BRAINCAKEThe Solar System and Galaxies
The Solar System consists of the Sun and all the objects that orbit it. The Sun is a star: a hot ball of gas that releases energy by nuclear fusion in its core.
Planets are objects that orbit a star, have enough mass for their own gravity to make them roughly spherical, and have cleared their orbit of most other objects. Our Solar System has eight planets. Dwarf planets, such as Pluto, are spherical but have not cleared their orbits.
Planetary satellites are bodies that orbit a planet. They may be natural moons, like the Moon orbiting the Earth, or artificial satellites.
Sign in free to see the rest of this lesson, the R.E.C.I.P.E. recall steps and the quiz
BrainCake is free. Make an account in seconds and pick up where this page stops.
More in Astrophysics and Cosmology
- Formation of a Star
- Evolution of a Low-Mass Star
- Evolution of a Massive Star
- White Dwarfs and the Chandrasekhar Limit
- Neutron Stars and Black Holes
- The Hertzsprung-Russell Diagram
- Energy Levels in Atoms
- Emission and Absorption Line Spectra
All 24 lessons in Astrophysics and Cosmology · All OCR A-level Physics topics