Let's dig in to some truly eyebrow-raising theories about aliens.

If there are so many planets, where the heck is everyone?

If there are so many planets, where the heck is everyone?

A video from Kurzgesagt digs into some truly eyebrow-raising questions about aliens. It starts with what physicists Enrico Fermi and Michael H. Hart got to wondering about. It's called the Fermi paradox, and it goes like this:

If...


  • There are 100 billion galaxies just in the observable universe
  • Which means there are 100 to 1,000 billion stars
  • Which means there are probably trillions of trillions of livable planets, so life could be, like, everywhere
  • And lots of these planets are older than Earth, so some of the theoretically more-developed folks/critters that might be on those planets could/should have figured out space travel by now

Then...

  • Where are they already?

Well, far far far far away, if they exist out in the larger universe.

The universe is expanding, so it would take us billions of years in the speediest spaceship to get to anybody outside of our galactic neighborhood.

All images by Kurzgesagt.

But if we think locally, it actually is possible.

In the Milky Way alone, there are likely to be about 4 billion habitable places to live.

And if just 0.1% of them actually have any life, that would be 4 million places somebody or something could be living. (The video incorrectly says "1 million." Hey, anyone can make a mistake.)

So the heavens should be teeming with spaceships.

So, um, where's the party? It may be due to those pesky things the video calls “filters."

For instance, maybe life requires a more particular set of conditions than we realize. Certainly, the universe hasn't always been very welcoming.

Maybe we're actually unique, or we could even be the first life anywhere.

Maybe some filters just make it really hard to keep living things alive. (Not to point any fingers here.)

It's also possible that an ancient advanced life-form has been watching us all along.

It could also be that we haven't seen anyone yet because that advanced life-form zaps away any civilization that advances to a certain point to preserve the galactic peace. Just saying.

But if we are alone, wow. That makes what we have even more important.

If we screw up this planet beyond saving, we could be eliminating the only life in the entire universe. Anywhere. Well, that's a big responsibility. After all, this universe is too beautiful not to be experienced by someone.

The video is tons of fun and full of big, weird ideas. Enjoy.

Heroes