Neutron Star Merger and the One Way Speed of Light and Gravity

In the pursuit of reconciling a 6,000-year-old universe with stars located billions of light-years away, Young-Earth Creationists (YEC) have proposed several creative models. These include the Anisotropic Synchrony Convention (ASC), Variable Speed of Light (VSL), and the Appearance of Age. However, the dawn of multi-messenger astronomy—the simultaneous observation of cosmic events via both light (electromagnetic waves) and gravity waves—has provided a rigorous empirical test that these models cannot survive. The 2017 detection of the neutron star merger GW170817 serves as a definitive "smoking gun" that confirms Einstein’s General Relativity while dismantling YEC physics.

1. Defeating the Anisotropic Synchrony Convention (ASC)

The ASC, championed by Dr. Jason Lisle, suggests that the "one-way" speed of light towards Earth is infinite. In this model, light from a distant star reaches us the moment it is emitted, effectively "resetting" the clock for the observer and bypassing the distant starlight problem.

Multi-messenger astronomy shatters this by introducing a second, independent "messenger": gravity waves.

• The Synchronized Arrival: During GW170817, the gravitational waves reached Earth first, followed a mere 1.7 seconds later by a gamma-ray burst (light).

• The Problem for ASC: If light traveled at infinite speed towards Earth while gravity waves traveled at the standard speed (c), the light should have arrived years or centuries before the gravity waves.

• The Conclusion: The near-simultaneous arrival proves that both light and gravity travel at the same finite speed (c). This forces the ASC to assume that gravity also travels at infinite speed toward Earth—a claim that lacks any physical basis and contradicts the way gravity waves are detected by independent sensors at different locations on Earth.

2. Defeating Variable Speed of Light (VSL)

The VSL hypothesis argues that the speed of light was significantly faster in the past (shortly after creation) and has since decayed to its current value. This would allow starlight from the edge of the universe to reach Earth within a few thousand years.

The multi-messenger data from GW170817 refutes this by verifying the constant ratio between light and gravity across 130 million light-years of travel.

• The Calibration: If the speed of light had been radically different in the past, we would expect a massive "decoupling" between light and gravity waves emitted from the same ancient event.

• The Evidence: Because both arrived within 1.7 seconds of each other after traveling for 130 million years, it confirms that the speed of light (and gravity) has remained remarkably stable. Even a minuscule change in c over that distance would have resulted in an arrival gap of years, not seconds.

3. Defeating the Appearance of Age

The "Appearance of Age" argument suggests that God created light "in transit," meaning the light we see from a distant supernova never actually came from a star; it was created as a functional beam already heading toward Earth.

Multi-messenger astronomy turns this into a theological and logical nightmare.

• Non-Light Messengers: For this argument to hold today, God would have to create not just "fake" light in transit, but also "fake" gravitational ripples in space-time and "fake" neutrino bursts, all perfectly synchronized to mimic a coherent physical event (a merger) that never happened.

• The "God as Deceiver" Dilemma: If the merger of GW170817 never occurred, then the complex data captured by LIGO (gravity) and Fermi (light) are essentially a divine "movie" of a fiction. This challenges the YEC premise of a rational, non-deceptive Creator, as the universe becomes an elaborate illusion rather than a testament to physical history.

4. Confirming General Relativity

Finally, multi-messenger astronomy provides the ultimate validation for Einstein’s General Relativity (GR). GR predicts that gravitational waves are "ripples in the fabric of spacetime" that must propagate at the speed of light (c).

The data from GW170817 matched Einstein’s equations to an astonishing degree of precision (within one part in 10^{15}). This confirmation is a blow to YEC because GR is the very framework that requires a massive, ancient universe to be stable. By proving that GR is correct through multi-messenger observations, we accept the mathematical necessity of an expanding universe that is billions of years old—leaving no room for the compressed timelines of Young-Earth models.

References

 * Abbott, B. P., et al. (2017). "Multi-messenger Observations of a Binary Neutron Star Merger." The Astrophysical Journal Letters.

 * Ligo Scientific Collaboration and Virgo Collaboration. (2019). "Tests of General Relativity with GW170817." Physical Review Letters.

Gravitational Wave Merger Simulation

This video provides a visual  simulation of how gravitational waves and light are emitted during a neutron star merger, illustrating why their near-simultaneous arrival is so significant for physics.