Image courtesy of Mirror.co.uk
A Laser Interferometer Gravitational-Wave Observatory (LIGO) near Livingston, Louisiana:
A laser sends out two perpendicular beams about 4 km long. These two beams should cancel each other out. However, if hit by a gravitational wave, one is squeezed and one is stretched leading to a detectable change.
In 1905, Albert Einstein came up with a physical theory called the “Special Theory of Relativity.” In 1915, he finished an expansion upon his theory and created the “General Theory of Relativity.” For now, I will put these ideas into layman’s terms. Normally, relativity works like this: if I am judging the speed of a moving car, the speed will appear differently based on whether I am standing still or moving. However, things change when we are talking about light. Light moves at speed “c” (3.00×108 m/s). If I were looking at a beam of light while standing still, it would appear to be moving at speed “c.” Special relativity says that if I started running and then looked at the beam of light again, it would still be moving at “c.” However, for this relationship to hold true, space and time must bend. Distorting space and time? That may sound like a line from Dr. Who, but it is a very legitimate physical phenomenon. Einstein said that an object could dent the fabric of the universe. If the object were big enough, the dent would pull objects towards it. As objects move, they could create gravitational waves, ripples in space itself (3). Theoretically, if these ripples were big enough, the right machine would be able to detect them. However, he struggled with this aspect of his theory for a long time, at one point even revoking it (1).
That was over 100 years ago. For decades, scientists were looking for these waves. The math said they were there, but no instrument had been able to record them (5). If someone could find these waves, it would open up a whole new section of science. Gravitational waves could be used to recorded data in a similar manner to light, but they are unimpeded by gas, dust, and even black holes (3). This reduces anomalies in data. At times, researchers such as Joseph Weber believed that they had found the waves, but the scientific community always disregarded such claims (5). In the 1990s, Congress approved a budget of two hundred million dollars to build two gravitational wave detectors in Washington and Louisiana (5). There was an entire discipline for studying the mathematics of gravitational waves. All the evidence suggested that they existed. Someone just had to find one.
On September 14, 2015 at 4:50 AM, everything changed. Two LIGO observatories, the ones Congress had approved many years before, recorded a small blip (1). This small blip was the first legitimate detection of these gravitational waves that Einstein had spoken of one hundred years prior. That blip was infinitesimally small in comparison to the humongous machines that detected it. The event this blip signified, however, was no small feat. At some point in the distant past, around 1.3 billion light years away, two humongous black holes collided. One black hole had the mass of twenty-nine of our suns and the other of about thirty-six suns. If that does not seem more powerful than the human mind could every really comprehend, keep in mind that the mass of one single sun is 1.989×1030 kg (6). When these two black holes collided, they combined and released energy equivalent to ~3 suns. I don’t have words to describe how big of a cosmic event that was, so I will let the science speak for itself. Energy was released in the form of gravitational waves, which traveled all the way across the universe to those LIGO detectors in Washington and Louisiana. The data directly matched Einstein’s predictions of relativity (7). A century later, there was finally data to back his ideas.
The science is amazing, awe-inspiring. I cannot help but go back to a quote from journalist Tom Siegfried. He said, “There’s a deeper sense in which both discoveries have something in common that reflects an even more outstanding realization: the power of the human mind to discern deeply hidden features of physical reality” (1). He goes on to say that, “Gravity waves will forever stand as a sign that the math conceived in the human mind coexists in some sense in the fabric of reality” (1). For a century, gravitational waves had never been detected. They were an idea thought up in someone’s mind and understood in the minds of others. However, no piece of technology had ever been found. There was no direct observation. Gravitational waves were just an idea. That idea was right, however.
I believe our greatest scientific tool is our own minds. There is nothing more powerful than a human’s ability to make connections and to turn numbers into ideas, which drive hundreds of millions of dollars of research. Einstein once doubted himself, just as we are likely to doubt ourselves. The human mind is an amazing thing with the immense power to persevere. Let your ideas be heard. Who is to say that the next Einstein, the next person who will change the world, is not here at Baylor University, sitting quietly on an amazing idea?
Katherine Estep is a sophomore BIC student majoring in neuroscience
Resources
- https://www.sciencenews.org/blog/context/gravity-waves-exemplify-power-intelligent-equations
- https://www.sciencenews.org/article/black-hole-heavyweights-triggered-gravity-wave-event?tgt=more
- https://www.sciencenews.org/article/gravity-waves-black-holes-verify-einsteins-prediction
- www.space.com/17661-theory-general-relativity.html
- Gravity’s Shadow: The Search for Gravitational Waves by Harry Collins
- http://www.space.com/17001-how-big-is-the-sun-size-of-the-sun.html
- Observation of Gravitational Waves from a Binary Black Hole Merger by B.P. Abbott
- https://www.youtube.com/watch?v=s06_jRK939I
- Potarf, Jordan. Personal interview. 18 Feb. 2016.