September 4th, 2022

Where are all the Aliens?

Unless you’re new to astronomy, space travel, stories about aliens, and generally everything cool about space, you have probably heard of the Drake equation and the Fermi Paradox already, so I’ll skip those definitions and get right to it. I think it all comes down to The Moon.

Specifically, I think our moon is an exceedingly rare thing. It’s true that all the other planets in our system also have moons, but they’re boring compared to ours. They’re too small compared to the parent planet’s size. Why is ours so huge, relatively speaking? And why do you need one that big for intelligent life, or life at all? It’s not so much the moon itself, but more about how it was created. Like many others, I find the theory that it was created by a collision with another early planet a compelling one. If it’s true, the collision did several rather violent things - all of them good for life here. It gave us our moon which causes the ebb and flow of the tides. This gentle washing in and out prevents stasis and stagnation. As with many things in the formula for life, you need just enough but not too much. These early tidal pools are believed to be essential for the forming of simple amino acids - the building blocks for life. The collision also knocked the early Earth off its axis. That tilt gives us seasons which also may have given early life that much-needed variation. But, it’s the Earth’s magnetic field that made the biggest difference. Without this, solar radiation would have sterilized nascent life. All of life needs energy from the sun, but again, not too much. All of these “just enough, but not too much” levels add up to a very rare environment that is perfect for life.

How many other rocky planets with plenty of water in the goldilocks zone are there out there? Probably a lot. How many got smacked by their brother so hard that a perfect moon came out? Probably not many and maybe zero.