Ask your kid to vaccum clean his room. What happens when he vaccum cleans his room. All the dust is sucked by a vaccum cleaner. A Black Hole is just like a giant vaccum cleaner cleaning the debris left behind in the outer space. But it is not the suction power that makes things fall into Black Hole instead it is some other force - the force of gravity. Let us understand this in detail.
A Black Hole is one of the strangest objects in space. It is an area in space where gravity is so strong that whatever comes under the influence of its gravity, will fall into it. Even light cannot escape from it. Because light cannot escape from it, Black Holes appear black. We know that light can travel faster than anything at a speed of 300,000 km/s. Imagine if light cannot escape from a Black Hole, nothing else that we know of can.
The term Black Hole is used because these giant objects look like black holes in space since they put out no light.
A Black Hole is not really a hole and it is not empty. It doesnot have a surface like planet or star. It is a region in space filled with a lot of material crammed into an extremely small space. Imagine your whole house stuffed in a small box. It is because of this that the Black Hole has a super strong gravity and this gravitational pull is so great that even light cannot escape.
FORMATION
Black Holes are formed from stars. When a massive star runs out of fuel (Hydrogen), and it no longer can support its weight, it explodes. This explosion is called Supernova. Then, due to pressure the star starts getting smaller and smaller squashing all its material. It becomes even smaller than atom. Imagine the entire star squashed into such small space. Due to its small size, enormous mass and huge density, the gravity is so strong that it will absorb light and become a Black Hole. Black Holes are formed only from a heavyweight star. These Black Holes can grow incredibly huge as they continue to absorb light and mass around them. They can even eat other stars surrounding them. So these Black Holes are the hungriest objects in space. Many scientist think that there are super-massive Black Holes at the center of the universe.
Can we see a Black Hole?
Since Black Holes don't reflect any light, we cannot see them. We can see the effect they have on the area of surface around them. By extremely high gravity, they pull in surrounding material at a very high speed causing this material to become very hot and emit X-rays. These rays help scientist find them.
Structure of Black Hole
Black Holes are made of three main parts:-
- Outer layer called outer event horizon.
We can escape from this zone as gravity is not as strong here.
- Middle layer called inner event horizon.
Here, there is no chance of escaping. The gravity is much stronger. So, anything that enters here gets captured and the objects start to fall towards the center of Black Hole.
- The center of Black Hole called singularity.
Here the gravity is strongest.
Types
Black Holes are of different sizes. Many are massive than our sun. Scientist think that the Black Holes are of two types:-
1) Stellar-mass Black Hole
Imagine a black round object 3 - 15 times bigger than our sun. Stellar type Black Hole is made when gigantic star reaches old age with all its fuel finished causing it to explode. This explosion is called Supernova. The material left from Supernova collapses in on itself transforming into a very compact object. This is how Stellar-mass Black Hole is made. These are found to be scattered in the galaxies.
2) Super-massive Black Hole
It is made when hundred million suns are all squashed into one place. As its name suggests, these are way too massive as compared to Stellar-mass. Actual formation of these type is still an open field of research. These Black Holes are known to occur in the center of almost all large galaxies known to us.
Is there a Black Hole at the center of our galaxy?
According to scientists, there is one super-massive Black Hole in the middle of our galaxy - the Milky way. It has the mass of about 3 million suns and is very far from Earth. Huge Black Holes are thought to occur naturally at the center of most galaxies and many have already been detected.
Are there many Black Holes in the galaxy?
There can be many Black Holes in a galaxy but most galaxies of the size of aur milky way or larger are thought to have gigantic Black Holes weighing millions or billions of times as much as sun at their centers. When galaxies merge, these Black Holes may spiral in towards one another and collide.
In recent studies, an international team which is lead by Stefanie Komossa of Germany has identified the first known case of super massive Black Hole flung from its host galaxy.
Interesting Facts:-
- Black Holes have the mass of several million suns.
- Black Holes differ from each other in mass and spin.
- They don't live forever, but slowly evaporate returning their energy to the universe .
- Black Holes are often surrounded by a ring of debris.
- Idea of Black Holes was first proposed by two different scientists in 18th century. John Michell and Pierre-Simone Laplace. In 1967, a physicist named John Wheeler coined the term Black Hole.
- Black Hole can suck up earth but scientist say that the nearest Black Hole which lies at the center of our galaxy is so far away from earth that it's virtually impossible.
- In December 2011, astronomers noticed that our galaxy's Black Hole has set its eyes on a nearby cloud of dust and gas. Scientists who have been watching this cloud for several years with huge telescopes in Chile, South Africa have noticed that not only is this cloud is moving in the direction of Black Hole, but it has also doubled its speed reaching more than 8 million km/hr. In couple of years, this super-massive Black Hole will get its meal.
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