I was watching the latest PBS SpaceTime
Why We Might Be Alone in the Universe and it got me wondering about the Drake equation:
Has anyone ever solved this equation from the other side? In other words, let's assume that Earth is the only technological civilization in the galaxy. So, N = 1. Going by that, what would this force the other variables to? How seemingly improbable are those?
I would guess:
R = Near Infinite (How big is the universe again?)
fp = 1 (I'd guess nearly every star has planets)
ne = 2 (Our solar system has Earth but Mars and Venus are almost suitable. Not including any moons either).
So these 3 variables, even if ne is much smaller, gets you a near infinite number of candidates.
That means that fl, fi, fc or L is near infinitely small to have the equation equal one. Even a million to one chance on all of them would leave you with billions of worlds.
Given that it's happened here, fl conditions must have happened elsewhere in such a large universe since it's just a balance of chemicals/conditions and scientists are leaning towards life being more common the we think. It'll be a small fraction but not infinitely small.
That means the issue is with evolution.
fi could be more than 1 on suitable worlds as we have multiple "intelligent" lifeforms on earth, the issue is fc because dolphins can't develop tech without fingers. Some worlds will have poor conditions that's only good for bateria though.
For fc we only have one animal lineage on earth using tools. I think birds have been seen using sticks but their limbs aren't suitable for further development. Even with Humans, multiple civilisations were not developing tech, it took a large contiguous population from Ireland to Japan to develop technology.
Then with L, it remains to be seen how long we will last . Some species have been around for a very long time (Turtles, Crocodiles, Sharks) and most died out. Unless climate change fucks the earth or science fucks our genome I think we will be OK.
For reference:
N = R* fp ne fl fi fc L where, N = The number of communicative civilizations R* = The rate of formation of suitable stars (stars such as our Sun) fp = The fraction of those stars with planets. (Current evidence indicates that planetary systems may be common for stars like the Sun.) ne = The number of Earth-like worlds per planetary system fl = The fraction of those Earth-like planets where life actually develops fi = The fraction of life sites where intelligence develops fc = The fraction of communicative planets (those on which electromagnetic communications technology develops) L = The 'lifetime' of communicating civilizations
So I would say that if N = 1, it'll be because there's a near infinitely small chance of the required technology developing.
You need :
1) A world with conditions that allows not just life but large animals to adapt to it.
2) Evolution to deliver eyes, fingers and a conscious brain. Not just plants.
3) A large enough contiguous population existing for long enough to develop the technology.
Evolution is the real miracle here.