Question

Which statements describe the planets? Check all that apply.

Mars and Venus are mostly rock.
The ancient Greeks discovered all the planets in the solar system.
Saturn is classified as a gas giant.
Jupiter is mostly rock surrounded by clouds.
Pluto is considered a dwarf planet.
Earth is much smaller than Uranus.

Answer 1

Correct:
- Mars and Venus are mostly rock. (They are terrestrial planets.)
- Saturn is classified as a gas giant. (Saturn is primarily hydrogen and helium.)
- Pluto is considered a dwarf planet. (IAU reclassified it in 2006.)
- Earth is much smaller than Uranus. (Uranus is several times larger in radius and far more massive.)

Incorrect:
- The ancient Greeks discovered all the planets in the solar system. (They knew only the naked-eye planets; Uranus, Neptune and Pluto were discovered much later.)
- Jupiter is mostly rock surrounded by clouds. (Jupiter is primarily hydrogen and helium gas with a possible small rocky/metal core.)