The world-famous scientist initially considered the detection of gravitational waves impossible. Finally, he made a significant contribution to confirming the opposite.
Over the past week, Slovakia has hosted a world-famous science figure, the well-known American astrophysicist Kip Thorn. He came at the invitation of the Eset Foundation to award the Eset Science Prize to exceptionally Slovak scientists.
In 2017, Thorne and two colleagues won the Nobel Prize for first direct detection of gravitational waves. These were also one of the topics of last week’s public discussion on the grounds of the historic building of the Slovak National Theater in Bratislava, where Thorne spoke with the British particle physicist and popularizer of science Brian Cox.
The American scientist clearly explained the principle of gravitational waves, but mainly described the way in which they can be recorded. He did not avoid thinking about the importance of gravitational waves in future observations. According to him, it is a means that can reveal the secret of the origin of the universe.
You can read this article thanks to ESET Science Award, an award that supports exceptional science in Slovakia.
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Einstein didn’t believe it either
“There are only two kinds of waves in the universe – gravitational and electromagnetic,” Thorne began answering the question of the nature of gravitational waves.
It is an anomaly where it acts to wave its own space. When a gravitational wave follows an object, it causes it to stretch slightly in width and then in height. “Only waves are created when accelerating objects with a huge weight,” Thorne added.
The existence of gravitational waves at the beginning of the last century was predicted by the French mathematician and theoretical physicist Jules Henri Poincaré. Later, Albert Einstein also addressed this idea. It turned out that their existence stems directly from his famous general theory of relativity.
Scientists have discovered gravitational waves that Einstein assumed existed
However, never this result. In 1936, together with physicist Nathan Rosen, he published an article claiming that gravitational waves could exist. According to his calculations, in addition to these waves, the equations predicted the existence of regions of infinite mass.
Howard P. Robertson, who pointed out the wrong approach to the issue. The fact that someone had reviewed the text before its publication angered Einstein, and he decided to withdraw the article. Later, his assistant convinced himself of the criticism and the corrected article was finally published.
The most accurate experiment of all time
Although Einstein was already convinced of the existence of gravitational waves, because of their weak manifestations he considered it impossible for humanity to ever be able to observe them.
Thorne shared this view when considering the design of devices for direct detection of gravitational waves.
“It was clear to me that it was hopeless. This will never succeed. It required the use of light to measure the movement of mirrors with an accuracy of ten million times less than the diameter of the atom, “said the scientist.
“Then I spent most of my career helping experimenters prove me wrong.”
We are on the trail of new, exotic particles. Gravitational waves will help
This principle is finally succeeded in the LIGO (Laser Interferometer Gravitational-Wave Observatory) experiment, which has been operating since 2002.
Two detectors located in Hanford, Washington, and Livingstone, Louisiana, are used for recording. Detectors consist of two genera placed at right angles. Both are four kilometers long.
A laser beam is emitted into the arms. At the beginning, it is divided into both arms by means of mirrors. In them, the rays are subsequently reflected from the mirror at the ends and then suddenly come to the detector.
Nevertheless, when a gravitational wave passes through LIGO, one of the arms is shortened. As a result, the rays do not reach the detector together. “It’s the most accurate measurement of all time,” says Thorne.
LIGO detector in Hanford.
Source: LIGO Laboratory
Exactly such an anomaly was observed by scientists on February 11, 2016. The recorded gravitational waves were created by the collision of two black holes with a mass 29- and 36-fold higher than the Sun.
About four months later, further observations follow. To date, up to 50 such events have been observed.
By observing gravitational waves, it is possible to obtain information about the objects that make them up. Thorne therefore sees in them a means that can reveal the secret of the origin of the universe: “The only thing that comes to us from the Big Bang period is intact are gravitational waves.”
However, he added that even if scientists recorded gravitational waves from the beginning of the universe in the coming decades, they probably would not yet understand this knowledge.
Record of a 2-hour discussion between Kip Thorn and Brian Cox (in English):