EARTH+MOON+SUN-What are there Rotational+Orbital Velocities?

I hear that the Moon is getting far from the Earth. This must mean the rotation of the Moon is slowing down. The "spin-orbit resonance" perhaps keeps the way the Moon looks as it does now.

resonance (PDF)
"The Moon, whose rotation period equals its orbital period around the Earth, thus allowing only one side of its surface to be seen from our planet, is a well-known example of a 1:1 spin- orbit resonance. "

Part of the answer is here :

the slowing spin of the earth

NASA Details Earthquake Affects on the Earth

NASA scientists using data from the Indonesian earthquake calculated it affected Earth's rotation, decreased the length of day, slightly changed the planet's shape, and shifted the North Pole by centimeters. The earthquake that created the huge tsunami also changed the Earth's rotation.

Dr. Benjamin Fong Chao, of NASA's Goddard Space Flight Center, Greenbelt, Md. and Dr. Richard Gross of NASA's Jet Propulsion Laboratory, Pasadena, Calif. said all earthquakes have some affect on Earth's rotation. It's just they are usually barely noticeable.

"Any worldly event that involves the movement of mass affects the Earth's rotation, from seasonal weather down to driving a car," Chao said.

Chao and Gross have been routinely calculating earthquakes' effects in changing the Earth's rotation in both length-of-day as well as changes in Earth's gravitational field. They also study changes in polar motion that is shifting the North Pole. The "mean North pole" was shifted by about 2.5 centimeters (1 inch) in the direction of 145º East Latitude. This shift east is continuing a long-term seismic trend identified in previous studies.

They also found the earthquake decreased the length of day by 2.68 microseconds. Physically this is like a spinning skater drawing arms closer to the body resulting in a faster spin. The quake also affected the Earth's shape. They found Earth's oblateness (flattening on the top and bulging at the equator) decreased by a small amount. It decreased about one part in 10 billion, continuing the trend of earthquakes making Earth less oblate.

To make a comparison about the mass that was shifted as a result of the earthquake, and how it affected the Earth, Chao compares it to the great Three-Gorge reservoir of China. If filled the gorge would hold 40 cubic kilometers (10 trillion gallons) of water. That shift of mass would increase the length of day by only 0.06 microseconds and make the Earth only very slightly more round in the middle and flat on the top. It would shift the pole position by about two centimeters (0.8 inch).

The researchers concluded the Sumatra earthquake caused a length of day (LOD) change too small to detect, but it can be calculated. It also caused an oblateness change barely detectable, and a pole shift large enough to be possibly identified. They hope to detect the LOD signal and pole shift when Earth rotation data from ground based and space-borne position sensors are reviewed.

The researchers used data from the Harvard University Centroid Moment Tensor database that catalogs large earthquakes. The data is calculated in a set of formulas, and the results are reported and updated on a NASA Web site.

The massive earthquake off the west coast of Indonesia on December 26, 2004, registered a magnitude of nine on the new "moment" scale (modified Richter scale) that indicates the size of earthquakes. It was the fourth largest earthquake in one hundred years and largest since the 1964 Prince William Sound, Alaska earthquake.

The devastating mega thrust earthquake occurred as a result of the India and Burma plates coming together. It was caused by the release of stresses that developed as the India plate slid beneath the overriding Burma plate. The fault dislocation, or earthquake, consisted of a downward sliding of one plate relative to the overlying plate. The net effect was a slightly more compact Earth. The India plate began its descent into the mantle at the Sunda trench that lies west of the earthquake's epicenter.

That's just plain wrong - sidereal calculation remains unaltered.

That's just plain wrong - sidereal calculation remains unaltered.

HofT wrote:

That's just plain wrong - sidereal calculation remains unaltered.

If a day shortened then a siderial day is shortened too, if you mean "to the distant star or galaxy" by "siderial."

Satt: explain to me in layman's terms how the recent tsunami caused the Earth's Day to change?

Due to the quake, a small component of the Earth's mass moved slightly closer to the center of the planet. This caused the planet to speed up through conservation of angular momentum (like an ice skater in a spin, pulling their arms in).

Satt - the India plate as you know split off Africa eons ago and crashed into Eurasia raising the Himalayan mountain chain. My question to you is: if its continued movement contributes to further heightening of said mountain chain - and all satellite measurements indicate that it does - wouldn't that counteract, negate, or even reverse the motion that you mention when analyzed in terms of geological ages rather than human lifetimes?

The devastating mega thrust earthquake occurred as a result of the India and Burma plates coming together. It was caused by the release of stresses that developed as the India plate slid beneath the overriding Burma plate.