The Moon: Our Astronomical Companion

The moon called Luna by the Romans, Selene and Artemis by the Greeks, and many other names in other mythologies, is Earth’s only natural satellite, our closest astronomical companion and it is the second brightest object in the sky after the Sun.  The moon has been a source of inspiration from 10th-century Japanese folktales to modern day science fiction.

The amount of time the Moon takes to complete one turn on its axis with respect to the stars is 27.3 days, and it’s called a sidereal day.  This corresponds with the Moons orbital period of the Earth which also takes just over 27 days meaning that the Earth and the moon are tidaly locked.  The time between successive new moon phases is 29 and a half Earth days. The moons phases are easy to describe. Basically half of the moon is always illuminated by the sun, what changes is the position of the moon itself and what aspects of it we are able to see from earth. The moon begins as a New Moon which is covered in shadow and not visible. In its orbit the Moon will gradually become increasingly brighter, referred to as “Waxing”, until it becomes a Full Moon.  After a Full Moon the Moon will gradually become darker, referred to as “Waning” as it makes its journey back into a New Moon where the cycle begins again.  This is actually very fascinating and I will talk about it in greater detail in another post.

The Moons atmosphere is extremely thin. This means that the surface of the Moon is unprotected from cosmic rays, meteorites and solar winds, and has huge temperature variations. The lack of atmosphere means no sound can be heard on the Moon, and the sky always appears black.  In fact due to this extreme heat and ultraviolet conditions on the moon the flags that have been left there 40 plus years ago have most likely been destroyed, and if they are still intact they would be bleached white. The surface of the moon is covered in dust with the same consistency as talcum powder.  The Moon has much weaker gravity than Earth, due to its smaller mass, so you would weigh about one sixth (16.5%) of your weight on Earth, making me about 2 stone or so!   Dark side of the moon is a myth! I’m talking about the misconception that one side of the Moon is always shrouded in darkness, not the Pink Floyd album.  While one side of the mood is all we can see the other side or far side of the Moon does see the sun’s rays. The rise and fall of the tides on Earth is caused by the the gravitational forces that the Moon exerts.  The moons Gravity causes bulges to move around the oceans as the Earth rotates, causing high and low tides around the globe.

The Moon was first visited by the Soviet spacecraft Luna 2 in 1959. It is the only extraterrestrial body to have been visited by humans. The first landing was on July 20, 1969  with Neil Armstrong on the Apollo 11 mission being the first man to step foot on its surface.  The last was in December 1972 with Gene Cernan on the Apollo 17 mission, since then the Moon has only be visited by unmanned vehicles.  The Moon is also the only body from which samples have been returned to Earth. In the summer of 1994, the Moon was very extensively mapped by the little spacecraft Clementine and again in 1999 by Lunar Prospector.

The Moon has always been a muse for me, its silver light cold hauntingly beautiful and mysterious, it is one of the reasons I am fascinated in astronomy.  I will be returning to the Moon in many other posts because there is just is so many fascinating subjects to cover!  Below are a few links to the sites I gathered my information on but I would like to advise you to check out www.astronomycast.com and www.universetoday.com and  earthsky.org. Photo Credit:  

Thanks To: theplanets.orgsolarsystem.nasa.gov, science.nationalgeographic.com,  universetoday.com,  space-facts.com,  astronomycast.com,  astronomyonline.org,  planetfacts.org earthsky.org

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