Physicists, astronomers, and aerospace engineers stand before an ever-expanding universe of possibilities, and new information and scientific breakthroughs are presenting exciting prospects for space exploration that we only thought possible in science fiction. For instance, this last February, scientists from LIGO (the Laser Interferometer Gravitational-Wave Observatory) confirmed that they were able to detect and observe gravitational waves, actual ripples through the fabric of space-time. In Part I of this series, we will examine this incredible phenomenon and how it changes our fundamental understanding of the universe. Look for Part II to learn how this discovery affects the field of aerospace engineering.
So what are gravitational waves, and why are they so important? Until recently, gravitational waves were nothing but speculation, just a concept. About 100 years ago, Albert Einstein considered gravitational waves when he developed his theory of general relativity; he theorized that massive objects like stars and planets cause distortions in space-time as they accelerate. Think of them like bowling balls distorting the fabric of a trampoline. When objects with mass accelerate towards one another, they send out waves at light-speed along the curved fabric of space-time surrounding them. The more mass an object has, the bigger the waves. But one of the most bizarre facts about gravitational waves, is that they do not interact with matter, meaning that as they travel along space-time, they pass through stars and planets unimpeded!
Einstein believed that if gravitational waves existed, that they would be too small to ever be detected. He wasn’t far off with that prediction; events that might cause gravitational waves to occur in areas of space at a considerable distance from Earth. Like ripples in a pond, the waves lose steam the farther they travel, so by the time they reach Earth they are smaller than they were at their point of origin. So how did LIGO manage to detect gravitational waves?
The LIGO “observatory” is comprised of two interferometers, one in Livingston, Louisiana and another in Hanford, Washington. Both are quite large, having two arms that are 2.5 miles long converging in a giant “L” shape and both are incredibly sensitive to vibration. Like other types of interferometers, the LIGO detectors utilize lasers and mirrors to create interference patterns that can be observed and analyzed. LIGO’s detectors are specially designed and perfectly suited to the detection of gravitational waves. If you are interested in learning more you can read about LIGO by clicking here.
Why All of This Matters
Besides being exciting and just plain cool, there are a few reasons why the detection of gravitational-waves matters.
- It provides a good deal of evidence to support Einstein’s general theory of relativity, which points to the idea that space isn’t merely a “void” but rather a 4-dimensional fabric that can bend and stretch, and these distortions would be understood to be the real cause of gravitational attraction.
- Gravitational-waves give us another way to observe the universe. If waves from the Big Bang could be detected, it would provide invaluable insight on how our universe was formed. They also provide evidence of objects that can’t be directly observed, such as black holes.
- Discovering and observing anything about space-time is a huge milestone in understanding how our universe works and takes us farther down the path of theoretical physics.
Stay tuned for Part II!