As far as colonizing the galaxy goes. I don't have the exact numbers of the milky way in my head anymore, but wouldn't it be possible for humans to just go from planet to planet slowly if we were capable of moving around close to the speed of light?
You can't just jump to the speed of light. You need to accelerate large amounts of mass to 99% the speed of light - it takes INCREDIBLE amounts of energy (E=MC^2 and we know what a large number C is).
Currently, the slowest form of propulsion, and the most fuel-efficient, is the ion engine. For the first half of your journey you would be pressed into your seat by acceleration, then the second half you would be turned around and pressed into your seat by deceleration. I guess we would probably need to be unconscious.
Proxima Centauri is the nearest star, and it is ONLY 4.24 light years away.
So if ionic propulsion were to be used for a mission to Proxima Centauri, the thrusters would need a huge source of energy production (i.e. nuclear power) and a large quantity of propellant (although still less than conventional rockets). But based on the assumption that a supply of 81.5 kg of xenon propellant translates into a maximum velocity of 56,000 km/hr (and that there are no other forms of propulsion available, such as a gravitational slingshot to accelerate it further), some calculations can be made.
In short, at a maximum velocity of 56,000 km/h, you would take over 81,000 years to traverse the 4.24 light years between Earth and Proxima Centauri. To put that time-scale into perspective, that would be over 2,700 human generations.
In short, at a maximum velocity of 56,000 km/h, you would take over 81,000 years to traverse the 4.24 light years between Earth and Proxima Centauri. To put that time-scale into perspective, that would be over 2,700 human generations.
Our Galaxy is 980,000 light years across. :/
