The Discovery of gravitational waves had been called the most significant scientific breakthrough of the 21st century. It is a revolutionary discovery by the world’s brightest minds in astrophysics. It had opened an entirely new way to look at the universe. Gravitational waves can allow us to rewind the time and unfold the hidden mysteries of the universe . The possibilities are endless.
What is Gravitational Wave?
Gravitational waves are ripples in space-time and are created when massive objects accelerate. These ripples would spread out like the ripples in a pond when a stone is tossed in. These waves are invisible and travel at the speed of light. As it passes by, it squeezes and stretches everything in its path. It is a kind of cosmic DNA, they carry the exact portraits of their origins. They reveal the nature of the universe which we can’t get from any other source.
Einstein predicted the existence of gravitational waves nearly a century ago. But even he thought we might never be able to detect these. They are vanishingly faint, pass through objects, and are invisible to optical and radio telescopes.
Before Einstein turned science upside down with his theory of general relativity, the world had a very different idea about gravity. Newton believed that all objects were attracted to each other by an invisible force. The bigger the object, the greater the force. But Newton’s theory had a flaw, and that is gravity could be communicated instantaneously.
According to Newton’s theory, if two planets from opposite sites of the universe are affecting each other’s gravity instantly without any delay, then that force must travel faster even than the light. But Einstein said that couldn’t be right because nothing is faster than the speed of light. That’s as fast as information can travel.
Einstein had a completely different way of explaining gravity. Einsteins’ theory proposes that gravity is not a force at all. He believed objects like star, planets, black holes distort space and time around them. Imagine space-time as a fabric, stretching out throughout space. Any object with sufficient mass will instantly change the shape of that fabric. This warping of space and time is what we experience as gravity.
How to detect Gravitational Wave
The detection of gravitational waves wasn’t possible without the most sensitive scientific device ever created. Until now, essentially, everything we found about the universe was observed through optical or radio telescopes. But unlike light or radio waves, these gravitational waves can pass straight through matter unchanged.
Gravitational-wave detectors are a new kind of telescope, and it allows us to use gravitational waves as the messenger. It will enable scientists to decode the gravity messages and tease out some of the purest physics of the universe. Things like how fast the black hole is spinning or how big it is when it swallows up its nearest neighbour.
LIGO was created to detect gravitational waves. The initial LIGO observatories were funded by the National Science Foundation ( NSF ) and operated by Caltech and MIT. LIGO comprises of two enormous laser interferometers, which are located 4000 kilometers apart. One of these interferometers is in Washington state, and the other is in Louisiana. It took more than a billion dollars to build the interferometers. LIGO is a device more sensitive than the world’s most powerful optical and radio telescopes.
LIGO is the most precise measuring instrument ever built. LIGO’s interferometers consist of two L-shaped detectors. Inside the detector, A laser beam is fired along with a stainless steel vacuum tube to a set of mirrors. These mirrors stand 4000 kilometers apart from each other.The mirrors weighing 90 pounds or 40 kg each are so sensitive that tapping one of them with a single toothpick creates a vibration that lasts for hours. The laser is split into two arms and travels to the end stations, bounces of the mirrors, and comes back. The lasers act as a ruler for the arms. It precisely measures the distance between the two mirrors. This whole process stretches and compresses space
LIGO had to overcome significant problems to produce an accurate result. Earth is moving, and they have to consider the movement of the ground at different frequencies. Other interferences, like cars and people walking on the road, earthquakes in other parts of the world, needed to be analyzed. All this information is examined to detect the movement of mirrors.
The observatories have an absurd level of precision. It’s like measuring the distance between here and the nearest star at the accuracy of a human hair. They have to clear the vacuum tubes to ensure dust and air particulates don’t affect the lasers. It’s a process that takes 40 days and enough air to inflate over five million footballs.
Gravitational Wave detection by LIGO
In 2016 for the first time, LIGO detected faint disturbances from deep space . 10 milliseconds later, the signal hits LIGO’s sister facility in Louisiana. Even they couldn’t believe it, but Gravitational waves had reached earth. These waves told a story from 1.3 billion years ago. It was a collision of two gravitational monsters, two black holes more than 60 times the mass of our sun. So powerful even light could not escape their pull. The black hole Collison released more energy in its final moments than all the stars in the universe combined.
As it was the waveform of a black hole merger, it revealed interesting things about the physics of black holes. That let astronomers test all their theories about the form and behavior of black holes and what current approaches might be lacking.
LIGO may be an incredible feat of human engineering, but it almost missed the rare event. LIGO was still in test mode when gravitational waves crashed into earth and lasted only a few minutes. It took five months of examination and re-checking. But the gravity waves were the real, just as Einstein predicted.
Less than four months after the first detection, LIGO measured a second burst of gravitational waves. Scientists said, these were created by another, less powerful, black hole merger. It proved that the first collision was not an isolated event. In fact, these massive releases of energy could be quite common in the universe.
Future of LIGO and Gravitational Wave
At LIGO’s 40-meter prototype lab at Cal Tech, scientists are working on the next-generation interferometer. The purpose is to test and run advanced experiments. They are using much smaller interferometers. It makes testing new technology and ideas much more manageable. Also, They are trying to make a better detector. One way of making better detectors is to make the temperature lower. By cryogenically cooling the detectors, outside interference can be significantly reduced.
LIGO is the beginning of gravitational wave astronomy. They have already taken some other initiatives, Including building a detector in space. That will take decades. But it will carry detection of gravitational waves to previously unimaginable new frontiers. Space offers almost limitless precision, free of interference over enormous distances.
Scientists believe if we can observe gravitational waves from the Big Bang, it will revolutionize our understanding of the universe. Gravitational waves can go back to the beginning of time. If we detect such waves, We may witness the birth of the universe. LIGO has a long time plan. They want to watch gravitational waves for the next 100-200 years and reveal to us mysteries from the deep space