Naked Science Forum
Non Life Sciences => Physics, Astronomy & Cosmology => Topic started by: Alan McDougall on 14/01/2009 08:52:29
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Greetings I am back much to the sorrow of some [:D]
My question might be silly, but we know a neutron star compacts matter hugely, a teaspoon of a neutron star matter might weight a billion tones.
The question I would like to pose, is if we could somehow scoop up a teaspoon of matter from a black hole , what would we find in our hypothetical teaspoon? Would it be, Concrete, tangible,, physical and a real material substance?????
If we manage the impossible and scoop up a teaspoon of the substance of a black hole how massive and dense it would be compared to our earth measure mass.
If we perform the impossible and we scoop up some of the black hole matter in our teaspoon and find it empty, where has the matter gone, has this matter vanished into another universe etc.
Is a black hole a hole or is it just a real concrete object
Alan
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This is a silly question that because it speculates on something that by definition cannot be performed. The mean densities of black holes of stellar mass are greater than that of neutron stars but obviously it is just not possible to "scoop material out" of them.
However there is an interesting fact that you might be interested in the bigger the black hole the less the mean density inside the event horizon The size of a black hole is a linear function of its mass. A black hoe with the mass of the sun is about one mile across a black hole with a billion solar masses is therefore a billion miles across (about as big as the orbits on Uranus or Neptune) and has a mean density less than that of the sun
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That was a new one to me Soulsurfer:)
You are talking about the diameter of the event horizon here?
And stating that we have a linear function following its (BH) mass?
But that the density falls of inside the EV the more mass a black hole accumulates.
How do we know that?
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SoulSurfer
This is a silly question that because it speculates on something that by definition cannot be performed. The mean densities of black holes of stellar mass are greater than that of neutron stars but obviously it is just not possible to "scoop material out" of them.
You say you are a professional scientist and so was Mr. Albert Einstein but he did not think it silly to do thought speculation. Most of his great theories were from just that type of thinking, for instance he said he thought "what would to be like to ride on a beam of light?, how silly is that.
I am no ignoramus I am just as educated as you but don't tell this to wear it visible to all hanging around my neck like a pendant
You have an attitude and you come across as someone who just wants to show other show stupid they relation to me.
Wake up man your ego has got the better of you
I am comfortable to think silly thoughts embraced by no less than Einstein in my approach
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As SoulSurfer said, the density of the BH varies according to it's size. However, the Schwarzschild radius for the Earth, with a mass of 5.9736×10^24 kg is just under 9mm, which should give you some idea of the magnitude of BH densities.
The important thing to remember is though, that that 9mm diameter is for the Event Horizon and so is the density for a region of space and not for the singularity itself, which may, or may not be a geometric point.
And then there's also the issue of gravitational time-dilation, which means that the rate of time slows to zero at the Schwarzschild radius, well before you reach the singularity; how can you do any physics without time?
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As SoulSurfer points out finding the density of matter beyond the EH is not amenable to experiment so we must rely on theory and guess work.
Although there is a substantial loss of mass due to radiation and blowing off of matter when a star collapses enough remains to establish an escape velocity of greater than c, this must have a greater density than the matter in a Neutron star and is presumably a quark soup where individual Baryons lose their identity.
This form of matter can be produced in heavy Ion colliders but without an intense gravitational field to confine it it has only a very short life.
Recent computations have shown that the mass of Baryons is much greater that the sum of the masses of their constituent Quarks and mostly derives from the binding energy of the Gluon's this I take it also applies to a quark soup.
I think it is a red herring to talk about the density of the EH the EH is rather like the sound barrier passing though would be traumatic for a small BH but would not be noticed for a multi billion Solar mass one.
Here is an article that discusses how the mass of Baryons is derived
http://www.nature.com/news/2008/081120/full/news.2008.1246.html
And here experimental work on Quark soup
http://www.bnl.gov/bnlweb/pubaf/pr/2003/RHIC-background-2.htm
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Alan McDougall I am totally in favour of thought experiments they are a great device to help learning and understanding there is however one important rule they must be physically achievable even if they are not practical. Einstein would have agreed totally with this.
Your experiment/question is of the order of how heavy are the angels dancing on a pinhead? i.e. it just has no real meaning
In your experiment describe a process of scooping some material from the inside of a black hole but this is clearly not possible.
If you had asked the question can we hazard a guess as to the possible density of material inside a black hole? this is a perfectly reasonable question and has a reasonable answer.
Now if you really intended to ask that question you should have asked it simply and directly and not dressed it up in an aura of false (and impossible)experimentation it is just unnecessarily confusing.
A practical guess at the maximum possible density of material inside a black hole is a Planck mass inside a Planck volume (a sphere with a diameter equal to the Planck length).
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Syphrum, My wild wild guess:)
If it is a quark soup it 'possibly' could be able to move faster than 'c' if 'matter' differs from that original soup, and also creates 'space':)
On the other hand it seems to me that anything moving faster than 'c' shouldn't be recognized by spacetime until the quark soup started to 'cool down'?
What do you mean by " Recent computations have shown that the mass of Baryons is much greater that the sum of the masses of their constituent "
Is it this?
"When theoretical physicists talk about the mass of a quark, they are referring to a parameter that appears in the Lagrangian with the dimensions of mass. In the standard model this parameter occurs due to the interaction between the quark field and the higgs particle and its roughly 2-5 MeV.
A proton is 3 quarks so you would expect something like 15 MeV (give or take) and instead you get 1 GeV. The point is that you shouldn't think of mass (when it comes to sub atomic particles) the same way you would talk about mass of say an orange."
And I still don't know why the density should go down as mass is added to a black hole?
If I would guess how mass may behave I say we have two ways to look at it.
In the observers (outside the EV) reference frame nothing will be happening.
But seen from the reference frame of the mass it all will fall in 'normal time' down to that 'center' where it should 'disappear' as 'matter'.
To me that mean that the bigger the black hole the more mass it will, from our view/frame outside the EV, consist of inside that EV, all of it moving ever so slowly inwards.
One alternative could be to say that as those Black Holes can't be born except in that beginning of the Big Bang then only the matter outside the EV (event horizon) from our frame seen, will be the matter 'moving in'.
All other matter inside might already have reached their 'destination' under that first creation as it then must have involved that inflationary period, which then could make a 'no space' space inside that EV.
If for example those super black holes residing in our galaxies center once was very tightly knitted together, and created from that first cooling of the quark soup.
Then 'split up' by the inflation that they might even have started by their creation.
Which then would eliminate the possibility's of that 'region' inside the EV to ever have any 'potential energy' as 'normal space' seems to have.
Yep, speculations is my forte::))
But I still want to know why the density might be lower inside a black holes event horizon the bigger it gets:)
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SoulSurfer
I will rephrase my question Is a black hole a physical "ORB" and black invisible due the fact light cannot escape is grip?
If it is just a almost infinitely dense ORB then the mass of substance it is made of must be hugely more massive and condensed than that of a neutron star.?
So as far as I can understand it it is not really a hole but a black unseeable ever shrinking "ORB" ant the term Black hole is a misnomer
My I ask another question?
Is there some reversal of entropy in the area of a black hole?
If it draws everything in its gravity grasp, then as far as I can see we have a phenomenon of low dense low temperature high entropy flowing into a hot high temperature low density area
My tiny mind thinks this is a micro reversal entropy, but a temporary one, in that even a black hole in the end must dissipate its energy into the universe and decay.
Alan
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One alternative could be to say that as those Black Holes can't be born except in that beginning of the Big Bang then only the matter outside the EV (event horizon) from our frame seen, will be the matter 'moving in'. All other matter inside might already have reached their 'destination' under that first creation as it then must have involved that inflationary period, which then could make a 'no space' space inside that EV.
If for example those super black holes residing in our galaxies center once was very tightly knitted together, and created from that first cooling of the quark soup.
Then 'split up' by the inflation that they might even have started by their creation.
Which then would eliminate the possibility's of that 'region' inside the EV to ever have any 'potential energy' as 'normal space' seems to have.
This is a sad sad thing :)
Quoting one self..
What I was wondering about here was if there could be something consisting of less than 'space'.
As we were talking about a black hole containing less density the 'bigger' it became.
And as space seems to contain 'energy'.
Also if black holes, as some say, only can be created at the big bang.
And how that might have looked.
And when and where 'inflation' then might have come in.
If it is as I'm starting to think then matter is the creation of space:)
Crazy isn't it.
So a black hole should then be able to create an awful lot of space.
But could it also be so 'strong' that it would eliminate 'space' itself?
As that is a area containing energy?.
And why i wondered that is because I'm wondering what 'distance' and 'motion' is.
But it attracts/creates a gravity well.
Doesn't that mean that it must contain 'ordinary' space inside that event horizon to allow that 'well' to exist?
If that is the truth, then how could it possibly do the same without any 'space' existing inside it?
But if it is a 'singularity' and matter breaks down, shouldn't space itself 'fold up' inside it?
So for both to be true it seems to me that one would need something that inside that EV wouldn't have a distance and no motion either.
The EV would then be the black hole as seen in spacetime.
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But reconsidering it:)
You could as easily say that as it 'folds up' on itself it will create a huge amount of space, as seen from the inside.
And that would make it more in line with how space is expected to be in there.
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As for wondering about the inflation and if black holes would have anything to do with it.
Once we must have had some sort of geometric point describing a beginning.
In that point our black holes might have been the first thing developing into matter?
I think inflation come just before the black holes, and that the black holes just might have been what started our spacetime, and where we have spacetime we have no inflation.
Also I wonder if one could see inflation as something moving inside of time, but outside our macroscopic arrow of time. That as it happened before any macroscopic 'structures'.
That's about it:)
And most probably totally wrong ::))
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yor_on
So a black hole should then be able to create an awful lot of space.
But could it also be so 'strong' that it would eliminate 'space' itself?
As that is a area containing energy?.
My question has still not being addressed. I will put it another way:
Is a black hole space time in another universe?
Or is a black hole just a massive solid object we cannot see?
Or is a black hole a white hole in another universe?
Our has universe could have been created from a white hole? This possibility has not been dismissed by many physicist
Or could our whole universe be the result of an enormous black hole from somewhere else?
Are we living inside the result of a colossal black hole?
Alan
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Allen McDougall
My ideas on the subject, yes a blackhole is a massive object that we cannot see (although there could be quite small if very short lived ones).
SoulSurfer
I like the idea of a Planck mass compressed into a Planck volume I have always been very unhappy with the idea of an infinite density singularity
Yor on
I was only quoting the article in NATURE I do not really understand the more subtle implications
PS if anyone with a subscription to NATURE could email me a copy I would be grateful, I read the full article when it was free but did not keep a copy
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yor_on
So a black hole should then be able to create an awful lot of space.
But could it also be so 'strong' that it would eliminate 'space' itself?
As that is a area containing energy?.
My question has still not being addressed. I will put it another way:
Is a black hole space time in another universe?
Or is a black hole just a massive solid object we cannot see?
Or is a black hole a white hole in another universe?
Our has universe could have been created from a white hole? This possibility has not been dismissed by many physicist
Or could our whole universe be the result of an enormous black hole from somewhere else?
Are we living inside the result of a colossal black hole?
Alan
I'm not the guy to ask Alan:)
I have as many questions as you.
In my 'book' (for now:) a black hole is a negation of spacetime internally but the possible constructor of it externally.
And if that makes sense you're welcome to my rabbidhole:)
As for a white hole?
http://en.wikipedia.org/wiki/White_hole#Origin
A white hole is said to 'spew' out matter, but, according to Hawkins they will appear as a black hole to us attracting matter at the same time.
Which makes me knit my eyebrows extensively in a crosswise manner:)
A object constantly receding from that in falling matter at 'light speed' at the same time it 'spews' out matter from the EV.
Possibly I got it wrong?
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Someone once wrote that a black hole has its 'singularity' behind it.
Would then a white hole have its 'singularity' before it?
But as they seem very unstable?
Maybe they could have been the 'kick of' of our universe.
I don't know.
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But we don't need that (yet).
We need first something to explain what we already have noticed.
The inflation.
Super big black holes in the middle of our galaxies.
And to my eyes, how to see gravity right.
As I see it as just another aspect of 'matter' then wherever you have that, or anything constructing a 'gravity well' you will have 'space'.
So a black hole 'works' to create space.
quark soup 'works' to allow inflation.
Both of them inside our known ideas.
And we know, as Feynman so fascinatingly explained, that time loses its arrow at a quantum level.
And if 'matter' is what introduces that arrow of time.
:)
Yep, this is my new rabbid hole.
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popular accounts of the big bang often suggest that the universe originated from a object the size of a grapefruit, I calculate that a 20cm diameter object of Planck density would have a mass of 2.91*10^91 Kg, how does that compare with the estimated mass of the universe ?.
Is that how this figure is derived ?.
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Alan McDougall we can never observe anything beyond the event horizon and can only model it based on our observations of the behaviour of matter. So your questions can never be answered directly and confirmed by measurement on an actual black hole.
In high energy complex collisions we can get some way into the region of interactions that happen inside stellar mass black holes as they continue to collapse. Hopefully in a few years time when the LHC gets round to colliding heavy nucleii we will get into new areas. Beyond that we are currently in the realms of theorists who tend only to use simple models and look at the limits. What really happens is almost certainly more complex. I have my own personal opinions and these are expressed in the "evolutionary cosmology" topic in the new theories area but these ideas are far from standard thinking.
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Soul Surfer
Alan McDougall we can never observe anything beyond the event horizon and can only model it based on our observations of the behaviour of matter. So your questions can never be answered directly and confirmed by measurement on an actual black hole
Of course this is true.
This might be resolve when and if, The equation for The Theory Everything TTOE is realised, One force which becoming many forces which flowed down many rivers becoming and fixing fundamental constants Luckily for us, as these fundamental laws made life possible in our universe constants
syhprum
Most astrophysicist that the universe started as singularity non dimensional point particle of infinite energy, smaller a quantum particle So size had no meaning in this event. [;)]
Some religions such as the Cabala or Indian philosophy believe that the universe was born from a cosmic egg, which hatched and formed the universe [???]
Alan
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The big problem with mathematical models is that mathematicians tend to rush off to the limits without trying to to look in detail about what might happen on the way. For example our universe is basically uninteresting mathematically because it all fades out into nothingness as things cool down and expand.
The same is true for the collapse inside a black hole they rush off to say it all collapses down to a point because they don't see any reason why it doesn't. they don't bother to examine in detail the behaviour of rapidly rotating material in detail as it collapses. This requires very complex mathematics and complex computational fluid dynamics.
We get exactly the same thing when people go back to the start of the big bang.
Now I believe Fred Hoyle with his "continuous creation" universe, that was clearly proved wrong, had at its root one important principle that is correct. The principle that the conservation of energy and angular momentum mean that on the very largest scale the universe must be essentially changeless in space and time. Although of course it may change and evolve locally as we see locally to us (our visible universe).
Recent theoretical studies of the basic equations of space and time suggest that as you head back towards the big bang you do reach a maximum density before which the universe was expanding. that is if you reverse time it was collapsing before it exploded. Perhaps this will satisfy your curiosity for the moment.
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I will never understand the fuss about the matter in the black hole. It's clear the black hole has matter. Not the usual elements but collapsed atoms. I mean how can smart guys like Hawkins and Einstein believe that there is a parallel universe matter escapes to.
That's the kind of thinking which people resort to when they don't know. Just get rid of the matter and send it to another universe [???] [:-\].
No hard feelings people.
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Infinite density is impossible. Mass can never be infinite and Volume of mass can never be zero. There always have to be a magnitude else it is not matter.
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If you by infinite density mean measurable density inside our universe, you're right Demadone.
All those places where we talk about there possibly being 'infinite density, or for that sake discussing anything without dimensions (photons?) we are defining something here, but not really inside 3D and time, it seems to me.
That is, we will not ever be able to measure them if they are this way.
That doesn't mean that those definitions need to be wrong:)
But we do have descriptions for them..
Singularities and enigmas::))