The Planets


The planets are divided in the two groups – Inner planets and Outer planets.

Inner planets – Mercury, Venus, Earth, Mars.

Outer planets – Jupiter, Saturn, Uranus, Neptune.


Closest planet to the Sun.

Mercury is only the second hottest planet.

Mercury is the smallest planet.

A year on Mercury takes 88 Earth days.


Venus is often called the Earth’s sister planet.

Longest rotation period of any planet.

Hottest planet in our solar system

Revolves around the sun in clockwise manner while most others are revolving in anti-clockwise.

No natural satellites (moons)

A year on Venus takes 225 Earth days.

Venus is the second brightest object in the night sky.


There is only one natural satellite of the planet Earth.

Has water in all three states – liquid, solid and gas.

Gasses present in the earth’s atmosphere are Nitrogen, Hydrogen, Oxygen, Carbon Dioxide etc

It takes 23 hour 56 minutes 46 seconds to rotate around its axis.

It takes 365.26 days to revolve around the Sun.

Moon is the only natural satellite of the Earth.


Known as the ‘Red Planet’ due to presence of iron-rich red soil.

Mars has the largest dust storms in the solar system.

Phobos and Deimos are the two moons of Mars.

Mars has the largest volcano in the solar system – Olympus Mons.


Largest planet of the solar system.

Has two and a half times the mass of all other planets put together.

Has the shortest rotation period.

A gas giant, primarily composed of hydrogen and helium with no discernible solid surface.

Has a giant storm (three times the diameter of earth) since 1831 called the ‘Great Red Spot’.

Has a faint ring around it.

Has 67 moons.

4 largest moons discovered by Galileo – Ganymede (largest moon in the solar system – bigger than Mercury), Callisto, Io (volcanic), Europa (has water-ice).

Missions to Jupiter: Galileo, Juno (upcoming)


Second largest planet in the Solar system.

Its density is less than the water.

Has a band of concentric rings revolving around it made up of tiny rocks and pieces of ice.

Has 62 moons.

Moons of Saturn: Titan is the largest (has a major atmosphere, complex organic chemistry and ICE VOLCANOES‼), Rhea (may have its own ring system), Enceladus.

Missions to Saturn: Cassini-Huygens.


Discovered by Sir William Herschel.

Blue-green (cyan) in colour.

Third biggest planet of the solar system.

Composed of Hydrogen, Helium, Water, Ammonia, Methane.

It is tilted sideways so that its poles lie where most other planets have their equators.

Has faint rings.

Has 27 known moons (5 main – Miranda, Ariel, Umbriel, Titania, Oberon).

Spacecraft Flyby: Voyager 2.


Discovered by mathematical predictions and disturbances in Uranus’ orbit.

First proposed by Alexis Bouvard, and first observed by Johann Galle.

Farthest planet from the Sun.

Primarily composed of hydrogen, helium, nitrogen, water, ammonia, methane.

Is blue in colour because of methane.

Has a storm called ‘Great Dark Spot’.

Has 14 known moons (Triton – largest)

Spacecraft Flyby: Voyager 2.


Used to be the ninth planet.

Demoted to status of “Dwarf Planet”.

Icy and cold.

Has five moons – Charon, Styx, Nix, Kerberos, Hydra.