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NASA Confirms Two Predictions of General Relativity

By May 12, 2011

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For those unfamiliar with scientific endeavour, the goal is to develop a theory about something. Then devise a means to test that theory by designing an experiment that can either confirm or refute the predictions made beforehand.

This same rigor is applied to all theories, and should a theory fail to match experiment then a rethink is mandated and the theory must be altered. So, in spite of the fact that Einstein's theory of general relativity is taught as virtual law at schools across the world, it still must stand up to the same scrutiny as any other.

With a theory as important as general relativity it is important to be thorough and precise. But therein lies the rub. While it is possible to do ground based experiments to explore the effects of gravity, many of the predictions made by Einstein's theory are scarcely measurable at this level.

Rather a massive body, like the Earth or Sun, is needed to explore some of the specific effects predicted by relativity.

Two of these effects are the geodetic effect, the warping of space time due to a massive body, and frame-dragging, which results from a spinning mass pulling space-time around it.

It was for the purpose of measuring these two effects that NASA launched Gravity Probe B in 2004. The orbiting laboratory used four extremely high precision gyroscopes to keep its eye focused on the star IM Pegasi while in polar orbit above the Earth.

If geodetic warping and frame-dragging effects were taking place then the gyroscopes would have to make slight, predicable shifts over time to keep the probe pointing true. Over the subsequent six years of operation researchers were able to determine that these effects, as predicted by relativity, are in fact real.

This is not the first time that predictions of general relativity have proven true, but what is unique about this discovery is the amount of precision that was required to even take the measurements and for how small an effect they were probing. So this certainly goes a long way in furthering our understanding of gravity and can hopefully pave the way for finding a more unified theory of the Universe.

Artist concept of Gravity Probe B orbiting the Earth to measure Earth's affect on space-time, a four-dimensional description of the universe including height, width, length, and time. Credit: NASA

Comments

May 16, 2011 at 3:05 pm
(1) Joe C. Smith says:

I believe that the rotation of an object in space does in fact have a pull of the space and space time that surrounds the object. If the object is spherical the equator or central axis of spin will have a degree of pull based upon the gravity (if present) of the object. We already know that for example a spinning basketball is submerged in water that the water flow around the basketball is measurable. Because of the outstanding work done by NASA and scientist in space on the earth, some points of proof have been given validity. The measurable degrees of pull will decrease with distance from the rotating body. I do believe that additional space experiments should be conducted to increase our knowledge and to prove beyond doubt that Einstein’s theory of relativity is 100% correct. We must continue to support NASA and all scientists that are working around the clock to gain insight and provide us with future discoveries of the birth and life of our Universe. I am proud of those that will lead us into the future.

May 17, 2011 at 8:36 am
(2) Jack Fanning says:

It’s a long time since my science classes in high school, but I seem to recall hypothesis preceded theory. However things do change. First year physics was prior to the Hiroshima atomic bomb. Second year was after.

May 20, 2011 at 10:56 am
(3) Ashish says:

each star, planet etc are a body submerged in the pool of space-time and as such just like a spinning basketball under water , it exters pull on space time…. if you see carefully the body itself i.e. star is a highly concentrated spinning space-time scenario as well. there is no such thing as matter but only a state of space-time at a certain moment of the universe. if u take out that spin then the body returns to its original form i.e. space & time. Great Work by NASA. The next step would be research industrial applications for it. It may take few hundred years though but we are in right direction. However that does not end there as well. If u dig even deeper we will eventually find that even space time is apparent to a certain moment of the level deeper but lets not go that way now. its too far on the scale for us to see. we have to wait few thousand years for that. Anyways lets support NASA in the pursuit of the ultimate truths of the universe.

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