How gravitational wave interferometers detect tiny changes in distance

A gravitational wave stops two laser beams from perfectly canceling

In a gravitational-wave detector, two laser beams normally return in a way that makes their light cancel out. A passing gravitational wave changes the lengths of the two paths by a tiny amount, so the cancellation is no longer perfect. Detecting this tiny change requires kilometer-long arms and extreme control of noise.

A short passage looks much longer

7 m → 30 m

At Rome’s Palazzo Spada, architect Francesco Borromini used columns that get smaller, a narrowing floor and a small statue to make a seven-meter passage appear thirty meters long.

The same physical feeling can become different emotions

In an experiment, people with the same physical arousal reported different emotions depending on how another person around them behaved. Some became angry while others were amused. The result suggests that bodily arousal alone does not decide which emotion we feel.

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How gravitational wave interferometers detect tiny changes in distance

A gravitational wave stops two laser beams from perfectly canceling

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