[ExI] NASA space probe proves Einstein correct
Damien Broderick
thespike at satx.rr.com
Thu May 5 03:42:39 UTC 2011
NASA space probe proves Einstein correct
Thursday, 5 May 2011
by Kerry Sheridan
Agence France-Presse
WASHINGTON: Huge objects in the universe distort space and time with the
force of their gravity, scientists said after a NASA probe confirmed two
key parts of Albert Einstein's theory of general relativity.
"Einstein survives," chuckled Francis Everitt, Stanford University
physicist and principal investigator for Gravity Probe B (GP-B), one of
the U.S. space agency's longest running projects.
The physics experiment was more than four decades in the making, and
finally launched in 2004.
The Earth in honey
"In Einstein's universe, space and time are warped by gravity. The Earth
distorts the space around it very slightly by its gravity," he said,
explaining the Jewish physicist's theory devised nearly 100 years ago,
long before the technology existed to test it.
"Imagine the Earth as if it were immersed in honey. As the planet
rotates, the honey around it would swirl, and it's the same with space
and time," said Everitt.
"GP-B confirmed two of the most profound predictions of Einstein's
universe, having far-reaching implications across astrophysics
research," he said, predicting the mission would "have a lasting legacy
on Earth and in space."
Confirmation of Einstein's theory
The satellite carried four advanced gyroscopes to measure geodetic
effect, or the warping of space and time around a gravitational body,
and frame-dragging, or how much a spinning object pulls space and time
with it when it turns.
If Einstein's theory were disproved, the "gyroscopes would point in the
same direction forever while in orbit", NASA said.
"But in confirmation of Einstein's general theory of relativity, the
gyroscopes experienced measurable, minute changes in the direction of
their spin as they were pulled by Earth's gravity."
Remarkably close to projections
The probe's measurements came remarkably close to Einstein's
projections, according to the findings published in Physical Review
Letters. The satellite, which wrapped up its data mission last year, was
first envisioned in 1959.
Leonard Schiff, head of Stanford's physics department, and George Pugh
of the Defense Department, dreamed up a satellite that would orbit the
Earth and test the notion. Everitt joined the project in 1962, followed
by NASA in 1963. "Forty-one years later, the satellite was launched into
orbit about 400 miles above Earth," NASA said.
The technologies created in the development of the gravity probe have
been used in making precise global position systems (GPS) and in gauging
the background radiation of the universe.
"That measurement is the underpinning of the 'big bang theory' and led
to the Nobel Prize for NASA's John Mather," NASA said.
More information about the extropy-chat
mailing list