planets.im
Planet file

The planet file

The Sun, eight planets, the Moon and Pluto, in order from the Sun. Every fact links to its source, checked 24 Oct 2026.

Rocky or giant?

  • The first four planets from the Sun, Mercury, Venus, Earth and Mars, are the inner planets, also known as the terrestrial (rocky) planets. [source]
  • The giant planets have no hard surface, just swirling gases above a core. Jupiter and Saturn are gas giants; Uranus and Neptune are ice giants. [source]
Our star, at the centre

The Sun

  • The Sun is a yellow dwarf star, a hot glowing ball of hydrogen and helium, and the only star in our solar system. [source]
  • The Sun holds 99.8% of all the mass in our solar system. [source]

Coming soon sun.planets.im

Planet 1 of 8 · rocky

Mercury

  • Mercury is the smallest planet and the nearest to the Sun. It’s only a little bigger than Earth’s Moon. [source]
  • The first four planets from the Sun, Mercury, Venus, Earth and Mars, are the inner planets, also known as the terrestrial (rocky) planets. [source]

Coming soon mercury.planets.im

Planet 2 of 8 · rocky

Venus

  • Venus is the hottest planet in the solar system, even hotter than Mercury. Its thick atmosphere traps heat in a runaway greenhouse effect. [source]
  • Venus spins slowly in the opposite direction from most planets. [source]

Coming soon venus.planets.im

Planet 3 of 8 · rocky

Earth

  • Earth is the third planet from the Sun, and the only place we know of with living things. [source]
  • The word “planet” goes back to the ancient Greek planētēs, which means “wanderer”. [source]

Coming soon earth.planets.im

Earth’s Moon

The Moon

  • The Moon is tidally locked to Earth, so we only ever see one side of it. Nobody saw the far side until a Soviet spacecraft flew past in 1959. [source]
  • The first definite discovery of water on the Moon was made in 2008 by India’s Chandrayaan-1 mission. [source]

Coming soon moon.planets.im

Planet 4 of 8 · rocky

Mars

  • Mars is the “Red Planet” because iron minerals in its dirt oxidise, or rust. [source]
  • Mars has the largest volcano in the solar system: Olympus Mons. [source]

Coming soon mars.planets.im

Planet 5 of 8 · gas giant

Jupiter

  • Jupiter is the fifth planet from the Sun and the largest in the solar system. [source]
  • Jupiter’s Great Red Spot is a giant storm that is bigger than Earth. [source]

Coming soon jupiter.planets.im

Planet 6 of 8 · gas giant

Saturn

  • Saturn is the sixth planet from the Sun and the second largest. [source]
  • Saturn isn’t the only planet with rings, but none are as spectacular or as complex as Saturn’s. [source]

Coming soon saturn.planets.im

Planet 7 of 8 · ice giant

Uranus

  • Uranus spins at nearly a right angle to its orbit, so it rolls around the Sun like a ball on its side. [source]
  • Uranus was the first planet found with the help of a telescope. William Herschel discovered it in 1781, and at first he thought it was a comet or a star. [source]

Coming soon uranus.planets.im

Planet 8 of 8 · ice giant

Neptune

  • Galileo saw Neptune through his small telescope in 1612 and 1613, but recorded it as a fixed star. [source]
  • Neptune was the first planet found by mathematical prediction rather than by watching the sky. Urbain Le Verrier worked out where it should be. [source]
  • Voyager 2 was the first spacecraft to fly past Neptune, in the summer of 1989. [source]

Coming soon neptune.planets.im

Dwarf planet since 2006

Pluto

  • Pluto was reclassified as a dwarf planet in 2006 by the International Astronomical Union. [source]
  • Pluto was named by an 11-year-old. In 1930 Venetia Burney, from Oxford, suggested the name of the Roman god of the underworld. [source]

Coming soon pluto.planets.im

Kit for looking up

Handy things for a clear night: Binoculars · A planisphere · A red torch · Solar system books for kids. These are Amazon UK search links. As an Amazon Associate I earn from qualifying purchases.