Credits: X-ray: NASA/CXC/SAO/D.Patnaude et al, Optical: ESO/VLT, Infrared: NASA/JPL/Caltech
It has all the ingredients of an epic story. An awe-inspiring plot, the inconceivable vastness, the ultimate destruction followed by an unimaginable creation. It also offers a flashback. The action begins about 30 years ago about 50 million light years from earth. A star, 20 times the mass of our sun, goes into oblivion flashing its death message to every corner of the cosmos. A Maryland school teacher, who happened to be an amateur astronomer, picked up that signals with a small telescope. Professional astronomers and their massive telescopes follow the event. The rest is told to us on November 15th, 2010, when NASA, for the first time, announced the birth date of a stellar black hole. The reports are that the baby black hole is feeding well on the cosmic materials and will thrive.
Ever since the theory of relativity predicted their existence and since John Wheeler called them black holes, they have become a household name. They represent the limit of human imagination. The active life of a star is a continuous battle of forces, gravity against nuclear force. The inevitable victory of gravity collapses the core of the star, and if the star is much massive than the sun, its destruction is the likely birth of a black hole .They come in different sizes and masses with millions of them in our own galaxy, yet they present an ongoing enigma to the scientists. Researchers haven't witnessed the birth of one, until now. But, this discovery is remarkable in many other ways too.
First of all, the supernova explosion that marked the end of the parent star, known as SN1979C, was detected by the former school teacher Gus Johnson in 1979, as it took place in a galaxy named M100, beyond our own. It turned out that the death of that star was an actual birth cry of a black hole, although it couldn't be confirmed at that time.
Usually the birth of a black hole is accompanied by bright gamma ray burst (GRB). But SN1979C was a different type of supernova with no such intense gamma rays. I quote Abraham Loeb, Professor of Astronomy, and Director of Institute for Theory and Computation at Harvard University, who is one of the key figures in the latest findings. "It is very difficult to detect this type of black hole birth because decades of X-ray observations are needed to make the case."
On a personal note, I must mention here, Professor Avi, as he is known, always responded and advised me when I was exploring the possibility of joining Harvard Smithsonian center as a visiting scholar . He is source of encouragement for young and creative researchers and I wish him and his team the very best.
The ensuing observation was made possible by the Chandra x-ray space telescope along with a bunch of other telescopes. The consistent and steady emission of x-rays detected during the period of 1995-2007 was considered as a major evidence of a black hole. The Chandra space telescope, named after Subrahmanyan Chandrasekhar, who is famously known for Chandrasekhar limit in astrophysics, is one of the major space telescopes operating in space along with Hubble. Coincidentally, October 19, 2010 was the 100th anniversary of the birth of Subrahmanyan Chandrasekhar.
I think, I should address two questions you might ask. Is this black hole really 30 years old? It is 30 years old, if our frame of reference is the earth but is 50 million years old based on the parent galaxy. But, that is irrelevant for earthlings. We are separated from that galaxy not just by space but by time as well. Time along with space limit our view of the universe. An observer in the vicinity of the galaxy would say it is 50 million years old.Finally, from the point of view of the light coming from the supernova, no time has passed no distance has crossed, so it is instantaneous. All are right. But for us, it is a baby black hole and it provides a rare opportunity to see how it develops from infancy and probably rules the cosmos one day.
Fine, we agree on the age of the black hole. What about the name? Astronomers don't name the black holes. Their destiny is to be known by the event that created them. The reason is simple. We can't see them at any wavelength, and names are given to something that can be observed. Their presence is inferred by the evidences. Yes, there is a dilemma-because the universe is a story being scripted by the laws of physics, given to all but it reveals to a few.