just a few days for the people on the ship.
    - Sanzig 2y ago
      At .99c, the Lorentz factor is only about 7, so 1 year of ship time for 7 years of earth time.
    - brandall10 2y ago
      .99c only dilates time by a factor of 7, so one year of time passed on a vehicle would yield ~7 light years. Heck, you have to get better than 5 nines to even compress a year into a day, .9999963c, which would take a freakish amount of energy to accelerate a KG to (3.3 × 10^19 J).
      - Retric 2y ago
        On top of this at 1g it takes ~1 year accelerating to that speed and another year decelerating. So even the nearest star is going to be a multi year subjective journey or a really unpleasant trip.
        llm_trw 2y ago
        This is assuming that you have to be conscious during the trip. Antimatter storage is a lot more scifi than human hibernation.
- jmyeet 2y ago
  The energy budget for any kind of interstellar travel is large, almost incomprehensibly large. Like many orders of magnitude greater than what our entire planet produces and consumes. The numbers you're quoting seem reasonably accurate but they also assume perfect mass-to-energy conversion, which we'd never get. It's why some kind of generation ship, that is basically a colony, is really the only conceivable method of traveling between stars. Also remember that whatever energy is produced by antimatter, you need more than that to produce the antimatter to begin with. Where are you getting that energy? I believe it's from solar power from a Dyson Swarm.
  - mrybczyn 2y ago
    We just have to get creative, or discover some new physics :-) In addition to the ark-ship colony, or the cryosleep slow ship: 1. Assuming it's a stream of robotic probes doing flybys, without decelerating, we have the Breakthrough Starshot approach. Maybe there's a way to use the target system's sun for solar sail braking? Send smart enough robots that have agency, that can do the exploring for us. 2. For human travel - it could just be a bunch of frozen embryos with a robotic nursemaid, accelerated via external propulsion and decelerated via nukes / high-g aerobraking... (Raised by Wolves had a cool introduction like this in the first episode - then went quickly downhill) 3. ...
    - jmyeet 2y ago
      "we need new physics" basically means "I hope this isn't true". I get it. I think many of us would like to wander the stars in a reasonable timeframe but there's simply no evidence the Universe works this way. As for cryosleep, this curently seems unlikely but not impossible. For one thing, the decay of radioactive elements in your body (primarily Carbon-14) would give you about a lethal dose of radiation after about a century. Some organisms have natural antifreeze and other means of surviving low temperatures. We do not. Freezing water tears our cells to shreds. Cryobabies and artifical wombs are another vector. This is nontrivial too but also, woould you trust the automation? Some AI might have to raise humans hundreds or thousands of years in the future without any context of what's happened in that time. We might be able to communicate with such a ship and update it but should it trust such updates? You're also creating a whole bunch of people who haven't consented to never see Earth. Generation ships have this problem too to some degree. That has questionable ethics. As for using the target star to decelerate, that's entirely possible. It's just a solar sail. And that might be the only way we could do interstellar travel anyway because of the reaction mass problem. But solar sails can only accelerate so fast. Travel too fast and you might not have time to decelerate as well. So you're still looking at hundreds of years most likely. It really seems like we need radical life extension while maintaining quality of life to make these time frames reasonable (relatively). That actually does seem doable.
- benlivengood 2y ago
  Hopefully Von Neumann probes will be much lighter than a Kg and we can construct receiving stations on the other end and transport the information we care about back and forth directly at light speed.
- TOMDM 2y ago
  Which is to say nothing of the mass of whatever containment equipment would be necessary. For stop and go; we'd be looking at something that could deploy a dyson swarm, generate and contain its own antimatter and then go again right? I should play universal paperclips again.
- davedx 2y ago
  Yup the problem with antimatter propulsion is it’s still subject to the tyranny of the rocket equation. The only way to escape that is to leverage energy external to the vehicle, like laser pushed light sales or relativistic railguns. You just can’t be carrying your own fuel around for an interstellar trip.
  - vivzkestrel 2y ago
    would be real nice to have a small device in your pocket that works at nano scale and converts input matter into output antimatter. Like feed it rock powder and you get antimatter rock powder. Would be real nice such a device could be made
- pdonis 2y ago
  > there is a kind of relativistic Tsiolkovsky equation for mass-energy propulsion vehicles that carry their own fuel Yes, it's called the relativistic rocket equation. https://math.ucr.edu/home/baez/physics/Relativity/SR/Rocket/rocket.html https://math.ucr.edu/home/baez/physics/Relativity/SR/Rocket/...
- deleted 2y ago
  [deleted]
atulsnj 2y ago
I am just thinking out loud and stupid but this could be something like the Cold Fusion/LENR or be actually something useful.
- m463 2y ago
  If you could figure out production and storage of antimatter, space travel would be very different. I remember reading a Robert L Forward book where he described all this in great detail. EDIT: I think the book was "Indistinguishable from Magic" which was interesting science-wise but not compelling as a science fiction book. He also seems to have written about antimatter directly: "Mirror Matter: Pioneering Antimatter Physics"
  - ClumsyPilot 2y ago
    You can start by getting nuclear rockets to work And imattwr is at the end of a tech tree that we have not started
- adrian_b 2y ago
  While it may be fun to write a paper that attempts to analyze the feasibility of using antimatter for energy storage, in real life this does not have any chances to be done, except in a very distant future, like at least a century or more likely several centuries from now. The energetic efficiency of producing antimatter in order to store energy in it is well approximated by zero. Storing antimatter requires a huge volume and mass per the energy stored and it also requires a continuous power consumption, so long term storage would degrade the energetic efficiency even more. There are methods of producing energy that nobody knows how they could be done, like nuclear fusion without producing neutrons (aneutronic fusion), but which nonetheless have a chance to be realized that is much, much greater than discovering a method of producing antimatter with high efficiency and also solving the problems of long term storage and of harnessing the energy produced by annihilation as intense destructive radiation. For now, the only realistic research target for improving space propulsion in the next few decades is the use of nuclear fission reactors, which could allow travel inside the Solar System with much more acceptable durations.
wsintra2022 2y ago
Why would carbon emissions be an issue in space propulsion?
- BurningFrog 2y ago
  It could only be an issue for the launch.
- mmh0000 2y ago
  And where is the carbon in space supposed to go? It’ll just stay there forever contaminating the space whales. We, as a responsible and intelligent species, must develop clean and sustainable fuels to protect the space whales and our future generations.
- olddustytrail 2y ago
  [flagged]
- weberer 2y ago
  I guess its just a keyword they have to put in for grants/funding purposes.
int0x29 2y ago
> Spacecrafts can traverse the Solar System to reach nearby stars in span of days to weeks Is there something I'm missing here? Proxima Centauri is 4+ light-years from us and firmly out of the solar system.
- sedatk 2y ago
  Relativity?
  - prox 2y ago
    At the actual speed of light, that’s still 4 lightyears. If you mean how much time will pass for the traveler, that might be it yeah.
    - sedatk 2y ago
      Yes, that’s what I mean.
- bboygravity 2y ago
  Traverse the solar system to reach the nearby star (the sun) maybe?
- m463 2y ago
  That is just sort of an ambiguous sentence. How about this one though: At a constant acceleration of 1 g, a rocket could travel the diameter of our galaxy in about 12 years ship time, and about 113,000 years planetary time. If the last half of the trip involves deceleration at 1 g, the trip would take about 24 years. If the trip is merely to the nearest star, with deceleration the last half of the way, it would take 3.6 years. https://en.wikipedia.org/wiki/Space_travel_under_constant_acceleration https://en.wikipedia.org/wiki/Space_travel_under_constant_ac...
- sethev 2y ago
  From the perspective of someone on the spaceship, this is absolutely possible by the laws of physics. It's a common misunderstanding that the speed of light is like a highway speed limit that's enforced by the universe. In reality, it means that light always travels at the speed of light and that you can never observe an object traveling faster than that. However, a key part of relativity is that the laws of physics are the same in every reference frame. If you're on a ship with sufficient fuel, you can keep accelerating forever and cover vast distances. You'll never reach a point where the universe prevents you from accelerating. If it were otherwise, then relativity wouldn't be true - because there would be special rules that apply to people traveling at a certain speed. That's the whole point of relativity is there can't be such laws because there isn't a preferred reference frame in the universe! However, the more you accelerate away from the earth the longer time will have passed on earth if you turn around and come back. Here's a calculator you can play with: https://spacetravel.simhub.online https://spacetravel.simhub.online As an example, if you could accelerate at 9.8 m/s (same as gravity - so you could walk around the 'back' of the ship as if in earth gravity), then you could travel 50 light years in 7.7 'ship years'. However, if you turned around and went back to earth 102 years would have passed there, even though you would only be ~15 years older.
airstrike 2y ago
Helpful "high-res" graphical abstract: https://ars.els-cdn.com/content/image/1-s2.0-S2666202724004518-ga1_lrg.jpg https://ars.els-cdn.com/content/image/1-s2.0-S26662027240045...
- Aachen 2y ago
  I can't read the smallest text, not sure I'd call it high res (unless the quotes are for sarcasm maybe?)
  - airstrike 2y ago
    I thought the same, but they called it high-res, so I had to put it in quotes...
JoshTriplett 2y ago
Is there any fundamental law of physics that says if you want to turn mc^2 energy into mass, that you have to create particle/antiparticle pairs together? Or could you, theoretically, create exclusively antimatter, and we just don't have a known method of doing so? In theory, could you use mc^2 energy to create a mass m of antimatter, combine it with m matter (which is rather more readily available), get 2mc^2 energy back out, and repeat, effectively consuming matter to make energy?
- master_crab 2y ago
  IANAP (physicist, just an Engineer) but any sort of reaction like this is probably pretty hard to control so you won’t get twice the energy. Just like with combustion engines, you’re probably looking at some significant percentage loss (~50%?) in efficiency from various things. (I’m sure there are other things that would also hinder the 2x outlook you are asking about)
  - JoshTriplett 2y ago
    Yeah, as the article here notes, the energy released is effectively an explosion, and harnessing that energy into something more useful is a substantial challenge. As is the concept of turning energy into specific (anti-)matter, which we have no idea how to do at the moment. This is more a theoretical question of whether any law of physics makes this impossible (e.g. you can't create unpaired particles), or whether this is theoretically possible but it's difficult to get enough efficiency to make it net positive. (We currently haven't even gotten fusion to be reliably net positive; practicality is as always a set of concerns all its own.)
    - api 2y ago
      Project Orion style pusher plate nuclear pulse designs can handle turning big boom boom into space propulsion but as the parent said you are not 100% efficient.
      - JoshTriplett 2y ago
asdff 2y ago
It seems there's some hard physical limits with regard to taking matter and moving it somewhere via propulsion. However, I wonder if we could get to a point where rather than spending energy to move something someplace, we consider the energy to reform a given structure identically somewhere else. I assume at some distance there is a tipping point where you now save energy building that structure in situ vs the energy spent to move a structure elsewhere. And there are probably environments where it is cheaper still to create this structure vs others. I'm not sure how to establish a distant build site without actually reaching it in some way though, but maybe such a thing is resolved in time.
- refulgentis 2y ago
  The problem I have with teleportation is that it seems we're closer to being reference types than value types, so I'm not sure a rebuilding in situ would work for the cases we care about. For static objects, I'm not sure how you'd get past the constraint that at some point you want mass somewhere else, and it needs to be moved.
- thrance 2y ago
  You could totally (at least in theory) make a super-precise MRI scan of your brain at nanometer scale, send this data to wherever you want to go as a coherent beam of light (laser) and have the guy on the other hand rebuild your brain atom by atom. To the brain that would awake on the other side, the trip would have been instantaneous. Wether it's still you or someone else, ask philosophers.
jmyeet 2y ago
One should view antimatter propulsion or energy as the ultimate battery. Why? Because antimatter needs to be manufactured. There's no natural source to mine. So whatever energy you get out, you had to spend at least that (because of thermodynamics, it's really more) to make the antimatter in the first place. So where do you get that energy in the first place? Everything leads back to solar power. In this case, since we're talking about far-future tech, we return to what I consider the most likely path for humanity: the Dyson Swarm. This is the sort of thing you can do with a truly mind-bogglingly large energy budget. And this matters because the energy budget, regardless of the energy source, for interstellar travel, is so ridiculously large.
greesil 2y ago
Is this reputable journal?
Pingk 2y ago
To make 1 gram of antimatter, from E=mc^2, would take about 90 Terajoules. For reference, the atomic bomb that dropped on Hiroshima released about 60 Terajoules of energy. So you would need at least (and with the efficiency loss of production, much more than) 1.5 Little Boy atomic bombs worth of energy to make a single gram of antimatter.
- micw 2y ago
  Or vice versa you can store the energy of 1.5 little boy atomic bombs into a handy gram of antimatter ...
- mr_toad 2y ago
  The Sun outputs the energy equivalent of over 4 million tons of matter every second. The same as the energy of over a billion hydrogen bombs every second. Only a tiny amount reaches the Earth, and we use only a tiny amount of that. But if we could capture even a small percentage of the total energy of the Sun we could produce antimatter by the ton.
  - thebruce87m 2y ago
    I always liked the star gate universe (?) series where the ships skimmed the stars they passed to charge up. We’ve essentially got a bunch of EV chargers dotted around the universe, although galaxy to galaxy might have some range anxiety.
fnord77 2y ago
They need a proof-reader. There's several grammar problems in that paper that seem like common ESL errors.
- calibas 2y ago
  That actually lends credibility as it probably wasn't written by an AI.
Animats 2y ago
The paper doesn't seem to go into the reaction mass issue much. What are they using for reaction mass? And how do you aim the exhaust? With fission nuclear propulsion you run out of reaction mass long before you're out of energy. It's a few times better than chemical fuels, but not 10x better.
- peterburkimsher 2y ago
  The antimatter exhaust could be aimed by putting matter behind it, but it would erode the matter. Better to have it in an electromagnetic field (torus + magnetic monopole) so it doesn't touch the matter. Those electromagnets would need power too, so I guess a battery or RNG (nuclear) solution could be used. What concerns me most is the radiation risk of travelling close to light speed. Surely we'd pass by some ionising radiation, or weakly-interacting neutrinos. I suppose the only way to be sure is to build a prototype and try it.
  - Animats 2y ago
    > I suppose the only way to be sure is to build a prototype and try it. Not in our planet's back yard. Maybe behind the moon.
  - kelnos 2y ago
    > What concerns me most is the radiation risk of travelling close to light speed. Surely we'd pass by some ionising radiation, or weakly-interacting neutrinos. It's much worse than that. At those speeds, the cosmic background radiation would get blue-shifted to the point that you'd be constantly bathed in x-rays and gamma rays.
- ianburrell 2y ago
  It is possible to use antimatter directly but it sounds like that only uses the pions with magnetic nozzle. The main use of antimatter is to heat reaction mass. The advantage over nuclear rocket is that the "temperature" of antimatter is really high so the specific impulse can also be high. One advantage is that can change the amount of reaction mass to get more thrust or better efficiency.
kristianp 2y ago
This is only slightly less practical than a black hole starship. https://en.m.wikipedia.org/wiki/Black_hole_starship https://en.m.wikipedia.org/wiki/Black_hole_starship
credit_guy 2y ago
Their graph with thrust/impulse for various rocket technologies [1] has a huge omission: project Orion [2], a rocket propelled by nuclear bombs. Too bad, this is by far the most promising and technology-ready rocket propulsion idea we have for deep space travel. Antimatter propulsion is pie in the sky, nuclear bomb propulsion is something we can do within a decade if we wanted to. [1] https://ars.els-cdn.com/content/image/1-s2.0-S2666202724004518-gr1_lrg.jpg https://ars.els-cdn.com/content/image/1-s2.0-S26662027240045... [2] https://en.wikipedia.org/wiki/Project_Orion_(nuclear_propulsion) https://en.wikipedia.org/wiki/Project_Orion_(nuclear_propuls...
- zizee 2y ago
  If you like Project Orion, you might like to read about the Medusa Drive, which is a related, but probably more promising concept using a sail instead of a giant pusher plate. https://www.centauri-dreams.org/2012/07/20/medusa-nuclear-pulse-propulsion-and-the-sail/ https://www.centauri-dreams.org/2012/07/20/medusa-nuclear-pu... https://m.youtube.com/watch?v=DYuBt2nFG98 https://m.youtube.com/watch?v=DYuBt2nFG98
  - credit_guy 2y ago
    Medusa Drive is interesting, and so are lots of other space propulsion idea, like the nuclear light bulb [1], the direct fusion drive [2], the fission fragment rocket [3] or the pulse nuclear thermal rocket [4]. The difference is that Project Orion was actually funded, and some of the smartest nuclear scientists worked on it for a few years. Of course, they never built the actual rocket, but they carried out a tremendous amount of theoretical and experimental work. All other designs were only done on paper. For Project Orion, they put actual spheres coated in graphite next to nuclear bombs to see if they withstand the explosion, while being inside the fireball. They did, and Scott Manley covered this in one of his youtube videos [5] (see 9:30 where he mentions the Orion project). They got a little island from the Navy where they could carry explosive tests. They built a conventionally powered version of the rocket. They found out by accident that adding a bit of oil on the pusher plate reduces the ablation significantly. They did a lot of testing to see if the pusher plate can withstand the various stresses. When someone comes up with a new idea for interstellar travel, they spend a few days thinking of a few aspect of the design, and then they publish a paper or write a novel. For Project Orion, they hired Ted Taylor, one of the greatest minds in nuclear weapons design, and they also hired Freeman Dyson, one of the greatest minds in the world in general. [1] https://en.wikipedia.org/wiki/Nuclear_lightbulb https://en.wikipedia.org/wiki/Nuclear_lightbulb [2] https://en.wikipedia.org/wiki/Direct_Fusion_Drive https://en.wikipedia.org/wiki/Direct_Fusion_Drive [3] https://en.wikipedia.org/wiki/Fission-fragment_rocket https://en.wikipedia.org/wiki/Fission-fragment_rocket [4] https://en.wikipedia.org/wiki/Pulsed_nuclear_thermal_rocket https://en.wikipedia.org/wiki/Pulsed_nuclear_thermal_rocket [5] https://www.youtube.com/watch?v=by1xpy8ob8E https://www.youtube.com/watch?v=by1xpy8ob8E
calibas 2y ago
Short answer: it's not happening yet. > A general conclusion was drawn that antimatter technology and its development for propulsion is still in its theoretical stages.
schobi 2y ago
I recently learned about an activity at CERN. They try to transport antiprotons to a different site for better analysis. "BASE STEP" https://home.cern/news/news/experiments/base-experiment-takes-big-step-towards-portable-antimatter https://home.cern/news/news/experiments/base-experiment-take... Surprisingly, antimatter can be stored for months. They built a 2.5 ton storage box, ultra high vacuum and magnetic trap and a loading mechanism. In a first trial they loaded 70 protons and drove around the campus on a truck. Impressive that this is even possible. But with 2.56 * 10^-15 Wh/kg still orders of magnitude from current batteries.
- sampo 2y ago
  > They built a 2.5 ton storage box The article says 1000 kilograms, that is 1 ton.
  - bobmcnamara 2y ago
    1 tonne
    - lazide 2y ago
      Yeah, which works out to 2200 lbs, give or take. Sounds like someone (LLM) then treated lbs like KG to turn that into tonnes again? Dumb. Easy to do if not paying attention.
twwwt 2y ago
I think we need a complete paradigm shift in the concept of traveling. Instead of traveling mass we need to think about traveling of information, assuming that information traveling is not subject to the same laws of physics that mass is. I hope quantum mechanics will be key here such that some day it will allow an organism that is some combination of mass and information to let the information travel rather than both together. I.e., we need to find solutions to decouple the information from the mass and let the information travel while the mass remains at essentially the „same“ position in space. I think this could allow us instant interstellar traveling, maybe with some overhead of preparation and finalization in the range of minutes or hours, i.e. in the time scale of classic human traveling.
- TheSpiceIsLife 2y ago
  Is my understanding correct that light (electromagnetic radiation, the whole spectrum) arrives instantaneously from the light’s frame of reference? (in a vacuum, etc).
- thrw42A8N 2y ago
  If I don't change position, then I'm not traveling. Information about me is not me.
  - twwwt 2y ago
    Define „I“. Are you mass (obviously) and information? I'm talking about information that you „have“ in the sense of the one that is part, or maybe more importantly, makes up your mind. If we were able to entangle it with a (partial) information set somewhere else in space then we could achieve what I would call information traveling. And since at quantum level there seems to be something very similar, I hope this would allow us „traveling without mass“.
    - thrw42A8N 2y ago
      Entanglement doesn't mean information actually travels from point A to point B. Imagine it like tearing paper into 2 pieces without looking at it. Then both pieces are taken away. And then you look at the exact shape of the cut - and you know that the other piece of paper mirrors it exactly. There was no actual travel of information, you had it the whole time - you just looked at it when it was convenient. Quantum entanglement is nicer than that because it can also guarantee single usage (or the key doesn't work) but it's not a magical telecommunication channel, you still need radio/laser/...
XorNot 2y ago
No mention of chemical stabilisation that I can see which is what you'd really to do if we were bulk producing antimatter: the idea is you produce a crystal lattice into which an anti-particle can be injected where it stably orbits due to the internal charge configuration. There's some possible ideas for how to do it out there, but obviously we kind of lack enough antimatter to go experimenting.
ItCouldBeWorse 2y ago
I guess many countries on a budget look at this as a "cheap" nuke nowadays, something a few extra steps of physics could make easy reachable, without having to pay for the whole nuclear force "shebang". Thanks russia, thanks china, thanks usa - one world locked in a eternal Mexican standoff it is. Future generations are going to look at the collapse of Assads regime as the last "downfalls" without nail-biting. I wouldnt want to work at the IAA right now.
- talldayo 2y ago
  > I guess many countries on a budget look at this as a "cheap" nuke nowadays, something a few extra steps of physics could make easy reachable Countries on a budget do not have the resources to create a CERN-like accelerator. In a relative sense, building a nuke with enriched uranium is the "cheap" option compared to amassing enough antimatter for even a kiloton yield. > Thanks russia, thanks china, thanks usa - one world locked in a eternal Mexican standoff it is We've been in this spot since the 60s. Nukes got the ball rolling and ICBMs hammered in the idea that you cannot escape nukes if your enemy doesn't want you to. > Future generations are going to look at the collapse of Assads regime as the last "downfalls" without nail-biting. Perhaps if they all live under rocks. The past 10 years of the Syrian revolution were absolutely a nailbiter, with Assad torturing, systematically executing and mass-burying his own citizens and political opposition. There were stockpiles of chemical weapons, underground concentration camps and Putin could launch an missile attack or airstrike with a phone call and enough money offered. Syria's citizens only knew they were safe when Assad ran out of money. They suffered under Russia's oppression for 10 long years and thousands of people died horrific and unjust deaths. If anything, the fact that Assad was allowed to keep Syria this long is a condemnation of western diplomacy as a whole.
mmmBacon 2y ago
From Fermilab’s antimatter factory: Antimatter is the opposite of matter, with the same mass but opposite electric charge. It's considered the rarest, most expensive, and potentially most dangerous substance on Earth. One gram of antimatter costs around $62.5 trillion Sounds like we won’t be using antimatter for anything practical for a long time.

163 points by belter 2y ago

jp57 2y ago

I don't have references in front of me, (EDIT: I do!) but IIRC it takes about a kilogram of mass-energy to accelerate a kilogram mass to about 0.85c. But that kilogram would have to be carrying another kilogram of matter/anti-matter fuel to decelerate again. So there is a kind of relativistic Tsiolkovsky equation for mass-energy propulsion vehicles that carry their own fuel. Zipping around the galaxy at 0.95c, stopping at destinations and then zipping off again will require carrying a lot of antimatter with you. EDIT: Thanks to Wolfram Alpha I was able to see that it the kinetic energy of 1 kg at 0.87c is very close to the mass energy of 1kg of matter.

m463 2y ago
If you could avoid accelerating so much and go a little slower, you could get better lypkg.
- jp57 2y ago
  Sure, and if you want to go at non-relativistic speeds you hardly need to carry much fuel at all.
api 2y ago
This is why there’s ideas like the Bussard ramjet, which may not work but try to work around this problem by using in situ mass-energy. Now I have read that it may be possible to use a powerful magnetic field to assist with slowing down by braking against the interstellar medium, which helps. The Avatar films have (in spite of very derivative plots) fairly realistic (at least physics wise) interstellar ships. They accelerate using beamed laser propulsion from the Sun and use antimatter rockets to decelerate, then repeat this in reverse to come home. One assumes they somehow recharge at their destination but this is not shown. Too bad all that cool tech is in service to humans who decided to be the bad guys from War of the Worlds. Still traveling that close to c brings up tons of other problems. Collision with a micrometeorite would be like an atomic explosion, and blue shifting of incident and cosmic background radiation would blast you in the head with x-rays and gamma rays. Those problems would demand more mass for active or passive shielding, and you’re already mass constrained. All things considered it’s way more practical to go slower — which could still be insanely fast e.g. 0.25c — and figure out how to cryosleep or become an AI that can just turn yourself off for the trip. Cryosleep for humans is a brutally hard biomedical problem but way easier than trying to approach the speed of light. There are other multicellular animals that can do it, albeit much simpler ones, so it’s probably possible. 0.25c allowing for acceleration and deceleration gets you to Centauri in around 25 years and to further star systems with promising exoplanets in hundreds of years. Then there’s generation ships, but that’s the kind of thing Mormons would do. :)
- PaulHoule 2y ago
  I'd imagine interstellar travelers who have mastered D+D fusion could break the journey down into hops of maybe 10,000 or 100,000 AU looking for large comets or plutoid objects which they could use to replenish their supplies. I'd imagine it would take them 10,000 years or so to make it to the next star system but they might not care if they can live a comfortable lifestyle in the great dark.
  - api 2y ago
    Something I didn’t think about: there is debate over how empty the space between stars is or whether there are a lot of rogue planets, comets, asteroids, maybe even exotic objects like asteroid or planet mass primordial black holes (these are a dark matter candidate). If the space between stars is not as empty as we imagine it opens other possibilities like flybys and refueling.
    - giantrobot 2y ago
      Interstellar space can be filled with junk yet still be effectively empty because it's so mind bogglingly large. Comets and rogue planets also aren't helpful unless 1) you can see/chart them ahead of time and 2) they're on the way to your destination. The first problem is a big challenge as they're cold, dark, and small. Just finding them to begin with is a giant problem. Accurately charting them is another order of magnitude increase in difficulty. Even tiny error bars in the measure of their proper motion means your spaceship can miss them by millions of miles. Even missing them by a dozen miles is the difference between life and death. Even with a huge catalog of extremely accurate interstellar fuel-capable objects they don't do you any good if they're not on the way to where you want to go. A meandering route to a destination in order to visit refueling stops adds tons of extra complexity and points of failure.
  - RajT88 2y ago
    Might I humbly recommend the disaster of a TV show "The Starlost".
    - 2y ago
thechao 2y ago
Even at .99c, everything interesting is years, decades, centuries, and millennia apart. All interstellar solutions include maintenance over millennia. Once you're doing that, relativistic velocity is just a hazard, not a boon. If we do conquer interstellar travel it'll probably be at 1% c. The factor of 10-20x scale won't matter to such long lived civilizations.
- weberer 2y ago
  From the perspective of someone on the ground, yes. But due to time dilation, it could be just a few days for the people on the ship.
  - Sanzig 2y ago
    At .99c, the Lorentz factor is only about 7, so 1 year of ship time for 7 years of earth time.
  - brandall10 2y ago
    .99c only dilates time by a factor of 7, so one year of time passed on a vehicle would yield ~7 light years. Heck, you have to get better than 5 nines to even compress a year into a day, .9999963c, which would take a freakish amount of energy to accelerate a KG to (3.3 × 10^19 J).
    - Retric 2y ago
      On top of this at 1g it takes ~1 year accelerating to that speed and another year decelerating. So even the nearest star is going to be a multi year subjective journey or a really unpleasant trip.
      - llm_trw 2y ago
        This is assuming that you have to be conscious during the trip. Antimatter storage is a lot more scifi than human hibernation.
jmyeet 2y ago
The energy budget for any kind of interstellar travel is large, almost incomprehensibly large. Like many orders of magnitude greater than what our entire planet produces and consumes. The numbers you're quoting seem reasonably accurate but they also assume perfect mass-to-energy conversion, which we'd never get. It's why some kind of generation ship, that is basically a colony, is really the only conceivable method of traveling between stars. Also remember that whatever energy is produced by antimatter, you need more than that to produce the antimatter to begin with. Where are you getting that energy? I believe it's from solar power from a Dyson Swarm.
- mrybczyn 2y ago
  We just have to get creative, or discover some new physics :-) In addition to the ark-ship colony, or the cryosleep slow ship: 1. Assuming it's a stream of robotic probes doing flybys, without decelerating, we have the Breakthrough Starshot approach. Maybe there's a way to use the target system's sun for solar sail braking? Send smart enough robots that have agency, that can do the exploring for us. 2. For human travel - it could just be a bunch of frozen embryos with a robotic nursemaid, accelerated via external propulsion and decelerated via nukes / high-g aerobraking... (Raised by Wolves had a cool introduction like this in the first episode - then went quickly downhill) 3. ...
  - jmyeet 2y ago
    "we need new physics" basically means "I hope this isn't true". I get it. I think many of us would like to wander the stars in a reasonable timeframe but there's simply no evidence the Universe works this way. As for cryosleep, this curently seems unlikely but not impossible. For one thing, the decay of radioactive elements in your body (primarily Carbon-14) would give you about a lethal dose of radiation after about a century. Some organisms have natural antifreeze and other means of surviving low temperatures. We do not. Freezing water tears our cells to shreds. Cryobabies and artifical wombs are another vector. This is nontrivial too but also, woould you trust the automation? Some AI might have to raise humans hundreds or thousands of years in the future without any context of what's happened in that time. We might be able to communicate with such a ship and update it but should it trust such updates? You're also creating a whole bunch of people who haven't consented to never see Earth. Generation ships have this problem too to some degree. That has questionable ethics. As for using the target star to decelerate, that's entirely possible. It's just a solar sail. And that might be the only way we could do interstellar travel anyway because of the reaction mass problem. But solar sails can only accelerate so fast. Travel too fast and you might not have time to decelerate as well. So you're still looking at hundreds of years most likely. It really seems like we need radical life extension while maintaining quality of life to make these time frames reasonable (relatively). That actually does seem doable.
benlivengood 2y ago
Hopefully Von Neumann probes will be much lighter than a Kg and we can construct receiving stations on the other end and transport the information we care about back and forth directly at light speed.
TOMDM 2y ago
Which is to say nothing of the mass of whatever containment equipment would be necessary. For stop and go; we'd be looking at something that could deploy a dyson swarm, generate and contain its own antimatter and then go again right? I should play universal paperclips again.
davedx 2y ago
Yup the problem with antimatter propulsion is it’s still subject to the tyranny of the rocket equation. The only way to escape that is to leverage energy external to the vehicle, like laser pushed light sales or relativistic railguns. You just can’t be carrying your own fuel around for an interstellar trip.
- vivzkestrel 2y ago
  would be real nice to have a small device in your pocket that works at nano scale and converts input matter into output antimatter. Like feed it rock powder and you get antimatter rock powder. Would be real nice such a device could be made
pdonis 2y ago
> there is a kind of relativistic Tsiolkovsky equation for mass-energy propulsion vehicles that carry their own fuel Yes, it's called the relativistic rocket equation. https://math.ucr.edu/home/baez/physics/Relativity/SR/Rocket/rocket.html https://math.ucr.edu/home/baez/physics/Relativity/SR/Rocket/...
deleted 2y ago
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atulsnj 2y ago

I am just thinking out loud and stupid but this could be something like the Cold Fusion/LENR or be actually something useful.

m463 2y ago
If you could figure out production and storage of antimatter, space travel would be very different. I remember reading a Robert L Forward book where he described all this in great detail. EDIT: I think the book was "Indistinguishable from Magic" which was interesting science-wise but not compelling as a science fiction book. He also seems to have written about antimatter directly: "Mirror Matter: Pioneering Antimatter Physics"
- ClumsyPilot 2y ago
  You can start by getting nuclear rockets to work And imattwr is at the end of a tech tree that we have not started
adrian_b 2y ago
While it may be fun to write a paper that attempts to analyze the feasibility of using antimatter for energy storage, in real life this does not have any chances to be done, except in a very distant future, like at least a century or more likely several centuries from now. The energetic efficiency of producing antimatter in order to store energy in it is well approximated by zero. Storing antimatter requires a huge volume and mass per the energy stored and it also requires a continuous power consumption, so long term storage would degrade the energetic efficiency even more. There are methods of producing energy that nobody knows how they could be done, like nuclear fusion without producing neutrons (aneutronic fusion), but which nonetheless have a chance to be realized that is much, much greater than discovering a method of producing antimatter with high efficiency and also solving the problems of long term storage and of harnessing the energy produced by annihilation as intense destructive radiation. For now, the only realistic research target for improving space propulsion in the next few decades is the use of nuclear fission reactors, which could allow travel inside the Solar System with much more acceptable durations.

wsintra2022 2y ago

Why would carbon emissions be an issue in space propulsion?

BurningFrog 2y ago
It could only be an issue for the launch.
mmh0000 2y ago
And where is the carbon in space supposed to go? It’ll just stay there forever contaminating the space whales. We, as a responsible and intelligent species, must develop clean and sustainable fuels to protect the space whales and our future generations.
olddustytrail 2y ago
[flagged]
weberer 2y ago
I guess its just a keyword they have to put in for grants/funding purposes.

int0x29 2y ago

> Spacecrafts can traverse the Solar System to reach nearby stars in span of days to weeks Is there something I'm missing here? Proxima Centauri is 4+ light-years from us and firmly out of the solar system.

sedatk 2y ago
Relativity?
- prox 2y ago
  At the actual speed of light, that’s still 4 lightyears. If you mean how much time will pass for the traveler, that might be it yeah.
  - sedatk 2y ago
    Yes, that’s what I mean.
bboygravity 2y ago
Traverse the solar system to reach the nearby star (the sun) maybe?
m463 2y ago
That is just sort of an ambiguous sentence. How about this one though: At a constant acceleration of 1 g, a rocket could travel the diameter of our galaxy in about 12 years ship time, and about 113,000 years planetary time. If the last half of the trip involves deceleration at 1 g, the trip would take about 24 years. If the trip is merely to the nearest star, with deceleration the last half of the way, it would take 3.6 years. https://en.wikipedia.org/wiki/Space_travel_under_constant_acceleration https://en.wikipedia.org/wiki/Space_travel_under_constant_ac...
sethev 2y ago
From the perspective of someone on the spaceship, this is absolutely possible by the laws of physics. It's a common misunderstanding that the speed of light is like a highway speed limit that's enforced by the universe. In reality, it means that light always travels at the speed of light and that you can never observe an object traveling faster than that. However, a key part of relativity is that the laws of physics are the same in every reference frame. If you're on a ship with sufficient fuel, you can keep accelerating forever and cover vast distances. You'll never reach a point where the universe prevents you from accelerating. If it were otherwise, then relativity wouldn't be true - because there would be special rules that apply to people traveling at a certain speed. That's the whole point of relativity is there can't be such laws because there isn't a preferred reference frame in the universe! However, the more you accelerate away from the earth the longer time will have passed on earth if you turn around and come back. Here's a calculator you can play with: https://spacetravel.simhub.online https://spacetravel.simhub.online As an example, if you could accelerate at 9.8 m/s (same as gravity - so you could walk around the 'back' of the ship as if in earth gravity), then you could travel 50 light years in 7.7 'ship years'. However, if you turned around and went back to earth 102 years would have passed there, even though you would only be ~15 years older.

airstrike 2y ago

Helpful "high-res" graphical abstract: https://ars.els-cdn.com/content/image/1-s2.0-S2666202724004518-ga1_lrg.jpg https://ars.els-cdn.com/content/image/1-s2.0-S26662027240045...

Aachen 2y ago
I can't read the smallest text, not sure I'd call it high res (unless the quotes are for sarcasm maybe?)
- airstrike 2y ago
  I thought the same, but they called it high-res, so I had to put it in quotes...

JoshTriplett 2y ago

Is there any fundamental law of physics that says if you want to turn mc^2 energy into mass, that you have to create particle/antiparticle pairs together? Or could you, theoretically, create exclusively antimatter, and we just don't have a known method of doing so? In theory, could you use mc^2 energy to create a mass m of antimatter, combine it with m matter (which is rather more readily available), get 2mc^2 energy back out, and repeat, effectively consuming matter to make energy?

master_crab 2y ago
IANAP (physicist, just an Engineer) but any sort of reaction like this is probably pretty hard to control so you won’t get twice the energy. Just like with combustion engines, you’re probably looking at some significant percentage loss (~50%?) in efficiency from various things. (I’m sure there are other things that would also hinder the 2x outlook you are asking about)
- JoshTriplett 2y ago
  Yeah, as the article here notes, the energy released is effectively an explosion, and harnessing that energy into something more useful is a substantial challenge. As is the concept of turning energy into specific (anti-)matter, which we have no idea how to do at the moment. This is more a theoretical question of whether any law of physics makes this impossible (e.g. you can't create unpaired particles), or whether this is theoretically possible but it's difficult to get enough efficiency to make it net positive. (We currently haven't even gotten fusion to be reliably net positive; practicality is as always a set of concerns all its own.)
  - api 2y ago
    Project Orion style pusher plate nuclear pulse designs can handle turning big boom boom into space propulsion but as the parent said you are not 100% efficient.
    - JoshTriplett 2y ago

asdff 2y ago

It seems there's some hard physical limits with regard to taking matter and moving it somewhere via propulsion. However, I wonder if we could get to a point where rather than spending energy to move something someplace, we consider the energy to reform a given structure identically somewhere else. I assume at some distance there is a tipping point where you now save energy building that structure in situ vs the energy spent to move a structure elsewhere. And there are probably environments where it is cheaper still to create this structure vs others. I'm not sure how to establish a distant build site without actually reaching it in some way though, but maybe such a thing is resolved in time.

refulgentis 2y ago
The problem I have with teleportation is that it seems we're closer to being reference types than value types, so I'm not sure a rebuilding in situ would work for the cases we care about. For static objects, I'm not sure how you'd get past the constraint that at some point you want mass somewhere else, and it needs to be moved.
thrance 2y ago
You could totally (at least in theory) make a super-precise MRI scan of your brain at nanometer scale, send this data to wherever you want to go as a coherent beam of light (laser) and have the guy on the other hand rebuild your brain atom by atom. To the brain that would awake on the other side, the trip would have been instantaneous. Wether it's still you or someone else, ask philosophers.

jmyeet 2y ago

One should view antimatter propulsion or energy as the ultimate battery. Why? Because antimatter needs to be manufactured. There's no natural source to mine. So whatever energy you get out, you had to spend at least that (because of thermodynamics, it's really more) to make the antimatter in the first place. So where do you get that energy in the first place? Everything leads back to solar power. In this case, since we're talking about far-future tech, we return to what I consider the most likely path for humanity: the Dyson Swarm. This is the sort of thing you can do with a truly mind-bogglingly large energy budget. And this matters because the energy budget, regardless of the energy source, for interstellar travel, is so ridiculously large.

greesil 2y ago

Is this reputable journal?

Pingk 2y ago

To make 1 gram of antimatter, from E=mc^2, would take about 90 Terajoules. For reference, the atomic bomb that dropped on Hiroshima released about 60 Terajoules of energy. So you would need at least (and with the efficiency loss of production, much more than) 1.5 Little Boy atomic bombs worth of energy to make a single gram of antimatter.

micw 2y ago
Or vice versa you can store the energy of 1.5 little boy atomic bombs into a handy gram of antimatter ...
mr_toad 2y ago
The Sun outputs the energy equivalent of over 4 million tons of matter every second. The same as the energy of over a billion hydrogen bombs every second. Only a tiny amount reaches the Earth, and we use only a tiny amount of that. But if we could capture even a small percentage of the total energy of the Sun we could produce antimatter by the ton.
- thebruce87m 2y ago
  I always liked the star gate universe (?) series where the ships skimmed the stars they passed to charge up. We’ve essentially got a bunch of EV chargers dotted around the universe, although galaxy to galaxy might have some range anxiety.

fnord77 2y ago

They need a proof-reader. There's several grammar problems in that paper that seem like common ESL errors.

calibas 2y ago
That actually lends credibility as it probably wasn't written by an AI.

Animats 2y ago

The paper doesn't seem to go into the reaction mass issue much. What are they using for reaction mass? And how do you aim the exhaust? With fission nuclear propulsion you run out of reaction mass long before you're out of energy. It's a few times better than chemical fuels, but not 10x better.

peterburkimsher 2y ago
The antimatter exhaust could be aimed by putting matter behind it, but it would erode the matter. Better to have it in an electromagnetic field (torus + magnetic monopole) so it doesn't touch the matter. Those electromagnets would need power too, so I guess a battery or RNG (nuclear) solution could be used. What concerns me most is the radiation risk of travelling close to light speed. Surely we'd pass by some ionising radiation, or weakly-interacting neutrinos. I suppose the only way to be sure is to build a prototype and try it.
- Animats 2y ago
  > I suppose the only way to be sure is to build a prototype and try it. Not in our planet's back yard. Maybe behind the moon.
- kelnos 2y ago
  > What concerns me most is the radiation risk of travelling close to light speed. Surely we'd pass by some ionising radiation, or weakly-interacting neutrinos. It's much worse than that. At those speeds, the cosmic background radiation would get blue-shifted to the point that you'd be constantly bathed in x-rays and gamma rays.
ianburrell 2y ago
It is possible to use antimatter directly but it sounds like that only uses the pions with magnetic nozzle. The main use of antimatter is to heat reaction mass. The advantage over nuclear rocket is that the "temperature" of antimatter is really high so the specific impulse can also be high. One advantage is that can change the amount of reaction mass to get more thrust or better efficiency.

kristianp 2y ago

This is only slightly less practical than a black hole starship. https://en.m.wikipedia.org/wiki/Black_hole_starship https://en.m.wikipedia.org/wiki/Black_hole_starship

credit_guy 2y ago

Their graph with thrust/impulse for various rocket technologies [1] has a huge omission: project Orion [2], a rocket propelled by nuclear bombs. Too bad, this is by far the most promising and technology-ready rocket propulsion idea we have for deep space travel. Antimatter propulsion is pie in the sky, nuclear bomb propulsion is something we can do within a decade if we wanted to. [1] https://ars.els-cdn.com/content/image/1-s2.0-S2666202724004518-gr1_lrg.jpg https://ars.els-cdn.com/content/image/1-s2.0-S26662027240045... [2] https://en.wikipedia.org/wiki/Project_Orion_(nuclear_propulsion) https://en.wikipedia.org/wiki/Project_Orion_(nuclear_propuls...

zizee 2y ago
If you like Project Orion, you might like to read about the Medusa Drive, which is a related, but probably more promising concept using a sail instead of a giant pusher plate. https://www.centauri-dreams.org/2012/07/20/medusa-nuclear-pulse-propulsion-and-the-sail/ https://www.centauri-dreams.org/2012/07/20/medusa-nuclear-pu... https://m.youtube.com/watch?v=DYuBt2nFG98 https://m.youtube.com/watch?v=DYuBt2nFG98
- credit_guy 2y ago
  Medusa Drive is interesting, and so are lots of other space propulsion idea, like the nuclear light bulb [1], the direct fusion drive [2], the fission fragment rocket [3] or the pulse nuclear thermal rocket [4]. The difference is that Project Orion was actually funded, and some of the smartest nuclear scientists worked on it for a few years. Of course, they never built the actual rocket, but they carried out a tremendous amount of theoretical and experimental work. All other designs were only done on paper. For Project Orion, they put actual spheres coated in graphite next to nuclear bombs to see if they withstand the explosion, while being inside the fireball. They did, and Scott Manley covered this in one of his youtube videos [5] (see 9:30 where he mentions the Orion project). They got a little island from the Navy where they could carry explosive tests. They built a conventionally powered version of the rocket. They found out by accident that adding a bit of oil on the pusher plate reduces the ablation significantly. They did a lot of testing to see if the pusher plate can withstand the various stresses. When someone comes up with a new idea for interstellar travel, they spend a few days thinking of a few aspect of the design, and then they publish a paper or write a novel. For Project Orion, they hired Ted Taylor, one of the greatest minds in nuclear weapons design, and they also hired Freeman Dyson, one of the greatest minds in the world in general. [1] https://en.wikipedia.org/wiki/Nuclear_lightbulb https://en.wikipedia.org/wiki/Nuclear_lightbulb [2] https://en.wikipedia.org/wiki/Direct_Fusion_Drive https://en.wikipedia.org/wiki/Direct_Fusion_Drive [3] https://en.wikipedia.org/wiki/Fission-fragment_rocket https://en.wikipedia.org/wiki/Fission-fragment_rocket [4] https://en.wikipedia.org/wiki/Pulsed_nuclear_thermal_rocket https://en.wikipedia.org/wiki/Pulsed_nuclear_thermal_rocket [5] https://www.youtube.com/watch?v=by1xpy8ob8E https://www.youtube.com/watch?v=by1xpy8ob8E

calibas 2y ago

Short answer: it's not happening yet. > A general conclusion was drawn that antimatter technology and its development for propulsion is still in its theoretical stages.

schobi 2y ago

I recently learned about an activity at CERN. They try to transport antiprotons to a different site for better analysis. "BASE STEP" https://home.cern/news/news/experiments/base-experiment-takes-big-step-towards-portable-antimatter https://home.cern/news/news/experiments/base-experiment-take... Surprisingly, antimatter can be stored for months. They built a 2.5 ton storage box, ultra high vacuum and magnetic trap and a loading mechanism. In a first trial they loaded 70 protons and drove around the campus on a truck. Impressive that this is even possible. But with 2.56 * 10^-15 Wh/kg still orders of magnitude from current batteries.

sampo 2y ago
> They built a 2.5 ton storage box The article says 1000 kilograms, that is 1 ton.
- bobmcnamara 2y ago
  1 tonne
  - lazide 2y ago
    Yeah, which works out to 2200 lbs, give or take. Sounds like someone (LLM) then treated lbs like KG to turn that into tonnes again? Dumb. Easy to do if not paying attention.

twwwt 2y ago

I think we need a complete paradigm shift in the concept of traveling. Instead of traveling mass we need to think about traveling of information, assuming that information traveling is not subject to the same laws of physics that mass is. I hope quantum mechanics will be key here such that some day it will allow an organism that is some combination of mass and information to let the information travel rather than both together. I.e., we need to find solutions to decouple the information from the mass and let the information travel while the mass remains at essentially the „same“ position in space. I think this could allow us instant interstellar traveling, maybe with some overhead of preparation and finalization in the range of minutes or hours, i.e. in the time scale of classic human traveling.

TheSpiceIsLife 2y ago
Is my understanding correct that light (electromagnetic radiation, the whole spectrum) arrives instantaneously from the light’s frame of reference? (in a vacuum, etc).
thrw42A8N 2y ago
If I don't change position, then I'm not traveling. Information about me is not me.
- twwwt 2y ago
  Define „I“. Are you mass (obviously) and information? I'm talking about information that you „have“ in the sense of the one that is part, or maybe more importantly, makes up your mind. If we were able to entangle it with a (partial) information set somewhere else in space then we could achieve what I would call information traveling. And since at quantum level there seems to be something very similar, I hope this would allow us „traveling without mass“.
  - thrw42A8N 2y ago
    Entanglement doesn't mean information actually travels from point A to point B. Imagine it like tearing paper into 2 pieces without looking at it. Then both pieces are taken away. And then you look at the exact shape of the cut - and you know that the other piece of paper mirrors it exactly. There was no actual travel of information, you had it the whole time - you just looked at it when it was convenient. Quantum entanglement is nicer than that because it can also guarantee single usage (or the key doesn't work) but it's not a magical telecommunication channel, you still need radio/laser/...

XorNot 2y ago

No mention of chemical stabilisation that I can see which is what you'd really to do if we were bulk producing antimatter: the idea is you produce a crystal lattice into which an anti-particle can be injected where it stably orbits due to the internal charge configuration. There's some possible ideas for how to do it out there, but obviously we kind of lack enough antimatter to go experimenting.

ItCouldBeWorse 2y ago

I guess many countries on a budget look at this as a "cheap" nuke nowadays, something a few extra steps of physics could make easy reachable, without having to pay for the whole nuclear force "shebang". Thanks russia, thanks china, thanks usa - one world locked in a eternal Mexican standoff it is. Future generations are going to look at the collapse of Assads regime as the last "downfalls" without nail-biting. I wouldnt want to work at the IAA right now.

talldayo 2y ago
> I guess many countries on a budget look at this as a "cheap" nuke nowadays, something a few extra steps of physics could make easy reachable Countries on a budget do not have the resources to create a CERN-like accelerator. In a relative sense, building a nuke with enriched uranium is the "cheap" option compared to amassing enough antimatter for even a kiloton yield. > Thanks russia, thanks china, thanks usa - one world locked in a eternal Mexican standoff it is We've been in this spot since the 60s. Nukes got the ball rolling and ICBMs hammered in the idea that you cannot escape nukes if your enemy doesn't want you to. > Future generations are going to look at the collapse of Assads regime as the last "downfalls" without nail-biting. Perhaps if they all live under rocks. The past 10 years of the Syrian revolution were absolutely a nailbiter, with Assad torturing, systematically executing and mass-burying his own citizens and political opposition. There were stockpiles of chemical weapons, underground concentration camps and Putin could launch an missile attack or airstrike with a phone call and enough money offered. Syria's citizens only knew they were safe when Assad ran out of money. They suffered under Russia's oppression for 10 long years and thousands of people died horrific and unjust deaths. If anything, the fact that Assad was allowed to keep Syria this long is a condemnation of western diplomacy as a whole.

mmmBacon 2y ago

From Fermilab’s antimatter factory: Antimatter is the opposite of matter, with the same mass but opposite electric charge. It's considered the rarest, most expensive, and potentially most dangerous substance on Earth. One gram of antimatter costs around $62.5 trillion Sounds like we won’t be using antimatter for anything practical for a long time.