The eight planets of our Solar System
- large globe-shaped objects that orbit a star, such as our Sun.
- begin life at the same time as their star – from the leftover clouds of gas and dust.
- planets are never more than 5% of the mass of our Sun – if they were bigger, they would be stars.
- terrestrial planets – surface of solid rock; others called gas planets – do not have a solid surface, just clouds.
- our Solar System has eight planets – Pluto was ninth, but it is very small and now it’s called a planetoid (dwarf planet).
- over 200 plants have been detached orbiting other stars – it’s called extra-solar planets.
- extra-solar planets are too far away to see, but can be detached by its making their stars appear to wobble.
- many known extra-solar planets are giants, bigger than Jupiter; they orbit rapidly, closer to their stars than Mercury is to the Sun.
- today improved detection techniques may reveal smaller planets orbiting further out in space.
Back to The Solar System page.