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Tuesday, March 15, 2011

Earthquake at Japan have moved Earth's axis and shortened days

The March 11, magnitude 9.0 earthquake in Japan may have shortened the length of each Earth day and shifted its axis. But don't worry—you won't notice the difference.

Using a United States Geological Survey estimate for how the fault responsible for the earthquake slipped, research scientist Richard Gross of NASA's Jet Propulsion Laboratory, Pasadena, Calif., applied a complex model to perform a preliminary theoretical calculation of how the Japan earthquake—the fifth largest since 1900—affected Earth's rotation. 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. Earth's figure axis should not be confused with its north-south axis; they are offset by about 10 meters (about 33 feet). 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.

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

In comparison, following last year's magnitude 8.8 earthquake in Chile, Gross estimated the Chile quake should have shortened the length of day by about 1.26 microseconds and shifted Earth's figure axis by about 8 centimeters (3 inches). A similar calculation performed after the 2004 magnitude 9.1 Sumatran earthquake revealed it should have shortened the length of day by 6.8 microseconds and shifted Earth's figure axis by about 7 centimeters, or 2.76 inches. How an individual earthquake affects Earth's rotation depends on its size (magnitude), location and the details of how the fault slipped.

Gross said that, in theory, anything that redistributes Earth's mass will change Earth's rotation.

"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," he 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 we 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. 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. He and other scientists will be investigating this as more data become available.

Gross said the changes in Earth's rotation and figure axis caused by earthquakes should not have any impacts on our daily lives. "These changes in Earth's rotation are perfectly natural and happen all the time," he said. "People shouldn't worry about them."

Source : NASA

Tuesday, March 8, 2011

NASA scientists in row over 'alien microbes'

WASHINGTON (AFP) - – Top NASA scientists said there was no scientific evidence to support a colleague's claim that fossils of alien microbes born in outer space had been found in meteorites on Earth.

The US space agency formally distanced itself from the paper by NASA scientist Richard Hoover, whose findings were published Friday in the peer-reviewed Journal of Cosmology, which is available free online.

"That is a claim that Mr Hoover has been making for some years," said Carl Pilcher, director of NASA's Astrobiology Institute.

"I am not aware of any support from other meteorite researchers for this rather extraordinary claim that this evidence of microbes was present in the meteorite before the meteorite arrived on Earth and and was not the result of contamination after the meteorite arrived on Earth," he told AFP.

"The simplest explanation is that there are microbes in the meteorites; they are Earth microbes. In other words, they are contamination."

Pilcher said the meteorites that Hoover studied fell to Earth 100 to 200 years ago and have been heavily handled by humans, "so you would expect to find microbes in these meteorites."

Paul Hertz, chief scientist of NASA's Science Mission Directorate in Washington, also issued a statement saying NASA did not support Hoover's findings.

"While we value the free exchange of ideas, data and information as part of scientific and technical inquiry, NASA cannot stand behind or support a scientific claim unless it has been peer-reviewed or thoroughly examined by other qualified experts," Hertz said.

"NASA also was unaware of the recent submission of the paper to the Journal of Cosmology or of the paper's subsequent publication."

He noted that the paper did not complete the peer-review process after being submitted in 2007 to the International Journal of Astrobiology.

According to the study, Hoover sliced open fragments of several types of carbonaceous chondrite meteorites, which can contain relatively high levels of water and organic materials, and looked inside with a powerful microscope, Field Emission Scanning Electron Microscopy (FESEM).

He found bacteria-like creatures, calling them "indigenous fossils" that originated beyond Earth and were not introduced here after the meteorites landed.

Hoover "concludes these fossilized bacteria are not Earthly contaminants but are the fossilized remains of living organisms which lived in the parent bodies of these meteors, e.g. comets, moons and other astral bodies," said the study.

"The implications are that life is everywhere, and that life on Earth may have come from other planets."

The journal's editor-in-chief, Rudy Schild of the Harvard-Smithsonian Center for Astrophysics, hailed Hoover as a "highly respected scientist and astrobiologist with a prestigious record of accomplishment at NASA."

The publication invited experts to weigh in on Hoover's claim, and both sceptics and supporters began publishing their commentaries on the journal's website Monday.

"While the evidence clearly indicates that the meteorites was eons ago populated with bacterial life, whether the meteorites are of actual extra-terrestrial origin might debatable," wrote Patrick Godon of Villanova University in Pennsylvania.

Michael Engel of the University of Oklahoma wrote: "Given the importance of this finding, it is essential to continue to seek new criteria more robust than visual similarity to clarify the origin(s) of these remarkable structures."

The journal did not immediately respond to requests for comment.

Pilcher described Hoover as a "NASA employee" who works in a solar physics branch of a NASA lab in the southeastern state of Alabama.

"He clearly does some very interesting microscopy. The actual measurements on these meteorites are very nice measurements, but I am not aware of any other qualification that Mr Hoover has in analysis of meteorites or in astrobiology," Pilcher said.

A NASA-funded study in December suggested that a previously unknown form of bacterium, found deep in a California lake, could thrive on arsenic, adding a new element to what scientists have long considered the six building blocks of life.

That study drew hefty criticism, particularly after NASA touted the announcement as evidence of extraterrestrial life. Scientists are currently attempting to replicate those findings.

source : Yahoo! News

Strange life signs found on meteorites - NASA scientist

WASHINGTON (Reuters) - A NASA scientist reports detecting tiny fossilized bacteria on three meteorites, and maintains these microscopic life forms are not native to Earth.

If confirmed, this research would suggest life in the universe is widespread and life on Earth may have come from elsewhere in the solar system, riding to our planet on space rocks like comets, moons and other astral bodies.

The study, published online late Friday in The Journal of Cosmology, is considered so controversial it is accompanied by a statement from the journal's editor seeking other scientific comment, which is to be published starting on Monday.

The central claim of the study by astrobiologist Richard Hoover is that there is evidence of microfossils similar to cyanobacteria -- blue-green algae, also known as pond scum -- on the freshly fractured inner surfaces of three meteorites.

These microscopic structures had lots of carbon, a marker for Earth-type life, and almost no nitrogen, Hoover said in a telephone interview on Sunday.

Nitrogen can also be a sign of Earthly life, but the lack of it only means that whatever nitrogen was in these structures has decomposed out into a gaseous form long ago, Hoover said.

"We have known for a long time that there were very interesting biomarkers in carbonaceous meteorites and the detection of structures that are very similar ... to known terrestrial cyanobacteria is interesting in that it indicates that life is not restricted to the planet Earth," Hoover said.

Hoover, based at NASA's Marshall Space Flight Center in Alabama, has specialized in the study of microscopic lifeforms that survive extreme environments such as glaciers, permafrost and geysers.

He is not the first to claim discovery of microscopic life from other worlds.

In 1996, NASA scientists presented research indicating a 4-billion-year-old meteorite found inAntarctica carried evidence of fossilized microbial life from Mars.

The initial discovery of the so-called Mars meteorite was greeted with acclaim and the rock unveiled at a standing room-only briefing at NASA headquarters in Washington.

Since then, however, criticism has surrounded that discovery and conclusive proof has been elusive.

Hoover's research may well meet the same fate. In a statement published with the online paper, the Journal of Cosmology's editor in chief, Rudy Schild, said in a statement:

"Dr. Richard Hoover is a highly respected scientist and astrobiologist with a prestigious record of accomplishment at NASA. Given the controversial nature of his discovery, we have invited 100 experts and have issued a general invitation to over 5,000 scientists from the scientific community to review the paper and to offer their critical analysis."

source : Yahoo! News

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