earth revolves round moon!

• October 29th, 2011, 08:33 AM
precious
earth revolves round moon!
is this possible in any way...... take in consideration revolution of earth,moon,sun, and sun cycle aroud a center in galaxy , galaxy rotation , revolution of galaxy around universse.
• October 29th, 2011, 08:35 AM
Strange
Actually they both revolve around their common center of mass or barycenter.
• October 29th, 2011, 08:41 AM
precious
• October 31st, 2011, 05:25 AM
Dumb Truck Driver
While that reply is technically accurate, the common COM is within the earth so we kinda wobble or more precisely, DONT wobble as much because the moon counters it.
• November 9th, 2011, 07:46 AM
precious
@ Dumb Trucck:: sir explain your point
• November 9th, 2011, 08:05 AM
Strange
The center of mass is inside the earth: Archive of Astronomy Questions and Answers
• November 9th, 2011, 10:56 AM
MeteorWayne
That's different than for the solar system, where there are years where the barycenter of the solar system is outside the surface of the sun. So the sun orbits the barycenter vof the solar system, as do the the planets, dwarf planets, comets, asteroids, and other things that go bump in the night.

[ATTACH=CONFIG]SS barycenter[/ATTACH]
• November 13th, 2011, 10:59 AM
Dumb Truck Driver
precious, the others have explained the barycenter but I'll explain the "wobble".

The earth "wobbles" like a toy top. Roughly every 26000 years it makes a full rotation.

While Polaris is currently near the center of the north celestial pole, that point is constantly moving and will trace an arc eventually so that Vega will be at the celestial north pole.

The current angle of the "wobble is 23.5 degrees but it varies anywhere from 21.5 to 24.5 degrees over a 41000 year period (figures aren't exact but rough).

Here's a guy with more time explaining it in detail. http://www.math.nus.edu.sg/aslaksen/...NOFTHEMOON.htm
• November 20th, 2011, 06:11 PM
kggf
Just a thought, the big bang set everything in motion, the earth moves around the sun in an orbit and the moving force keeps earth at its distance while the moon revolves around it and both gravity's causes them to wobble around in there own gravity pool while the mass and movement keep the moon and earth apart, movement and gravity, lovely!
• November 21st, 2011, 07:40 AM
precious
"Wobbling" is new for me.
thanx
• November 29th, 2011, 10:41 AM
matterdoc
If a person run around a friend who is walking, it will be very easy to note the person's path cannot form a geometrically closed figure. If the friend starts to run, the person will not be able to go around his friend at all. Similarly, no free body can orbit around another moving free body in geometrically closed paths (circular or elliptical). Sun is a moving body.
• November 29th, 2011, 10:43 AM
Strange
Quote:

Originally Posted by matterdoc
If a person run around a friend who is walking, it will be very easy to note the person's path cannot form a geometrically closed figure. If the friend starts to run, the person will not be able to go around his friend at all. Similarly, no free body can orbit around another moving free body in geometrically closed paths (circular or elliptical). Sun is a moving body.

Depends on the frame of reference. And so ... what?