This continues from my earlier article "Ten reasons not to live on Mars, great place to Explore." Many of the ideas in that article apply not just to Mars but to the solar system generally.

The origin of life remains a great mystery in biology. Continental drift has erased most of the record, until all that's left of the first half billion years of evolution are some millimeter sized zircons embedded in later rocks. These can tell us the composition of the early Earth's atmosphere (through pockets of air trapped in the crystals) but not much else. And there is much to discover. The most primitive microbes we know are far too large to be the first living cells, and modern DNA based life is far too complex.

You've probably seen movies of orbital space habs spinning for artificial gravity. But did you know, that nobody has ever tested this to see how it works out in practise? We know that weightlessnes is bad for health, especially long term, with many potentially serious medical issues. But do we need full g, or Mars g, or lunar g to stay healthy? Nobody knows. Can we cope with a spinning hab a few meters across or do we need to think about a huge hab or tether system a couple of hundred meters across or larger? Again nobody knows. 

We have learnt so much about the geology of other planets. Our spacecraft have discovered ancient oceans and rivers on Mars, and have found possible habitats for life. But we haven't discovered this life itself, and we know nothing at all about extraterrestrial biology. Why is life so hard to spot? Is it there at all, and if so, why is it hidden from view, and how can we find it?

One of the best places to look for this life might be here:

Would you want to live on a "snowball planet", covered with ice sheets and glaciers all the way to the equator? Mars only looks warm because the photos are digitally adjusted to match brighter lighting on Earth, and because it lost most of its water long ago.

It's so cold at the equator (warmest places on Mars) that carbon dioxide could freeze to dry ice at night. On Earth this only happens in the coldest spots in the interior of Antarctica in the middle of winter.

This is just one of many reasons why Mars is less than ideal as a place to live. This is an update of my Ten Reasons not to Live on Mars, Great Place to Explore.

In Trouble with Terraforming Mars, I looked at many things that could go wrong with such a project. But setting aside those issues, Mars terraforming takes us far into the realm of magical thinking - where if you can imagine something vividly, you can make it happen. 

In this imagined future, with the ability to use giant space mirrors to warm up Mars, it is also easy to solve the energy crisis on Earth - just beam all the energy we need back to Earth from space solar power stations. With the fine control we need over planetary atmospheres, it is a trivial matter to adjust levels of CO₂ from 0.04% back to 0.03% and stop global warming instantly.