Geology Home Page physical geology historical geology planetary gems
Roger Weller, geology instructor
by Roy Fox
What Makes The Moon
The Earth’s one and only Moon, known as Luna, orbits around the Earth and
although this has been the case for billions of years, this was not always so.
Many speculate and debate as to where the true origins of our moon may exist.
Some say that the moon is a captured celestial body, while others say that it
was formed from the debris left over during Earth’s own creation. The most
likely hypothesis as to the origin of our moon is that a large planet sized
object, perhaps the size of Mars, crashed into the Earth billions of years ago
flinging Earth debris into space. This debris eventually formed into the moon as
we know it today. This hypothesis is very likely because most of the composition
of the moon is greatly similar to the materials making up the Earth itself.
Moon is very important for life on Earth and without it life might have ended up
very different than it is today. Without the moon the Earth would have no tidal
forces working at the oceans. Billions of years ago these tidal forces may have
contributed to the creation of the first microbial life forms on the Earth.
Without the Moon, Earth might not have ever developed life. When astronauts
landed on the moon and gathered samples, these samples of lunar rocks and
material where found to be similar to the composition of the Earth as well. The
composition of the Moon is very similar to Earth, the Moon has been orbiting the
Earth for billions of years, and there are many theories as to why the Moon is
the way that it is.
In the 1970’s when the Apollo astronauts visited the Moon, the samples of lunar
rocks and soil brought back where tested and found to be similar to the
composition of the Earth itself. The composition of the Moon’s surface was manly
oxygen and silicon, identical to what can be found in the Earth’s crust. Though
there are many speculations as to why and how, the facts show that the lunar
surface is very much the same as the composition of the Earth itself. As for the
composition of the interior of the Moon, it is a mystery. Because none have
returned to the Moon since the original Apollo missions no one can study in
greater detail what lies in the deep crust and inner parts of the Moon.
billions of years the Moon has orbited the Earth. Although when in the Moon’s
earlier days it orbited much closer to the Earth than it does now. With every
orbit around the Earth the moon gets a little bit further away. This has been
occurring for anywhere between three and four billion years, as carbon dating
showed in the samples brought back to Earth. Over the course of that time the
Moon has been bombarded by giant meteor craters, untouched by time and perfectly
preserved in the cold and silent void of space. The meteorites themselves would
undoubtedly be very similar to meteorite fragments found on Earth, mostly
consisting of iron and other trace elements. Although the Moon has orbited the
Earth for Eons, The questions of the moons origin itself are still being
The Moon, being so similar to the planet Earth could only mean one logical conclusion, that it is made up of the same material. Most scientists today believe that the moon was created in a giant impact between a large Mars sized object and the Earth around four and a half billion years ago. The impact was a glancing blow, not enough to destroy the Earth, but just enough to knock dust and debris out into space around the Earth. The large dusty rings that surrounded the Earth perhaps four billion years ago eventually formed into a close orbiting moon. Over the next four billion years, the moon would slowly drift outward until it is where we see it today.
The geology and geography of the Moon is fascinating, the very study of the rocks and minerals we may gather from the moon in the future, should we ever return to the moon, could answer questions about the origins of the Earth itself. The minerals and elements of the moon lie almost perfectly preserved over the billions of years since the Earth and Moon where created. Many mysteries rest beneath the surface of the Moon, perhaps the very original rocks and minerals of the Earth before the existence of the Moon sit somewhere on or beneath the cold lunar surface waiting for some future scientist, explorer, or geologist to discover.
Cain, Fraser. “What is the moon Made of?” Universe Today. (November 3, 2008). Web. April
“Earth’s Moon: Formation, Composition and Orbit.” Space.com. Web. April 15, 2012.
“Formation of the Moon” Photograph. Universe Today. n.p., n.d. Web. April 24, 2012.
“NASA Has Lost Hundreds of its Moon Rocks, New Report Says.” Photograph. space.com.
n.p.,n.d. Web. April 24, 2012.
“Scientists discover water on the moon is widespread, similar to Earth’s.” Photograph. Infinite
Unknown. n.p.,n.d. Web. April 24, 2012.
“The Composition of the Moon.” pd.astro.it. Web. April 17, 2012.
“The Composition Of The Moon.” studyworld.com. Web. April 18, 2012.
“Water On The Moon” Photograph. spaceopedia.com. n.p., n.d. Web. April 24, 2012.