Because there have only been a few manned lunar landings, very little is known about what the moon is made of. And because these samples have only been collected from a few small sites, what is known refers to a tiny proportion of the Moon's crust and lunar soil called regolith.
Often argued about and hotly debated, working from the centre to the surface of the moon what is currently known about the moon, or has at least been suggested by scientists, can be found below.
3 - In addition to iron, the total number of elements to comprise the dense alloy forming the Moon's core. These 'chemical' elements are sulphur (shown on the periodic table as S), and nickel (shown on the periodic table as NI). This extends for up to a radius of 10 kilometres to the inner cores outer edge.
3 - like the solid inner core, the total number of elements thought to make up the slightly molten outer core. Thought to be as hot as 1600-1700 K (Kelvin), this super hot outer core therefore also comprises iron, nickel, and as much as 6% sulphur.
At as much as 1700K, this make the outer core of the Moon as hot as 1426.85 Celsius!
4 - one more element than those thought to make up the inner and outer core, the number of elements thought to comprise the Moon's 'mantle' which begins approximately 50km below the surface. These are iron, clinopyroxene, olivine, and orthopyroxene - although the exact amounts remain unknown.
6 - the number of manned lunar landings. With so small a number of such landings, it has been suggested that the 50 km thick crust of the Moon contains the elements listed below.
43% - the proportion of lunar crust made of oxygen.
20% - the percentage of lunar crust to consist of silicon.
10 - 13% - the percent of lunar crust made up of iron.
6 -19% - the proportion of magnesium found within the lunar crust.
3 - 8% - the percentage of calcium also found within this particular stratum.
3 - 7% - the amount of aluminium found within the lunar crust.
0.18% titanium, 0.12% manganese, and 0.42% of chromium.
Even smaller trace elements within the crust include uranium, thorium, potassium, and hydrogen.
2 – the number of rock 'types' to have been retrieved from the lunar soil on which forms the outer layer of the Moon's crust. Known as the regolith, these igneous rocks are mafic plutonic, and maria basalt. Both of these formed when lava on the Moon's surface cooled thousands of years ago.
Varying from site to site, the lunar surface known as regolith is between 3 – 20 meters thick. Soil is a rather misleading description, and unlike the soil on Earth is actually a hard concrete like substance.
© 2013 - Dave Fowler, History in Numbers.
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