Today’s Wonder of the Day was inspired by Arshdeep. Arshdeep Wonders, “What is the Fermi Paradox?” Thanks for WONDERing with us, Arshdeep!

Do you think there could be life on other planets? Do you believe UFO sightings? How about the secrets of Area 51? Many kids and adults alike gaze up at the stars on clear nights and WONDER the same thing. Is there anyone else out there?

After all, the Milky Way galaxy alone is enormous. It has billions of stars, each one orbited by planets. And of course, some of those planets are able to host life, like Earth is. Considering the sheer size of the universe, it seems almost certain that life must exist somewhere else, right?

If that’s the case, then… where is everybody?

That’s the question Enrico Fermi asked at lunch one day in 1950. It got him—and many others—thinking. Fermi, a physicist, was one of the greatest scientific minds of his time. He made the world’s first nuclear reactor, worked on the Manhattan Project, and won a Nobel Prize for Physics. Yet he couldn’t answer this question, which came to be known as the Fermi Paradox. If there is other intelligent life in the universe, then why haven’t we found it?

And why hasn’t it found us? Many stars are billions of years older than Earth’s sun. That means life could have started on other planets much earlier than life on Earth. Wouldn’t that give alien life a head start on technology? 

Then where are all the super-fast interstellar rockets? Where are the alien colonies on other planets? Where are the radio signals from alien life? Astronomers have looked deep into space. Why haven’t they found anything?

There are many answers to this question. One is obvious—aliens don’t exist. That would mean that conditions on Earth are so rare that it’s the only planet able to support life. However, this doesn’t seem likely. Experts estimate that there are 100 Earth-like planets for every grain of sand on Earth. That’s… a lot of planets. Could Earth really be the only one with life?

Another explanation is that alien life has already been to Earth. It could have visited before humans were intelligent enough to notice. Or maybe aliens visited during the time of the dinosaurs

Some people believe that intelligent life is out there, but that it’s far away. Maybe Earth is very, very far from the center of life in the universe. That would mean it’s just taking a very long time for other intelligent life to find us—or for us to find it.

Others say aliens could be trying to communicate with Earth, but human technology isn’t advanced enough to hear them. Or maybe humans are just unable to perceive aliens because they live in a different dimension

On the other hand, many people think that humans HAVE encountered other life. People who have seen UFOs would argue the evidence is right in front of us. Still others say aliens are just a conspiracy theory and don’t exist at all. 

Can you solve the Fermi Paradox? Which explanation do you think makes the most sense? Maybe you have a better answer! What do you think the stars hold? Will humans ever find alien life?

Standards: NGSS.ESS1.A, CCRA.L.3, CCRA.L.6, CCRA.R.4, CCRA.R.1, CCRA.R.2, CCRA.R.3, CCRA.R.10, CCRA.SL.1, CCRA.W.3, CCRA.L.1, CCRA.L.2, CCRA.SL.1, CCRA.SL.2

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Tomorrow’s Wonder of the Day might just teach you something about yourself.