The movie Interstellar, released in 2014, directed by Christopher Nolan and co-produced by Nobel Laureate Physicist Kip Thorne, caught every Physics lovers imagination. With its excellent graphics rendered by computer simulations of the equations behind black holes, left many people with a yearning to see a real image of a Black Hole
Almost 5 years down the line, on 10th April 2019, eight radio observatories across four different continents released an image of the ‘Event Horizon’ of a Black Hole, the mysterious Astrophysical objects that don’t even allow light to escape its gravitational influence. But the key question is, what are Black Holes?
A star is held stable under the influence of two opposing forces viz it’s own gravity which is inward and the force generated out of Nuclear Fusion, which is outward. Once the star exhausts its nuclear fuel i.e. hydrogen, it collapses under its own gravity. As a result, too many electrons/neutrons try to occupy the same state which causes an outward pressure called as degeneracy pressure; according to Pauli’s exclusion principle. This degeneracy pressure prevents the star from its further collapse under its own gravity to a point of singularity. Owing to this, the star ends up being a cool, stable, but extremely dense object. At least that is what physicists believed until 1940!
Chandrashekhar limit: a precursor to Black Holes
In 1940 J Robert Oppenheimer-the man who led the development of the first nuclear weapons-proved otherwise, stating that a star which is larger than 3.0 times the solar mass, condenses into a point of singularity called as a frozen star, to be coined as Black Hole by John Wheeler in 1967. However, it is noteworthy that Oppenheimer’s assertion was based on the foundation laid by and Indian Astrophysicist Dr. Subramanian Chandrashekhar. According to Chandrashekhar’s theory, if the dying star is larger than 1.4 times the solar mass, there are no stable solutions. This theory was virulently opposed by Sir Arthur Eddington until Oppenheimer proved otherwise. The above condition formulated by Chandrashekhar is famously known as Chandrashekhar limit. Later on, he received a Nobel prize for the theory of evolution of stars.
As the physics of Black Holes evolved, many eminent physicists contributed to it, including the likes of Stephen Hawking, a function called as Mock Modular Form was developed by Ken Ono of Emory University, which helped with Entropy calculation of Black Holes. Entropy is the measure of disorder within a system. Also, a paper Quantum Black Holes, Wall Crossing, and MockModular Forms was published in 2012 by three scientists named Atish Dabholkar, Sameer Murthy, and Don Zagier. These mock modular forms are an outgrowth of the Mock Theta Functions, first envisioned by the legendary Indian mathematician Srinivasa Ramanujan. Surprisingly, these mock theta functions were cryptically written down by Ramanujan on his death bed, with a hunch about how they behaved. He thought that the patterns followed by these functions were revealed to him by Goddess Namgiri!
As in any other field of scientific endeavor, India has had a rich legacy of astrophysicists and mathematicians, the two mentioned above being the most renowned ones. However, the former was undermined probably due to racism/ lack of open-mindedness, while the latter was unfortunate to die an early death.