[0:00]If aliens looked at Earth from really far away, would they know we're here?
[0:03]Imagine little aliens speeding toward us, but their tech is the same level as ours.
[0:08]Astronomers just wrote a real paper about what they'd see.
[0:11]At 100 light years away, they'd reach the farthest our earliest radio waves have traveled.
[0:15]But the aliens don't see them because these radio waves have spread out so much that they're indistinguishable from the background static of the universe.
[0:23]But at 65 light years, they could see signals from NASA's deep space network, massive radio antennas that let us talk to our own distant spacecraft.
[0:31]But they keep coming at 6.5 light years away.
[0:34]They can use one of the techniques that we use for discovering Earth-like planets to see that our planet has chemical signs of industrialized life.
[0:41]Now they're passing our nearest star, and surprisingly, this is the first time they can see signals from our cell phones.
[0:47]And as they enter our solar system and pass between Uranus and Saturn, they can see our city lights and our satellites.
[0:54]And finally, there we are! For more optimistic science and tech stories, subscribe.
