Originally Posted by
The Atheist
I suspect whoever wrote that was fooling with you.
Proxima Centauri is roughly 5 light years, or 47 trillion km distant.
To reach there in 50 years would need a speed of 10% of the speed of light.
Light travels at about a billion km an hour, so we would need to be travelling at 100,000,000 km/h.
Given that current technology only allows us to travel at ~50,000 km/h, we haven't got a clue as to what kind of propulsion might be needed to attain that kind of speed. You can't make rockets go faster by building them bigger, so it's impossible to put an energy value on the question. Whether humans could withstand being propelled 20,000 times faster than ever before is moot.
Even the escape velocity of the sun (sorry to pour cold water on Mr Spock) is a measly 2,000,000 km/h, still only 2% of the speed needed to get to Proxima Centauri in time for the half-century party.