Study shows Mercury shrank 23km due to internal cooling
Turns out Mercury, our solar system's smallest planet, has been shrinking way more quickly than scientists expected.
New research shows its diameter has dropped by about 23km since it first formed, mostly because it's losing heat from the inside.
This surprising find could totally shift how we understand what Mercury is made of and how it's changed over time.
BepiColombo to orbit Mercury November 2026
Scientists say Mercury has shrunk 10% to 30% more than earlier estimates, describing the process as "like a balloon left out in the cold."
Debris from ancient impacts might be hiding just how much the planet has actually contracted.
Looking ahead, the BepiColombo spacecraft (from Europe and Japan) will start orbiting Mercury in November 2026, giving us a closer look at its surface and helping us figure out what's really going on beneath all those cracks and cliffs.