DailyDirt: Mysterious Black Holes
from the urls-we-dig-up dept
The nature of black holes has been debated for years, as astronomers and physicists are puzzled by how these objects absorb matter/energy without violating agree-upon rules of the universe. Maybe black holes don’t exist the way we thought they did? Or perhaps the laws of physics aren’t quite right yet? (Or both!) Here are just a few links on these mysterious entities that are thankfully very far away.
- Black holes may not be entirely black, as some particles can escape the extreme gravitational pull as Hawking radiation. Black holes might “evaporate” away over time (in about 10^67 years) or they might leave behind some super dark remnants. The ongoing debate about the ultimate fate of a black hole hasn’t been resolved just yet. [url]
- Japanese astronomers have recently reported the discovery of three intermediate black hole (IMBH) candidates. Astronomers have previously seen “small” black holes (~10x the mass of the sun) and supermassive black holes (millions/billions of times the mass of our sun), but black holes that are in-between in size are still a bit of a puzzle. [url]
- Stephen Hawking has published a paper saying that black holes have no “event horizon” (the theoretical boundary beyond which nothing can escape the black hole) and proposes an “apparent horizon” which pulls everything in but also leaks some stuff out. Hawking hasn’t formalized this assertion, and he says whoever does will have to explain a grand unified theory of everything at the same time. [url]
If you’d like to read more awesome and interesting stuff, check out this unrelated (but not entirely random!) Techdirt post via StumbleUpon.
Filed Under: apparent horizon, astronomy, astrophysics, black holes, event horizon, gut, hawking radiation, imbh, intermediate black hole, stephen hawking
Comments on “DailyDirt: Mysterious Black Holes”
Black holes and stuff "in between"...
My wife is a particle physicist at FermiLab, and my father was an astro-physicist who studied cosmic rays and mesons. To say that this is cool stuff is an understatement! My father would love the work that Hawking et al are doing. FWIW, Fred Hoyle was a close family friend.
Needless to say, we know a lot less about this subject than we need in order to help make sense of this crazy universe!
My wife went to Cern a couple of years ago for some meetings about the search for the Higgs Bozon. All I got was a tee-shirt with the Higgs math printed on it… 🙂
Re: Black holes and stuff "in between"...
would love to come to your family BBQ’s.
Mis-spelling
Bozon -> Boson… Sorry dad!
so if a black hole evaporates over time, and loses mass, and mass is gravity, as the gravity gets less, and the mass gets less, at some point gravity will be lower than the speed of light, and it will no longer be a black hole, and everything in it will come out !
Re: Re:
“mass is gravity”
This is incorrect.
“as the gravity gets less, and the mass gets less, at some point gravity will be lower than the speed of light”
I’d love to see the math, please continue.
“it will no longer be a black hole, and everything in it will come out !”
Like some sort of cosmic fart? Is there any evidence of this occurring?
The problem with Black Holes is
they are a great theoretical object (great for stories to tell by the fire side), but cannot exist in our universe. Since time dilation is a function of increased gravitational fields and the gravitational field of a black hole is such that light cannot escape, time has stopped at event horizon relative to rest of universe.
So while time passes for us, it passes so much more slowly the closer to such a gravitational entity. Hence, as far as we are concerned, the collapse of even a single massive body is “The Never Ending Story”.
It puzzles me why so many intelligent people believe in such entities. It is like Zeno’s Dichotomy paradox in reverse. They use mathematics to prove the existence of such entities in very specific environment and then extrapolate to our universe. Crazy mon.
But then again we do have the conflict between string theorists and and antagonists (Peter Woit and company), where they have taken up their standards of war and fight to the death to show each other wrong.
One day, I can only hope that these intelligent men and women can stop and smell the roses and step back to take a close look at what they are saying and realise that for the time being the universe is huge, we are small and very finite and our understanding the nature of the universe and the world we live on is still very limited and very incomplete. The fun is in exploring and coming up with ways to model what we see to make new things and do new things.
We have really got to get back to seeing that these things are fun.
Re: The freezing of time
I have thought about it, and I subsume that matter cannot fall trough the event horizon because the speed of time would be zero, but the same consideration have to be made for all directions including matter that would be moving away from the gravitational pull.
This would have a profound effect on the pressure particles close to a event horizon can exert on particles further out. Fewer photons would exert pressure for the same reason.
It follows that the reduction in the speed of time in the center might be as important as the gravitational pull itself in triggering the collapse.
As the surrounding matter falls towards the center the gravitational well deepens and time gets frozen gradually further from the center.
If nothing can fall through the event horizon, then nothing can escape it either.
This would explain both what triggers the collaps, the release of energy in the supernova, and why black holes are rather dark.
Re: The problem with Black Holes is
“they are a great theoretical object”
– Gravity is a theoretical force … so what?
“but cannot exist in our universe”
– Do you allow them to exist in other universes?
“the gravitational field of a black hole is such that light cannot escape”
– Some theories dispute this
“It puzzles me why so many intelligent people believe in such entities.”
– Use of the term “believe” is questionable in this realm.
“They use mathematics to prove the existence of such entities in very specific environment and then extrapolate to our universe. Crazy mon. “
– Yeah, those people are so crazy
“fight to the death”
– I doubt that
“One day, I can only hope that these intelligent men and women can stop “
– Why?
Re: The problem with Black Holes is
they are a great theoretical object (great for stories to tell by the fire side), but cannot exist in our universe.
I’m still waiting for an explanation of why all these cosmologists are wrong and black holes are impossible.
Re: Re: The problem with Black Holes is
By their own rules, it takes an infinite amount of time for a black hole to be created and by their own rules the universe has existed only for a finite time.
Simple, No? (reference anyone)
Re: Re: Re: The problem with Black Holes is
Yes, I would like a reference for it taking an infinite amount of time for a black hole to be created. I’ve never heard of that.
Re: Re: Re:2 The problem with Black Holes is
Time dilation. There are a number of papers and videos referencing this particular dichotomy of black holes on both sides of the argument. However, I have not seen any of the proponents give a clear rebuttal to the premise that black holes cannot form in our universe.
The “reference anyone” was for the “Simple, No?”, a sad attempt at humour – reference is for an ad on tv.
Re: Re: Re:3 The problem with Black Holes is
Just saying “time dilation” doesn’t explain why it would take an infinite amount of time for a black hole to form.
However, I have not seen any of the proponents give a clear rebuttal to the premise that black holes cannot form in our universe.
Can you link to a clear rebuttal to the premise that they can?
Which says?
That from our point of observation that we will never see a black hole form since it will take an infinite amount of time relative to us.
Therefore, anything that they may consider to be a black hole in the universe (including the one they purport existing at the centre of our galaxy) isn’t and is some other phenomenon. Which leads to the next question, what is actually there? What assumptions have been made that are incorrect and what alternatives can then be hypothesised?
Re: Which says?
” it will take an infinite amount of time relative to us.”
You state this as though it were fact – it is not.
Re: Re: Which says?
I state this by their own rules.
Re: Re: Re: Which says?
You state that as though there were only one theory.
Nobody truly knows (for now).
Interesting articles and comments. The problem with many of these theories is that they rely on logic. This logic is born from what we currently understand about the universe we inhabit, some of which still hasn’t been proven, some of which hasn’t even been theorized yet for that matter. For all we know, all physical laws may break down inside the event horizon of a black hole should one exist, making a logical analysis based on not only what we know, but what we think we know, and even what we perceive (or think we perceive, being fallible), entirely impossible.
Re: Nobody truly knows (for now).
The problem with many of these theories is that they rely on logic.
Actually they’re based mostly on math.
Re: Re: Nobody truly knows (for now).
Math is logic. 😉
Re: Re: Re: Nobody truly knows (for now).
They’re related of course, but I wouldn’t say math IS logic, or a subset of logic. More like logic is one tool that can be a part of mathematics.
http://en.wikipedia.org/wiki/Logic
http://en.wikipedia.org/wiki/Mathematics
Re: Re: Re:2 Nobody truly knows (for now).
Math may not be logic, but it is logical! 🙂
Hawking radiation
Black holes may not be entirely black, as some particles can escape the extreme gravitational pull as Hawking radiation.
Hawking radiation isn’t particles escaping from inside the event horizon, just to clarify. It’s when a pair of virtual particles forms, which would normally immediately annihilate each other, except that they form on opposite sides of the event horizon. One is sucked in, the other is not.
Re: Hawking radiation
Hawking radiation is about non-observable entities doing non-observable actions at a non-observable place. The problem with “virtual” particles is that they are non-observable. The are purported to exist because the mathematical model requires them to being mathematically consistent. There is no actual requirement for them to actually exist.
What the true nature of the universe from sub-atomic to super-galactic is probably even stranger than any model that has been devised by men (or women). Our models are a simplification for our use to provide a workable understanding of the natural world.
Re: Re: Hawking radiation
Hawking radiation is about non-observable entities doing non-observable actions at a non-observable place.
Hawking radiation is a prediction based on science that’s been proven reliable. It has not been confirmed, but it would be foolish to assert that it could never be.
The are purported to exist because the mathematical model requires them to being mathematically consistent. There is no actual requirement for them to actually exist.
There’s no requirement for anything to exist. But some things do.
Re: Re: Re: Hawking radiation
So, my statements still stand.
Re: Re: Re:2 Hawking radiation
So, my statements still stand.
Yes, your completely unsubstantiated statements still stand as an expression of your opinion.
Re: Re: Re:3 Hawking radiation
It just doesn’t matter…
It just doesn’t matter…
It just doesn’t matter…
Was this post about black holes inspired by the recent death of Maximilian Schell (Dr. Hans Reinhardt)?