Searching for aliens isn’t bizarre. What’s bizarre is that we haven’t found them.

The latest episode of our Netflix show, Explained, tackles the possibilities of extraterrestrial life.

There are about 10^22 stars in the universe. That’s about 10,000 stars for every grain of sand on Earth.

Let’s say 5 percent of those stars are similar to our solar system’s sun. That’s 500 billion billion suns out there. (Yep, billion billion is not a typo.)

And scientists estimate that 1 in 5 of those suns has an Earth-like planet.

Given those numbers, many scientists are confident that there is life to be found beyond Earth. If not, Earth would be a scientific miracle.

So if the probability of alien life in the universe is so high, why haven’t we found it yet?

Vox tackled this question in the ninth episode of our new Netflix show, Explained. We’ll have new episodes every Wednesday on topics ranging from cryptocurrency to the racial wealth gap and cricket. If you like our videos, then you’ll love this show; it’s our most ambitious video project to date.

To watch, search “Explained” on Netflix or go to Netflix.com/explained. Click the “My List” button to make sure you don’t miss an episode!