About a century ago (for math geniuses- that’s 1915) Albert Einstein came up with this outrageous (at least for that era) General Theory of Relativity. One aspect of Einstein’s theory is that space is not an empty box (what the….who now?) Yup, apparently you know nothing, right? Anyhow, space-time is a fabric.
So, when I say Universe doesn’t think of a black empty area, but rather think a black rubber sheet pulled very tight. Now, if you drop a brick on this rubber sheet, it will bend. This is how space-time works, as per Einstein.
Any object which has mass and is moving creates ripples which he called Gravitational Waves. A small object, like you and me (yes you are a tiny object in the big picture), forms minute waves while a big object, like a black hole, creates huge ripples. Imagine a canoe moving on a lake and then a cruise ship moving on a sea.
Both of these create waves in water but the degree differs. Similarly, when black holes collide with each other they bend and stretch the space-time fabric creating huge ripples.
Though a crucial part of the General Relativity, gravitational waves were not detected directly for a long time. Maths could prove them, circumstantial evidence could prove them but there was no physical proof. Fast forward 100 long years (2015, tadaah!) and we finally have evidence.
Last year LIGO (think a gigantic lab with gadgetry) started an experiment that detected the presence of Gravitational Waves in September for the first time ever. In February 2016 they made it official that a “chirp” was seen in the data signifying the presence of G.W. due to the collision of two black holes that were approximately 30X bigger than our Sun. It was a Eureka moment for the world of astronomy.
Now for the zinger……
After 100 years of silence, we detected them yet again in December 2015. This was announced in June 2016 validating that the first data was not a fluke. This time around the two colliding black holes was smaller but the signal was visible for a longer time period. Scientists called it a “squeak” instead of a “chirp”.
What is the whole brouhaha about them? Besides proving a 100-year-old theory, what you need to keep in mind is that when scientists study Gravitational Waves they are actually looking back in time. These Waves are the result of an action that took place billions of years in the past. Another reason is that they usher a new way to study space.
Till now the farthest we could see and observe in the Universe was limited to us “because the universe was opaque to light for the first 380,000 years or so”. But Gravitational Waves can pass through anything plus the data they carry is not affected by it.
What this means is they can be used to gain knowledge about the very start of the Big Bang. We can know everything, since the very beginning of time for humans.