Black hole formation

[Ophiolite]

Well done ed84c that was good effort; through this week I'll try to unravel these enigmas unless anyone else can enlighten us how about Ophiolite if anyone can it's you let's not hope we're in the dark for too long.....

As I always say in these circumstances, eschew obfuscation.

[ed84c]

adj; Not going straight to the point, round about.

 

Is that right?

[Sayonara]

Kind of. It also means "twisted back on itself". Like your oblique abdominals.

[RawThinkTank]

I'm sure there are a lot of things that have been observed you aren't aware of; that doesn't mean none of them were observed.

 

I am not saying anything here. All I am saying is that Ur trying to distort facts here. Maybe as an owner of SFN someone has paid U 2 do so. Any ways the fact that will go down the history is that U delibrately ignored my post and concentrated on the observations that are as usual wrongly interpreted by humans.

[Ophiolite]

I am not saying anything here. All I am saying is ......

Make up your mind. Are you saying something or are you not?

I am saying ..that Ur trying to distort facts here. Maybe as an owner of SFN someone has paid U 2 do so.

Why would anyone be interested in doing that? Besides we all know Sayonara will happily distort facts on a pro bono basis.

Any ways the fact that will go down the history is that U delibrately ignored my post ......

We are creating history here on science forums? Wow!

U.......concentrated on the observations that are as usual wrongly interpreted by humans.

So which species interprets these observations correctly?

[RawThinkTank]

Well I am leaving this forum to create my own based on majority , so see ya all later.

 

And thats becuase people here have powers to close others threads.

 

http://www.scienceforums.net/forums/showthread.php?t=7601

[Sayonara]

I am not saying anything here. All I am saying is that Ur trying to distort facts here. Maybe as an owner of SFN someone has paid U 2 do so. Any ways the fact that will go down the history is that U delibrately ignored my post and concentrated on the observations that are as usual wrongly interpreted by humans.

If by 'ignore' you mean replied to, and by 'distort facts' you mean point out that it was fairly meaningless, then yes - guilty as charged.

 

I was paid by the illuminati to undermine your groundbreaking work.

 

 

Well I am leaving this forum to create my own based on majority , so see ya all later.

I wouldn't count on it.

 

 

And thats becuase people here have powers to close others threads.

As opposed to what, voting on it?

[Jacques]

The theory tell us that (http://hyperphysics.phy-astr.gsu.edu/hbase/astro/blkhol.html#c1)

But this neutron force is the last stand, and our best calculations indicate that this repulsion which prevents collapse cannot withstand the gravity force of masses greater than 2 to 3 solar masses.

So a neutron star of 3 solar mass always colapse to a black hole.

The neutron star radius is decrease with time. When it start being a neutron start it was many kilometers of radius and is going to zero radius.

Now what will see Jo from is base situated at a safe distance from the neutron star who start to collapse. How fast would it go ?

Joe see the radius shrinking realy fast. From 30km in radius to 20km it took less than one second (on Joe's time). The gravity of that mass will produce some time dilatation.

You will find the gravitational time dilatation equation:

http://hyperphysics.phy-astr.gsu.edu/hbase/relativ/gratim.html#c4

I try to reproduce it here:

T=T0 / (1-(2GM/Rc^2)^.5)

You can see that when the radius get smaller the time dilatation increase.

I can also see that when 2GM/Rc^2 approach 1, the time dilatation tend to infinity (time stop).

Let find the radius where the time stop:

2GM/Rc^2=1

2GM/c^2=R

G=6.67*10^-11 m3 kg-1 s-2

M=3 Solar mass= 6*10^30 kg

c=3*10^8 m

R=2*6.67*10^-11*6*10^30/ 3*10^8*3*10^8

R=8.899 km

So Joe's see's the neutron star shrinking slower and slower. If he stay there an infinit time he will see the radius at 8.899 km.

Also 8.899 km is the Schwarzchild radius, where a neutron star start to bee a blackhole.

Conclusion a blackhole would take a infinite time to form.

The "singularity" will never have time to form.

 

Is there something I am missing ???

[Rootje]

Hm no-one seems to bother posting on-topic information here, but instead are preocupied with some real mature and scientific posting.

 

Anyway, Remember the Twin paradox? The twin that's been traveling at lightspeed (rel. to earth) returns years younger then the one that stayed behind.

 

The twin that stayed behind is like any outside observer. So indeed, in the black hole case, before an actual singularity is formed in the centre of the star (for any observer in the neighbourhood of the centre), the entire lifetime of the universe flashes by. And even if you wait far outside the Schwarzchild radius until the end of existence to see a singularity, Hawkings-radiation has already vaporized the black hole again.

 

Simply put black holes do exist, but not in singularity form, just a very very heavy object in a very very small volume, with some characteristics of a singularity but not all.

 

And something else; suppose we have a collapsing Neutron star, electrons have already merged with protons, gravity pulls stronger untill every empty space between the particles is occupied with some sort of matter, however can you compress it further then that? Doesn't matter come across "quark-resistance" or something?

[Guest Risen]

http://zebu.uoregon.edu/~imamura/122/mar13/bhform.html

To answer the original question, I present a theory: just before the black hole forms, as the shock wave travels throughout the neutron star, the matter that makes up the NS is dispersed somewhat, reducing the gravity the NS creates and disposing of the Schwarzchild radius, allowing the final collapse to take place before Infinity's End.

[Martin]

Brava Rootie,

bravo jacques,

you are both still asking and trying to understand BH!

 

I think someone who understands about BH about as well as anyone in the world at present is Abhay Ashtekar at Penn State, also Bojowald at Potsdam. the quantum theory of gravity does not have BH singularities.

those two (Asht. and Bojo.) are collaborating on some new research that will give a quantum picture of BH.

 

(it is the classical 1915 pre-quantum theory of Gen Rel that has the singularities that are so problematical, so one must quantize the theory and make the singularity go away before it will make sense near center of BH)

 

there is a talk which one can download, given by Ashtekar about BH, I will get the link. Maybe someone would like to listen to the lecture and watch the slides.

 

many things that Rootie and Jacques and others have said are right but I still think that it is too early and that the real story of BH can only come out from the Quantum Gravity theory still under construction

 

...The twin that stayed behind is like any outside observer. So indeed' date=' in the black hole case, before an actual singularity is formed in the centre of the star (for any observer in the neighbourhood of the centre), the entire lifetime of the universe flashes by. And even if you wait far outside the Schwarzchild radius until the end of existence to see a singularity, Hawkings-radiation has already vaporized the black hole again.

 

Simply put black holes [i']do[/i] exist, but not in singularity form, just a very very heavy object in a very very small volume, with some characteristics of a singularity but not all.

...

 

if you want there is a recent short Ashtekar article Gravity and the Quantum that gives an overview of quantum gravity

http://arxiv.org/abs/gr-qc/0410054

 

but for the seminar talk

http://www.phys.psu.edu/events/

go back to Fall 2004 seminars and you will find

http://www.phys.psu.edu/events/index.html?event_id=934&event_type_ids=0&span=2004-08-20.2004-12-25

this is Abhay's slides

click on audio to get the sound.

 

Eventually this will all be slicked up and brought out as a finished paper.

they are beginning to unravel the mystery of what forms at the pit of a hole INSTEAD of a singularity and to understand what happens as this eventually evaporates.

(there is the BH information paradox also to be resolved and he talks about that)

this is a September 2004 talk so it is after hawking July 2004 highly publicized announcement (which is still dubious because followup details have not been forthcoming) so in some sense Ashtekar takes up where Hawking left off