" Gravitational waves were detected today! But, what are they? "
LIGO Feel That Space (The Weeknd parody).
what are gravitational waves?
how scientists observed ripples in the fabric of spacetime for the first time?What Colliding Black Holes Sound Like?
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Since Albert Einstein first predicted their existence a century ago (in his general theory of relativity) physicists have been on the hunt for gravitational waves, ripples in the fabric of space-time. That hunt is now over. Gravitational waves exist, and we’ve found them. That’s according to researchers at the Laser Interferometer Gravitational Wave Observatory (LIGO), who have been holed up for weeks, working round-the-clock to confirm that the very first direct detection of gravitational waves is the real deal. False signals have been detected before, and even though the rumors first reported by Gizmodo have been flying for a month, the LIGO team wanted to be absolutely certain before making an official announcement. Now for the first time, scientists in the LIGO Scientific Collaboration, with a prominent role played by researchers at MIT and Caltech — have directly observed the ripples of gravitational waves in an instrument on Earth. In so doing, they have again dramatically confirmed Einstein’s theory of general relativity and opened up a new way in which to view the universe. That announcement has just come. Gravitational waves were observed on September 14th, 2015 by both of the LIGO detectors, located in Livingston, Louisiana, and Hanford, Washington. The source? A supermassive black hole collision that took place 1.3 billion years ago. When it occurred, about three times the mass of the sun was converted to energy in a fraction of a second. LIGO has a great hands-on museum to for kids. The Exhibit Interferometer: The best way to understand an interferometer is to see one in action. The model interferometer uses a split laser beam to project fringe patterns on a screen. A photodiode is used to illustrate the effect of a vibration on the interferometer. By tapping the interferometer kiosk, you can mimic the effect a gravitational wave has on LIGO - it alters the relationship between the two halves of the split beam. In the model, you can see this when the fringe pattern on the screen is disturbed. The photodiode in the model detects this interference and translates a sound to a speaker for you to hear. The model interferometer was designed and constructed by the Ann Arbor Hands On Museum in collaboration with University of Michigan physicists. |
