Department of Energy Argonne National Laboratory Office of Science NEWTON's Homepage NEWTON's Homepage
NEWTON, Ask A Scientist!
NEWTON Home Page NEWTON Teachers Visit Our Archives Ask A Question How To Ask A Question Question of the Week Our Expert Scientists Volunteer at NEWTON! Frequently Asked Questions Referencing NEWTON About NEWTON About Ask A Scientist Education At Argonne Orbital Synchrony
Name: John
Status: educator
Age: 40s
Location: N/A
Country: N/A
Date: 7/24/2003


Question:
I am literally amazed at the fact that our Moon rotates in synchrony with its revolution around Earth! Such that we observe essentially the same "face" at all times. What is the probability of this phenomenon? Is it common for any celestial body in rotation/revolution to have this "almost exact" synchrony? As we postulate the probability of additional "life systems" in the universe, this relationship between Earth and her Moon seems to be inappropriately taken for granted!


Replies:
It is not a coincidence or an accident. When something as large as the moon revolves while in orbit, a lot of energy is lost to internal friction, and the loss comes out of the moon's energy of revolution. The reason energy is lost to internal friction is pretty simple: the part of the moon nearest us would not stay in the same orbit as the rest of it if it were not attached. The result is a tidal force that stretches and squashes the moon as it revolves. Because the moon is not perfectly elastic, the stretching and squashing causes energy of revolution to be converted into heat.

Tim Mooney



Click here to return to the Physics Archives

NEWTON is an electronic community for Science, Math, and Computer Science K-12 Educators, sponsored and operated by Argonne National Laboratory's Educational Programs, Andrew Skipor, Ph.D., Head of Educational Programs.

For assistance with NEWTON contact a System Operator (help@newton.dep.anl.gov), or at Argonne's Educational Programs

NEWTON AND ASK A SCIENTIST
Educational Programs
Building 360
9700 S. Cass Ave.
Argonne, Illinois
60439-4845, USA
Update: June 2012
Weclome To Newton

Argonne National Laboratory