Ever since the foundation of astronomy, mankind has relied on what they could see to determine what is out there in the universe. Now, a new way of observing the universe has been discovered. On February 10, it was revealed that gravitational waves, long hypothesized but never observed, were discovered by the Laser Interferometer Gravitational-Wave Observatories (LIGO for short) located in Hanford, Washington and Livingston, Louisiana. Gravitational waves were first proposed 100 years ago by Albert Einstein with his theory of relativity. Essentially, when massive stellar events happen such as a supernova, the displaced energy from that event disperse in great gravitational waves that spread across spacetime like ripples on a still pond. In the case of what was observed by the LIGO, the gravitational wave was caused by two black holes merging one billion years ago. In addition to discovering gravitational waves, this was the first observation of black holes merging. The black holes in question were 36 and 29 solar masses. In order for a black hole to exist, it must be at least the size of three solar masses. The merging of these two large black holes and the resulting displaced energy was enough that it reached one billion years after the incident occurred.
The observatories that picked up the gravitational wave are L-shaped, and have arms 2-and-half miles long, with mirrors at the ends of each arm. These mirrors, made of what Sky and Telescope calls “ultrapure, superpolished…quartz…” have been “…seismically isolated…” from any outside interference, including noise. A laser light is pointed at a divider in the middle, which is split into two beams that go down the arms, is reflected back by the mirrors, and is diverted back into a light detector. Under normal circumstances, these mirrors do not move, and because the beams cancel each other out, LIGO’s detector sees no light. When a passing gravitational wave passes by the Earth however, the resulting passage cause the mirrors to move ever so slightly. These movements are tiny, less than a fraction the size of an atom. However, these observatories are so sensitive, that according to ScienceDaily, they are able to pick up the movements of these mirrors even if they move a distance of less than one-ten-thousandth the diameter of a proton. It was precisely such a movement that the LIGO picked up on Sept.ember 14, 2015. The machine, picking up the invisible ebb and flow of the universe, transferred that gravitational wave into a sound wave that scientists were able to hear. It is important to note however that the gravitational wave did not make that sound, but that the LIGO transferred the wave into a sound. The findings passed a series of examinations, reached a five-sigma result (which is the highest vote of confidence that scientists can give for accuracy), and has since been published in a peer-reviewed journal.
At first, scientists were unsure if the LIGO observatories were going to be successful. The observatories did not pick up any kind of detection. However, when scientists installed upgrades to the LIGO, they picked up a signal. The detection range on the original LIGO was just under the range needed to detect gravitational waves. All of the advanced LIGO specs have not been met yet, but when they are, scientists expect to see more gravitational waves.
With the discovery of gravitational waves, new possibilities for viewing what is beyond the solar system have now been opened. For the first time, astronomers have the ability to map unmapped parts of the universe. It will also be able to help with understanding black holes. Dr. Hawthorne-Allen,
Associate Professor of Physics at Concord University, hopes that this discovery will help us further understand what is out there, and hopes that this will help people to understand that there are no black holes in the solar system, and that they are not coming any closer. She also wishes to say that it is important to understand that these gravitational waves do not physically vibrate the Earth in any meaningful way, merely one-one-thousandth of a proton. In any case, some are calling this one of the greatest scientific discoveries of century, and is the next step in learning what is exactly out there. The scientific findings are available in the journal Physical Review Letters.