Planets Vocabulary

The planet Earth on which we live is part of the solar system. The Sun is a star at the centre of the solar system, and eight* planets and other bodies revolve around it.

solar system

The eight planets, in order from the Sun, are:

Terrestrial (Latin terra = earth) planets are so called because they have a mainly solid, rocky structure similar to Earth's.

Below are listed the eight planets of the solar system with vocabulary and related facts and figures.

Mercury

position from Sun: 1
distance from Sun: 58,000,000 km
diameter: 4,879 km
type: terrestrial planet
position within solar system: inner planet
time to orbit around Sun: 88 days**
visible to naked eye from Earth? yes
when discovered: unknown
god: Mercurius, Roman messenger god
superlative(s): smallest planet, closest to Sun, fastest
adjective: Mercurian
demonym (name of fictional inhabitant): a Mercurian
moons: 0

Venus

position from Sun: 2
distance from Sun: 108,000,000 km
diameter: 12,104 km
type: terrestrial planet
position within solar system: inner planet
time to orbit around Sun: 225 days
visible to naked eye from Earth? yes
when discovered: unknown
god: Venus, Roman goddess of love and beauty
superlative(s): brightest, hottest
adjective: Venusian
demonym (name of fictional inhabitant): a Venusian
moons: 0

Earth

position from Sun: 3
distance from Sun: 150,000,000 km
diameter: 12,756 km
type: terrestrial planet
position within solar system: inner planet
time to orbit around Sun: 365 days
visible to naked eye from Earth? n/a
when discovered: unknown
god: none
superlative(s): (supports life)
adjective: earthly, terrestrian
demonym (name of fictional inhabitant): an Earthling
moons: 1

Mars

position from Sun: 4
distance from Sun: 228,000,000 km
diameter: 6,794 km
type: terrestrial planet
position within solar system: inner planet
time to orbit around Sun: 697 days
visible to naked eye from Earth? yes
when discovered: unknown
god: Mars, Roman god of war
superlative(s): largest volcano (Olympus Mons)
adjective: Martian
demonym (name of fictional inhabitant): a Martian
moons: 2

Jupiter

position from Sun: 5
distance from Sun: 778,000,000 km
diameter: 142,984 km
type: gas giant
position within solar system: outer planet
time to orbit around Sun: 11.6 years**
visible to naked eye from Earth? yes
when discovered: unknown
god: Iuppiter, Iovis, Jovis, Pater, Roman king of the gods
superlative(s): largest planet, most moons, largest moon (Ganymede)
adjective: Jovian
demonym (name of fictional inhabitant): a Jovian
moons: 76 + ring system

Saturn

position from Sun: 6
distance from Sun: 1,427,000,000 km
diameter: 120,536 km
type: gas giant
position within solar system: outer planet
time to orbit around Sun: 29.46 years
visible to naked eye from Earth? yes
when discovered: unknown
god: Saturnus, Roman god of agriculture and time
superlative(s): biggest ring system, lightest planet in weight
adjective: Saturnian
demonym (name of fictional inhabitant): a Saturnian
moons: 20 + ring system

Uranus

position from Sun: 7
distance from Sun: 2,870,000,000 km
diameter: 51,118 km
type: ice giant
position within solar system: outer planet
time to orbit around Sun: 84 years
visible to naked eye from Earth? no
when discovered: 1781
god: Ouranos, Greek god of the sky
superlative(s): coldest planet, rotates on its side
adjective: Uranian
demonym (name of fictional inhabitant): a Uranian
moons: 27 + ring system

Neptune

position from Sun: 8
distance from Sun: 4,497,000,000 km
diameter: 49,528 km
type: ice giant
position within solar system: outer planet
time to orbit around Sun: 165 years
visible to naked eye from Earth? no
when discovered: 1846
god: Neptunus, Roman god of the sea
superlative(s): furthest from Sun; slowest; highest sustained wind speeds
adjective: Neptunian
demonym (name of fictional inhabitant): a Neptunian
moons: 14 + ring system

*Previously, the "dwarf planet" Pluto (beyond Neptune) was considered to be a full-fledged planet and the solar system was said to have nine planets. Pluto had been discovered as a "new" planet in 1930 but was effectively downgraded by the International Astronomical Union in 2006.

**Days and years above refer to days and years on Earth. For example, a year on Neptune (the time Neptune takes to orbit the Sun) is equal to 165 Earth years.

Planets Vocabulary Chart
See the above information in table form (printable).

Planet Names
How the planets got their names, and the language around them