[Myto]

You could get to the nearest star in a few years and to the other side of the galaxy well within a human lifetime with "just" constant 1 g acceleration. Obviously this is far from easy but it doesn't seem like it is necessarily out of reach given a few thousand more years of continued technological development.

[aardvark179]

The quotes you put round just are doing a lot of heavy lifting. If you had a perfect photon rocket you’d only need 1000000000 kg of fuel for each kg of payload to do 1g to the centre of our galaxy and slow down again.

Okay, maybe you can use a laser or something so you don’t have to carry the fuel with you, but you’ll still need a staggering amount of energy because the rocket equation is a harsh mistress, and the relativistic version is even worse.

[actually_a_dog]

Yes, and there are at least 76 stars (i.e. potentially interesting destinations) within 100 light years of us [0]. So, assuming you can set an arbitrary course at 0.95c, and decelerate without turning the humans inside your ship to organic goo, you can reach quite a few interesting places.

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[0]: http://www.solstation.com/stars3/100-as.htm