Astronomers Discover First Ever Isolated Black Hole Just Chilling In Space
As everyone awaits the James Webb Space Telescope to become ready to begin taking pictures of the Universe, they are still utilizing its predecessor the Hubble Telescope to make astounding discoveries. A group of astrophysicists and astronomers took advantage of Hubble's ability to peer into deep space in their hunt for black holes. In research that took two years of planning, and six years of observing with Hubble, they believe they have discovered an isolated stellar-mass black hole for the first time ever.
Lead author, Kailash Sahu, an astrophysicist at the Space Telescope Institute in Baltimore, believes that there should be approximately 100 million stellar-mass black holes in the Universe. Until now, all of the stellar-mass black holes that have been discovered existed in binary systems with partners like neutron stars. Sahu, however, thinks that the majority of the Milky Way's stellar-mass black holes should be singletons.
Until now, no one had been able to find an isolated black hole. Black holes are especially hard to detect, because they absorb any light that falls into them. Black holes that exist in binary systems are easier to detect, due to the interactions that occur with their partners producing light or gravitational waves which can indicate a black hole exists. Lone black holes do not have a partner to interact with, therefore making them much harder to discover.
Sahu told Space.com, "If you can detect and measure the bending of light caused by these massive objects, it's possible to detect them and measure their masses." He continued explaining, "This microlensing phenomenon is caused by an intervening object, which can be a star or a white dwarf or a neutron star or a black hole or so on. The survey programs typically detect about 2,000 microlensing events per year. A small number of them are expected to be caused by black holes."
A black hole's microlensing event is expected to have a long duration and is expected to be dark. Sahu said that these these are the two main determining criteria in locating and identifying black holes in deep space. In order to differentiate an isolated black hole from a small-mass star is that a black hole will deflect the light from background stars enough that it can be measured with the use of Hubble. Sahu stated, "If the Hubble observations show large deflection but no light from the lens, then it would be a black hole."
The discovery of an isolated stellar-mass black hole utilizing Hubble makes one wonder what scientists will be able to discover once Webb is up and running. We await on pins and needles to see what else can be discovered and what questions can be answered.