Curiosity of Black Holes
By Bathiya Senevirathna
The world started to talk more and more about black holes
after the recent image of M 87. Even people from different fields other than the
astronomical field have started searching and discovering about black holes. First
of all we come across with a common question that anyone would ask , What is a
black hole?
The answer is pretty much simple and most of them in the community are not so aware of this. So basically a black hole is a huge amount of matter packed in to a tiny area. It’s like an object ten times bigger than the sun squeezed in to sphere with a diameter of a cricket ground, well that’s relatively pretty small after squeezing, and will result a strong gravitational field so we call this thing as a black hole.
The answer is pretty much simple and most of them in the community are not so aware of this. So basically a black hole is a huge amount of matter packed in to a tiny area. It’s like an object ten times bigger than the sun squeezed in to sphere with a diameter of a cricket ground, well that’s relatively pretty small after squeezing, and will result a strong gravitational field so we call this thing as a black hole.
The specialty of a Black hole is it will suck everything
around them, yes the everything which will enter its gravitational field. What
does this mean? As mentioned above it creates a massive gravitational force
because of the compressed mass in it, so anything falls on to a black hole
cannot escape from it’s gravitational field, even the fastest thing we know so
far which is light, will not be able to escape from a black hole, not only
light the other types of electromagnetic radiation(EMR) cannot also escape from
a black hole. Therefore we cannot directly observe a black hole with telescopes
that detect x-rays, light or other forms of EMR. Basically we cannot see a
black hole. Only thing that we would be able to observe is the event horizon. Event
horizon is the boundary defining the region of space around a black hole from
which nothing can escape.
The first person to discover and predict on black holes was Albert
Einstein. Scientist believe black holes are formed when a massive star dies. When
a massive star dies in a supernova explosion it leaves behind a small dense
remnant core, so Einstein theoretically showed that if the mass of this star is
equal or more than three times the mass of the sun that no force can keep the
star from collapsing under the influence of gravity. This is the basic behavior
of a black hole. There are variety of black holes in the universe which can be categories
by the size and there can be enormous number of black holes in the universe.
The main four types of black holes are micro, stellar, intermediate and
supermassive. Scientist believe micro black holes are formed shortly after the
big bang, these types of black holes remain purely theoretical and are
theorized to be as small as an atom, but with a mass rivaling that of a large
mountain. Stellar black holes can be formed by the gravitational collapse of a
massive star, they can have a mass up to twenty times than the mass of the Sun.
Intermediate-mass black holes are larger than a stellar black hole and smaller
than a supermassive black hole and this will not form by collapsing of a one
star in fact scientist have predicted three possible formations of an
intermediate black hole.
1)Merging of stellar black holes and other compact objects
by means of accretion.
2Runway collision of
massive stars in dense stellar clusters.
3)As a result of the big
bang.
Supermassive black holes having
a mass more than one million times of the mass of the Sun. Every galaxy has a
supermassive black hole at the center of the galaxy. “Sagittarius A” is the
black hole which is at the center of our galaxy(Milky way). Till 4/10/19 we
didn’t get to see a real image of a black hole all we had were imaginary
pictures.
Surprisingly with the help
of the event horizon telescope scientists were able to take the first picture
of a black hole from the galaxy M 87, this image that already matched the
predicted images and Einstein’s theories on warm holes. The black hole at M 87
galaxy is 55 million light years away from
the Earth and mass of this black hole is about 6.5 billion times the mass of the Sun, but obviously this is
way more farer than the black hole in our galaxy, so you might think why they
took an image of this when we have a black hole pretty much closer to the Earth,
it’s because of the accuracy, though M 87 is far away it’s massive than the “Sagittarius
A” and which is more noticeable for the Event horizon telescope and since this
is the first time maybe they didn’t wanted to take a risk. For those who had
that question has a good news because astronomers and scientist are now working
on “Sagittarius A” and within one or two years we will be able to compare these
two black holes.
Image Sources
- http://livescience.com/
- http://newscientist.com/
- http://theverge.com/
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