Colonies on the Moon

 We're about to go back to the moon for the first time since the 1970s, with the aim of having permanently occupied colonies.  Will this lead to people living their lives entirely on the moon?  Perhaps, but I don't think that will happen for a long time, if ever.  Sure, once we have enough people up there, life happens and some of them will die, and probably a few will be born.  But there are a lot of reasons the moon is not a good place for "settlements" as opposed to scientific research operations.

There are plenty of reasons a colony on the moon will be useful.  For example, radio noise from earth will be sharply reduced on the "back side" of the moon, the side that permanently faces away from earth.  This makes it an excellent place to install radio telescopes, includeing massive interferometers and gravity wave detectors.  But these things will operate almost entirely remotely.  The people who do construction and maintenance will live elsewhere--while on the moon, most likely deep underground.

Because the moon is well outside the protective magnetic field of the earth, people staying on the moon will be exposed to high levels of cosmic rays and other radiation, as well as high level of micrometeorite impacts.  People will need to live inside thick shells.  They can venture out inside thinner shells for a few hours, but they are taking a risk.  The lunar astronauts of the 1970s received a level of exposure comparable to a few medical X-Rays from that period, but the longest of them was only outside the earth's protection for 12 days.  People working outside for months on end will get sick.  They must spend as much of their time as possible deep underground, and when they need to be close, mostly do it from heavily shielded vehicles. 

The second problem is low gravity.   Our experiments so far have shown that exposure to microgravity does permanent damage.  The moon is not microgravity, but it is 1/6th of the earth's.  It's hard to imagine that not causing some damage.   One year is really too much for a human to be in zero G.  Let's guess it's 6 years for the moon.  This is plenty of time to get some real work on the moon, and even engage is real life there, but I'm pretty sure there will be a medical limit.

 I think we can compare it to the south pole.  There are lots of people who stay down there for a year, but they generally come back.  There's nobody that actually lives there, although the base is permanently occupied.  I happen to have two scientist friends who have over-wintered there.  They're both back in the US now.  There are lots of other bases in extreme places with similar, rotating crews, and I'm certain that the moon will join them.