I find black holes to be the most bizarre objects in the universe. They have densities so high that it boggles the mind and gravitational fields so strong that not even light can escape their pull. The theory of general relativity (GR), developed over 100 years ago by Albert Einstein, predicts the existence of these unusual objects. As black holes move through space, the intense gravitational fields warp the fabric of space-time, creating ripples called gravitational waves. Although a wealth of observational evidence indicates black holes exist, the crucial gravitational waves predicted by GR have eluded scientists for over a century—until now.
On February 11, 2016, scientists working with the Laser Interferometer Gravitational-Wave Observatory (LIGO) detector announced the first observation of gravitational waves from the merger of two black holes. (See the full press conference here.) According to the scientific paper that detailed the find, the gravitational wave signature appeared on September 14, 2015, and it matches the expectations of a collision between two black holes with masses of 36 and 29 times the mass of the sun. Given the difference in the timing of the signals at the two LIGO installations (one in Livingston, LA, the other in Hanford, WA), calculations indicate that the black hole merger occurred around one billion light-years away in the direction of the southern hemisphere.1
The detection of gravitational waves opens up an exciting avenue to explore the universe. In this specific instance, it demonstrates the existence of black holes with masses 10 to 50 times that of the sun and that these black holes reside in binary (two-star) systems.
What Does This Discovery Mean for Us?
As astronomers determine the frequency and distribution of binary black holes, they will gain a better understanding of how the universe developed. The evidence of gravitational waves from black hole collisions also provides hope that scientists will find gravitational waves from the earliest moments of the universe. These waves will allow scientists to directly probe events before the emission of the cosmic microwave background radiation (left over from the beginning) that is the limit for electromagnetic radiation. It is an unprecedented snapshot into the briefest of moments after the beginning of the universe.
Obviously, the detection of gravitational waves confirms the validity of general relativity—not that scientists really had much doubt. One important apologetic point raised by this confirmation relates to the philosophical ideas embodied in GR. The starting point for Einstein in developing GR was the notion that the laws of physics are constant throughout the universe and at all times—a notion that corresponds to the biblical description of creation. Coupled with the expansion of the universe, GR strongly supports the fact that the universe had a beginning.
Although black holes rank in the class of the bizarre, they also provide a powerful tool to understand the fundamental characteristics of the universe. The existence of gravitational waves affirms important biblical descriptions of the universe and offers the hope of exploring the most extreme conditions conceivable.
For more details of this exciting find, see RTB’s breaking news web page.
- B. P. Abbott et al., “Observation of Gravitational Waves from a Binary Black Hole Merger,” Physical Review Letters 116 (February 2016): id. 061102, doi:10.1103/PhysRevLett.116.061102.