Deciphering Gravitational Waves, with Janna Levin – StarTalk All-Stars
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Deep Dive
Why did the discovery of gravitational waves cause such a huge public reaction?
The discovery of gravitational waves caused a significant public reaction because it was a groundbreaking confirmation of Einstein's theory of general relativity, opening a new window into the universe. The announcement was so impactful that it halted daily activities, capturing global attention and excitement.
Why are gravitational waves described as a distortion of space and time?
Gravitational waves are described as a distortion of space and time because they are ripples in the fabric of spacetime caused by the acceleration of massive objects. These waves stretch and compress space in a perpendicular direction to their motion, and the effect is measured as a change in distance between objects.
Why did Rainer Weiss face skepticism when he first proposed building LIGO?
Rainer Weiss faced skepticism when he first proposed building LIGO because the concept of measuring an incredibly small effect, a strain of 10 to the minus 21, seemed practically impossible. Additionally, there was doubt about the existence of black holes, which were expected to be the primary sources of gravitational waves.
Why are gravitational waves so hard to detect?
Gravitational waves are hard to detect because they cause extremely tiny distortions in space-time, on the order of a millionth of a trillionth of a meter. The strain is 10 to the minus 21, and the effect is so subtle that it requires highly sensitive instruments like LIGO to measure it.
Why did Einstein initially doubt the physical significance of gravitational waves?
Einstein initially doubted the physical significance of gravitational waves because his calculations suggested that the energy and forces required to produce detectable waves were so immense that it would be practically impossible. He believed that the waves would not have any measurable physical consequences.
Why is the first detection of gravitational waves by LIGO considered a major milestone in astrophysics?
The first detection of gravitational waves by LIGO is considered a major milestone because it confirmed a key prediction of Einstein's theory of general relativity and opened a new way to observe the universe. This detection provided direct evidence of black hole collisions and allowed scientists to study phenomena that are invisible to traditional telescopes.
Why can't gravitational waves be used for time travel?
Gravitational waves cannot be used for time travel because they do not have the capability to manipulate time in a way that would allow for backward or forward travel. While they can stretch and compress space, they do not affect the flow of time in a manner that would enable time travel.
Why are LIGO's mirrors displaced by such a small amount?
LIGO's mirrors are displaced by an extremely small amount, about 10 to the minus 18 meters, because the strain of gravitational waves is incredibly small, around 10 to the minus 21. The mirrors are part of a highly sensitive interferometer designed to detect these minute changes in distance over a four-kilometer baseline.
Why did the first gravitational wave detection only last a quarter of a second?
The first gravitational wave detection lasted only a quarter of a second because the two black holes were only in LIGO's sensitive frequency band during the final moments of their collision. As they spiraled closer, the frequency of the waves increased, and LIGO was only able to detect the waves once they entered its operational range.
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