The surface of Mercury is filled with craters, ridges and steep cliffs. Over billions of years, as the planet's interior cooled, the planet also shrank. Just as the skin of a drying fruit wrinkles when what is inside it shrinks, Mercury's rocky surface crumpled into ridges and cliffs as its int...
Source: [Phys.org](https://phys.org/news/2026-09-masked-tectonic-mercury-visible-scars.html)