Mars has about 30% of the gravity of the earth. hence, if you stayed on Mars for a long time, your muscles and bones would weaken. eventually, you would be in a state that would make it very difficult to return to the earth. Or would you adapt after a few years?
Drudge reports that over 200,000 people have expressed interest in moving to Mars-I find this amazing. Life there would be pretty boring , I would imagine.
The real questions are things that cannot be resolved via experiments we can even perform at all.
For example, supposedly some very nasty long term microgravity effects include retinal detachment, as well as the bone marrow loss problems.
Those problems are bad enough (if the astronauts eventually go blind, well, you’re basically hosed) but the real problem is that we don’t actually know if 1/3 G is enough to prevent them.
There’s no way to test this with existing facilities and tech- no environment exists anywhere where there’s only 1/3 G. You’d have to do something like build a big centrifuge module on the ISS and test people inside it for years.
You mean like Texas?
It ain’t the kind of place to raise your kids.
And there’s no reason we couldn’t do that, except that for various political reasons, the ISS has turned into a thing that exists only for its own sake. We don’t have a centrifuge on the ISS, because the purpose of the ISS is to test the effect of zero gravity on humans and other systems. Why do we want to test the effects of zero gravity on humans? So we can put them in space on zero-g space stations. Why are the space stations zero-g? Because they don’t have centrifuges, and so on.
As it is, though, the longest any humans have ever been in a fractional-g environment is the few days the astronauts spent on the Moon.