Submitted by Rick Hamell: The devastating 2004 Sumatran earthquake, which caused the worst tsunami in modern times, should have left a detectable scar on Earth's gravity field, European scientists said Monday. A satellite planned for launch next year could detect the blemish, they said.The magnitude 9.3 earthquake has already been said to have shortened the day by fractions of a second, shifted the North Pole by an inch, and made the planet less fat around the middle.The new prediction comes from Roberto Sabadini and Giorgio Dalla Via at the University of Milan. The idea is fairly straightforward. The strength of Earth's gravity varies depending on the depth of a trench or height of a mountain, as well as the density of material. Even changing tides alter the gravity field. The Dec. 26, 2004 quake lifted an 18-foot (6 meter) ledge along a 620-mile (1,000 kilometer) fault.Gravity variations are measured using the geoid, which is similar to sea-level. The geoid is a hypothetical "surface" around the Earth at which the planet's gravitational pull is the same everywhere.

Over dense areas, the geoid moves away from the real surface, and where gravity is less, the geoid moves closer to the real surface.The Sumatran quake, the geoid moved as much as 0.7 inches (18 millimeters), the scientists predict.The variations in the gravity field are already studied from space with NASA's GRACE mission.

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its funny how nature seems to oppose matter, and not the vaccum...creating gravity.

I personally don't think that the human race has any idea what nature is capable of. This quake was devastating, yes, but I'm willing to bet it is only a speck in what nature could really unleash.

The worst is yet to come...

I'm really curious how an earthquake can shorten a day, even by fractions of a second. But, I never got good grades in Science anyway, so I probably wouldn't understand.

I think by disrupting the rotation. It caused something like a stutter in the way the Earth revolves (sorta making it jump forward), thereby making the day just a fraction shorter.

picture an ice skater doing a spin....When they pull their arms in close to their body they spin faster. Same idea here, Less fat around the middle (IE. smaller diameter) the faster the spin the shorter the day.

This is an interesting read. I didn't realize that the earthquake caused this much disruption.I agree with Zachary that mother nature could cause a bigger interruption if she wanted to.