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  • There are probably 10,000 stars for every grain of sand on Earth in the observable universe.

  • We know that there might be trillions of planets.

  • So where are all the aliens?

  • This is the Fermi Paradox.

  • If you want to know more about it, watch part one.

  • Here we look to the possible solutions to the Fermi Paradox.

  • So will we be destroyed or does a glorious future await us?

  • Space travel is hard, over possible it's an enormous challenge to travel to other stars.

  • Massive amounts of materials have to be put into orbits and assembled.

  • A journey of maybe thousands of years needs to be survived by population big enough to stop from a scratch.

  • And the planet might be not as hospitable as it seems from afar.

  • It was already extremely hard to set up a spaceship that could survive the trip.

  • And interstellar invasion might be impossible to pull off.

  • Also consider time, the universe is very old.

  • On Earth there's been life for at least 3.6 billion years.

  • Intelligent human life for about 250,000 years.

  • But only for about a century have we had the technology to communicate over great distances.

  • There might have been grand alien empires that stretched across thousands of systems and existed for millions of years

  • and we might just have missed them.

  • There might be grandiose ruins washing away on distant worlds.

  • 99% of all species on Earth have died out.

  • It's easy to argue that this will be our fate sooner or later.

  • Intelligent life may develop, spread over a few systems and die off over and over again.

  • But galactic civilizations might never meet.

  • So may be it's a unifying experience for life in the universe to look at the stars and wonder "Where is everyone?"

  • But there is no reason to assume aliens are like us

  • or that our logic applies to them

  • It might just be that our means of communications are extremely primitive and outdated.

  • Imagine sitting in a house with a morse co-transmitter, you'd keep sending messages but nobody would answer

  • and you would feel pretty lonely, may be we're still undetectable for intelligent species

  • and we'll remain so until we learn to communicate properly.

  • And even if we met aliens we might be too different to be able to communicate with them in a meaningful way.

  • Imagine the smartest squirrel you can,

  • no matter how hard you try, you won't be able to explain our society to it

  • After all from the squirrel's perspective a tree is all that sophisticated intelligence like itself needs to survive.

  • So she learns cutting down whole forest is madness but we don't destroy forest because we hate squirrels.

  • We just want the resources

  • The squirrel's wishes and the squirrel's survival are no concern to us.

  • A Type 3 civilization in need of resources may treat us in a similar way.

  • They might just evaporate our oceans to make collecting whatever they need easier.

  • One of the aliens might think for second "Ughh tiny little aches, they built really cute concrete structures, oh well now they're dead."

  • before activating warp speed.

  • But if there is a civilization out there that wants to eliminate other species,

  • it far more likely that it will be motivated by culture rather than by economics.

  • And anyway it will be more effective to automate the process by constructing the perfect weapon,

  • a self replicating space probes made from nano-machines.

  • They operate on molecular level incredibly fast and deadly,

  • with the power to attack and dismantle anything in an instant.

  • You only need to give them four instructions.

  • One, fine a planet with life.

  • Two, disassemble everything on this planet into its component parts.

  • Three, use the resources to build new space probes.

  • Four, repeat.

  • A doomsday machine like this could render a galaxy sterile in a few million years,

  • but why would you flight light years to get the resources or commit genocide.

  • The speed of light is actually not very fast,

  • if someone could travel at the speed of light, it will still take 10,000 years to cross the milky way once

  • and you'll probably travel way slower.

  • There might be way more enjoyable things than destroying civilizations and building empires.

  • An interesting concept is the Matrioshka Brain.

  • A mega-structure surrounding a star,

  • a computer of such computing power that an entire species could upload their consciousness and exist in a simulated universe.

  • Potentially, one could experience an eternity of pure ecstasies without ever being born or sad, a perfect life.

  • If built around the red dwarfs, this computer could be powered for about ten trillions years.

  • Who would want to conquer the galaxy or make contact with other life forms if this were an option.

  • All these solutions to the Fermi Paradox have one problem.

  • We don't know where the borders of technology are.

  • We could be close to the limit or nowhere near it.

  • And super technology awaits us,

  • granting us immortality, transporting us to other galaxies, elevating us to the level of gods.

  • One thing we do have to acknowledge is that we really don't know anything.

  • Humans have spent more than ninety percent of their existence as hunters-gatherers.

  • 500 years ago we thought we were the center of the universe.

  • 200 years ago we stopped using human labors as the main source of the energy.

  • 30 years ago we had apocalyptic weapons pointed at each other because of political disagreement.

  • In the galactic time scale we are embryos,

  • we've come far but still have a long way to go.

  • The mindset that we really are the center of the universe is still strong in humans,

  • so it's easy to make arrogant assumptions about life in the universe.

  • But in the end, there's only one way to find out right?

There are probably 10,000 stars for every grain of sand on Earth in the observable universe.

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