Planet Facts
PLANET FACTS
The home of interesting planet facts for kids and adults.
Interesting facts about planets
Planets in our solar system can be divided into two groups.
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![Photo of earth]()
Terrestrial Planets
More facts about terrestrial planetsTerrestrial planets are "rocky" the surfaces are characterised by mountains, craters, canyons and volcanoes.
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![Photo of saturn]()
There are 8 planets within our Solar System.
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![Picture of Mercury]()
Mercury
More facts about MercuryThe smallest planet in our solar system and closest to the sun.
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![Picture of Venus]()
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![Picture of Earth]()
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![Picture of Mars]()
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![Picture of Jupiter]()
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![Picture of Saturn]()
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![Picture of Uranus]()
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![Picture of Neptune]()
The Planets Factfile
| Planet | Diameter | Distance from the sun | Length of year |
|---|---|---|---|
| Mercury | 4,879 km | 57,909,227 km | 88 Earth days |
| Venus | 12,104 km | 108,209,475 km | 225 Earth Days |
| Earth | 12,742 km | 149,598,262 km | 365.24 Earth Days |
| Mars | 6,772 km | 227,943,824 km | 1.9 Earth Years |
| Jupiter | 139,882 km | 778,340,821 km | 11.9 Earth Years |
| Saturn | 116, 464 km | 1,426,666,422 km | 29.5 Earth Years |
| Uranus | 50,724 km | 2,870,658,186 km | 84.0 Earth Years |
| Neptune | 49,244 km | 4,498,396,441 km | 164.8 Earth Years |
What is a planet?
In 2006, the International Astronomical Union
voted on the definition of a planet.
A planet is a celestial body that
- Is in orbit around the sun,
- has sufficient mass for its self gravity to overcome rigid body forces so that it assumes a hydrostatic equilibrium (nearly round shape), and
- has cleared the neighbourhood around its orbit.
In more layman's terms:
- A planet must orbit the sun
- Have enough self gravity to create a nearly round shape.
- Have a clear orbit path.
Did you know?
Up until the new definition Pluto was classed as a planet within our solar system. It is now defined as a Dwarf planet.
