How Asteroids Differ From Planets

In a galactic episode of MinutePhysics, narrator Henry Reich explains via whiteboard animation how asteroids differ from planets, thus requiring a different scientific classification.

Asteroids, it turns out, are not just miniatureversion of the larger planets, but are in fact the fragments from the collisions and disintegrationof fully formed planets (or protoplanets), ratherthan miniature versions of the larger planets.

It turns out that the composition of asteroids are completely different from that of planets. Scientists discovered in 1953 that asteroids are just broken pieces from other planets and don't have enough energy to sort the materials properly.

When planetsform, the release of gravitational potentialenergy partially melts their interiors, causingheavy elements to sink to the core and lightermaterials to float upwards, sorting into layers. If asteroids were formed like planets,but smaller, they would each be made of a mix of materials, and would be too small to haveenough energy to sort the materials into layers. If instead asteroids were relics from collisions

This discovery caused asteroids to be re-classified and demoted into a secondary class.

So. The asteroids were demoted to non-planet status, not by a vote,nor from a dislike of a long list of planets, but due to a scientific discovery that asteroids are, in fact, physically different from everything else that we call planets. The discovery meant they were split off (in the minds of scientists) into their own group, and those scientistsorganically stopped calling them planets.

subscribe to the Laughing Squid Newsletter

The post How Asteroids Differ From Planets was originally published on Laughing Squid.