Can anyone tell me the basics of Quasar?Note: Means that how it is

[vinayjain]

Can anyone tell me the basics of Quasar?

Note: Means that how it is created when there is only one dimension exists in a black hole and what is the reaction that occurs which emits so much light that it can be seen through millions of light year.

 

[Chronos]

A quasar is believed to be the output of a well fed, supermassive black hole. Infalling matter is shredded by the black hole and emits immense amounts of radiation.

 

[vinayjain]

can it be a bit more ellaborative?

 

[Chronos]

Atoms accelerate to incredible velocities as they approach the event horizon. Collisions between these accelerated atoms result in highly energetic photon emissions.

 

[vinayjain]

what will going to happen when a quasar completes its life of emmision?

 

[Janus]

what will going to happen when a quasar completes its life of emmision?

It becomes a "quiet" black hole like the one at the center of our galaxy.

 

[vinayjain]

It becomes a "quiet" black hole like the one at the center of our galaxy.

What is the nature of a silent black hole?

Means will it going to pull things around it and after gattering enough element it will again become quasar or it is something else.

 

[Drakkith]

What is the nature of a silent black hole?

Means will it going to pull things around it and after gattering enough element it will again become quasar or it is something else.

It means that there is current little to no material falling into the black hole, meaning that there is little to no emissions from the accretion disk, if there is one still. If a star is suddenly perturbed and is sent into an unstable orbit around it, eventually being shredded and falling in, then the black hole would no longer be silent.

 

[bombadil]

In general, most if not all galaxies are thought to contain supermassive black hole's that went through some quasar phase (including our own Milky Way) at some point in the past. We think this is true because there are large-scale galaxy characteristics that correlate with the mass of the supermassive black hole. These large-scale properties span many thousands of light years well beyond the gravitational influence of the black hole, and are related to http://en.wikipedia.org/wiki/M-sigma_relation" .

 

[vinayjain]

Can anyone please clarify my doubt...

What I have read about the power source of the quasar is the supermassive black hole at the centre of the quasar which has a mass of million or even billion times the mass of sun...At the center of a quasar, the black hole is surrounded by a large, rotating cloud of gas. As the gas falls into the black hole, it is heated up to millions of degrees. The gas emits thermal radiation due to its enormous heat. This thermal radiation spans the spectrum, making the quasar bright in the visible spectrum as well as x-rays.

Now when not even light can pass through a black hole as its escape velocity is more thn the speed of the light than how could these radiation comes out and illuminates quasar.

 

[phyzguy]

Can anyone please clarify my doubt...

What I have read about the power source of the quasar is the supermassive black hole at the centre of the quasar which has a mass of million or even billion times the mass of sun...At the center of a quasar, the black hole is surrounded by a large, rotating cloud of gas. As the gas falls into the black hole, it is heated up to millions of degrees. The gas emits thermal radiation due to its enormous heat. This thermal radiation spans the spectrum, making the quasar bright in the visible spectrum as well as x-rays.

Now when not even light can pass through a black hole as its escape velocity is more thn the speed of the light than how could these radiation comes out and illuminates quasar.

You have it about right. The point that you are missing is that the large rotating cloud of gas (which is called the 'accretion disk') is well outside the event hroizon of the black hole. So radiation emitted from this accretion disk can still leave the vicinity of the black hole and be seen by external observers. Eventually all of the matter that is feeding the accretion disk falls into the event horizon, and then the black hole goes quiet, like the one at the center of our galaxy.

 

[vinayjain]

then the black hole goes quiet, like the one at the center of our galaxy.

Please clarify my other doubt which come from this statement....This means that at some point of time our galxy also have a quasar at the centre...so now what i have read about a quasar is that it emits jets while a quasar is in running status and these jets destroy everything in path to some extent then how come our galaxy stars are not affeted by that and if thy were affected then how come there is no residual of those stars found floating here and there in the galaxy

 

[Drakkith]

Please clarify my other doubt which come from this statement....This means that at some point of time our galxy also have a quasar at the centre...so now what i have read about a quasar is that it emits jets while a quasar is in running status and these jets destroy everything in path to some extent then how come our galaxy stars are not affeted by that and if thy were affected then how come there is no residual of those stars found floating here and there in the galaxy

The jets are usually not in the plane of the galaxy, but near perpendicular to it, meaning that most of the galaxy is not touched by them. Also, even if there were plenty of stars in the way of the jets, enough time has passed that new stars could have formed to replace those lost or that other stars were perturbed in their orbits and "migrated" to a new orbit similar to destroyed stars. Also, the jets don't exactly "destroy everything in their path". At a distance of 33 light years, the brightest quasar seen yet would look as bright as the sun. That is far from the needed intensity to destroy anything that has already formed, such as stars. Over time the jets can push gas and dust outward, but not destroy stars unless they are extremely close.

 

[vinayjain]

The jets are usually not in the plane of the galaxy, but near perpendicular to it, meaning that most of the galaxy is not touched by them. Also, even if there were plenty of stars in the way of the jets, enough time has passed that new stars could have formed to replace those lost or that other stars were perturbed in their orbits and "migrated" to a new orbit similar to destroyed stars. Also, the jets don't exactly "destroy everything in their path". At a distance of 33 light years, the brightest quasar seen yet would look as bright as the sun. That is far from the needed intensity to destroy anything that has already formed, such as stars. Over time the jets can push gas and dust outward, but not destroy stars unless they are extremely close.

Is it possible that our milky way was he quasar at some point and when the fuel goes off it is made like this and we get a supermassive black hole at the centre and if it can be true than the quasar which is now known as milky way would be a part other galaxy which has expanded far beyond than milky way and we are not able to recognise...please clarify

 

[Drakkith]

Is it possible that our milky way was he quasar at some point and when the fuel goes off it is made like this and we get a supermassive black hole at the centre and if it can be true than the quasar which is now known as milky way would be a part other galaxy which has expanded far beyond than milky way and we are not able to recognise...please clarify

I can't understand what you're asking, none of it makes any sense.

 

[vinayjain]

I am asking that it is said many a times that when a quasar ceases it becomes a galaxy so i am asking that is it possible that our milky way galaxy is formed when a quasar ceased and left a supermassive black hole at the centre which is there in our galaxy...

 

[Drakkith]

I am asking that it is said many a times that when a quasar ceases it becomes a galaxy so i am asking that is it possible that our milky way galaxy is formed when a quasar ceased and left a supermassive black hole at the centre which is there in our galaxy...

I don't know what you read that said galaxies only form after quasars, that isn't true. Supermassive black holes form during the initial galaxy formation process. A quasar is nothing but a very active black hole of a galactic nucleus. Quasars don't cease and leave behind a black hole, it a quasar only occurs because there is already a black hole there to cause the accretion disc to form.

 

[vinayjain]

I don't know what you read that said galaxies only form after quasars, that isn't true. Supermassive black holes form during the initial galaxy formation process. A quasar is nothing but a very active black hole of a galactic nucleus. Quasars don't cease and leave behind a black hole, it a quasar only occurs because there is already a black hole there to cause the accretion disc to form.

These quaar mysteries are

 

[Drakkith]

These quaar mysteries are

How so?

 

[vinayjain]

How so?

because what exactly is going on there we didn't know

 

[Drakkith]

because what exactly is going on there we didn't know

Perhaps I misunderstood your "Yuck" smiley.

 

[vinayjain]

cn anyone please tell me that what probably happen to a black hole when its life is complete

 

[Drakkith]

cn anyone please tell me that what probably happen to a black hole when its life is complete

See here: http://en.wikipedia.org/wiki/Black_hole#Formation_and_evolution

 

[vinayjain]

just curious about something: when there are no dimensions exists near the centre of black hole and singularity comes when u go closer and closer at the centre of the black hole so every matter which is merged inside the black hole cannot increase the mass of the black hole as it is like the matter is destroyed to make it dimensionless so how does a black hole increase its mass during its phase of life......

 

[Drakkith]

just curious about something: when there are no dimensions exists near the centre of black hole and singularity comes when u go closer and closer at the centre of the black hole so every matter which is merged inside the black hole cannot increase the mass of the black hole as it is like the matter is destroyed to make it dimensionless so how does a black hole increase its mass during its phase of life......

Where does it say that dimensions disappear inside a black hole?

 

[vinayjain]

Where does it say that dimensions disappear inside a black hole?

sorry I actually misunderstood something......but actually want to know something else i.e.

The expansion of our universe is going on increasing day by day and since its speed is increasing there might be time coming in future that its expansion speed will cross the speed of light and in that case visualizing any object in the universe will become impossible is that true....

 

[Drakkith]

sorry I actually misunderstood something......but actually want to know something else i.e.

The expansion of our universe is going on increasing day by day and since its speed is increasing there might be time coming in future that its expansion speed will cross the speed of light and in that case visualizing any object in the universe will become impossible is that true....

Expansion is not a speed, it is a rate. It is already the case that galaxies beyond a certain distance from us (Tens of billions of light years I think) are receding at a velocity greater than c. HOWEVER, this is because space is being created (or expanding) in between us and "carrying" the galaxy away from us. If we could cut away all the space between our 2 galaxies both would be traveling through local space at a similar velocity. This is why it doesn't break relativity, because it is not traveling THROUGH space at greater than c.

See here: http://en.wikipedia.org/wiki/Metric_expansion_of_space