It showed that while the dark patches did contain graphite, it was far from being pure – more like ordinary rock debris with a few percent of graphite mixed into it. The study analyzed data collected by MESSENGER when the spacecraft was within 100 kilometers of the surface. That is strange because the other rocky planets have a lot less carbon on their surfaces, and carbonaceous asteroids from which a carbon-rich planet could form are much further from the sun than Mercury’s present orbit. But now research suggests that this crust was indeed made largely out of graphite. ![]() Weird CompositionĪ graphite crust on Mercury used to seem unlikely, especially if you assume that its carbon content is similar to that of Earth or Mars. In fact, the only mineral likely to crystallize that would have been able to float is graphite, the soft, dark form of carbon used in pencil “lead”. However, it turns out that a lack of iron would make Mercury’s original magma ocean less dense than the moon’s, so that any anorthite crystals that grew would sink rather than float upward to produce bright spots. But they could not work out what makes this material so dark, especially as MESSENGER proved that Mercury’s surface is remarkably poor in iron, which could have darkened it. They identified some particularly dark patches, dubbed “low reflectance material”, which apparently have been dug up to the surface as comets and asteroids hit it. (Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington/Quickmap)Īll those lava sheets must have been erupted on top of something – so where is Mercury’s oldest crust, and what was it made of? This is a problem that Mercury scientists have been grappling with since MESSENGER made its first flyby in 2008. The highlands are the moon’s oldest crust and were formed from a pile up of crystals called anorthite, which rose to the top of the global magma ocean that covered the moon in the aftermath of its violent birth.Ī 2,000-kilometer-wide area of Mercury. The MErcury Surface, Space Environment, Geochemistry, and Ranging (MESSENGER) spacecraft launched on August 3rd, 2004, it entered orbit around Mercury on Maand ended its mission on April 30th, 2015 when it deliberately plunged into the surface or Mercury. Look at the moon and you’ll see dark lava flows that have been erupted over the brighter-looking terrain of the lunar highlands. ![]() Research has now started to throw up answers – but these are raising a lot of new questions. safe address biker friend quick map meaning badoo frost names experiment u. Scientists are also struggling to understand why Mercury is so dark and what its earliest planetary crust, created as the newly-formed planet cooled down, was made of. This is incredibly odd as these kind of substances most likely would disappear during a hot or violent birth – exactly the type of birth a planet so close to the sun, such as Mercury, would have had. NASA’s MESSENGER probe already has revealed that the planet is surprisingly rich in elements that easily evaporate from the surface, such as sulphur, chlorine, sodium and potassium. For such a tiny planet, Mercury is a pretty big puzzle for researchers.
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