Okay, to seriously talk about the “are we alone in the universe” question.
Nearly everywhere you look on Earth, there’s life. Deep deep deep underground, there is microscopic life that has adapted and thrives in conditions that would be lethal to us.
Earth seems so perfectly made to support life, but that is a total illusion. We are the ones who are in fact tuned by evolution, as is the other life on and under the surface of the earth.
Let’s assume that for there to be advanced life; advanced enough to be sending signals into space, their situation must be quite like ours: a star with a similar size and mass to our sun, a planet that has a reasonably stable atmosphere and a core that is hot enough for convection to happen to generate a magnetic field to protect them from the deadly solar wind… etc etc…
Life developed on this planet over billions of years, they found out about technology, and then they thought what the hell, let’s travel to another star or send out signals for people to see if they’re out there. How likely is this to happen?
The Drake equation, yeah!
This equation helps us make an estimate about the number of civilisations in the galaxy capable of sending signals into space.
LETS GO!
Our galaxy has ~200 billion stars in it. About 10% of these stars have a similar feature list to our star; the sun. 10% of 200 billion is 20 billion.
How many of these stars will have planets? Well, recently we’ve been able to study these stars close enough to determine that a hell of a lot of them do.
How likely is it that these planets are like Earth? Even if we assign a far lower than reality number to this, say 1%, then there are still millions of stars out there with planets like ours.
For the next steps in the equation, we basically have to guess how many planets have life, how many have life capable of technology…
The number of other planets in our galaxy that have intelligent life is anywhere between MILLIONS and zero.
Maybe we really are alone in the galaxy, and the many trillions of light years don’t harbor anything intelligent outside of the twenty or so thousand cubic miles that is the Earth and it’s atmosphere.
There’s another thing to think about though, too. Life took billions of years to evolve on this planet, and only in the last few have we developed technology that could potentially communicate with an alien species. How long are we going to be around with this level of technology? Few thousand years? Maybe a million (that’s definitely a stretch).
It’s quite possible that all advanced life is eventually killed off by some sort of natural disaster, or simply gets to the point where it kills itself. Nuclear weapons, anyone?
SO?
When we look at the probability of there not only being other life in our local area of the universe, but life being at the same or similar stage of evolution to us, suddenly the probability of us ever speaking or seeing aliens drops to within a hairline of zero.
Conclusion: There probably has been life exactly like us an uncountable amount of times before, and there will be again, all over our local bit of the universe and beyond. Is it there right now? Local enough for us to speak to? Probably not.
I fucking loved this subject as a kid, and still read quite a lot about it today. Don’t think I’m a genius though, I was flicking through books and blog posts all the time while writing this to remember the things I wanted to bring up.
To go back to my first point about life tuning itself to it’s surroundings, you must also consider that there will be some life elsewhere in the universe that thrives in conditions completely unlike ours. Maybe a horrendously high or low temperature, or a completely acidic atmosphere. It’s hard for us to know. There are some microorganisms that are unaffected by most forms of radiation. It’s quite possible that there is life thriving around some red giant. Who knows.
THE END AND I’M GOING TO BED
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