Black Hole Blues and Other Songs from Outer Space | Janna Levin | Talks at Google

TL;DR

In February 2016, an obscure experiment called LIGO made the first detection of gravitational waves, which are ripples in the fabric of spacetime caused by the collision of two black holes. These waves were detected using two interferometers and confirmed a major prediction of Albert Einstein's general theory of relativity.

Transcript

JANNA LEVIN: Thanks for having me. It's really great to be here Google. I'm always curious as to what Google is up to. So maybe I get to ask you guys questions after the talk. It's about this detection that I want to talk today. I don't know if people heard, on February 11th, 2016, just this year, there was an announcement made about an otherwise v... Read More

Key Insights

• 🤗 The first detection of gravitational waves confirmed a major prediction of Einstein's theory of general relativity and opened up a new field of astrophysics.
• 👋 LIGO is comprised of two interferometers that record the ringing of spacetime caused by gravitational waves.
• 🖤 Detecting gravitational waves from black hole collisions has provided valuable information about the size and frequency of these events.
• 👋 Future gravitational wave detectors and space-borne observatories will improve our ability to detect and study gravitational waves from various astrophysical phenomena.

Questions & Answers

Q: How do the gravitational waves detected by LIGO differ from light waves?

Gravitational waves are ripples in the fabric of spacetime caused by the acceleration of masses, while light waves are electromagnetic radiation. Gravitational waves cannot be seen, but they can be "heard" using the LIGO interferometers.

Q: How do the gravitational waves emitted by black holes affect spacetime?

Black holes create curves in spacetime, and when they accelerate or collide, the curves themselves move and adjust, creating gravitational waves. These waves travel at the speed of light and cause a stretching and squeezing of spacetime.

Q: Can gravitational waves be detected from anywhere in the universe?

Gravitational waves can be detected from anywhere in the universe, but their strength decreases with distance. LIGO is sensitive to gravitational waves within the human auditory range, but future detectors and space-borne observatories may be able to detect lower frequency waves from more distant sources.

Q: What other astrophysical phenomena could be detected using gravitational wave observatories?

Gravitational wave observatories can detect a range of cataclysmic events, such as black hole collisions, neutron star mergers, and supernovae. They may also uncover new phenomena in the universe that have not yet been predicted or observed.

Summary & Key Takeaways

• On September 14, 2015, the Laser Interferometer Gravitational-Wave Observatory (LIGO) made the first detection of gravitational waves produced by the collision of two black holes.

• LIGO consists of two interferometers, one in Louisiana and one in Washington, which record the ringing of spacetime caused by the waves.

• The detection confirmed Albert Einstein's theory of general relativity and opened up a new field of astrophysics for studying the universe.