|Supermassive Black Holes
Black holes with millions and even billions of solar
masses are believed to occupy the centers or nuclei of many galaxies.
Unlike stellar black holes, the origins of supermassive
black holes and the evolution of galaxies remain a mystery because the
nuclei of galaxies are often hidden from observation by dense dust and
However, that does not stop us from reviewing how
we believe supermassive black holes can be formed.
At the Center of the Galaxy
In the nucleus
of a galaxy, hundreds of millions of stars are densely clustered up as
they orbit and spin around. All of these stars are traveling at various
speeds and "every now and then" will crash into another star. If the stars
collide into each other, chances are they will annihilate each other throwing
out gas everywhere (like parts in a huge car crash).
But if they are moving close enough to each other's velocity, their
gravity would attract each other. The two stars would combine or coalesce
or to form one massive star.
From here, many things can happen:
The massive stars might coalesce with other massive stars to form a very
massive star which sooner or later would collapse into a very massive black
hole. With time, the very massive black hole would consume millions of
stars and grow into a supermassive black hole.
The released stellar gas from the smashing of stars would collect together
and form a huge cloud of dense stellar gas. New stars could form from this
cloud. These new stars, more massive than before, would collide into other
stars releasing even more stellar gas into the cloud. After many cycles,
this cloud might become so dense as to collapse under its own gravity to
form a supermassive black hole.
A supermassive black hole could form from any or a combination
of these scenarios. And unsurprisingly, it could form from possibilities
we have yet to dream of.
Instead of collapsing, the gas cloud could form one very unstable supermassive
star which would almost instantly collapse into a supermassive black hole.
Or the supermassive black hole was already in the center of the galaxy
to begin with. During the galaxy's early formation, the core could have
undergone a catastrophic gravitational collapse creating a supermassive black hole.
Continue to Formation of Black Holes Review.
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