In February of 2016, the scientific world proved that Einstein’s predictions of gravitational waves were more than speculations. Einstein had predicted the existence of gravitational waves 100 years ago, but until Feburary, scientists had no substantial proof that they existed. After only a week of screening, the LIGO observatory, a coalition of scientists at MIT and CalTech, recorded several instances of gravitational waves passing through the earth. While many physicists jumped for joy and instantly knew the significance of the findings, most people were left scratching their heads in contemplation of what a gravitational wave would look like or even why it would be significant.
In order to begin understanding gravitational waves, it is important to recall the most fundamental concept underlying Einstein’s theory of general relativity. The concept is that gravity is the result of mass bending the curvature of spacetime. This phenomena can be modeled by placing a bowling ball on a stretchy fabric and observing the resulting stretch and indentation of the fabric. Imagine that the bowling ball is pushed and begins to move across the fabric. This would cause the fabric to move in a slight ripple as the bowling ball displaces the fabric. This ripple of the stretchy fabric in our bowling ball analogy would translate to the dimensions of space time stretching and shrinking do to the movement of a large mass. This is exactly what a gravitational wave is.
One question that instantly springs to many minds is, “By how much do the dimensions of space stretch?” When a gravitational wave passes by earth, do we ignorantly stretch by kilometers? Luckily, that is not the case. During LIGO’s observatory period during February 2016, they recorded gravitational waves resulting from two merging black holes. The collision of two supermassive objects only caused space about 1/100,000 of a nanometer, about the width of an atomic nucleus.
The next question that many would ask is, “What is the significance of these gravitational waves?”
Doctor Iair Arcavi, a NASA Einstein Postdoctoral Fellow at UCSB explained, “Telescopes can only collect light, so data becomes muddled. In the past astrophysicists have only been able to see the stars, now we are able to hear their movements. It is like you are at a party, and you can only see people, but suddenly you can hear too.”
The confirmation of these gravitational waves is very exciting and will lead to many more discoveries and a generally deeper understanding of massive astrological events including the merging of black holes, neutron stars, and even the beginning of the universe.
Photo Courtesy/ Charly W. Karl