Trappist 1e

On my walk this morning I was thinking about all I know about Astronomy which includes some of the more popular exo-planets found within their star's Goldilocks zone, including Trappist 1e. It is a tidally locked planet about the same size and density of Earth with a gravity slightly less that is about 40 light years away. Little is known about the atmosphere, if even there is one, though it is known that it is not a Hydrogen heavy atmosphere as a spectroscopy reading did not find this to be; this leaves a higher chance it is a human friendly atmosphere.

It orbits the Trappist star which is an ultra-cool dwarf star and emits to 1e's sun-side only the barest amount of light, described as being between the light just after sunset, or a little brighter than a night with a visible full moon. It is not clear from what I have read about what we know about the star's radiation hitting 1e. Here on Earth we have an inherent electromagnetic field that protects us from harmful rays from our Sun, hopefully either the Trappist star as an ultra-cool dwarf emits very little radiation, and/or 1e has it's own electromagnetic field to protect it. We will assume going forward that the amount of radiation reaching 1e's surface matches what we get here.

What is also known, being in the Goldilocks zone is that liquid water can exist at the temperature of the planet, and it is presumed that there is already water on the surface. Having water on the surface would definitely make it amenable to human colonization.

During my walk I did not take into account that so little light reaches the surface; this would be cause for a perpetual seasonal affective disorder unless something was done to assist in providing the right quality of light in a diurnal pattern on the sun side of 1e. The dark side of 1e will be perpetually facing away from the Trappist sun and so on that side we can take advantage of the darkness for things like astronomy telescopes and other science or industry that could be done in colder temperatures.

Given this lower sun light reaching the surface also changes an idea I had on my walk. The idea was that the sun side would be much brighter and hotter and the dark side much cooler and, well, dark. There could be deeply buried infrastructure to pipe heat from the sun side to provide district heating to the dark side, and similarly, pipe cold from the dark side to the sun side to provide cooling; and perhaps it is the same system.

If it was hot and bright and arid on the sun side, it would only be the terminal line (the line around the circumference of the planet where the sunlight ends and the dark side begins) where we could live. My idea was to have a circum-planet train line about 10 degrees into the sun side of the planet that runs counter-clockwise and another circum-planet train line about 10 degrees into the dark side of the planet that runs clockwise with most of the population living within those 20 degrees of planetary surface. 

I had a bunch of other ideas, but with the low insolation it makes the sun side of 1e more hospitable across the sun side rather than just at the terminal line and with the low light, having photovoltaics may not work very well. It could be there is sufficient wind to provide that kind of energy; or if we can travel 40 light years, perhaps we have finally mastered fusion power.

Anyhow, I enjoy the idea of living on the terminal line with swimming pools and tropical beaches on the sun side and hockey arenas and ski hills on the dark side.