Back to all articles

Planets Must Meet 3 Criteria.

To be considered a planet, space objects must: 1) Orbit their host star, which in our solar system is the Sun 2) Be mostly round in shape and 3) Be large enough that their gravity clears away any other objects of similar size near their orbit. These defining criteria were put into place in 2006 by the International Astronomical Union (IAU). If you’ve ever wondered, Pluto is no longer considered a planet because it does not meet the third criterion.

Share this article