3 ms·

Furtunately, once you leave the sun's gravitational pull (enough), you can accelerate at a constant rate. So "even" if you accelerate at 0.1g, you can reach 0.7

Furtunately, once you leave the sun's gravitational pull (enough), you can accelerate at a constant rate. So "even" if you accelerate at 0.1g, you can reach 0.7c in 100 years. So if we had such an engine and an energy source, we could get to that planet in 200-300 years. The cool thing is, technology innovations are accelerating as well, so we will develop better engines faster than the old ones will arrive to the destination. It's a cool race.

avar 16y ago
You might not need an engine on the craft, just a big reflector and a tightly focused beam on some planetary body that bombarded it with photons. The problem then would be slowing down at the other end though.
- hugh3 16y ago
  Fire a mirror off ahead of you?
  - Zaak 16y ago
    In the book Rocheworld, they do just that. The light sail splits in two, with the outer portion curving to reflect light from the propulsion laser back onto the inner portion to slow down the ship.
StavrosK 16y ago
> The cool thing is, technology innovations are accelerating as well, so we will develop better engines faster than the old ones will arrive to the destination. So all we have to do is wait long enough, and at some point we will have already gotten there.
jared314 16y ago
> The cool thing is, technology innovations are accelerating as well, so we will develop better engines faster than the old ones will arrive to the destination. The plot of Lost In Space (1998) contained that premise.
- chasingsparks 16y ago
  (As did, to a degree, the conclusion of Ender's Game.)
  - dctoedt 16y ago
    And Robert A. Heinlein's 1956 http://en.wikipedia.org/wiki/Time_for_the_Stars http://en.wikipedia.org/wiki/Time_for_the_Stars, one of his "juveniles" that I liked as a teenager.