[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.