Astronomers Detect First-Ever ‘Kilonova’

For the first time, scientists have detected gravitational waves — ripples in the fabric of space and time created by objects moving in the universe — from two neutron stars colliding in a phenomenon known as a kilonova.

According to The Verge, the event was detectable by regular light telescopes. Previous detections have come from the mergers of black holes, which do not emit light. But neutron stars are the very dense leftovers of stars after they’ve collapsed. So when they spun around each other and then collided, they created a giant fireball of light that was visible to telescopes on Earth, reports The Verge. 

The signal was picked up by three different gravitational wave observatories around the globe on Aug. 17: the dual US-based observatories operated by LIGO and Virgo, which is located in Italy. Astronomers were able to locate the area where the merger occurred, and narrowed it down to a small patch of the southern sky, reports The Verge. 

Once they narrowed down the general area, LIGO got thousands of astronomers operating 70 ground-based and space-based telescopes to search the sky. According to The Verge, they eventually spotted the “explosive leftovers” of the merge and continued to observe the event for weeks after the collision.

LIGO made the first wave detection in history last year. Astronomers had been trying to figure out how to detect these ripples for over a century. They were first predicted by Albert Einstein in his theory of general relativity. However, according to The Verge, detecting the waves is very hard. Many of the smaller waves cannot be picked up from Earth, so scientists have to look for the waves coming from massive objects moving at rapid speeds, like merging black holes and neutron stars.

Before these objects collide, The Verge writes, they actually spiral around each other, growing “closer and closer over time.” The spinning increases so much that the objects are going to each other a few times every second, and then they finally collide. This activity creates gravitational waves.