This year’s Nobel prize in Physics has been awarded for the discovery of one of the darkest and most mysterious objects in the universe. The award was announced by the Royal Swedish Academy of Sciences, located in Stockholm Sweden at around 11:55 CEST (3:25 IST). The winners, Roger Penrose, Reinhard Genzel and Andrea Ghez, share the Nobel prize for their work on Black Holes.
English physicist and Mathematician Roger Penrose has been awarded half the Nobel prize for “the discovery that Black hole formation is a robust prediction of the general theory of relativity”.
German physicist, Reinhard Genzel and American Astronomer Andrea ghez have been awarded 1/4th of the Nobel Prize each for “the discovery of a supermassive compact object at the centre of our galaxy”.
From theory to discovery
Roger Penrose’s theoretical contributions to the idea of Black Holes:
In the year 1915, the famous physicist Albert Einstein published a revolutionary paper on a new theory of gravity. The theory, known as the General Theory of Relativity, superseded Newtonian ideas of gravity. It completely reimagined our idea of space and time. But, with any new great theory, comes multiple new predictions for the universe. In case of General Relativity, one certainly stood out. Using his equations, Albert Einstein predicted the existence of an object so massive and so dense that not even light could escape it. This was really mind boggling, so much so that most physicists, including Einstein refuted its existence.
But, 10 years after Albert Einstein’s death, Roger Penrose set out to prove (theoretically) that Black Holes can exist in the known universe. He worked out new mathematical concepts to expand the General Theory of Relativity and show that Black Holes could actually form. His contributions to the Theory of General Relativity are considered to be one of the greatest since Einstein.
Discovery of the black hole at the center of the Milky Way- Sagittarius A:
Almost 100 years ago, Astronomer Harlow Shapely figured out the direction of the Centre of the Milky Way, in the direction of the constellation Sagittarius. In later years, astronomers detected a strong radio source in the Centre of the galaxy which was given the name Sagittarius A. It was pretty clear to astronomers that Sagittarius A was in the exact centre of the Milky Way and that all the stars in our galaxy revolved around it.
By the 1990s, telescope technology improved significantly. During this time, both Reinhard Genzel and Andrea Ghez (the 2020 winners) lead a team of astronomers that pointed their telescopes to the centre of our Galaxy. Both teams found something really astonishing. They found stars circling around an object they could not observe at all. Another astonishing discovery was the speed at which the stars were whizzing around the unknown objects.
One star, named S2, was completing an orbit around the Milky Way in just 16 years. this is an extremely short time compared to the 200 million+ years our sun takes to revolve around the galaxy. The two teams mapped the orbit of S2 and calculated the mass of the unknown object. The calculations of the two teams were in agreement and they showed that our galaxy was hiding an object 4 million times the mass of the sun.
In a few years time, we might get a first look at Sagittarius A! A photograph of Sagittarius A is next in line for the Event Horizon telescope (EHT), the virtual Earth-sized telescope that gave us the first picture of a Black Hole (M87) in 2019.