Scientists Just Found an Invisible Black Hole for the First Time—And It's 4X Bigger Than the Sun
Black holes are inherently very cool, and considering the really weird (and sometimes gassy) things that happen around them, astronomers are always on the lookout for more of these hungry space anomalies.
This should, in theory, be fairly straightforward—black holes act like interstellar drains, with light and matter circling endlessly around these incredibly dense pockets of timespace so that they appear like a halo of light in the midst of the sky.
Astronomers using ESO's MUSE instrument on the #VLT have discovered a star in the cluster NGC 3201 that appears to be orbiting an invisible black hole. Artist's impression: @ESO / L. Calçada/spaceengine.org https://t.co/5gAXJzHrWH pic.twitter.com/P8IfynzXCV— ESO (@ESO) January 17, 2018
There's just one problem: as it turns out, not all black holes are constantly sucking in light. A dormant black hole, while still exerting a phenomenal gravitational force on its surroundings, would be entirely invisible to anyone who passed by.
Such a black hole has recently been discovered by astronomers, in a breakthrough piece of research that has, for the first time, managed to spot one of these huge anomalies based entirely on its gravitational pull.
Based on the readings that scientists have managed to take from this beast, it's four times bigger than our sun, but isn't drawing in or spitting out any light whatsoever. Alone it sits, invisible, at the center of a modest cluster of stars.
Globular star clusters are essentially little pockets of stars, containing around 10,000 suns apiece, which rotate as they orbit a larger galaxy. One such globular cluster, NGC 3201, drew scientists' attentions as they examined the cluster to learn what was at the heart of it.
The discovery: a large, dormant black hole, the first of its kind to be discovered simply through measuring gravitational waves. After all, it's hard to spot cool stuff in space when the stuff in question is completely devoid of light.
According to Benjamin Giesers, lead author on the study that unveiled the existence of this dormant black hole:
"Until recently, it was assumed that almost all black holes would disappear from globular clusters after a short time and that systems like this should not even exist! But clearly this is not the case—our discovery is the first direct detection of the gravitational effects of a stellar-mass black hole in a globular cluster. This finding helps in understanding the formation of globular clusters and the evolution of black holes and binary systems—vital in the context of understanding gravitational wave sources."
The discovery of this invisible black hole shows just how little we understand about the universe around us, and what may or may not be possible—or even commonplace—outside our own stellar neighborhood.
There's a lot more to learn before we can have a solid grasp on what is and isn't possible among the stars, and just because something hasn't been spotted yet, it's by no means proof that it doesn't exist.
For now, perhaps the best attitude when it comes to the cosmos is one of optimism: there's still a lot of cool stuff to be discovered, and finding out the mysteries of the universe is going to be a lot of fun.