The planet Mercury is the closest in the Solar System to the Sun. It is the second smallest planet in the Solar system after Pluto, and is about a third of the size of Earth.
The length of days and years on Mercury are vastly different to those on Earth. Mercury rotates on its axis once every 58.9 Earth days. It circles the Sun once every 87.9 Earth days. In other words, if you were to stay up from sunrise to sunset on Mercury, you would need to be awake for two Mercury years, or 176 Earth days!
Being the closest planet to the Sun, Mercury experiences the hottest surface temperatures out of all the planets in the solar system, but it also sees a broader range of temperatures too. The lack of any substantial atmosphere contributes to this range in temperatures. The atmosphere is very thin and is made up of helium and sodium.
The side of the planet nearest to the sun has temperatures reaching up to 427C. In comparison, the side in night time experiences temperatures which fall as low as -183C.
Although closest to the Sun, Mercury's slow orbit means it also experiences extreme coldness. Radar imagery which is used to study Mercury from Earth, shows reflectivity near the north and south poles. It is suggested this could be an indication that ice has formed there. If the areas are shadowed, possibly by a crater, it is thought this could be the case. There are two suggestions about where the ice has come from; one is from meteorite bombardment, the other is planetary outgassing. Meteorites were thought to carry vast quantities of water in the past.
As Mercury is so far away, very little exploration has been carried out. The only spacecraft to travel there was in 1974, by the Mariner 10. Over three trips it imaged around half of the planet. To date the other half is still untouched, so a true picture of the planet, or its weather, is not known.
Mercury does not have a moon and its gravity is about a third of that of the Earth. Its diameter is 3,025 miles.
Related Articles:
- Mercury weather
- Venus weather
- Mars weather
- Saturn weather
- Uranus weather
- Neptune weather
- Pluto weather
