I keep a running list of the reasons why we should consider Earth as rare in the Universe.
Two additions I’ve recently added are this:
• Theia’s impact delivered more than just iron and nickel to Earth’s core (producing an extra large magnetosphere) but also (probably) delivered additional carbon, nitrogen and sulfur — chemicals which, like oxygen and hydrogen, are volatile and tend to get boiled off during a planet’s accretion phase (forming from the solar system’s proto-disc).
• Tidally locked planets and moons would lose their magnetosphere (the dynamo engine within a iron molten cored planet). Without this magnetic shield solar and cosmic radiation would ravage any life that had arisen on the planet.
The reason I keep this list is that it supports the 2^Nth theory I maintain about how to calculate a Rare Earth.
The “Two to the N’th” theory is an approximate probability that describes the uniqueness in the Universe of a electromagnetic-energy manipulating species — that is, us. Essentially, all factors that contributed to the existence of humanity can be distilled down to coin flips. Every coin flip = 50% probability. Add up a bunch of coin flips (landing on heads) and you get a probability that represents how unique we are.
For instance: If we assume that one out of every two stars in the Universe/Galaxy is singular not binary (binary star systems are too unstable to support planetary life) that’s coin flip number one (2^1). Of those, if half are the right size (a very conservative estimate) — another coin flip (2^2). If you examine all the factors, turn them into 50% (one flip) or 25% (two flips) or 12.5% (three flips) etc. you end up with a whole load of coin flips or powers of two (2^Nth).
I’ve done the compilation (that is, keeping this growing list) and determined that over 60 is the current number of coin flips that all landed up “heads” which represents how lucky/unique we are in the universe. The probability of flipping 60 coins and ALL OF THEM landing heads — represents the probability of Humanity.
How often would 60 coin flips all land on heads? Well, we know it happened at least once (that US!). But what is 2^60th power?
The probability of Humanity is 1 out of 1.1 quintillion. Is that rare? Probably.
I continue to collect these “features” which helped contribute to our existence. I suspect that we’ll get to seventy here some time soon: 2^70 = 1 sextillion.
Here’s a handy approximator:
- 2^10 = ~one thousand
- 2^20 = ~one million
- 2^30 = ~one billion
- 2^40 = ~one trillion
- 2^50 = ~one quadrillion
- 2^60 = ~one quintillion
- 2^70 = ~one sextillion (or one billion trillion)