A Life-Changing Gift Helps Explain Why We're Here
On October 16, 2017, the physicists and astronomers who comprise the Laser Interferometer Gravitational-Wave Observatory (LIGO) and the Virgo gravitational wave telescope research teams announced a discovery resulting from the largest scientific research collaboration in the history of mankind. Scientists at 952 different research institutions participated. More than 4,600 astronomers, about a third of the world's total population of research astronomers, at 70 different observatories contributed to the research findings. Radio astronomer Alessandra Corsi at Texas Tech University called the discovery "a big gift that nature has given us" and "a life-changing event."1
A Monumental Discovery
So what was the "big gift" and what made its discovery "life-changing"?
Let's answer the "what" question first. The discovery was the fifth detection of a gravity wave event—but unlike the previous four such detections, which were all the result of the merging of two black holes, this one turned out to be the first-ever observation of gravity waves from the merger of two neutron stars.
What made this gift especially big was that the gravity waves from the merging of the two stars were observed by both the LIGO and the Virgo gravity wave telescopes. The three locations of the gravity wave detectors—Hanford, Washington; Livingston, Louisiana; and Pisa, Italy—allowed the researchers to roughly locate the gravity wave event to within 60 square degrees in the sky. The LIGO and Virgo scientists promptly alerted astronomers around the world to perform follow-up observations at multiple wavelengths. These observations led to the pinpointing of the exact location of the neutron star merging event.
The event occurred on August 17, 2017, at 12:41 universal time, 6,200 light-years from the nucleus of the large elliptical galaxy NGC 4993 (see arrow at left).2 NGC 4993 is 130 million light-years from Earth in the Hydra constellation.3 It is a little closer to us than the center of the Virgo cluster of galaxies.
Black holes contain no matter that might radiate light. Thus, since the previous four gravity wave detections were of the merging of two black holes, the events produced no emissions of light. Neutron stars, in contrast, do contain matter that can emit light, and astronomers calculated that the merging of two such stars should spew debris that emits light at all wavelengths.
Two seconds after the detection of the gravity wave signal, the Fermi Gamma-Ray Space Telescope detected a brief gamma-ray burst from the event.4 A few hours later, astronomers at five observatories identified the light source of the event. Over the course of the next several days, they observed the neutron star merging event fade from a bright blue color to a dim red color. About two weeks later, the merging event began to emit both X-rays and radio waves.
The wealth of data accumulated by the 4,600-plus astronomers at the 70 observatories and 952 research institutions5 led to several outstanding discoveries. Here are three major ones.
--Origin of Short Gamma-Ray Bursts
First, the data gathered from the neutron star merging event enabled scientists to solve the mystery of the origin of short gamma-ray burst events. Gamma-ray bursts range from 10 milliseconds to a few hours in duration. Several hundred have been observed. Orbiting satellites currently detect an average of one gamma-ray burst per day. None have been detected any closer than 130 million light-years away.
Theoretical physicists had determined that the only conceivable source of gamma-ray bursts shorter than two seconds in duration was the merging of two neutron stars to form a black hole. Until the August 17 gravity wave event, however, they lacked confirmation of this theory. The multi-wavelength observations of that event clinched their conclusion. From now on, astronomers can be confident that whenever a short gamma-ray burst accompanies a gravity wave detection, they are looking at the merger of two neutron stars.
The lack of nearby gamma-ray bursts, by the way, is a good thing, since they are deadly for life. In fact, the frequency of gamma-ray bursts, by itself, rules out 90 percent of all galaxies as possible candidates for harboring enduring life.
--Reality of Kilonovae
A second outstanding discovery from the neutron star merging event was the confirmation of the existence of kilonovae. For decades, astronomers had hypothesized the existence of kilonovae, or macronovae, events that would briefly outshine ordinary novae by about a thousand times, but not approach the brilliance of a supernova, which is about 40,000-50,000 times brighter than the brightest novae.
Theoreticians had calculated that the merging of two neutron stars should result in such furious radioactive decay of heavy radioisotopes as to produce an emission of light at least a thousand times brighter than an ordinary nova. They had also determined that such radioactive decay should produce an emission of bright blue light that, over a few days, would transition to dimmer red light as the daughter products of the radioactive decay absorbed the blue wavelengths of the initial light emission. Multi-wavelength observations of the August 17 gravity wave event confirmed all the theoreticians' deductions.6
--Source of r-Process Elements
A third finding stemming from the event was the discovery of the source of r-process elements. The periodic table contains 94 naturally occurring elements. (Plutonium and neptunium, though present on the early Earth, have long since decayed away, leaving just 92 today in Earth's crust.) Several decades ago, astronomers and physicists established with high accuracy how stars and supernovae manufacture the elements lighter than iron and half of the elements that are heavier than iron—known as the s-process elements. They also successfully determined the means by which the other half of the elements heavier than iron—the r-process elements—are formed. However, they were stymied in their attempts to explain the source of the r-process elements.
The term "r-process" is shorthand for "rapid neutron capture process," and it entails a succession of rapid neutron captures that result in lighter elements being transformed into heavier elements. The process is viable only where there is an extremely high flux of free neutrons. The neutron-rich debris thrown off from the merging of two neutron stars provides just such a high flux of free neutrons. The multi-wavelength observations of the August 2017 gravity wave event affirmed that the merger of the two neutron stars indeed efficiently produced those elements.7
Benefits to Humanity
This brings us back to the second question posed at the beginning of this article: What made the detection of the neutron star merger such a "life-changing event"? The answer has to do with the production of those r-process elements.
Not only did the observations of the August 2017 event affirm that the merger of two neutron stars produces r-process elements, but they also established that most, if not nearly all, of the r-process elements that exist on Earth and elsewhere in the universe came from neutron star merging events.8 Theoretical work shows that efficient r-process production requires exquisite fine-tuning of the properties of neutrinos and the weak nuclear force.9
These elements include such valuable metals as silver, gold, platinum, palladium, osmium, thorium, and uranium. The radioactive decay of Earth's superabundance of thorium (Earth is overabundant by a factor of 610)10 and uranium (Earth is overabundant by a factor of 340)11 explains to a large degree its enduring strong magnetic field, which is crucial for preventing the erosion of its atmosphere and the protection of life from deadly solar and cosmic radiation.
Earth's superabundance of thorium and uranium also explains its enduring plate tectonics, which transformed Earth from a waterworld with only water on its surface into a planet with both permanent surface oceans and surface continents. Without this transformation, nutrients crucial for sustaining life could not be adequately recycled. Earth would quickly have become permanently sterile.
If it were not for primordial Earth being strongly salted by r-process elements produced by neutron star merger events, any kind of advanced civilization on our planet would be impossible. It is doubtful that humanity would have advanced even beyond stone-age technology if there had been no corrosion-resistant gold and silver to pave the way for metallurgy.
Without the silver, gold, platinum, palladium, and osmium produced by neutron star merger events, we would lack the catalysts and electronics components that our high-technology civilization demands. We would also lack chemotherapy drugs and many other chemical compounds that sustain our high standard of health.
Much to Be Grateful For
The discoveries from the August 2017 gravity wave event show multiple ways in which God has bestowed upon us his bountiful providence. In giving astronomers the capability of learning so much about neutron star merging events, he enabled them to uncover yet more of the glory of his creation. In exposing primordial Earth to such a rich source of r-process elements from nearby neutron star mergers, he provided for the launching and sustaining of the high-technology civilization and effective health treatments we enjoy today. And in providing that all neutron star merging events would be extremely distant from Earth during the human era, he has ensured that they would pose no risk to human survival. The heavens indeed proclaim the glory and righteousness of God.
Hugh RossPhD, is an astrophysicist and the founder and president of the science-faith think tank Reasons to Believe (RTB).
Get Salvo in your inbox! This article originally appeared in Salvo, Issue #45, Summer 2018 Copyright © 2026 Salvo | www.salvomag.com https://salvomag.com/article/salvo45/star-merger
