Astronomy
How Gravitational Wave Observatories Detect Merging Black Holes
Quick fact
LIGO's detectors can measure changes in length as small as 1/10,000th the width of a proton—equivalent to detecting a change in the distance from Earth to the nearest star of just a few millimeters.
Why this is interesting
Imagine detecting ripples in the fabric of space itself, caused by black holes crashing together billions of light-years away. How can we possibly measure something so tiny?