A word you can easily win a game of Scrabble with in Dutch: achtergrondzwaartekrachtsgolven or gravitational wave background in English. But what is this phenomenon? In an article in New Scientist, Nikhef researcher Chris van den Broeck and others explain how astronomers first found signs of the gravitational wave background: a noise of gravitational waves that is believed to be present throughout the universe.
Gravitational waves are ripples in the fabric of space and time, similar to the ripples you see when you throw a stone into a pond. They occur during violent cosmic events such as collisions between black holes.
When such an event occurs at a relatively small distance from Earth, the LIGO and Virgo detectors can measure the resulting gravitational wave. In this way, the detectors have uncovered over 50 cosmic clashes since 2015.