Ground Zero

Why Einstein’s Theory Is Such a Big Deal

When I shared with my wife the thrilling news that general relativity had just passed seven more tests of its certainty and accuracy, she looked at me blankly and asked, “So, why should I care about this, Hugh?” When she realized I was eager to write on this topic one more time, she urged me not to—unless I could make clear to her, and to anyone else who is not an astrophysicist, why this finding is such a big deal.

Today, I’m attempting to take up her challenge. Frankly, the answer is not all that complicated. It really comes down to pulsars and patience. I’ll admit that my explanation of what the tests revealed may seem a wee bit technical; so, for Kathy’s sake and yours, I’ll preview the bottom line right up front: The reliability of Einstein’s theory of general relativity (GR) holds monumental significance for our trust in the existence of the Creator—not just a force of physics, but the Creator-God revealed in the Bible.

For more than 2,500 years, the Bible alone claimed that the universe had a beginning, a beginning that included the creation of space and time. Hence, GR implies that the universe is not eternal and self-existing but rather that it was created ex nihilo at some point in the finite past. GR, too, implies the existence of a causal agent—one that exists beyond matter and energy, time and space—to cause it all to come into existence.

If GR is real, then it provides evidence that the Bible’s creation narrative is securely, demonstrably rooted in reality, not in fantasy. So it is exciting news that findings from a recent 16-year scientific study support the reality of general relativity. And now, for the details.

The New Research

New radio-wave measurements from two “heavy” stars (in this case, pulsars) have provided weighty evidence. A team of 29 astronomers just published results from their 16-year study of the subtle orbital changes in the binary pulsar system PSR  J0737-3039A/B—the only known system in which two pulsars (neutron stars emitting regular pulsating radiation toward Earth) are locked into an orbit with each other (see figure on page 43).¹

I refer to these two pulsars as “heavy” because the diameter of each is about 116,000 times smaller than the Sun’s and yet their mass is slightly greater than the Sun’s. Their densities exceed 2  billion tons per teaspoonful! They’re called pulsars because their radio emissions pulsate regularly from their extraordinarily powerful magnetic fields as they rotate rapidly. These beams of radiation “pulse” into our view, like the beams from a lighthouse.

The rate of these pulsations is astounding. In the PSR  J0737-3039 system, Pulsar  A rotates every 22.70 milliseconds, and Pulsar  B every 2.77 milliseconds. This means radio astronomers can observe 44 pulses of radiation per second from A and 361 pulses per second from B.

Meanwhile, Pulsar  B makes a complete orbit around Pulsar  A every 2.454 hours. This orbital period is the shortest yet known for any binary system involving neutron stars. It is three times shorter than that of the pulsar-neutron star system PSR  B1913+16, which delivered the previous best tests of GR and resulted in a Nobel Prize in Physics for Joseph Taylor and Russell Hulse in 1993.

Gravitational theories (such as GR) can best be tested where at least one of the neutron stars in a binary system happens to be a pulsar, but the theoretical ideal is a system in which both neutron stars are pulsars. The opportunity for accuracy increases still more if the two pulsars have a short orbital period and a somewhat eccentric (as opposed to a nearly circular) orbit and if their orbital planes are closely aligned with our line of sight from Earth. It is utterly remarkable—some would dare to say a miraculous gift—that the only known binary pulsar to manifest all these optimal features for testing theories of gravity is accessible to us.

Seven Tests

Beginning in 2003, astronomer Michael Kramer and his team used six of the world’s largest radio telescopes, as well as the Very Long Baseline Array (VLBA), to measure PSR  J0737-3039’s pulses. The VLBA consists of ten 25-meter radio telescopes stretching from Hawaii to the Virgin Islands, all linked together to work as one interferometer. (An interferometer measures the interference pattern created by two or more sources of waves, in this case, light waves at radio wavelengths.) The VLBA was crucial for determining an accurate direct-distance measurement to PSR  J0737-3039, without which precision tests of GR would not have been possible.

Kramer’s team remained patient. They continued observing the PSR  J0737-3039 pulsars month after month, year after year, without publishing any results. Even when the LIGO and Virgo Collaborations (gravity wave telescope research teams) published their direct detections of the gravity waves predicted by GR from the mergers of black holes and neutron stars in 2016,² Kramer’s team continued their painstaking work. They waited until they had accumulated enough measurements to determine the energy emitted by gravitational waves to 1,000 times greater precision than the measurements achieved by the LIGO and Virgo gravitational wave telescopes.

Prior to this study, GR had already passed every experimental and observational test astronomers and physicists were able to devise. These previous tests are described in my book The Creator and the Cosmos.³ Only one possibility existed in which an alternate theory of gravity, if it existed, could be discerned, and that was within the extremely strong gravitational fields that exist near neutron stars and black holes. And such fields are exactly what this binary pulsar within our range of detection provided!

What the Tests Accomplished

The patience of Kramer’s team paid off. By observing minuscule reductions in the neutron stars’ masses and tiny variations in their orbital features (shape and size) and in the timing of their pulses, Kramer and his colleagues were able to achieve seven distinct tests of GR.

Two of the seven tests had never before been performed. In one, Kramer’s team showed how photons from one of the neutron stars slowed down and how their directional path bent as they passed through the intense gravitational field of the other neutron star. The effects they observed fit what GR predicted. Another was their demonstration of the manner in which gravity distorted the shape of the neutron stars’ orbit—again, just as GR predicted.

The results of the seven tests, expressed as observations compared to GR theoretical predictions, are as follows:⁴

The first test in this list, the Shapiro delay, is named for Irwin Shapiro, who made the first high-precision tests of GR back in the 1970s.10 As a young member of Caltech’s astronomical research staff not long thereafter, I enjoyed several conversations with him about GR tests and their implications.

Physical & Philosophical Implications

The patience of Kramer’s team was rewarded with new insights not only about GR but also about the properties of the interstellar medium between PSR  J0737-3039 and Earth. Ongoing observations of PSR  J0737-3039 are expected to produce even more insights. As we gain more comprehensive knowledge of the interstellar and intergalactic media, we will be able to develop more detailed Big Bang origin models. Future observations also may deliver more comprehensive and detailed models for the formation of binary pulsar systems, the likelihood of discovering more of these systems, and new insights into particle creation models.

The most exciting outcome from the astronomers’ results is that GR now stands even taller as the most exhaustively tested and firmly established principle in physics—confirmed under all gravitational field regimes. Insofar as GR accurately and comprehensively describes gravity and, thus, the universe’s space-time fabric, it is fully consistent with the biblical model of cosmic creation.

This affirmation is good news for all theists, especially Christians. The space-time theorems proved that the universe had a beginning.¹¹ This beginning includes the origin of space and time. The proof follows if the universe contains mass and GR reliably describes the dynamics of massive bodies in the universe. Each of us, and each star and galaxy, is evidence that the universe indeed contains mass. Thanks to the exhaustive testing of GR described here, we can be confident that GR reliably describes the dynamics of all massive bodies in the universe. Therefore, a Causal Agent beyond space and time must have intentionally brought into existence this universe of matter, energy, space, and time, just as the Bible has declared for thousands of years.¹²

Notes
1. Michael Kramer et al., “Strong-Field Gravity Tests with the Double Pulsar,” Physical Review X, 11, 041050 (Dec. 13, 2021): https://journals.aps.org/prx/pdf/10.1103/PhysRevX.11.041050.
2. B. P. Abbott et al., “Astrophysical Implications of the Binary Black Hole Merger GW150914,”  Astrophysical Journal Letters , 818, no. 2 (Feb. 11, 2016): https://iopscience.iop.org/article/10.3847/2041-8205/818/2/L22; Hugh Ross, “How Gravitational Waves Help Explain the Universe’s History,” Reasons to Believe (Mar. 10, 2016): https://reasons.org/explore/publications/articles/how-gravitational-waves-help-explain-the-universe-s-history.
3. Hugh Ross, The Creator and the Cosmos, 4th ed. (RTB Press, 2018), 114–120.
4. Kramer et al., “Strong-Field Gravity Tests,” 37.
5. The Shapiro time delay effect refers to light taking longer to travel to a target when that light must pass by a massive body.
6. Time dilation is the elapsed time difference between two clocks due to a difference in gravitational potential at the clocks’ locations.
7. In a binary star system, periastron advance refers to one star’s movement toward that position in its orbit that brings it closest to its companion star.
8. Gravitational wave emission refers to the propagation of waves outward from accelerated masses.
9. Spin precession refers to the distortion of space near a massive body generated by the spin of the massive body.
10. Irwin I. Shapiro, “Fourth Test of General Relativity,” Physical Review Letters 13, no. 26 (Dec. 28, 1964): https://paulba.no/paper/Shapiro_1964.pdf.
11. Arvind Borde, Alan H. Guth, and Alexander Vilenkin, “Inflationary Spacetimes Are Incomplete in Past Directions,” Physical Review Letters 90, no. 15 (April 18, 2003): id. 151031, doi:10.1103/PhysRevLett.90.151301; Aron  C. Wall, “The Generalized Second Law Implies a Quantum Singularity Theorem,” Classical and Quantum Gravity 30, no. 16 (July 12, 2013): id. 165003, doi:10.1088/0264-9381/30/16/165003; Alexander Vilenkin and Aron  C. Wall, “Cosmological Singularity Theorems and Black Holes,” Physical Review D 89, no. 6 (March 2014): id. 064035, doi:10.1103/PhysRevD.89.064035.
12. Hugh Ross with John Rea, “Big Bang—The Bible Taught It First!”, Reasons to Believe (July 1, 2000): https://reasons.org/explore/publications/rtb-101/big-bang-the-bible-taught-it-first; Hugh Ross, “Does the Bible Teach Big Bang Cosmology?”, Reasons to Believe (Aug. 26, 2019): https://reasons.org/explore/blogs/todays-new-reason-to-believe/does-the-bible-teach-big-bang-cosmology.