[buboard]

It takes the same amount of energy to accelerate at any speed in space. The limit is our determination really, it is possible to visit our nearby star with ~200 hydrogen bombs

[majewsky]

No it doesn't. Your mass increases the faster you go, so that more and more energy needs to be expended to accelerate more. At 50% light speed, you're 15% heavier. At 90% light speed, you're 129% heavier. At 99% light speed, you're 608% heavier. Your mass goes to infinity as you approach the speed of light, which is why the speed of light is unattainable for objects that have mass.

[buboard]

right i assumed low-relativistic speeds. also i got the number of bombs wrong, it's 300.000 not 200. Here's the relevant pbs video

https://www.youtube.com/watch?v=EzZGPCyrpSU

[adrianN]

And objects that have to carry their own fuel have problems even at much lower speeds.

[adrianN]

It doesn't take the same amount of energy to accelerate (and later brake) to 0.5c as it does to accelerate to 0.1c.

[garmaine]

0.1c would be sufficient for a single generation ship.

[adrianN]

Depends on where you want to go. The universe is a pretty big place.