What is the Fermi Paradox?

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Please literally explain it like I’m 5! TIA

Edit- thank you for all the comments and particularly for the links to videos and further info. I will enjoy trawling my way through it all! I’m so glad I asked this question i find it so mind blowingly interesting

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21 Answers

Anonymous 0 Comments

Here’s how I would explain it to a five year old.

Remember when we went to see the monster trucks? We went to the stadium? Remember how it was so big and there were so many seats?

Well, Imagine Earth is one of those seats and we’re sitting in it. The monster trucks are zooming around but all of the other seats are empty. You might think, “Why am I the only one here? Am I special? Was I the only one that got told about the monster trucks?”

“Maybe I’m early. Maybe everyone is still parking and they’ll be here any minute. Or maybe there is a security guard that doesn’t want to let anyone through. Oh, or maybe there’s some people way over there but I can’t see them. Maybe the whole stadium is full but everyone is hiding.”

There could be lots of reasons why we’re the only one in the stadium right now. We have some smart people trying to figure out where everyone else is and hopefully they’ll find them soon.

Anonymous 0 Comments

Enrico Fermi was a Professionally Smart Dude. He was a physicist and one of the dudes who worked on the Manhattan Project, the top secret American program to build the world’s first Atomic Bomb.

Interestingly, an atomic bomb is an **uncontrolled** nuclear reaction. Well, they all thought it would be a good idea, before they produced an UNcontrolled reaction, maybe they should try making a CONTROLLED reaction first, and Fermi was the dude they put in charge of that. He created the Chicago Pile, the first self-sustaining nuclear reactor. He called it a Pile because he was Italian by birth, spoke Italian as his native language, and he thought English was adorable. Like, what is it? I dunno man it’s just a bunch of nuclear stuff in a heap. A pile. A pile of nuclear stuff. He loved English because it could be direct and pragmatic like that.

Anyway Fermi was rare because he was good at making stuff (like the Chicago Pile) but he was also very good at thinking about stuff. There’s an entire class of subatomic particle named after him. The Fermion. Because he was the first dude to figure out how to statistically model the behavior of certain particles.

So Fermi is a professionally smart dude and he’s working at the desert lab where they originally developed the Atomic Bomb. He worked on the bomb in the 40s, they drop the bomb(s) in 1945, a lot of the people working there feel like “job done!” and go home, but Fermi wasn’t ever really bomb-oriented. He was the dude in charge of the first reactor and he, and a lot of the guys who kept working there, were interested in non-destructive uses of nuclear power.

The point is, when dude went to lunch in the cafeteria every day, he was sitting around eating egg salad sandwiches with some of the smartest guys on the planet. They talk about all sorts of stuff, baseball, movies. But something interesting has happened every since they dropped the bomb. People start talking about UFOs.

This wasn’t really a thing before 1945, but now suddenly people think there might be Space Aliens visiting Earth for no obvious reason. And the guys in the cafeteria talk about this.

Nowadays, we know a LOT about how the universe works, but back then, not so much. Still figuring it out. Fermi and those folks were among the first generation to **really** start figuring out the nuts and bolts of how reality works, and we owe much of our current understanding to the scientists of the 20th Century.

For instance, before about 1930, everyone assumed that all the lights you see in the sky are stars, and that “our universe” and “our galaxy” were basically the same thing. One galaxy, lots of stars.

Well Fermi is in the cafeteria with his buddies and it’s been about 20 years since humans have discovered that actually some of those lights in the sky are OTHER GALAXIES WTF?! Like, our galaxy has BILLIONS of stars in it, and it turns out there are literally BILLIONS of other galaxies!

Hang in there, we’re almost done.

One of the foundational assumptions of physics is “The universe is basically the same all over.” Whatever magnets do here on Earth, probably the same thing they’d do on any other planet anywhere else in the universe. Unless we have a reason to believe something’s unusual, we assume it’s not unusual.

Now, we are well aware that something MAY be unusual, but unless we have a reason to believe it IS unusual, we assume it’s not.

So, our solar system. Nine planets. One of them has people on it. Back in the 1950s, we had no evidence of planets orbiting other stars. But that was only because our telescopes weren’t good enough to see things like planets around other stars. Even the closest star is way too far away. And they knew that. They knew their telescopes were shit back then.

These guys knew A: we’ve never seen any planets orbiting other stars but B: that’s because our telescopes are shit. There doesn’t appear to be anything special about our solar system. There are *probably* lots of solar systems out there.” (spoilers, there are!)

So. Our solar system, not unusual. Universe, turns out to be massive with billions of galaxies each with billions of stars. And everyone’s talking about UFOs now because it’s the 50s and they don’t have Fortnite yet.

And one day at lunch, Fermi says… “So where IS everybody??”

That’s it. That’s the paradox. IF there’s nothing unusual about our solar system AND there are literally tens of trillions of solar systems out there…where are all the other people? Why isn’t the sky bursting with radio communication between interstellar civilizations? You know, maybe an actual visit would be a pain in the ass and there’s no reason for an interstellar civilization to know we’re here in the first place, but wouldn’t we be able to pick up there communications??

And it’s been SEVENTY YEARS and we have WAY BETTER tech than anyone back then and still…nothing. Zero.

So, that’s it. That’s the Fermi Paradox. Everyone has an idea about WHY we’ve never heard from anyone, or ever seen anyone. But no one…knows WHY we appear to be alone. Every IDEA you read about why we’ve never heard from anyone…is just a guess. And your guess is as good as theirs.

Anonymous 0 Comments

Kurzgesagt does a good job of laying it out:

Anonymous 0 Comments

So many planet. So many planet that may hold life. But where life?

Anonymous 0 Comments

Imagine it this way: you wake in your house with your pets. The bird is chirping in its cage, fish are swimming, dog is scratching fleas, cat is stalking a bug, hamster is hamstering, ferrets are getting into your large hydron coll-…. Roomba.There’s even a goat and chicken in the backyard. Life is good. But as you’re standing outside watering your flowers, watching aphids destroy you vegetables, and avoiding a bee you stop and look around, beyond your yard, into the surrounding neighborhood. It’s quiet. There’s no people out. More than that, there’s no animals! No birds or bugs. There’s not even trees or plants or flowers. While your yard and house is teeming with life…. No one is in your neighborhood. Nothing living, exists beyond your lush green lawn. Odd, right?

You can’t really leave your house to explore so you climb to the roof and start looking around. You see more of the same. Lots of rocks. Plenty of sand. But no life… not even decaying houses to show life was once there. It’s untouched barren land as far as you can see. So you build a some robot friends and send them out to explore for you. They head out of your yard… past your block… beyond your neighborhood… far into the city…. And further still. They travel into the country side beyond the city, into the land that borders your city area. And all they send back is more of the same. Cold rocks with no sign of neighbors, no sign of vegetation, no sign it was ever even there. You’ve figured out approximately how large earth is (theoretically) and you know you still have lots of land to cover …. But you really should have come across even a *sign* of life. A foot print. A dry leaf. Animal bones. Feathers. Soil! water! Fossils! Sea shells! An old Nokia! SOMETHING!…

But your farthest reaching robot friends have reported back from beyond your borders…. Nothing.

So you’re standing in your lush green yard with abundant water and animals everywhere and food growing like crazy and this chaotically diverse buzzing-with-life plot of land that you simply woke up on… and it appears to be the only even remotely living thing for miles all around you… even when you find a chunk of land that has all the same variables as your yard (not too warm or cold, weather just right, etc) nothing appears to grow there, not even weeds.

Why?

Why is your yard the only speck of green in a world of cold non living rock? Your yard can’t be the only thing on the entire gigantic earth with life on it… can it?

Where are all the neighbors?

Anonymous 0 Comments

There is a really in depth podcast about this called The End of the World with Josh Clark. I know this is ELI5 but it’s such a good series and definite worth the listen.

Anonymous 0 Comments

No-one here is actually explaining it like you’re five, so I’ll try.

Space is very big. There should be aliens everywhere. But we can’t see any. Is it because

-We’re the only ones here?

-We’re the only ones who lived long enough to get smart.

-We haven’t killed ourselves like everyone else yet but we will soon (scary)

-Something else is killing all the aliens and we’re next. (Scarier)

Anonymous 0 Comments

I’m surprised that all the answers are talking about size and not time.

The Fermi paradox is that the universe is really old and we’ve only been around for a tiny fraction of it. So there should have been at least one intelligent space going civilization what showed up before us and colonized the whole galaxy in less than 100 million years. But we don’t see any. So why is that?

Anonymous 0 Comments

https://waitbutwhy.com/2014/05/fermi-paradox.html This is the best article I’ve come across, and it has really easy to understand pictures (also I just love this site and everything he writes 😆)

Anonymous 0 Comments

The paradox is that it should be impossible that we have not seen evidence of life in space based on how much we can see.

Additionally, consider that our planet is only 4.5 billion years old, and humans developed within 200,000 years. Consider how our technology has advanced in 100 years. Now ask yourself why planets 10 billion years old or older havent managed to produce a species we can see evidence of in its 25million + more attempts at 200,000 years.

Honestly the
[Kurzgesagt](https://www.youtube.com/watch?v=sNhhvQGsMEc) video will eli5 better than any post probably. Also watch/ read about the great filter for great info on the same topic.