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?
Next, watch these handpicked videos:
• How to Find a Living Planet
• Bill Nye explains the Webb Space Telescope’s first images
• The Top 5 Places to Look for Alien Life
• Ocean Moon, Ocean World: The water beneath Europa’s icy surface