35 minutes ago, Strange said:

Unless you want to end up millions of miles away!

Yes, it's a different story if you want to get to Mars, say. It would be theoretically possible to accelerate at 9.81 m/s²  for half the trip, and then turn around and point the other way, and decelerate at the same rate for the other half to slow down. The problem is the huge amounts of fuel that would take, as mentioned above. So they will probably send a spinning ship, and work out how to cope with the effects of accelerating that, and slowing it down. Or, the travellers would have to be weightless for a long time on a non-spinning ship, which would affect their health.

Edit: There's loads more of this on the "What does it take to create a planet" thread, in the same section of modern physics :     

 

Edited January 10, 20187 yr by mistermack

19 hours ago, Raider5678 said:

"Additionally, you'd stop accelerating at 9.81 m/s within a hundred days, long before you reached even 1/3rd the speed of light because the exhaust from the engines would no longer be moving faster then you're moving away from it, resulting in less and less thrust the closer you got to exhaust velocity."

Day 100: I've escaped the Exhaust, I'm now moving faster than it, but if I slow down they'll catch me again. Those days were torturous, I'm so glad I got away.