A Black Hole: Not the void in my chest where my heart should be.

Artist’s depiction of HB 6819

A recent paper published by astronomers from the European Southern Observatory, ESO, states astronomers have discovered a new black hole. The recently found stellar object is reportedly the closest to earth to be found and has given supporting evidence of many more black holes present throughout our universe.  

Black holes are not a recently discovered phenomena. Albert Einstein referenced these objects in 1916, when he developed his famous theory of general relativity. Since Einstein, many astronomers have worked to confirm their existence.  The first black hole was finally confirmed to exist in 1971.

Millions of black holes are thought to exist in isolation, with nothing orbiting them, thus making them impossible to observe. Some black holes however have been found to have orbiting companions where the invisible black hole is acting as the center of the system keeping objects in orbit with its gravitational pull, much like the sun in our solar system. 

What makes ESO’s recent discovery so interesting is that this particular black hole lies within the confines of what was originally thought to be a double star system. Due to the recent discovery of a third object, the black hole, the double star system is now categorized as a triple star system. 

Eloquently named HR 6819, the triple star system is 1000 light years from earth and is part of the constellation Telescopium. Based on HR 6819’s seemingly robot-generated name one assumes astronomers are not worried about creative names for objects beyond our solar system. HR 6819 is close enough to be seen with the naked eye on a clear night which is a first for a black hole and it’s companion stars.

Black holes are a major area of research in the field of astronomy though minimal observation has been accomplished due the fact they are essentially invisible. No visible light is emitted due to the extreme gravitational force generated by the singularity at the black holes center. They are observed primarily by tracking the gravitational behavior of visible objects orbiting them or, under the right conditions, by electromagnetic radiation jettisoned out into space during the early stages of their life cycle. Meaning black holes are not unstoppable destroyers of their surrounding environments.  Essentially black holes will collect a certain amount of matter from their surroundings and eventually stop. This leaves them dormant and completely silent. 

Artist’s depiction of a black hole emitting x-rays and with an accretion disk.

Black holes are formed upon the death of super massive stars in our universe. Once fusion ceases with these stars the relentless battle against gravity is finally lost. This defeat causes the star to explode violently in the form of a supernovae. The remnants of the star’s core which is expelled during the explosion eventually collapse upon themselves, creating a singularity. These singularities cause space time to warp radically leaving an event horizon upon which being crossed nothing will escape unless traveling faster than the speed of light. 

Artist’s depiction of a black hole warping space time

In this type of extreme environment our known laws of physics break down. The intense gravity warps space time so radically nothing beyond the event horizon can not be released. Accretion disks, which consist of swirling gas and particles, form around the outskirts of the black hole’s perimeter. These disks consist of remnants of objects being drawn into the black hole. This matter and gas are heated to extreme temperatures by friction. This super-heated gaseous disk emits electromagnetic radiation in the X-ray part of the spectrum. Astronomers observe this radiation using X-ray telescopes in order to determine the presence of these invisible objects. 

Once black holes stop devouring surrounding objects they no longer emit x-rays.  Therein lies the problem with finding black holes throughout the universe. Astronomers theorize there should be millions of these relatively small, idle black holes throughout the universe.  

How do the researchers identify them? Frankly, not necessarily by looking for them directly. Astronomers stumble upon their presence by the luck of the draw, as seen in the ESO’s recent findings. 

Using the FEROS Spectrograph, which is installed within the MPG/ESO 2.2-metre telescope in La Silla, Chile, the team were tracking the orbits of two companion stars within HR 6819. While analyzing the data they recorded the team found a massive invisible gravitational object in the center of the system. The astronomers found one of the stars was in fact orbiting this invisible object once every forty days. This black hole has the mass four times that of our sun. Using the information gathered while tracking the gravitational movement of the companion stars, the research team was able to determine the mass of the invisible object they were bonded to. Something this size, which is not emitting any electromagnetic source must be a black hole.

This recent discovery has influenced astronomers to attempt identify more black holes within similar systems and closer to earth. The star system, LB-1, has been identified to be a potential triple system.  Additional observation and research will be needed in order to confirm this however.  LB-1 will be observed in attempts to determine if the system contains a black hole as well. 

By studying black holes astronomers are attempting to gather more information on the formation and life cycle of super massive stars. The recent discovery of the black hole in HR 6819 gives evidence to supernovas being in some cases symmetrical. It has been thought that supernovae explosions send matter into the cosmos asymmetrically, meaning more matter is emitted in one direction and the remaining black hole is propelled in another. Finding a black hole bonded to a star leads astronomers to believe that the supernovae explosion, which caused the formation of the black hole, was in fact symmetrical and allowed the black hole to stay in place. 

Supernovae Explosion from Hubble Space Telescope

As astronomy moves forwards with advancements in instrumentation, theory and observation, more and more of our questions will be answered.  We are living in an exciting time, having access to these advances and discoveries. We are finding hidden mysteries of the universe more and more often.  With all these strides being taken, eventually a bigger mystery will be unveiled and I for one eagerly await the show.

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