NASA discovers smallest of the most massive black holes. Confused? read on.

Science and Tech

A Sloan Digital Sky Survey image of RGG 118, a galaxy containing the smallest supermassive black hole ever detected. The inset is a Chandra image showing hot gas around the black hole.
Credits: NASA/CXC/Univ of Michigan/V.F.Baldassare, et al; Optical: SDSS A Sloan Digital Sky Survey image of RGG 118, a galaxy containing the smallest supermassive black hole ever detected. The inset is a Chandra image showing hot gas around the black hole. Credits: NASA/CXC/Univ of Michigan/V.F.Baldassare, et al; Optical: SDSS

NASA has uncovered the smallest super massive black hole ever detected. The new data was released on Tuesday from NASA’s Chandra X-ray Observatory and the 6.5-meter Clay Telescope in Chile. The discovery of Cygnus X-1 could provide clues on how larger black holes formed along with their host galaxies 13 billion years or more in the past.

The tiny black hole is located at the center of a dwarf disk galaxy RGG 118, located about 340 million light years from Earth.

The smallest of the massive?

The black hole is nearly 100 times less massive than the super massive black hole found in the center of the Milky Way, NASA said. The black hole is about 200,000 times less massive than the heaviest black holes found in the centers of other galaxies.

Astronomers believe this discovery will help them understand the formation of  solar mass black holes that date back to a billion years after the big bang. These black holes are currently undetectable due to the absence of suitable technology. This newest discovery will help astronomers study nearby small super massive black holes, NASA said.

What is a Black Hole?

agn_illustration

An artist’s conception shows a black hole surrounded by a disk of hot gas, and a large doughnut or torus of cooler gas and dust. The light blue ring on the back of the torus is due to the fluorescence of iron atoms excited by X-rays from the hot gas disk. (Credit: Illustration: NASA/CXC/M.Weiss)

A black hole refers to a region of space where the gravitational force is so strong that no light can escape. The term was first coined in 1967 by Princeton physicist John Wheeler although reference to black holes can be found in Einstein’s Theory of General Relativity.

As the name suggests, a black hole is black in color due to the absence of light. So how do astronomers and scientists study them? Astronomers measure light ( visible), X-rays and radio waves emitted by objects/material that are located in the immediate environment of a black hole.

For example, when a normal star orbits around a black hole, we can measure the speed of the star by studying the visible light that it emits. Knowledge of this speed can be combined with the laws of gravity to prove that the star is in fact orbiting a black hole, instead of something else. It also yields the mass of the black hole. Alternatively, when gas orbits around a black hole it tends to get very hot due to friction. It then starts emitting X-rays and radio waves. So black holes can also often be found and studied by looking for bright sources of X-rays and radio waves in the sky, Hubblesite.org explains.

In the case of this latest discovery, the Chandra X-ray Observatory was able to detect the black hole’s presence due to X-rays from “hot gas swirling towards the black hole.”

This chart illustrates the relative masses of super-dense cosmic objects, ranging from white dwarfs to the supermassive black holes encased in the cores of most galaxies. The first three "dead" stars at left all form when stars more massive than our sun explode; the more massive the star, the more massive the stellar remnant, or compact object, is left behind. Image credit: NASA/JPL-Caltech

This chart illustrates the relative masses of super-dense cosmic objects, ranging from white dwarfs to the supermassive black holes encased in the cores of most galaxies. The first three “dead” stars at left all form when stars more massive than our sun explode; the more massive the star, the more massive the stellar remnant, or compact object, is left behind. Image credit: NASA/JPL-Caltech

Black holes can be classified based on their mass, the way they spin and their electric charge.

There are three kinds of black holes:

Stellar Black Holes

Stellar black holes have a solar mass (a measurement used for stars, clusters, nebulae and galaxies) that is less than 100 times that of the sun. These black holes form when a star, towards the end of its life, collapses due to gravity, according to the Cosmos Encyclopedia of Astronomy. Not all stars form black holes. Smaller stars form white dwarfs or neutron stars. Larger stellar black holes exist at the center of galaxies.

Intermediate Black Holes

Intermediate black holes have a solar mass of between 100 to 1 million. They are between a stellar black hole and super massive black hole. The existence of super massive black holes have been questioned for years, although recent discoveries have pointed towards the existence of a medium-sized black hole. The exact cause for their formation is still unknown although some astronomers believe that they are formed when super massive black holes collapse.

Super massive Black Holes

Super massive black holes are the largest kind of black holes. They can have a solar mass of  hundreds of thousands to billions.  There are multiple theories about how super massive black holes are formed. One theory states that they are formed by massive clouds of gas that may have been left behind during the formation of the galaxy. Another possible reason is that they are formed from stellar black holes which grow in size or due to the merging of a cluster of black holes.

Data from NASA, Cosmos Encyclopedia of Astronomy, Chandra X-ray Observatory, Wikipedia, Hubblesite.org