Life began on the Earth around 3.5 billion years ago. Has the same thing happened somewhere else in the universe? On an icy moon? On a planet in the Goldilocks zone of a distant star? Imagine if hypothetical aliens were looking for signs of life in our solar system. How might they investigate us from so far away?

Astronomers at the Royal Observatory Greenwich explain how we might detect each other with current technologies like ours in this animation with Beakus: Are there aliens?

Next: How to Find a Living Planet, Ocean Moon, Ocean World: The water beneath Europa’s icy surface, and The Top 5 Places to Look for Alien Life.

Bonus: Carl Sagan’s Cosmic Calendar from Cosmos.

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