Our Smallest Planet, Mercury, Is Shrinking

As some of us may know (or at least I hope this is a well-known fact), Mercury is the smallest and closest planet to the Sun. When it comes to this planet, I feel like those are the two main facts you need to know about it. If you want to be extra and impress your friends or colleagues, you might even think to add that Mercury is the only planet in our solar system that’s shrinking; you heard me right!

When NASA’s Mariner 10 mission approached Mercury, scientists discovered that the planet was shrinking as its core was cooling down. The thing is, this thermal contraction began around 3 billion years ago, and it’s still going on. 

If you don’t believe that the planet is shrinking, there is proof of this with some being quite recent and some dating as far back as 1974. This year, the Mariner 10 photographed slopes on Mercury’s surface called lobate scraps. These scraps are created when a planet’s interior contracts as it cools, allowing the planet’s crust to develop “thrust faults.” Think of it like a rotting apple that gradually becomes wrinkly, and its flesh shrivels up. 

More data has been shared that shows the planet's shrivelling features, such as a valley near the fault zone. These valleys are known as garbens (ye,s I know, a weird name) and have been theorized to be around 300 million years old. While it is unclear whether Mercury is currently shrinking, we do know for a fact that it was shrinking 300 million years ago. While this may sound like a long time, 300 million years is nothing in geological terms. 

Mercury still currently houses many mysteries, which is why sending missions to study the planet closely has been of great priority among certain scientists. Hopefully, we’ll have the answer to the oddity of this planet and whether it is shrivelling up like an apple!  

https://www.popularmechanics.com/space/solar-system/a45431594/why-is-mercury-shrinking/