Black holes are areas in the universe where gravity pulls in everything, even light. Nothing can get out and all objects are squeezed into a tiny space. Because there is no light in black holes we cannot see them. But scientists can detect the immense gravity and radiation around them. They are the most mysterious objects in astronomy. Scientists think that the first black holes were formed when the universe began about 13 billion of years ago.
Albert Einstein was the first scientist to predict that black holes existed. But it was in 1971 that the first black hole was actually discovered.
Black holes can have various sizes, some may be even as small as an atom. But they all have one thing in common – a very large mass.
There are three kinds of black holes :
A stellar occurs when very large stars burn away the rest of the fuel that they have and collapse. It is so massive that several of our suns could fit in it. Our sun, however, could never become a stellar because it is too small.
Supermassives are the largest and most dominating black holes in our universe. They have masses of a million or more suns put together. Every galaxy has a supermassive in its centre. As they become larger and larger they pull in more material. The black hole at the centre of our Milky Way is four million times as massive as our sun and surrounded by very hot gas.
Intermediate mass black holes have not been found yet, but scientists think they probably exist. They have the mass of between a hundred and a thousand suns.
A black hole consists of three parts:
The outer event horizon is the farthest away from the centre. Gravity here is not so strong and you would be able to escape from it.
The inner event horizon is the middle part of a black hole. In this area an object would be slowly pulled to the centre.
The singularity is the centre of a black hole, where gravity is strongest.
Scientists Discover Gravitational Waves
Not to be left out, NASA is ensuring that this week of recognition for black holes is a memorable one. The space agency has been providing links to an array of content on its Black Hole Week website with new elements added each day.
Taking a look at the sheer density of resources NASA is offering may leave even hardened space fans leaving as if they are falling into a black hole themselves but in a good way!
Black holes are cosmic events born when massive stars reach the end of their nuclear fuel-burning lives and can no longer support themselves against complete gravitational collapse.
This collapsing matter is so dense it creates a region of space so distorted and warped that at its edge not even light is fast enough to escape its gravitational influence. This light-trapping outer boundary is called "the event horizon."
NASA started the week on Monday with some content that much like the event horizon of a black hole does to anything that crosses it, grabs the attention and doesn't let go.
First up was an animation produced by NASA's Goddard Space Flight Center Conceptual Image Lab that begins at the sun and pulls back to reveal elements of the solar system and the size of the supermassive black holes. These are the most tremendously large black holes with masses that can be millions or even billions of times that of the sun which are believed to sit at the heart of most large galaxies.
NASA estimated the size of the supermassive black holes by calculating their "shadow" which is twice the size of the black holes event horizon, the diameter of which can, in turn, be calculated by using the mass of the black hole. The greater the mass, the wider the spherical boundary of its event horizon and thus the wider its shadow.
You must be logged in to post a comment.