Reasons to Believe

Einstein Passes a Probing Test

Few theories have undergone testing as thoroughly as Einstein’s theory of general relativity and come through with such flying colors. But, of course, for a theory that has such far-reaching consequences, it must be subjected to everything we can throw at it. For us at RTB, it is a key scientific component for believing in the transcendent beginning of the universe.

A similar kind of testing for Newton’s laws of motion back at the beginning of the twentieth century led to questioning Newton’s correctness in describing the results of the Michelson-Morley Experiment (see the really cool graphic here). Einstein’s answer was special relativity. It was also the application of Newton’s laws to atomic-level phenomena that led to the development of quantum mechanics.

The upshot is that thorough testing reveals cracks in any explanation or theory and leads to the next generation of discoveries. This is the way science works—always questioning and testing any hypothesis in order to make the next breakthrough. We are told in Scripture to do the same thing with regard to everything in life, as Paul tells the Thessalonians to “test everything. Hold on to the good” (1 Thess. 5:21).

Three years ago NASA in collaboration with Stanford University put up a very sophisticated satellite, called Gravity Probe B, that circles the Earth. Basically, this satellite houses several high-precision gyroscopes (more than a million times better than the best inertial navigation gyroscopes) and a small telescope that can, over time, measure slight perturbations in the gravitational field surrounding the Earth. Einstein’s general relativity predicts the gyroscopes will measure two very small effects. The first, called the geodetic effect, is a measure of how much the Earth distorts the local space-time in which it resides. The second, called the frame-dragging effect, is a measure of how much the local space-time is twisted by the rotation of the Earth. The graphic below (from the Stanford Web site) gives a visual picture of what is happening.

Reporting at a recent American Physical Society meeting, Francis Everitt reported the initial results from three years of data collecting. The satellite gyroscopes were able to measure a shift in angle of 0.0018 degrees in the plane of the spacecraft’s orbit. This measurement demonstrated the correctness of Einstein’s theory with regard to the geodetic effect to an accuracy of about 1 percent (in terms of the error bar). The next result, not due until December 2007, is expected to measure the frame-dragging effect by a shift of only 0.000011 degrees in the plane of the Earth’s equator. This smaller angle requires more processing and calibration before it can demonstrate the correctness (or incorrectness!) of Einstein’s theory.

But so far, Einstein has again passed the test!

Subjects: Einstein / Relativity

Dr. David Rogstad

Dr. Dave Rogstad received his PhD in physics from Caltech and worked over 30 years for NASA’s Jet Propulsion Laboratory. Though now retired, Dave continues to serve as an RTB board member and participates regularly in several RTB podcasts.