National Geographic News
Illustration: A gravity probe measures Earth's effect on space-time.

An artist's concept of Gravity Probe B orbiting Earth, which is warping spacetime.

Illustration courtesy NASA

Ker Than

for National Geographic News

Published May 5, 2011

Two key predictions of Albert Einstein's general theory of relativity have been confirmed by NASA's Gravity Probe B mission, scientists announced this week.

"We've completed this landmark experiment testing Einstein's universe, and Einstein survives," principal investigator Francis Everitt, of Stanford University in California, said during a press briefing.

(Also see "Einstein's Gravity Confirmed on a Cosmic Scale.")

Launched in 2004, the Gravity Probe B mission used four ultraprecise gyroscopes—devices used to measure orientation—housed in a satellite to measure two aspects of Einstein's theory about gravity.

The first is the geodetic effect, which is the warping of space and time—or spacetime—around a gravitational body, such as a planet.

One common way to visualize the geodetic effect is to think of Earth as a bowling ball and spacetime as a trampoline. Earth's gravity warps spacetime the same way a bowling ball weighs down the middle of a trampoline.

The second effect of gravity tested by Gravity Probe B is frame dragging, which is the amount that a spinning object pulls the fabric of spacetime along with it.

Doing What Einstein Thought Impossible

To conduct these tests, Gravity Probe B used a device called a star tracker to keep one end pointed at a single star, IM Pegasi, while in a polar orbit 400 miles (644 kilometers) above Earth.

If we lived in a universe that behaved as envisioned by Isaac Newton—in which the geodetic effect and frame dragging don't occur—then the gyroscopes would stay aligned with the star forever.

In Einstein's universe, however, the direction of the spin axis of Gravity Probe B's gyroscopes should gradually change due to the mass and rotation of Earth.

"Imagine the Earth is immersed in honey, and you can imagine the honey would be dragged around and [an object in the honey] would also be dragged around," Everitt said. "That's what happens in the gyroscope."

Sifting through the data, the team found evidence of an angular change in the gyroscopes' orientation of about 6,600 milliarcseconds over the course of a year.

A milliarcsecond, Everitt explained, "is the width of a human hair seen at the distance of 10 miles [16 kilometers]. It really is a rather small angle, and this is the accuracy which Gravity Probe B had to achieve."

The change is so small, in fact, that Einstein didn't think measuring it was even possible.

In his 1953 book The Meaning of Relativity, Einstein wrote that frame-dragging effects "are actually present according to our theory, although their magnitude is so small that confirmation of them by laboratory experiments is not to be thought of."

But now, "thanks to NASA," Everitt said, "we've done more than think about them. We've actually measured them."

Gravity Findings to Unravel Distant Mysteries?

Although the results are only now being released, the Gravity Probe B satellite has completed its work, and it was decommissioned in December 2010.

Funded since 1963, Gravity Probe B is one of the longest running projects in NASA history. Scientists had the idea for the experiment before the required technology—such as the star tracker and gyroscopes—even existed.

The probe's predecessor, Gravity Probe A, was launched in 1976 and also confirmed a key aspect of Einstein's general theory of relativity, namely that a clock on Earth will run slower than one aboard an orbiting spacecraft. (Related: "Einstein's Relativity Affects Aging on Earth [Slightly].")

While it's been widely accepted that the geodetic effect and frame dragging occur, it was important to confirm them with experiments, physicist Clifford Will, of Washington University in St. Louis, said at the press conference.

"While the result in this case does support Einstein, it didn't have to," he said.

In addition, the findings, detailed online in the journal Physical Review Letters, may help scientists understand some of the most cataclysmic events in the universe.

"Measuring the frame-dragging effect caused by the Earth's rotation has implications beyond our planet," said Will, who was not involved in the Gravity Probe B project.

For example, he said, frame dragging likely plays a role in triggering energetic bursts from quasars, very distant galaxies that have actively feeding—and rapidly rotating—supermassive black holes at their hearts.

Also see Space-Time "Ripples" Created by Merging Black Holes? >>

1 comments
Carlos Borge
Carlos Borge

For Lesage

Carlos Borgea

Summary

This argumentation aim is to show that despite light speed does not depend on the light source speed, it depends on the adopted referential system, and that gravitation is due to the waves and particles that fill up the space, this is the Lesage theory of gravitation. If you think that two photons that travel side by side at the same light bean have speed of magnitude c in relation to each other then we can not agree with you.

Key words: Relativity theory, Lesage theory of gravitation, Michelson-Morley experiment, Morley-Miller experiment, the Newtonian constant, gravimeter.

Contents

1.Discussion about light speed ...………………………………………………...1

2.Discussion about gravitation …………………………………………………..1

3.Conclusions…………………………………………………………………….2

1. Discussion about light speed

Let us consider three cylindrical, horizontal, and rectilinear light beans A, B, and D travelling at the laboratory at Case Western Reserve University in Cleveland, Ohio, where Michelson and Morley, and Morley and Miller have made their experiments1 (1880-1930).

            Let us suppose that A and B are parallels to each other, and travel in opposite directions, and that D is perpendicular to A and B.

Let us suppose yet that A, B, and D travel with speed of magnitude c in relation to a Cartesian coordinate system attached to the laboratory.

( c = 3.0 x 108 m/s). This is what Michelson and Morley have found. Morley and Miller have found a difference of 10 km/s between A and D speeds.

Let us consider yet four photons a1 and a2 that travel side by side at the bean A, b and d pertaining to the beans B and D respectively.

According to good reason a1 and a2 have null or almost null speeds in relation to each other, a1 and b have speed of magnitude 2c in relation to each other, and at last photons b and d travel with speed of magnitude 1.41 c in relation to each other, and it does not matter if Michelson-Morley or Miller-Morley were right.

When postulate that light speed does not depend on the adopted system of reference2, Special Theory of Relativity affirm that these three referred speeds have magnitude c. This is out of good reason.

To quote Einstein2: “…the concept empty space loses its meaning.” (Note to the fifteenth edition, June 9th, 1952.)

2. Discussion about gravitation

There is a sea of stars producing waves and particles around us. There are other sources of waves and particles in the Universe.

Near the Earth surface there are more waves and particles downwards than upwards.

Why?

Because the upwards waves and particles have crossed our Earth and part of them were absorbed by the planet.

And in addition?

These waves and particles cross matter, interact with atoms, and push more downwards than upwards!

Then bodies fall.

Then molecules of solids are vibrating all the time.

If you use a gravimeter below a source mass to measure the Newtonian constant G, you are in fact measuring the magnitude of downwards waves and particles. Then you will find a value greater than the recommended codata value G = 6.67 x 10-11 (SI).

Varga et al3found 65 mGal instead of 56 mGal, 16% greater than forecast.

On the other hand, if you use the gravimeter above the source mass to measure G, you are measuring the magnitude of the upwards waves and particles. In this case you will find a value smaller than the codata value.

Varga et al3found 49 mGal instead of 56 mGal.

For more information look for Island effect theory of gravitation4.

3.Conclusions

Despite light speed does not depend on the speed of its source, it depends on the adopted system of reference like to any other wave. According to this Special and General Theories of Relativity are wrong theories and have to be abandoned by scientific community. For more information, please look for: Lesage theory of gravitation4.


a Paulista University

R. Dr. Luiz Migliano, 761, bloco C, Apto. 54, São Paulo, SP, Brazil, 05711-001.

3 P. Varga, A. Hajósy and G. Cisapó, Geophys. J. Int. 120, pp. 745-757 (Fig.8), (1995).

4 Carlos Borge, ‘Island effect theory of gravitation – Lesage-Brush’s theory’, PUBLICAÇÃO IF 1616/2005.

o link to this article: http://repositorio.if.usp.br/xmlui/bitstream/handle/1396/45/pd1616.pdf?sequence=1


1 Roberto Lalli, ‘The Reception of Miller’s Ether Drift Experiments in the USA; The History of a Controversy in Relativity Revolution’, Annals of Science, Vol. 69, No. 2, April 2012, 153-214.

To link to this article: http://dx.doi.org/10.1080/00033790.2011.637473

2 Albert Einstein, Relativity The Special and The General Theory – A clear explanation that anyone can understand, Cap. VI & VII, (New York 1961). Alternative document: David Halliday, Robert Resnick, and Jearl Walker, Fundamentals of Physics (Fourth Edition)Extended, chapter 42-3, (New York 1993).

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