Comment by jballanc | Hacker News Reader

Comment by jballanc | Hacker News Reader

Parent Full thread

Even at 50% the speed of light, adding in a fudge factor for acceleration/deceleration, you're still talking about a trip time of 50 yrs. Even if you go all Neon Genesis and send 15 year olds on the journey, they'll be at retirement age by the time they arrive.

In other words, you'd almost definitely have to send a generation ship. Which means you'd have to have already figured things like artificial gravity, giving birth and raising children in space, etc. It wouldn't be too hard to imagine taking earth values for day/night and gravity, and then gradually over 50 years adjusting them so that, by the time you arrive, you'd have acclimatized to those values on the new world.

Also, nuclear sub crews live 18 hour days, so it's definitely doable.

Interestingly, while on earth 50 years will have elapsed, because of time dilation on the ship only about 40 years will have elapsed. It will get exponentially closer to 0 elapsed time as the speed approaches c. At 90% c only about 20 years will have elapsed [1]. Equivalently, as the travelers approach c, the distance to the destination will appear shorter.

[1] disclaimer: I didn't do the math, i just googled the tables.

The math is actually quite simple to do yourself, your dilation factor is just 1 / sqrt(1-x^2), where x is a percentage of c from 0 to 1. So at 0c, your factor is 1 (obviously), at .5c it's 1.15, and at .9c it's 2.294.

Divide the elapsed time in the stationary reference frame by the dilation factor and you get values that roughly agree with yours.

Of course at 0.9c, the non dilated travel time is 22 years, brought down to less than 10 years due to time dilation.

oh, yes of course, going faster you would obviously arrive earlier even in earth frame of reference :)

We can call it "The B Ark".

But I don't want to die from a disease contracted from a dirty telephone!

Send robots with a genome database so that they can regenerate and raise humans at the end phase of the trip. Or just cut out the humans altogether and let the machines be our legacy.

There's also time dilation but not much at that speed.

Some kind of sleep hibernation tech, might make it possible to kind of stop or dramatically slow down aging.

Reply on news.ycombinator.com