Question: is it possible to use comets to through us out of the Suns orbit to avoid the heat of its rays in a couple billion years?

James Pope answered on 11 Mar 2015:

Hi Harry,
So, the Sun is soon to expand and scorch the Earth (as in the Doctor Who episode in 2005) and we lack the ability to fly spaceships away from it, but only the short distance to a comet.

We have landed on a comet, this year the Philae lander launched by the European Space Agency a decade ago, landed, bounced then landed on the surface of the 67P comet. So we can get to a comet and hitch a lift.

While we are in our solar system and near the sun, we would get light from the sun so we could use solar power to heat and power our survival capsule that we are using for the journey, so at first we would be fine. But as we exited the solar system we would lose the light and therefore we would lose the energy.

So, to put your plan into action, we would need a way of making energy with only a limited amount of supplies. If we could find a way to generate energy, our next issue would be water. Most comets are made of ice and rock, so if we could use this ice without destabilsing the comets structure, then we would have water and we could grow food from seeds, we’d have to be vegeitarians though!

So in summary, there are some tricky technical challenges, but I guess in theory it could be possible, with the right comet. However, I think that even the biggest comet would only support a small colony of humans escaping Earth.