Astronomers across the world announced on June 29 that they have found the first evidence of a long-believed form of gravitational waves that create a “background hum” rumbling throughout the universe.
The breakthrough has been made by hundreds of scientists using radio telescopes in North America, Europe, China, India, and Australia after years of work. It has been hailed as a major milestone that opens a new window into the universe.
Gravitational waves are ripples in the fabric of the universe that travel through everything at the speed of light. First predicted by Albert Einstein more than a century ago, their existence was not confirmed until 2015, when the US and Italian observatories detected the first gravitational waves created by two black holes colliding. These high-frequency waves were the result of a single violent event that sends a strong, short burst rippling towards Earth.
However, for decades, scientists have been looking for low-frequency gravitational waves, which they believed to be constantly rolling through space like background noise. Working together under the International Pulsar Timing Array consortium, scientists revealed that they have finally found strong evidence of these background waves.
To find evidence, astronomers looked at pulsars, the dead cores of stars that exploded in a supernova. Radio telescopes around the world were aimed at 115 pulsars throughout the Milky Way. Scientists then measured the incredibly small differences in the timing of the pulses and detected changes of less than one millionth of a second across more than 20 years.