Comment by sheepscreek 4 days ago
Not with light speed travel. At even 1% the speed of light, the travel time diminishes significantly:
- Titan, Io and Ganymede are only 2.5 days away - Pluto is about 23 days
Edit: Even at such speeds, we still can’t visit a nearby star system in a reasonable time-frame. Oh well.
Doesn't this depend on the initial distance to the destination? I'm thinking you have to be going ~140M light-years for cosmic expansion to exceed 1%c, and Proxima Centauri is only ~4 light-years away
There's nothing about 0.1c or even 0.999c travel that's detrimental to meatbags. They would both feel exactly the same to the traveler. If your (for now) imaginary rocket could accelerate at a constant, gentle 1G, you could reach 0.1c in about a month (traveler's time), and you could reach 0.999c in about 44 months. Building and fueling such a rocket is the hard part.
It depends on how you define the bounds of the Solar System, but eg. a flight from Pluto at its most distant to the same distance on the opposite side of the sun that hits .1C at peak needs ~5G for the entire duration. And it seems quite wasteful to bother getting up to speed before immediately reversing the acceleration.
If you're travelling between points in the Oort Cloud, 1G should be more than sufficient to hit .1c on the trip.
My point was that the GP talked about flight times assuming instantaneous acceleration and deceleration. Also, 1G of acceleration sustained over a month is more or less impossible for meatbag-sized spacecraft, especially if you need to also accelerate all the fuel you’ll need to decelerate. The rocket equation is simply way too brutal. Something like nuclear pulse propulsion might come close. Or antimatter propulsion if we’ll ever be able to create and store entire moles worth of antimatter.
As time passes, the universe is expanding infinitely in every direction from every point.
Even if we could travel at 1 percent the speed of light, the "destination" would be inflating away from us at much greater relatavistic speed.
To your point, this is less an issue with solar or extra solar objects.