The final assignment in Cosmology Class counted for most of our grade and I wanted to do something special. The junior students were mostly creating comets and asteroids, which was easy. More ambitious students were creating stars, or even black holes. Only a few students were creating planets.
Making planets was where I saw an opportunity. While others were designing gaseous planets, rocky planets, planets with volcanoes, and planets with rings, I wanted a planet where things moved around and reformed, multiplied, interacted, and did interesting stuff. I wanted a planet with creatures that were self-aware. In short, I wanted a planet with LIFE!
It would be a challenge but if I could pull it off, I would be sure to get an A, or even an A+! At the outset, my planet needed a nutrient transport system. A polar liquid made of two hydrogens and an oxygen was perfect for this, but it had to be at just the right temperature to keep it from solidifying or becoming a gas. That meant orbiting the planet around the right size star, and spinning the planet to warm it uniformly.
And I’m not bragging, but in a moment of brilliance I realized that if I covered 70% of the planet’s surface with this liquid—I called it water—that same spin would get the water to circulate in the oceans. This was an original idea. Nobody else was putting that much water on their planets. Creating the oceans meant hitting the planet with H2O-rich asteroids at exactly the right time in its life cycle. One of the junior students offered to help by creating the asteroids. She was cute and I kind of liked her, so I brought her in to help.
Our planet had to be the right size, too.
Our planet had to be the right size, too. If it wasn’t big enough its gravity would be too weak to retain the gaseous water; too big and our organisms wouldn’t be able stand against the gravity. So far, so good… We had the right initial conditions. Now we had to protect the life on it from all the things that could kill it. There were a lot of those. We used an atmosphere to shield it from small meteors, and by getting early organisms to release oxygen from the ocean, we could get ozone in the upper atmosphere to create a UV shield.
There were also cosmic rays and charged particles from the Sun to worry about. My new partner suggested a molten core with iron in it to create a magnetic field that would protect against those. I don’t know if I would have thought of that. She was pretty good. Finally, we put some big planets in outer orbits so their gravitational fields would draw away larger asteroids that might be a problem.
We put in a lot of other details that are too numerous to mention. At 4.5 billion years into it, we have recently managed to create sentient life! None of our classmates have even come close to this and I’m sure we’ll get an A if our life forms don’t kill themselves before the end of the semester.