The solar system is named solar system because planets and dwarf planets, moons and various celestial bodies all orbit around the sun. The planets in the solar system are Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune. The dwarf planets comprise of Ceres, Pluto, Haumea, Makemake and Eris, the dwarf formerly known as a planet. Ceres is located between Mars and Jupiter, while Pluto, Haumea, Makemake and Eris are all behind Neptune.
The order of the planets based on the distance they orbit from the Sun is as follows:
- Mercury – 57.910.000 km (0.38 astronomical unit, or AU) from the Sun
- Venus – 108.200.000 km (0.72 AU) from the Sun
- Earth is 149.600.000 km (1.00 AU) from the Sun
- Mars is 227.940.000 km (1.52 AU) from the Sun
- Jupiter is 778.330.000 km (5.20 AU) from the Sun
- Saturn is 1.429.400.000 km (9.54 AU) from the Sun
- Uranus is 2.870.990.000 km (19.218 AU) from the Sun
- Neptune is 4.504.000.000 km (30.06 AU) from the Sun.
If you were to identify planets in order of their size, the largest would be:
- Jupiter at 142.984 km at its equator,
- Saturn at 120.536 km
- Uranus is 51.118 km
- Neptune 49.532 km
- Earth 12.756 km
- Venus 12.103km
- Mars 6.794 km
- Mercury 4.880km
The disparity may be understandable as Saturn and Jupiter are gas giants, while Uranus and Neptune are ice giants. The remaining planets are smaller by virtue of their having solid rocky surfaces. The size of Jupiter is such that it could fit all the other planets inside it.
Defining the order of the planets by their discovery date can be subjective.
Bright planets like Venus have been observed since ancient times. Mercury, however, has the earliest recorded observations that date to at least 400 BC; Greek astronomers thought the planet was two separate objects. Mars was always visible to the naked eye; in 400 BC it was known as the Star of Death to Babylonians because of its red glow showed up brightly the black night sky. The discovery of Venus is credited to Pythagoras in the 600 BC, but the mathematician thought it orbited Earth. In 1610, Galileo was the first person to observe the moons around Jupiter. He was also the first person to observe Saturn through a telescope that year, although ancient civilizations had known of the planet too. Uranus was discovered by William Herschel in 1781, making it the first planet to be discovered in modern times. Later, Neptune was observed by Galle and d’Arrest in 1846 thanks to predictions made from calculations based on the locations of Jupiter, Saturn and Uranus. It’s not possible to determine when Earth was discovered, although mankind realized in the 16th century that it was just another planet and not the center of the universe.
Order of the planets by the numbers of the moons:
Earth is not the only planet to have a moon in its orbit. Here is list ordered by the number of the moons:
- Jupiter heads the list with 63 known satellites.
- Saturn has 34 moons that have been named
- Uranus has 27 (21 named)
- Neptune has 13 moons, 6 of which are unnamed and Mars has 2 moons.
- Earth has 1 moon.
- Venus and Mercury have no moons.
Dwarf planets ordered by the size are:
- Eris 2400 km at diameter
- Pluto 2306 km
- Makemake 1500 km
- Haumea 1150 km
- Ceres 974.6 km
Dwarf planets ordered by the distance from the sun:
- Ceres 413 700 000 km
- Pluto 5 906 380 000 km
- Haumea 6 484 000 000 km
- Makemake 6 850 000 000 km
- Eris 10 210 000 000 km