If an asteroid is massive enough to be rounded by gravity, and so be roughly spherical, it would be considered a dwarf planet rather than an asteroid. However, there’s not a clear distinction …

These larger moons are not physically distinct from the dwarf planets, but do not fit the IAU definition because they do not directly orbit the Sun. (Indeed, Neptune's moon Triton is a …

Dec 30, 2022 · The consensus that asteroids are not planets dates to more than 50 years before the 2006 IAU definition. But pinpointing exactly why astronomers changed their mind is not as …

Because they are smaller, dwarf planets lack the gravitational forces needed to pull in and accumulate all of the material found in their orbits. Each known dwarf planet in our solar …

It is far less common, however, for a planet to be locked synchronously with its moon. The Pluto-Charon system is the only planet-moon system in our solar system locked synchronously …

Under this model, Pluto was demoted to a dwarf planet, while other solar objects that were too big to be classified as asteroids but did not meet the requirements for a planet were also classified …

What's the difference between an asteroid, a comet, and a dwarf planet? Asteroids are left-over inner solar system objects, comets left-over outer solar system objects, and dwarf planets are …

This definition came into place in 2005, which is why Pluto was eventually demoted into a dwarf planet as it has yet to clear all the similar sized celestial bodies that orbit its local region.

Nov 28, 2025 · Unlike major planets, these bodies are not massive enough to have swept up most smaller nearby bodies by gravitational attraction; they thus failed to grow larger. The IAU …

Apr 29, 2025 · Dwarf planets like Pluto were defined as objects that orbit the Sun, and are nearly round, but have not been able to clear their orbit of debris. So far, the IAU has only recognized …