Astronomy
Gravitational Waves from Binary Black Hole Mergers
Quick fact
The first detected gravitational wave signal, GW150914, was produced by the merger of two black holes with masses about 36 and 29 times the Sun's mass, which released more energy in half a second than all the stars in the observable universe combined.
Why this is interesting
You've probably seen ripples when you toss a stone into a pond. But what if the universe itself could ripple? In 2015, scientists detected ripples in space and time from two black holes crashing into each other a billion light-years away.