In early 2016, a group of scientists at LIGO observatory made an incredible announcement-detection of gravitational waves. Gravitational waves are ripples in curvature of space-time. Till then, gravitational waves were considered as a theoretical concept. This discovery is not momentous just because gravitational waves were discovered but also because nobody had ever seen two supermassive black holes orbiting so close to each other. This system is called Binary Black Hole (BBH).
BINARY BLACK HOLE:-
Binary black hole is a system which consists of two super
massive black holes orbiting close to each other. Like ordinary black holes,
BBH is also divided into stellar (black holes formed by gravitationalcollapse of a massive star) black holes. For many years, proving the
existence of binary black hole was difficult because of nature of black holes
itself and limited detection methods. When two black holes orbit close to each
other, they give out immense amount of gravitational waves, in a specific
waveform, that can be calculated by general relativity. All this was considered
only as concept in 20th and early 21st century. It became a huge and
interesting subject to study.
But all this became a history when a team of scientists at
LIGO discovered gravitational waves. Since then a few group of astronomers have
discovered more supermassive black holes pairs.
And now a group of scientist from Pune, India and Rochester Institute of
Technology have discovered a pair which is closest. It is just 400 million
light years away, in a galaxy named NGC 7674.
The study was led by Preeti Kharb, from the National Centre
for Radio Astrophysics at Pune University in India and co-authored by Dharam
Vir Lal, also at Pune University and Merritt at RIT.
Although the term “400 million light years” may seem a quite
a large number, it is the closest pair ever discovered to our galaxy. Also, the
pair of supermassive black holes each weighs more than a million times the mass
of our sun. Hence considering this factors and how rare BBH are, they are big
deal!
To add to this, these black holes are orbiting only one
light year away apart from each other. Again, one light year is a big number
for us but considering there masses; they are orbiting quite close to each
other. Eventually they will get closer to each other and finally get merged.
When this happens, strong gravitational signal will be created in outer space.
It is estimated that these two black holes will take another
million years to collapse into each other and create a gravitational signal.
Hopefully till then, someone will be still around to receive it!
Amazing info for astro enthusiasts 🖖🖖
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