Mercury planet4/25/2023 ![]() Mercury's exosphere is constantly evolving: while the solar wind continuously blows it away, intense gusts from the Sun also constantly super-heat more of the planet's crust, thereby replenishing Mercury's gassy envelope. For the most part, this outer layer is made up of particles coming from solar winds and elements from Mercury's crust (such as hydrogen, helium, oxygen and sodium) that are vaporized by the intense heat of the Sun. Mercury's atmosphere is so thin and fragile that it is instead considered an exosphere: a very thin volume of matter that surrounds a planet, but is not dense enough to behave like an atmosphere. Scientists believe that frozen water may exist in these craters. Some of Mercury's craters have shaded sections that are never exposed to the Sun. Mercury's surface remains the most mysterious of all the rocky planets, though, as no lander has ever explored it. Its surface is littered with craters that have accumulated and remained unchanged over billions of years, since the planet has no significant geological activity or atmosphere. SurfaceĪt first glance Mercury looks a lot like Earth's Moon. The opposite effect happens at sunset, with the Sun setting and briefly rising before finally setting completely. Because of this, the morning Sun appears to rise briefly, set, and continue rising again from certain spots on the surface of the small planet. Mercury's orbit is also the least circular of all the planets and looks somewhat egg-shaped. Just like Earth, Mercury also rotates on its own axis, but much more slowly: one day-night cycle on Mercury takes the equivalent of 176 Earth days, or two full Mercurian years! Mercury’s rotation in relation to distant stars takes 59 Earth days. Named after the Roman messenger of the gods, who was known for being very swift, Mercury takes only 88 days to complete one orbit around the Sun – the shortest year of all planets. The planet has a surprisingly large iron core, which may have formed because the early Sun heated and vaporized rock on Mercury's surface. Mercury is the closest planet to the Sun, which likely influenced its composition and formation. Our Sun was born at its centre, and the planets were created about 4.5 billion years ago from particles sticking together along rings in the disc. It launched in 2018 and should arrive in 2025.Like all the other planets, Mercury was likely formed in the large cloud of gas, dust and ice of the ancient solar system, which collapsed into a spinning disc. The next mission to Mercury, BepiColombo, is a joint mission between the European Space Agency (ESA) and the Japan Aerospace Exploration Agency (JAXA). It mapped the whole surface and found further evidence of frozen water. MESSENGER launched in 2004 and orbited Mercury between 20. Mariner 10 launched in 1973 and mapped almost half of Mercury’s surface by 1975. These are NASA’s Mariner 10 and MESSENGER spacecraft. Only two spacecraft have been to Mercury. Hermes was later named Mercury by the Romans and was considered the messenger of the gods. The ancient Greeks gave Mercury two names: Apollo, which was visible at sunrise, and Hermes, which was visible at sunset. It’s best viewed early in the morning or at twilight. Mercury is bright when viewed from Earth but it’s difficult to observe as it’s usually hidden in the light of the Sun. Radar observations conducted by the Goldstone antenna in California and the Very Large Array in New Mexico in the early 1990s suggested that frozen water exists at the bottom of deep craters on Mercury’s poles. Unlike the Moon, however, it has a massive iron core that generates a magnetic field about 1% as strong as the Earth’s. It has no satellites of its own and, like the Moon, it’s not massive enough to sustain an atmosphere. It has at least as many craters and is covered with dust. Mercury is a rocky planet, similar to the Moon. This is due to the effects of general relativity (discussed in Chapter 8). ![]() This means that its orbit is more elliptical than the orbits of the other planets, which are very close to being circular. Mercury also has the most eccentric orbit of all the planets in the Solar System. The length of the day (1-3) is longer than the rotation period of the planet (1-2).
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