How quickly could humankind colonize 10 nearest star systems?

Just as soon as we can solve the problem of only going 20 times slower than 1 tenth the speed of light, our fastest speed to date. Sadly, the ability for humans to send humans to other stars will most likely never happen.

How close are we to commercialising space travel? 

We have already commercialized space travel. Private companies are now being paid to resupply the International Space Station on a regular basis, and commercial companies are hiring SpaceX, another commercial company, to place satellites into orbit.

spacex-falcon-heavy-elon-musk-china-europe-esa-nasa-mars-sls-boeing

If aliens in our galaxy are exponentially super advanced, why have they not completely colonized the entire Milky Way by now?

Well, let’s not put the cart before the horse. Right now we don’t know for sure that any life exists anywhere other than Earth. We suppose it does by mathematical calculations, but we haven’t even found a fossil of a microbe from space.

Secondly, suppose there is some super advanced civilization (your use of “exponentially” doesn’t seem to make any sense), the reason they probably haven’t completely colonized the entire Milky Way Galaxy is that for them, as for us, the laws of physics make it pretty much impossible to achieve interstellar travel because of the vast distances involved. And even if they could colonize some surrounding systems by now, it would take light and radio waves 100,000 years to reach us from the other side of the galaxy.

Perhaps human race’s home was not Earth in the first place, but in another planet, and we came here to prevent extinction

Mechanical, intentional interstellar travel is unlikely since the distances are far too great to imagine. The best anyone could achieve is interplanetary travel within one’s own solar system. Therefore, if we pass the buck and say life didn’t start here but started somewhere else and arrived here, it would have had to arrive on a rock or asteroid as a microbe and somehow survive a fiery entry through Earth’s atmosphere and it would have had to survive the vacuum and temperature extremes of space. If the rock came from outside the solar system it would have had to survive a long, long time.

Would you rather live on Mars or on the Moon?

Since both the Moon and Mars would require a carefully constructed closed airtight environment or else people will die, I’d take the Moon because it’s easier to leave the Moon and go back to Earth if something starts to go wrong. On the other hand, it’s not so easy to leave Mars and go back to Earth.

Partial lunar eclipse
I took this photo from the street in front of my house in Amarillo, Texas, during a partial lunar eclipse. You can see the upper left corner of the moon is darker. The green light in the foreground is a streetlight on Pagoda Drive, Amarillo.

When is the next time a human will walk on the moon?

After awhile, walking on the moon got old. It cost a whole lot of money and there wasn’t much to do there. The Vietnam war was sucking the budget. We were sending men up there to kick around the dust and rocks, drive rovers around, and it – as I said – cost a lot. Can you give me a good reason to go back?

If Mars were somehow pulled into the Goldilocks zone, and assuming it was not on a collision course with the Earth, could it be rendered habitable?

My opinion about Mars is evolving, it would seem.

I used to think it was useless for us to go to Mars, and it still is. However, what’s changing is that we are going to go to Mars anyway, and that’s really kind of a revelation that we will eventually become a multi-planet species.

The problem with Mars, I think, is it’s too small.

The size of the planet means two things: one, the planet’s central core cooled off early on it its history, essentially destroying the magnetic field of the planet, and two, without enough gravity you’d need at atmosphere much deeper than Earth to achieve the same pressure.

There’s a third problem, too. No nitrogen to speak of.

These problems would not be solved by dragging the planet closer to the sun. It is basically, as far as we can tell, a dead planet.