Gravitational Waves: The Ripple Heard Around the Universe

Confused about the hype? Here’s what you need to know.

A few weeks ago, the scientific community was able to detect that two black holes, each about thirty times the mass of the sun violently collided to merge into an even more massive black hole about sixty times the mass of the sun. Although this news is fresh for us, it’s old news for the universe, having happened 1.3 billion years ago!

However, the fact that we even know is extraordinary because this event occurred 1.3 billion light years away from us (with just one light year being about six trillion miles). How do we know about something that happened billions of trillions of miles away? It’s thanks to a type of wave never detected or even confirmed to exist before the black-hole event, known as gravitational waves.

Gravity as waves? In order to understand this, you have to redefine how you think about gravity. Gravity is really the curvature of time and space. Something with an enormous mass like a star can curve time and space. When the huge mass moves, or accelerates, there are ripples in spacetime where space is stretching and compressing- these are known as gravitational waves.

images
Visualization of gravity- sheet represents spacetime

Why did it take us until 2016 to find them? Einstein actually predicted their existence a century ago in 1916 as part of his theory of general relativity. But gravitational waves are very small since gravity is the weakest of the fundamental forces holding the universe together. It takes an extremely sensitive instrument to detect these waves and they must be caused by the most violent disturbances in nature such as two neutron stars or two black holes merging. The larger the masses, the larger the ripples in timespace. It was very lucky that the black holes merged when they did. Interestingly, the waves come in at frequency audible to humans so it was if as if this event could even be heard.  

How do gravitational waves impact the future of science and the world we live in?

Ripples in spacetime as far as back as the birth of the universe are prevalent and if picked up by our sensors can help support the theory of big bang and fill in gaps as to how our universe was created.

Previously, light, or electromagnetic radiation, such as radio waves were primarily used for understanding the universe. However, they are easily scattered or blocked by matter in the universe. Gravitational waves can travel with very little interference. Because gravitational waves can come out of cataclysmic events such as supernovas relatively unimpeded, they can paint a very clear picture of the event; unlike light which is easily blocked by dust or gas before reaching Earth.

Furthermore, researchers are hoping gravitational waves will shed light on the quantum level of gravity. Currently, the theoretical particle with no mass, the graviton is believed to make up gravitational waves similar to how the massless photons make up light (electromagnetic waves). Although discovery of the waves have not yet supported the existence of gravitons, further data can illuminate gravity’s particle nature.

The discovery even threw around talk of time travel because it bolstered Einstein’s general relativity, a theory dealing with concepts like time dilation. Einstein had actually predicted that time travel could be possible. Although Einstein turns out to be right much of the time, there is little at the moment for gravitational waves to point in the direction of time travel. Scientists urge an open mind, however, because history has shown that advances that exciting new discoveries, like this one, unravel are not immediately apparent. Just like how when general relativity was introduced, no one knew it could one day be crucial for GPS technology.

time-travel

Even if gravitational waves don’t necessarily mean the start of a time traveling age, the discovery is a huge milestone for mankind. Don’t ever let your eyes fool you into thinking the space beyond our atmosphere is  bleak, dull, or void of life because if you look a few trillion miles in a given direction there may be stars exploding, black holes colliding, galaxies forming, all these terrible and wonderful cataclysms that before could happen completely unbeknownst to us. Gravitational waves is yet another key to the infinite secrets the universe beholds and gives us an ear to the major events that affect the cosmos. By daring to look outside our small world, we can continuously burst the boundaries of our limited imagination as we now uncover deeper truths about the extraordinary space beyond.  

By: Shivanie Rambaran

Sources:

http://gizmodo.com/your-questions-about-gravitational-waves-answered-1758269933

http://www.abc.net.au/news/2016-02-16/gravitational-waves-how-small-are-they/7163438

http://www.usnews.com/news/articles/2016-02-23/discovery-of-gravitational-waves-makes-time-travel-mathematically-possible

http://www.sciencealert.com/watch-this-is-what-gravitational-waves-sound-like

 

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