Changes in Earth's rotation by Japan quake have no impact on human life: U.S. scientist

LOS ANGELES, March 14 (Xinhua) -- The changes in Earth's rotation and figure axis caused by Japan's 9-magnitude earthquake should not have any impacts on people's daily lives, NASA's Jet Propulsion Laboratory (JPL) said on Monday.

"These changes in Earth's rotation are perfectly natural and happen all the time," JPL scientist Richard Gross said in a press release.

Using a U.S. Geological Survey estimate for how the fault responsible for the earthquake slipped, Gross applied a complex model to perform a preliminary theoretical calculation of how the Japan earthquake affected Earth's rotation, according to the release.

His calculations indicate that by changing the distribution of Earth's mass, the Japanese earthquake should have caused Earth to rotate a bit faster, shortening the length of the day by about 1.8 microseconds (a microsecond is one millionth of a second).

The calculations also show the Japan quake should have shifted the position of Earth's figure axis (the axis about which Earth's mass is balanced) by about 17 centimeters (6.5 inches), towards 133 degrees east longitude, said JPL in Pasadena, Los Angeles.

This shift in Earth's figure axis will cause Earth to wobble a bit differently as it rotates, but it will not cause a shift of Earth's axis in space -- only external forces such as the gravitational attraction of the sun, moon and planets can do that, according to JPL.

Both calculations will likely change as data on the quake are further refined, JPL said.

"People shouldn't worry about them (the changes)," Gross said.

"Earth's rotation changes all the time as a result of not only earthquakes, but also the much larger effects of changes in atmospheric winds and oceanic currents," Gross said.

"Over the course of a year, the length of the day increases and decreases by about a millisecond, or about 550 times larger than the change caused by the Japanese earthquake. The position of Earth's figure axis also changes all the time, by about 1 meter (3.3 feet) over the course of a year, or about six times more than the change that should have been caused by the Japan quake."

Gross said that while scientists can measure the effects of the atmosphere and ocean on Earth's rotation, the effects of earthquakes, at least up until now, have been too small to measure.

The computed change in the length of day caused by earthquakes is much smaller than the accuracy with which scientists can currently measure changes in the length of the day, he said.

However, since the position of the figure axis can be measured to an accuracy of about 5 centimeters (2 inches), the estimated 17-centimeter shift in the figure axis from the Japan quake may actually be large enough to observe if scientists can adequately remove the larger effects of the atmosphere and ocean from the Earth rotation measurements, Gross added.

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NASA's Glory satellite launch fails

The Taurus XL rocket built by Orbital Sciences failed to lift NASA's Earth-observation satellite into orbit and plummeted into the Pacific Ocean. The failed mission cost $424 million.

A rocket, standing more than nine stories tall, blasted off from Vandenberg Air Force Base but failed to lift a NASA Earth-observation satellite into orbit and plummeted into the Pacific Ocean. The failed mission cost $424 million, the space agency said.

It is the second consecutive time that NASA has encountered the problem with the Taurus XL rocket built by Orbital Sciences Corp. of Dulles, Va.

NASA scientists believe the launch on Friday failed because the satellite's protective cover, which opens like a clamshell, did not separate as expected.

"Obviously, this is a terrific disappointment and we feel bad for letting NASA … down," said Barron Beneski, an Orbital Sciences spokesman. "People have dedicated years of their lives into this."

NASA's Glory satellite was designed to help scientists understand how the sun and particles of matter in the atmosphere called aerosols affect the Earth's climate. It was also built by Orbital in Virginia.

Everything seemed to go as planned from Vandenberg, located northwest of Santa Barbara, shortly after the 3:09 a.m. PST liftoff. Three minutes later, the cover was supposed to separate and the satellite was expected to enter orbit. That didn't happen.

"We failed to make orbit," Omar Baez, NASA's launch director, said at a news conference. "All indications are that the satellite and the rocket are in the southern Pacific Ocean somewhere."

It marks the second time in a row that NASA has encountered a problem with the protective shell separating from the satellite. The space agency's previous Taurus XL launch attempt on Feb. 24, 2009, carrying another Earth science spacecraft, dubbed the Orbiting Carbon Observatory, also failed to reach orbit because of lack of separation.

Orbital Sciences and NASA investigated the matter and believed that they had identified the problem. On Friday, Orbital Sciences said it was too early to tell whether the latest failure was linked to the issue they previously encountered.

"Understandably, people are thinking this is the same problem all over again," Beneski said. "It's too early to tell. We have to evaluate all the data before we can say that's true."

Although the satellite probably will never be recovered, sensors on the spacecraft captured enough information for engineers to identify a problem, Beneski said.

Since 1994, Orbital Sciences has attempted to launch a Taurus XL rocket a total of nine times. It has been successful in six of those attempts.

"That's not a great record," said Marco Caceres, senior space analyst for research firm Teal Group Corp. "Part of the problem is that the Taurus just doesn't launch enough. It's hard to develop a launch rhythm if the rocket is only going up once every few years."

Both Orbital Sciences and NASA plan to create investigation boards made up of engineers and scientists to evaluate the cause of Friday's failure.

NASA has another Earth sciences satellite slated to launch on a Taurus rocket in 2013. The space agency plans to wait and see the results of the investigation board before it goes forward with the launch.

Orbital Sciences shares lost 30 cents, or about 2%, on Friday, closing at $18.17.

Also Friday, the launch attempt of the U.S. Air Force's X-37B Orbital Test Vehicle from Cape Canaveral, Fla., was scrubbed because of bad weather. The launch was rescheduled for Saturday at 1:09 p.m. PST.


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