Showing posts with label black hole. Show all posts
Showing posts with label black hole. Show all posts

Wednesday, April 5, 2017

Radiation from Nearby Galaxies Helped Fuel First Monster Black Holes


Presence of Supermassive Blackholes – Confusion of Astronomers

The presence of supermassive black holes towards the beginning of the creation has given rise to confusion to astronomers from the time of their discovery, more than a decade back. A supermassive black hole is considered to be formed over billions of years, though more than two dozen of these behemoths have been seen within 800 million years of the Big Bang 13.8 billion of years ago.

A team of researchers from Dublin City University, Georgia Tech, Columbia University as well as the University of Helsinki, in their new study in the journal `Nature Astronomy’, showed signs of one concept on how these antique black holes which seemed to be around billion times heavier than the sun could be formed and seemed to put on weight rapidly.

The researchers showed that a black hole could swiftly develop towards the core of its host galaxy if an adjoining galaxy and seemed to emit sufficient radiation to switch off its capability to form stars. Hence restricted, the host galaxy is inclined to cultivate till it ultimately collapses, forming a black hole which feeds on the left over gas, and later, dust, dying stars, and perhaps other black holes, that become great colossal.

Collapse of Galaxy/Formation of a Million-solar-mass BlackHole

According to co-author, Zoltan Haiman, an astronomy professor at Columbia University commented that the collapse of the galaxy and the formation of a million-solar-mass black hole took around 100,000 years — a glitch in planetary times and a few hundred million years later, it had grown into a billion-solar-mass supermassive black hole.

This seemed to be much quicker than expected. Stars and galaxies in the early creation had been formed as molecular hydrogen cooled and flattened to primordial plasma of hydrogen and helium. This environment had limited black holes from growing very big since molecular hydrogen would turn gas into stars adequately far away to escape the black holes, gravitational pull.

Astronomers had come up with a number of methods that supermassive black holes could have overcome this obstacle. Haiman together with his colleagues, in their 2008 research had hypothesized that radiation from a considerable nearest galaxy could divide molecular hydrogen into a atomic hydrogen causing the nascent black hole together with its host galaxy to collapse instead of spawning new clusters of stars.

Research - Effects of Gravity/Fluid/Dynamics/Chemistry/Radiation

A study after this, headed by Eli Visbal a postdoctoral researcher a Columbia then had summed that the nearby galaxy could have been around 100 million times much bigger than the sun to emit adequate radiation in order to stop star formation.

 However, being comparatively rare, adequate galaxies of this size seemed to exist in the initial creation to describe the supermassive black holes witnessed so far. Presently the study, headed by John Regan, a postdoctoral researcher at Ireland’s Dublin City University, had displayed the procedure utilising software established by Columbia’s Greg Bryan wherein his study comprised of the effects of gravity, fluid dynamics, chemistry as well as radiation.

 Few days subsequently of crunching the numbers on a processer, the researchers established that the adjoining galaxy could have been smaller as well as closer than earlier assessed. A study co-author John Wise, the Dunn Family Associate Professor in Georgia Tech’s College of Physics, had commented that the nearby galaxy could not be too close, or too far away, and similar to the Goldilocks principle, excessively hot or cold.

Friday, March 4, 2016

Five-Dimensional Black Hole Could 'Break' General Relativity


Researchers Successful in Simulating Black Hole

Researchers from the University of Cambridge and Queen Mary University of London have been successful in simulating a black hole in the shape of a very thin ring giving rise to a series of `bulges’ that are linked by strings which tend to get thin over a period of time.

The strings ultimately become so thin that they pinch off into a sequence of tiny black hole identical to how a thin stream of water from a tap tends to break into droplets. In 2002, ring-shaped black holes were discovered by theoretical physicists. However, this is the first time that its dynamics has been simulated successfully on utilising supercomputers.

If this kind of black hole tends to form, it would lead in the appearance of a `naked singularity’ causing the equation behind general relativity to break down. The result of the same had been published in the journal – Physical Review Letters. General relativity supports the present understanding of gravity which is everything from the estimation of the age of the stars in the universe to the GPS signals we tend to depend on, while navigating and is based on Einstein’s equation.

Singularity – A Point where Gravity is Intense

The theory, partly informs us, that matter distortions its surrounding space-time and what is known as gravity is the outcome of that distortion. Since it was published in the 100 years, general relativity had passed through every test which had been thrown at it though one of its restrictions is the presence of singularities. Singularity is a point wherein gravity seems to be so intense that space, time as well as the laws of physics tends to break down. General relativity forecasts that singularities occur towards the centre of black holes and tends to be surrounded by an event horizon which is the point of no return where gravitational pull becomes very strong.

 Escape seems impossible which means that it cannot be observed from outside. Markus Kunesch, study co-author and a PhD student at Cambridge’s Department of Applied Mathematics and Theoretical Physics – DAMTP said that as long as singularities remains hidden behind an event horizon, they do not tend to cause trouble and general relativity holds the cosmic censorship conjecture and this is always the case.

As long as the cosmic censorship conjecture tends to be valid, they can safely forecast the future outside the black holes. Since ultimately what is being done in physics is to forecast the future given knowledge regarding the state of the universe now’.

Physicist Researching General Relativity in Higher Dimension

We tend to think of the universe prevailing in three dimensions and the fourth dimension of time, which when combined is referred as space-time. However, in branches of theoretical physics like string theory, the universe could be of as many as 11 dimensions.

Extra dimensions can be big and expansive or it could be curled up, tiny as well as hard to notice and because human can directly only see three dimensions, the presence of extra dimensions can only be concluded through high energy experiments like those directed at Large Hadron Collider.

The theory of Einstein does not state how many dimensions seem to be in the universe. Hence theoretical physicists have been researching general relativity in higher dimension to check if cosmic censorship still tends to hold. The finding of ring-shaped holes in five dimensions has directed the researchers to hypothesise that they can break up and lead to a naked singularity.

Tuesday, January 27, 2015

Kerr Black Hole

Kerr Black Hole – An Uncharged Black Hole

A Kerr black hole is an uncharged black hole, a kind of a black hole which possesses only mass and angular momentum,that tends to rotate around a central axis and is named after Roy Kerr, a New Zealand mathematician who became the first person to solve the field equations. In 1963, Kerr had achieved something which eluded other scientist for around 47 years and he found the solution of Einstein’s general theory of relativity for a situation of this type.

He describes the space outside a rotating star or black hole and his solution has been described as `the most important exact solution to any equation in physics. Kerr black holes could be the most common in nature as the massive stars from which they form, possess rotation though no overall charge, before they collapse at the end of the life. With the principle of conservation of angular momentum, most of the spin is retained by the black hole after the star’s terminal collapse. A Kerr black hole comprises of the distinct regions namely ring singularity, ergosphere, inner and outer event horizons and static limits – the boundary between the ergosphere and the normal space.

Kerr Black Hole - Theoretical

At every event horizon, the roles of space and time tend to change and in the case of a Kerr black hole, space and time swap places twice which are the result of the metrical geometry equations of Kerr. While the singularity is also a temporary one, it can be avoided.

The concept focuses on neutron stars which are massive collapsed stars, the size of Manhattan though with a mass of Earth’s sun and if the dying stars collapse into a rotating ring of neutron stars, the Kerr postulates and their centrifugal force would prevent them from turning into a singularity. Kerr is of the belief that since the black hole does not have singularity; it would be quite safe to enter without any fear of the infinite gravitational force at the centre.

There is a possibility of escaping a black hole though not through the same way one went in. By leaving the black hole one will find either a region of negative space, - the physical explanation of which is unknown or in a different universe. Kerr black holes are purely theoretical and if they tend to exist, they offer adventurous time traveller, a one way trip in the past of the future.

Deepened Understanding of Astrophysics & Gravitational Theory

Though a tremendously advanced civilization could develop a means of calibrating a method of time travel, it is not possible to tell where or when a wild Kerr black hole could leave you.His achievement of identifying an exact solution for the rotating case, was something several people were speculating about and was a revolution in astrophysics and brought in a decade which could be known as `the Golden Age of Black Hole Physics’ when General Relativity saw Renaissance. The Kerr solution has pivoted in deepening our understanding of astrophysics as well as gravitational theory and over the years since its discovery, several new effects emerged in the Kerr solution - a rotating objects drags space with it which would be impossible in Newton’s theory.

Thursday, January 7, 2010

The unknown mystery about black hole!!!!!!!

What are black holes? You just imagine a void of very very small in size which is enormously dense which engulf the objects which comes with in its surroundings. Here a simple explanation for a black hole. Black hole is a star which collapsed under its own mass few times and it becomes more compact every time. Because of its enormously high density this endless chasm sucks everything with in its vicinity and absolutely nothing can escape from its attraction.

The name 'BLACK HOLE' was coined by John Weeler, a famous astrophysicist of American origin. While deriving the theory of relativity Albert Einstein told about the black holes but none of the scientist thought about it.

While we are discussing about a black hole, we are fully against the Newton's force of attraction between two objects.

For your convenience let me explain to you with sun as an example. If our sun has to be changed to be a black hole the following things has to be take place. First the diameter of the sun has to be compressed to make it a ball of one kilometer radius (now the diameter of Sun is 1392000Km) while doing so its density will be increased and hence it’s mass will be equal to 1000000000000000000000000000000 Kg. Similarly if you convert earth in to a black hole it will be a ball of 1cm radius and of mass 10 power 25Kg( 1 followed by twenty five zeros) Now the earth's diameter of earth is 12756Km.
Now I hope you have a brief outline about a black hole. Now let’s go through the general process of creation of black hole.

Stars are of huge balls of gases mostly Hydrogen. Their energy is derived from nuclear fusion of Hydrogen into Helium (Nuclear fusion is a clear source of energy occurs in very high temperature and pressure). Once the stars weight and the energy produced balances each other then they will be stable. They will not collapse as long as the energy production takes place the will be stars. But once the energy production reduced due to lack of fuels the stars implodes in on itself simultaneously its radius also reduce. After few collapses their radius reduced to a greater extent and becomes a black hole.

Here the problem for astrophysicist is discovering black hole in the universe. Since they are not visible we can not find them as visible object. But they can be finding out by using a different phenomenon of binary stars.

Binary stars are the two stars rotation around each other. If one star become a black hole the other will tumble down and will be absorbed, while it is absorbed there is a disc of dust called accretion disc form around the hole. The very hot matter inside the black hole is extremely accelerated and hence releases strong radio waves. Using these radio waves we can find the black hole. The velocity of disc rotation is directly proportional to the mass of the black hole.

According the scientists the galaxies rotate like a centrifuge. The total mass of the stars and other objects at the centre holds the stars in the outer edges hold them in place. Hence we can arrive at this following conclusion that the mass of all matter of stars is not sufficient to hold the very distant stars therefore some invisible gigantic black holes at the centre are exert force on the stars at the outer

Here a point to note: The time stops inside a black hole which is a unique and very important point in the space and time relationship.