William Reville
The detection of gravitational waves will provide for a better understanding of creation, writes Prof. William Reville
Scientists working on the Laser Interferometer Gravitational-Wave Observatory (LIGO) made the stunning announcement recently that they had detected gravitational waves, confirming Albert Einstein’s prediction that these waves exist.
The waves originated 1.3 billion years ago when two black holes, one 29 times and the other 36 times as massive as our sun, collided. This massive crash sent gravitational waves, ripples in the fabric of space-time, streaming outwards just as dropping a pebble into a still pond of water sends waves streaming outwards from that point disturbance. This discovery opens the door to a new era of astronomical observations using gravitational waves, allowing us to see further out into space and further back in time. It seems to me that this discovery has no major implications for Christianity.
Albert Einstein’s special theory of relativity published in 1905 describes how the world looks to observers moving in straight lines at steady velocities.
Einstein’s general theory of relativity published in 1915 describes how the world looks to observers moving in a non-uniform manner, accelerating and decelerating. This theory developed an entirely new theory of gravity. Einstein’s theories are cornerstones of modern physics and have passed all tests of their validity
Classical physics viewed space as a continuous phase with three dimensions and time as a separate two-dimensional line that moves inexorably from the past to the present and into the future.
Continuum
However, the special theory of relativity showed that space and time are not separate entities but are bound together into a four dimensional space-time continuum (three space dimensions and one time dimension). The shape of the space-time continuum is distorted by the presence of matter and Einstein explained that such deformations account for the ‘force’ of gravity that affects the trajectories of moving objects.
Imagine the space-time continuum as a flat stretched rubbery surface. Place a heavy cannon ball onto this surface and it will make a marked local depression where it lies. This is how a large lump of matter distorts the space-time continuum.
Now imagine a ball-bearing rolling along the rubbery elastic surface in a straight line making only a small indentation.
However, as it approaches the cannon ball it follows a curved path along the cannonball’s distortion of the elastic surface.
When a small object moves near a massive object it follows a curved path. Objects follow a path of least resistance through the space-time continuum and the path is curved when space-time is distorted.
A rule of thumb says ‘matter tells space how to curve, space tells matter how to move’. This is the modern model for the force of gravity.
Now imagine two cannon balls rapidly approaching each other on this rubbery elastic surface, until they violently collide. The collision will cause a wave ripple to move outwards from the site of the collision through the rubbery space-time continuum.
These are gravitational waves and they move at the speed of light.
Predicted
Gravitational waves were predicted by Einstein but they are very weak and Einstein thought that they would never be detected by any physical detector.
But, gravitational waves were detected by LIGO on September 14, 2015.
As waves of gravitational energy ripple across the universe they alternately stretch and squeeze the space they pass through. LIGO was able to detect this squeezing and stretching, but sensitive as LIGO is, it can only detect strong gravitational waves created by dramatic events such as the collision of two black holes.
It is estimated that in the black holes collision detected by LIGO, about three times the mass of the Sun was converted into gravitational waves in less than one second, generating a peak power output about 50 times that of the entire visible universe.
LIGO detected the warping of space-time using two L-shaped detectors, one located in Livingston, Louisiana and the other in Hanford, Washington, almost 2000 miles apart. Each L detector registered the gravitational wave.
Each arm of the L is 4 km long. Near the point where both arms meet a beam of laser light is simultaneously shot down each arm and is reflected back by a mirror at the far end of the arm to the starting point. As a gravitational wave passes, it compresses one arm of the L and stretches the other.
The beam of light passing along the stretched arm takes slightly longer to get back to the starting point than the light traveling along the compressed arm. And this is how the gravitational waves were detected. LIGO is unbelievably sensitive – the change in the length of each arm is far smaller than the width of an atomic nucleus.
The ability to detect gravitational waves opens up fantastic prospects for astronomy.
Black holes
It should now be possible to probe the majority of the universe (the ‘dark’ universe) invisible to the light telescopes used at the moment. It should be possible to investigate black holes and look much deeper into the universe and thus farther back in time. Although difficult to detect, the information carried by gravitational waves is very pure.
The waves are scarcely affected by materials they pass through, so they faithfully retain the information about the event that caused them. For example, dust prevents astronomers seeing light from whole regions of our own galaxy, and we cannot see the early part of the Big Bang with conventional telescopes because the very early universe was opaque to light. With gravitational waves we may eventually see the Big Bang.
The LIGO work detected, but did not discover gravitational waves – observations in the 1970s and 1980s allowed science to infer the existence of gravitational waves.
As far as I can see, the only implication that the detection of gravitational waves has for Christian faith is that it allows us to further understand the wonderful mechanisms that underpin the creation.
We might resonate with Einstein on this point, who once declared: “I want to know how God created this world. I want to know His thoughts.”
*William Reville is an Emeritus Professor of Biochemistry at UCC http://understandingscience.ucc.ie
