Resolves YES when humanity becomes aware of any spaceship travelling at >10% of the speed of light (either domestic or alien origin)
Resolves no in 9999 but it could be re-resolved if we meet aliens after 9999 and they say they were totally doing that before 9999.
from comments: "“A spaceship, at the bare minimum, has to contain either a computer or a brain, and some capability for receiving and transmitting signals intelligently. So a bullet or a relativistic jet is not a spaceship.”
By the classical tsiolkovsky equation, a 95% fuel ship has to have an effective exhaust velocity of 1/3 of its final velocity. Protons at c/30 have an energy around 1 MeV. Meaning they'd have to be accelerated through a million volt potential in an ion drive. Or 2+ million volts if we're dealing with heavier atoms that have neutrons. That seems challenging from an engineering standpoint but perhaps doable. Plenty of materials with a dielectric strength >50Mv/m
@RobertCousineau I wouldn't say the below is truly a truly a crux as I don't think fusion is required for this to be likely (although it definitely does make it more likely), but it is a strong characteristic disagreement.
I added a new 10k Yes limit at 66%.
@JonathanRay and if you want to protect it with a magnetic deflector there are problems:
1. a lot of the interstellar medium is neutral hydrogen
2. deflector drag scales as the square of ship radius, but available fuel scales as the cube of ship radius, so this probably doesn't work at small scales.
it might be feasible with fission powered ion drive to get enough delta-v to transfer to a highly elliptical orbit around the milky way which passes close enough to the supermassive black hole to reach 10% c -- if the ship isn't destroyed by radiation or collisions with debris in that high density zone first
@JonathanRay This makes no sense. Here’s a very obvious counter-example (I guess it’s only a 1500x increase but it’s also only in about 130 years, vs 8000 in this market)
@benshindel there were a lot of low hanging fruit when cars were first invented and most of that increase on the log scale was frontloaded in the first 20 years
@JonathanRay Space travel was making that kind of rapid progress in the 1950s but it's been a mature industry for half a century
@benshindel if it is capable of sending us a message from alpha centauri, yes. I doubt anything that small could hold an adequate transmitter.
Project Daedalus, with 70's (expectation of) very plausible tech, was estimating it probable to get up to around .12c using a fusion rocket.
https://en.wikipedia.org/wiki/Project_Daedalus
a potential crux: https://manifold.markets/JonathanRay/dark-matter-used-as-reaction-mass-b
@JonathanRay some way of interacting with dark matter efficiently to push it around would make this a zillion times easier because then you don't have to carry all the reaction mass with you.
@JonathanRay Ridiculously easy. If you don't need to throw away reaction mass to accelerate, it's just a matter of dumping energy into your motor. For example, at 100% drive efficiency, a 100 ton craft with a 1 Gigawatt reactor could reach .1 c in ~41 years. Adjust for whatever efficiencies your drive might have and how good a reactor we might have once such a thing would be discovered. For many values, the time required is quite short.
Still voting No on that question though. I think dark matter really only interacts with gravity, and there's no way we're getting some kind of gravity-wave-ramscoop in 100 years.
Yes on this question though. 9999 is a long time to build Project Daedalus.