Even though it is the only celestial body on which man has set foot, the Moon remains mysterious for us even today. Interestingly, it is the only natural satellite of our planet. The distance from the Earth to Moon is 238,857 miles, when measured from the center of each of these two entities. The orbital period of the Moon is 27 days, 7 hours, and 43.1 minutes. We do know quite a few facts about this lunar body, but when it comes to its composition, we can't help, but rely on assumptions.
How is Its Composition Determined?
Several theories about the origin of the Moon have been making the rounds of astronomy circles. Among all these theories, the Big Impact theory is by far the most convincing according to the scientists. According to this theory, a solar body of the size of Mars collided with the Earth, due to which the planet lost a chunk of its mass, which eventually went on to become its lone natural satellite. Other than such theories, various unmanned and manned missions to the Moon, satellites in the orbit, geochemical mapping, and geophysical techniques have played a crucial role in helping us study the geology of the Moon's surface.
What is the Moon Made of?
The mass of the Moon is 7.3477 × 1022 kg, while its surface area is 3.793 × 107 km2. Like our planet, even the Moon is divided into three layers: the crust, mantle, and core. Its crust is predominantly made up of anorthositic rocks. It contains oxygen, silicon, iron, magnesium, calcium, and aluminum. Its thickness is estimated to be around 50 km from the surface. Other than these elements, the crust also features traces of hydrogen, potassium, titanium, uranium, and thorium. As we go deeper, we come across the mantle of the Moon. This layer is made up of minerals such as olivine and orthopyroxene. Studies reveal that the Moon's mantle is much richer in iron content than that of the Earth. The center of the Moon, i.e., the core, is about 300 to 350 km in radius and constitutes approximately 20 percent of the total lunar body. Scientists believe that its core is made up of metallic iron with traces of nickel and/or sulfur. Studies pertaining to the time-variable rotation of the Moon suggests that its core is in a semi-molten state.
In November 2009, NASA revealed that they had found concrete evidence of the presence of water on the surface of the Moon. The discovery, which was based on the data compiled by NASA's LCROSS lunar impact mission, has been one of the greatest achievements for mankind. As of now, we can only hope that more of such expeditions end up on a successful note, so that we get to know more about our celestial neighbor.