Guwahati, March 20: An Assamese scientist in the US has led observations that have found that the super massive black hole at the centre of the Milky Way galaxy consumed its last big meal six million years ago.
Rongmon Bordoloi and his colleagues at the Massachusetts Institute of Technology used Nasa's Hubble Space Telescope to calculate the age of colossal bubbles of gas associated with that last meal.
As the black hole - the remains of a massive star that has exhausted all fuel and collapsed into an object with such a strong gravitational pull, it sucks in everything around it and not even light can escape it - consumed its meal, it left behind bubbles of gas that now billow above and below the centre of the galaxy.
"For the first time, we are able to predict the black hole's last big meal," Bordoloi told The Telegraph during a telephone interview from Boston. "What we found is that a very strong event happened six to nine million years ago. It may have been a cloud of gas flowing into the black hole. Ever since, the black hole has just been eating snacks."
The black hole, about 27,000 light years from Earth, has the mass of about 4.5 million sun-like stars. Materials moving too close get caught in its powerful gravity and swirls around it until they eventually fall in.
Nasa's Fermi Gamma Ray Space Telescope discovered the bubbles in 2010. Now, Bordoloi and his colleagues have used an instrument aboard Hubble called the cosmic origin spectrograph (COS) to analyse ultraviolet rays from 47 distant quasars, or intensely bright cores of distant galaxies.
Their analysis of the emissions from the 47 quasars helped them trace the motion of gas through one of the bubbles linked to the Milky Way's black hole. Imprinted in the quasar's light as it passes through the Milky Way's bubble is information about the speed, composition and temperature of the gas inside the bubble.
"These observations allowed us to map the velocity of the gas and calculate when the bubbles formed," Bordoloi said.
"We could map the motion of the gas because we are a part of the Milky Way. This vantage point gives us a front-row seat to do this."
Bordoloi was one of 17 scientists selected for the Hubble post-doctoral fellowship program to conduct research at the Space Telescope Science Institute (STScI) in Baltimore, Maryland, USA. His parents hope this discovery is just "the start" of his journey.
"Since his childhood, he had this will to find a third angle in everything. It is this curiosity and the will to have an in-depth observation that helped him to make this finding. He would never rest until he understood the science underlying a phenomenon," Pradip Bordoloi, his father and a retired government employee, told The Telegraph. "During the two years of his research, he used to spend the greater part of his day in the laboratory."
Bordoloi passed his HSLC from Balya Bhawan, an Assamese-medium school in Jorhat, higher secondary and graduation from the Jorhat Institute for Science and Technology, post-graduation from Gauhati University and completed his doctorate at the coveted EidgenÃssische Technische Hochschule in Zurich, Switzerland.