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Saturday, 7 May 2016

Mercury (planet)

The Romans named the planet after the swift-footed Roman messenger god, Mercury (Latin Mercurius), which they equated with the Greek Hermes, because it moves across the sky faster than any other planet. The symbol for Mercury is based on Hermes' staff.

On March 29, 1974, NASA's Mariner 10 became the first ever space probe to fly by Mercury. Launched on November 3, 1973, it first flew to Venus and then, using Venus' gravity to modify its trajectory, swung around to visit Mercury.

Mariner 10, the first probe to visit Mercury

Mariner 10 mapped about 45% of the planet’s surface from 1974 to 1975. The second probe to visit Mercury, the MESSENGER spacecraft, finished mapping the planet in March 2013.

Mercury is the smallest planet in the Solar System with a radius of 2,439.7 kilometers (1515.9 miles). Saturn's moon Titan and Jupiter's moon Ganymede are both larger than Mercury.

Mercury is made of about 70% metallic and 30% silicate material meaning it has a greater mass than the largest moons in the solar system.

Mercury's density is the second highest in the Solar System at 5.427 g/cm³, only a little bit less than Earth’s.

Mercury has a large iron core, which gives off a magnetic field about 1% as strong as that of the Earth.

A day on Mercury is twice as long as its year.

Full-color image of Mercury from first MESSENGER flyby

Surface temperatures can be anywhere from about −183 °C to 427 °C, (−297 °F to 801 °F), with the subsolar point being the hottest and the bottoms of craters near the poles being the coldest.

Mercury has the greatest temperature change from day to night: 840°F in the day, plummeting to -275°F at night.

Even though Mercury is the closest planet to the Sun, it is not the warmest. This is because it has no atmosphere, so any heat that the Sun gives to it quickly escapes into space.

The craters on Mercury are named after various composers, writers, artists and suchlike, the only stipulation being that they had to be famous for at least 50 years and dead for more than three years prior to nomination.

Interior of Abedin crater

The Japanese for Wednesday translates as 'Water day' as the planet Mercury was known as the 'water star'.

Mercury probably smells like moist, metallic burps, since its atmosphere consists of magnesium, calcium, sodium, and water.

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