The quietest places on Earth
Chapter 1

Einstein's wild prediction

Chapter 2

The ultimate measuring sticks

Chapter 3

The day the universe trembled

Chapter 4

The future of wave hunting

YOUR GOAL

Master of Ripples in spacetime

Ch 2 · The ultimate measuring sticks
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artiteacher The quietest places on Earth

Jul 12

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artiteacher The ultimate measuring sticks

We catch the ripples as the stars collide, Sensing a shift smaller than a proton wide.

Jul 10

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artiteacher Bouncing lasers to measure protons

Jul 12

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The quietest places on Earth

artiteacher To hear the universe, detectors must filter out footsteps, earthquakes, and even ocean waves.

Jul 10

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Bouncing lasers to measure protons

artiteacher Laser beams split and bounce off mirrors to detect changes in distance smaller than an atom.

Jul 10

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Spacetime Ripple Ruler
BETA

artiteacher Slide your ruler across cosmic ripples to discover how massive collisions warp spacetime.

Jul 10

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Fun Fact

LIGO's extreme vacuum: The air pressure inside LIGO's giant beam tubes is reduced to one-trillionth of an atmosphere, making it one of the largest pure vacuum chambers on Earth.

Jul 10

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Glossary
laser (noun)
A device that produces an intense, narrow beam of coherent monochromatic light. In 2015, LIGO used highly stable lasers to detect cosmic ripples from a binary black hole merger.

Jul 10

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Gossip

Which detector location sounds the coolest to visit?

Jul 10

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Quiz

How do scientists isolate LIGO's mirrors from ground vibrations?

Jul 10

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artiteacher A global network of ears

Jul 12

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Gossip

Would you work in an ultra-quiet facility?

Jul 10

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Quiz

What instrument does LIGO use to measure the microscopic changes in its arm lengths?

Jul 10

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artiteacher Inside the giant L-shaped detectors

Jul 12

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Quiz

What special feature helps Japan's KAGRA detector reduce environmental noise?

Jul 10

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Quiz

By what fraction of a proton's width does a typical gravitational wave change LIGO's arm length?

Jul 10

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Quiz

How long are the perpendicular arms of the LIGO detectors in the United States?

Jul 10

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Quiz

Why does the LIGO experiment require at least two separate detectors in the United States?

Jul 10

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Quiz

What shape are the detector facilities of LIGO and Virgo?

Jul 10

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Quiz

Where is the Virgo gravitational wave detector located?

Jul 10