Astronomy/face of moon

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Expert: Steven LJ Russo - 3/7/2006


Question
A very talented student  of mine just asked me a good question which I'm having a tough time answering: If the moon's rotation and revolution around the Earth are not exactly equal, why doesn't our view of the moon change over a period of time. Why do we see the same face that was seen hundreds of years ago?  

Answer
Becky:

You are correct to say that the rotation and revolution period are not equal, although many of us teach that it is.

Technically speaking, along with rotation and revolution, the Moon has about 10 other motions, wiggles, and wobbles that it goes through.  Waaaaayyyyy too long to go into here.

These other "motions" actually lets us see around 59 percent of the lunar surface, so technically speaking, 9 percent of the "dark side".

But, since they are just about equal, the "same side" is always visible, and will always be.

Go to this web site for more info on the Moons appearance:

http://www.fourmilab.ch/earthview/moon_ap_per.html

Steve

www.look-to-the-skies.com

Astronomy

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Steven LJ Russo

Expertise

As a space science educator in a planetarium, my work centers around teaching people about the night sky and the solar system. I have a strong background in those areas, plus the history of NASA and spaceflight, and meteorology.

Experience

Experience in the area. I have been an amateur astronomer for 47 years, and have been teachng space science in planetariums for 34 years. For 15 years I was a radio and television meteorologist, and for the past 20 years I have been a space science writer for two newspapers in New York State. I am a member of the Middle Atlantic Planetarium Society and the International Planetarium Society. I have had a number of articles published in several astronomy journals, including "The Constellation" and the "Planetarian". Education/Credentials. I hold a B. S. from Wagner College and an M. S. from State University of New York at Oswego. Awards and Honors. I have been awarded the "Fellows" award from the International Planetarium Society for more than 20 years of continuous service in the planetarium field.

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