![Numerical simulations of the gravitational waves emitted by the inspiral and merger of two black holes. The colored contours around each black hole represent the amplitude of the gravitational radiation; the blue lines represent the orbits of the black holes and the green arrows represent their spins. [Credit: C. Henze/NASA Ames Research Center, February 11, 2016 Physics 9,17]](https://www.ohio-forum.com/wp-content/uploads/2016/02/GravWavillustration.jpg)
[Credit: C. Henze/NASA Ames Research Center, February 11, 2016 Physics 9,17]
They accomplished this using an extremely sensitive device called the Laser Interferometry Gravitational ¬wave Detector, or LIGO, which can measure tiny ripples in the fabric of space¬time, writes Dr. Kenneth Hicks, Professor of Physics & Astronomy at Ohio University, in the February 12 Columbus Dispatch.
Why is this discovery such a big thing?
When Galileo looked at the night sky for the first time with the telescope, he saw things that no one had ever seen before. He discovered moons orbiting Jupiter, something that could not be seen with the naked eye. At that time, the telescope was new technology.
When the Hubble telescope was put into orbit and sent back its first clear images, the pictures were breathtaking. The new technology of space telescopes made this possible.
Now, this new technology called LIGO allows us to “hear” the most violent events in the universe, such as when two black holes collide, through the “sound” of gravitational waves.
Just as a microphone can pick up tiny vibrations from sound waves, LIGO can sense even smaller vibrations as gravitational waves pass through Earth.
The vibrations are so small, they only shake back and forth a distance of one-thousandth of the radius of a proton. It required years of research and development to achieve this incredible feat of technology.
The signal LIGO measured was an oscillation that increased in frequency over the span of about 0.15 seconds, seen simultaneously at both LIGO facilities, one in Washington state and the other in Louisiana.
Now that we have the most sensitive microphone ever built, funded by the National Science Foundation at about $1 billion over 40 years, what is the payoff?
In addition to a probable Nobel prize, this discovery opens a new chapter for astronomy and cosmology. Understanding our place in the universe is at the heart of this science.
In 1916, Einstein predicted the existence of gravitational waves as part of his general theory of relativity. Later, Einstein’s theory was used to show that the universe started with the Big Bang. Ever since, astronomers have made more and more precise tests of Einstein’s theory and its implications for how the universe began.
The measurement of gravitational waves is yet one more confirmation that Einstein’s theory is correct. It also tells us, for the first time, that two black holes can spiral together and collide, forming one larger black hole. This was science fiction until LIGO measured it.
Read Hicks’ column in the Columbus Dispatch.
Read “Viewpoint: The First Sounds of Merging Black Holes” in APS Physics
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