WHAT ARE BLACK HOLES?
As most of you are aware BLACK HOLE is a region of space in which the gravitational field is so powerful that nothing, not even electromagnetic radiation can escape from it. Dur to this black holes can not be seen (as they absorbs light radiations) but can only be experienced by their ultra strong gravitational pull. That's why they are named as BLACK HOLE.. They continue to grow in size by absorbing any matter that comes in range of their gravitational field.
HOW MUCH THEY CAN GROW?
Till now it was not sure that what can be maximum size of a black hole. These black holes are now known to exist throughout the Universe and the largest and most massive are at the centers of the largest galaxies. These "ultra-massive" black holes have reported to have mass about One Billion Times that of our own Sun.
CONCEPT OF UPPER MASS LIMIT
According to the new research by Priyamvada Natarajan, an Associate Professor of Astronomy and Physics at Yale University and a fellow at the Radcliffe Institute for Advanced Study, it has been proved, that even the biggest of these Black Holes can't keep growing forever. Instead, they appear to curb their own growth - once they accumulate about 10 billion times the mass of the Sun.
THEORY BEHIND THIS RESEARCH
Normally Black Holes continue to accumulate mass by absorbing matter from neighboring gas, dust and stars. But according to new research by Priyamvada Natarajan, that it is possible only to a certain limit, irrespective of the position of black hole. The reason behind this is that, "Eventually these Black Holes reach the point when they radiate so much energy as they consume their surroundings that they end up interfering with the very gas supply that feeds them, which may interrupt nearby star formation."
EXPERIMENT BY PRIYAMVADA NATARAJAN
Natarajan used existing Optical and X-ray Data of these Ultra-Massive Black Holes to show that, in order for those various observations to be consistent, the black holes must essentially stop at some point in their evolution. This helped her to prove this fact that these black holes can not grow indefinitely in mass and there is some upper mass limit of black holes.