No Black Holes

http://www.badastronomy.com/bablog/2007/06/19/news-do-black-holes-really-exist/

This would throw a spanner in the works, is there enough observational
evidence to dismiss this article?

 

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I found that article fascinating and very readable...however, all things considered I really know nothing about it

 

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From the view inside the black hole, everything appears normal (dependent of course, on whether an observation can be made from inside a black hole). The view to outside the hole is somewhat different. This is only relevant to the fact that the hole should form normally from that view.

Now, although the mass has collapsed and formed, an observer outside beyond the event horizon is viewing what's left of the light propagating from the collapsed object... light that has undergone relativistic effects from the gravity. Those effects are what the author is referring.

The object, having formed, WILL take on an event horizon in which any light that manages to escape beyond it will be shifted red, everything else will not be seen beyond the horizon.

The author is therefore mistaken in his theory that the black hole will not appear to form based on his assumption that light slows down in a strong gravitational field.

 

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But the collapse will be affected by time dilation just the same as the light escaping it. Wouldn't the material collapsing to form the black hole experience time slowing down as well? If that's the case, it'll never quite reach the point of singularity, will it? Light would always be able to escape, albeit very very slowly.

 

Then, you are also assuming light slows down in a gravitational field, it does not. Light certainly loses energy "climbing out of a gravity well" with the result of shifting to the red spectrum, but it still travels at c.

 

i dont see how light can experience time dilation. if it did, since it is already traveling at c, that means that time would be stopped for it, but that is obviously not the case or else all light would be frozen

 

Once, I posted on a college physics department announcement board some PR for my book Dark Visitor, which is about a possible cosmic disaster for Earth. (Small black hole is now approaching Earth near solar system and will slightly change Earth's orbit, cause a permanent Ice Age.) As I know the what captures a male students interest, the headline was:

Black Hole is Coming for You.

 

I think the whole presumption of a black hole is absolutely rediculous the way they would have you look at these "holes" in space.

Truthfully there is nothing "holy" about black holes. They are supermassive spheres of atomic matter which get such massive gravity that not even light escapes, but to presume that a black hole is actually a hole in space-time is like saying we can cut up the fabric of space and make it look like a paper snowflake, but thats not possible because space is 3D, not 2D, obviously.

Its not a hole, its merely a supermassive sphere with supermassive gravity, SHEESH I cannot believe all the relativistic bullshit society is forced to wade through.

Don't even get me started on "worm holes." (a big dumb presumption made by scientists who have been drinking too much crude oil)

 

Sci-Phenomena: Does crude oil give you a buzz? If so, I would like give it a try the next time I have dinner at one of my favorite BYOB restaurants. I wonder if I will like it more than Baja Luna or Tequilla Rose.

Where can you buy crude oil? How potent is it? If it is as strong as whisky or scotch, I will not like it.

Others: Some here do not realize that black hole is cute jargon rather than a scientific description of the phenomenon. It is used due to the fact that an isolated black hole might be interpreted by our senses as a hole in space leading to a dark region, since there would be no light emitted from it.

The event horizon of a black hole expands in finite time due to infalling mass. If you consider a single particle (say a neutron) falling toward the event horizon, the General Relativity equations describe the time for reaching the horizon as infiniite from the point of view of a distant observer.

The situation is different for a black hole sucking in large amounts of mass. Suppose that black hole A has mass M and event horizon radious R, while black hole B has mass M + DeltaM and event horizon radius R + DeltaR. If mass DeltaM falls within DeltaR of event horizon A, the event horizon will expand to R + DeltaR. Thus the infalling matter will be inside the new event horizon without having reached the old event horizon.

 

Well then it'll be redshifted to near infinity. Anyway the point was the infalling matter would experience time more and more slowly as referenced from a distant observer, the closer it gets to forming a black hole the longer it takes to complete the process. The singularity is never formed. It still looks like a black hole from the outside, without the equation breaking zero-radius-infinite-density point in the middle.

Why does the infalling matter contribute to the black hole's mass when it crosses the event horizon? If the event horizon is just an 'imaginary line' of sorts x distance from the singularity at which nothing can escape, how can matter become 'part of' the black hole just by crossing it, without ever reaching the singularity itself?

Not saying it doesn't, just don't quite understand how.

 

Are you talking Gravstar?

 

The original linked article says something similar - that infalling mass never quite crosses the event horizon because time slows down infinitely in that region. So it follows that all matter ever accreted by a black hole since its formation will pile up just outside the event horizon. This would form a shell or torus of ever-increasing mass and density - eventually, enough mass to function as a black hole in its own right? As Dinosaur suggested, a second event horizon should form (or almost form...

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) outside the first one, expanding the radius of the black hole.

And in fact, since virtually any mass (above an instant quantum-evaporation threshold of about 0.0005 grams) can become a black hole if sufficiently compressed, there ought to be a new event horizon formed almost as soon as the original black hole begins accreting anything. Succesive horizons will form continuously during accretion, and the black hole will expand steadily. Which is exactly what mainstream astrophysics predicts black holes do.
Thus, Fishtail's article doesn't challenge the accepted picture as such.

Another thought, though: if time does, indeed, effectively stop at an event horizon, then a space traveller who approached the hole this closely should see unimaginable future aeons elapse very quickly. He/she/it might even hang around on the horizon for only hours or minutes, subjectively - and see the external Universe disintegrate, all stars die, all baryonic matter decay, and ultimately watch the black hole evaporate, with nothing left to accrete.

If a spacecraft could reach the event horizon without being crushed and shredded by tidal forces - which might be possible with a supermassive black hole, whose radius is large enough for the tidal effect on small approaching objects to be manageable - then the occupants could be around 10^100 years from now, and witness the very last gasp of the Universe as the supermassive black holes finally expire.

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: Of course, there would be nothing at all to do or see after that... or would there..?

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B*g%er - I really killed this thread, didn't I? That will teach me to pontificate as lengthily as Tiassa or Fraggle Rocker!

 

That may be the appearance from an outside observer, but the process completes normally as time appears normal to an observer within the hole.

 

Sure, but in this case the entire universe could be thought of as an outside observer. If one second within the forming black hole equates to billions of years on the outside then it should be safe to say the singularity may never form. The singularity may take 3 seconds 'local time' to form, but to the rest of the universe those 3 seconds may appear to take 30 billion years. In that case wouldn't the frame of reference inside the black hole be irrelevent?

 

lol. a good sexual related eye catcher is nice for capturing male attention.

peace.

 

What the outside observer would view is a brief glimpse of the collapsing star fading to nothing (redshifted, as well) as the object ceases to emit light and would be left looking at the event horizon.

 

Well, actually what us 'outside observers' witness is an exploding star, a supernova. What actually happens to the core of the star is hidden by the intense radiation from the supernova, which glows for days sometimes. We do know a black hole is not as easily formed as basic theory predicts. It has been discovered that a supernova explosion of a star with an estimated mass 40 times greater than our sun produced a neutron star, not a black hole as expected. A link:
http://chandra.harvard.edu/press/05_releases/press_110205.html

 

Maybe I'm not communicating my point clearly enough. One of the biggest problems with black hole theory is the singularity at the center, a point of infinite density where all laws of physics seem to break down. Now, if the time dilation between the collapsing star and the outside observer (the universe) is large enough the universe could run through its entire course of existence before the singularity has time to form. Or the black hole could evaporate before the singularity has time to form. In essence, it doesn't matter that time seems to pass normally inside the forming black hole because it will either evaporate or reach its demise along with the rest of the universe before the singularity can form.

So to an outside observer an event horizon appears without the messy singularity that would otherwise defy all laws of physics. You don't need a singularity to have an event horizon, and I think that's what the article in the OP was all about. The universe would never hold a singularity, because any matter collapsing that far will experience time so slowly (relative to the rest of the universe) that it will simply never collapse all the way.

 

Xelios

I do understand what you're trying to say, but beyond the event horizon is where the laws of physics breaks down. In other words, whatever will form there, a singularity or other such object, will form normally, and most likely very quickly, under the conditions of massive gravity.