Mercury isn’t just the smallest planet—it’s actually been shrinking for billions of years! Scientists just used a new method to figure out exactly how much it’s lost, and it turns out Mercury has shrunk by up to 5.6 km as it cooled down. The planet’s surface is covered in huge “wrinkles” from all the contracting. Basically, Mercury is the ultimate glow-down story in our solar system! #Science #Mercury #SpaceFacts