NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington; Insider
- A new study suggests the smallest planet in our solar system is getting even smaller.
- The moon-sized planet is shrinking as its insides cool down.
- Mercury's diameter has declined by some 9 miles, and is still wasting away.
Mercury, the smallest planet in the solar system, is getting even — and getting more wrinkles as it does, a new study suggests.