Why do astronomers think mars would be a good place to visit and perhaps live?

Answer 1

Nobody ever suggested that Mars would be a "good" place to visit or live.

But the fact is that if we ever reach the point where it's physically and financially
practical to land people on an alien (non-Earth) planet, and if there's ever a good
reason to do that, then Mars is the first one we're going to be able to head for.

Venus is closer, but the surface of Venus is like living inside a pottery kiln and
breathing sulfuric acid, so it's been moved down on the priority list.

In any case, it's going to be quite a while yet. So far, we've been able to land 24 people
on the moon, so you might think that we're ready to just take a slightly different route
and go to Mars instead. Actually, there's a little more to it:

-- Nobody has been to the Moon in over 40 years now.

-- The farthest from Earth that anybody has been since then ... the people who flew the
Space Shuttle or spent time on the International Space Station, never got farther than
about 0.0013 of the distance to the moon.

-- The closest that Mars ever gets to us is about 190 times farther than the distance to the
Moon, and for a good part of every year it's as much as 580 times as far ! (And the first
people who visit Mars will probably want to be able to come back.)

-- Science-wise, the machines we've been sending to Mars have been doing a faster and cheaper
job than human people, they're getting better and better, and have no interest in coming back.