WORLD - ALL

The mystery of how Earth got its Moon is one step closer to being solved.
The European Space Agency’s lunar-orbiting craft called SMART-1 has completed the first detailed chemical mapping of the lunar surface. The detected chemicals, such as calcium and magnesium, give a boost to the longstanding theory that the Moon was formed from the debris flung into space after a collision between early Earth and a Mars-size planet, Space.com reported.
Calcium, in particular, is found deep inside Earth. So if the Moon has a lot of calcium, then perhaps it is made of material that was once inside our planet. Armed with miniaturized instruments–including an ultra-compact electronic camera, an X-ray telescope the size of a toaster for mapping chemical composition, and high-tech communication gadgets–SMART-1 had lofty goals. It was to pin down out how the Moon came to exist, search for water locked up as ice in the depths of Sun-deprived craters, and map the mineral composition of the Moon’s crust.
Prior to the Apollo missions, there was no consensus among planetary scientists regarding the Moon’s formation. One theory claimed that the Earth and the Moon formed at the same time from the same disk of swirling dust and gas, while another purported that the Moon is a scoop of Earth that split off in the early stages of our solar system.
Besides sending home awe-inspiring photos, the Apollo missions delivered 842 pounds (382 kilograms) of lunar rocks and soil–the first pieces of chemical evidence to help explain the Moon’s formation.
The favored theory now describes a violent collision between the Earth and a planet-size object, which hurled molten rocks and dust from both contenders into space. Over time, the debris congealed into the Moon.
With most Moon know-how coming from Apollo’s six landing sites, scientists saw lots of room for error. To solve the lunar-forming puzzle, a global investigation of the entire surface was needed.
Enter SMART-1 (Small Missions for Advanced Research and Technology), a spacecraft equipped with seven high-tech instruments that would give a detailed map of both chemical make-up and topography over the Moon’s entire surface.
One of the most important devices, D-CIXS recorded hours of X-ray data. When the Sun’s rays hit the Moon, the X-rays caused atoms to fluoresce and emit their own X-rays. The D-CIXS (Demonstration Compact Imaging X-ray Spectrometer) telescope translated the amount of energy released into the type and abundance of different elements.
D-CIXS detected the major components of rocks: aluminum, silicon, magnesium, and calcium. However, elements like calcium are not homogenously mixed throughout the Moon. To paint a three-dimensional picture of the chemical composition, planetary scientists needed both surface and “bulk“ data. 

Article source: http://www.iran-daily.com/