- the nearest planet to the Sun is Mercury.
- during its orbit – it is between 29 and 44 million miles away from the Sun.
- Mercury has the fastest orbit – one orbit around the Sun takes just 88 days – compare our Earth takes one year around the Sun in 365 days; just over four times around the Sun as Earth around once.
- twice during Mercury orbit – it gets very close to the Sun and speeds up so much that our Sun seems to go backwards in the Sky.
- Mercury rotates once every 59 days – the time between one sunrise and the next is 176 days (diagram)
- temperatures change from -180ºc at night to more than 430ºc during the day (hot enough to melt lead metal.)
- the crust and mantle are made largely of rock, but the core (75% of the core’s diameter is solid iron.) (diagram)
- Mercury’s dusty surface is pocked by craters made by space debris crashing onto it.
- with 6% of Earth’s mass, Mercury is so small that its gravity can only hold on a very thin atmosphere.
- Mercury is so small that Mercury’s core has cooled and become solid (not the same as our Earth’s core) – as happened, Mercury shrunk and its surface wrinkled. (photo)
- Craters on Mercury discovered by USA’s Mariner 10 space probe have names such as Bach, Beethoven, Wagner, Shakespeare and Tolstoy.
- discovered in 1974; the largest feature on Mercury is a huge impact crater – it called the Caloris Basin – around 810 miles across and 1¼ miles deep.
Transits of Mercury
Next Transit of Mercury for the UK Observers
- 2003 Transit of Mercury in the UK (Wednesday 7th May 2003.)
- 2016 Transit of Mercury in the UK (Monday 9th May 2016)
- 2019 Transit of Mercury in the UK (Monday 11th November 2019)
- 2032 Transit of Mercury in the UK (Sunday 7th November 2032)
- 2039 Transit of Mercury in the UK (Saturday 7th May 2039)
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