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Slowly Pulling Facts from Black Holes
lee1 writes "Astronomers have proven the existence of the event horizon, the 'point of no return' that surrounds black holes. An MIT and Harvard team said they showed its existence by looking for X-ray bursts from neutron stars and more compact objects thought to be black holes." Relatedly beuges writes "IOL is reporting that by tracking the death spiral of cosmic gas at the center of a galaxy called NGC1097, scientists figured that material moving at 177 000km an hour would still take eons to cross into a black hole. 'It would take 200 000 years for gas to travel the last leg of its one-way journey,' Kambiz Fathi of Rochester Institute of Technology told reporters at a meeting of the American Astronomical Society."
Not another story about SCO...
So even if God does answer my prayers and my boss gets sucked into a black hole, it'll take forever.
Someone save me from this sanity.
Actually, I don't understand it at all. Why would the matter spiral in. Why won't it stay in orbit? What is slowing the matter down to make the orbit decay?
Oh well, what the hell...
I wouldn't be too sure about that. For centuries man thought it impossible to prove the existence of atoms, things so small one could never discern them not even with the best of microscopes. Right now we know about the existance of even smaller things in our universe...
So what makes you think that we'll never be able to prove the existence of places we could never visit in physical form, not even in the strongest and most powerful of spaceships? ;)
Install windows on my workstation? You crazy? Got any idea how much I paid for the damn thing?
177000 Km/hr... or 49166.67 m/s... why is there no metric second?
You can't orbit a black hole inside the event horizon without going faster than the speed of light.
Pardon, hour-ish metric units of time. Here comes the onslaught of nanosecond wisecracks...
And also without direct observation of the poster by the scientists in question, since they already presented their poster the day before yesterday at the poster session at AAS. When I first read in TFA that they'd be presenting their results at the AAS Winter Meeting , I thought it might be cool to see the talk or poster, but alas, it already happened.
Although I'm actually a condensed-matter physicist, as per the other posts on the phase-transitions thread I just typed up. But my girlfriend will be at AAS, so that's always a good excuse to anonymously crash the festivities :-)
make world, not war
Stephen Hawking's recent concession that black holes do not irretrievably eradicate information after all has garnered much attention. In my opinion, it is refreshing to see the public focused, if just for a moment, on an important conundrum that has fascinated theoretical physicists for three decades, and prompted much conceptual progress. The scientific issues, however, remain much less settled than Dr. Hawking's celebrated wager on the question. He most recently pronounced: "If you jump into a black hole, your mass energy will be returned to our universe, but in a mangled form, which contains information about what you were like but in an unrecognizable state." These ideas are profound and will have a lasting effect on our scientific theories as well as life as we know it.
310316400000000 km is the last leg of the journey?
FYI, that's 2,074,335.22 Astronomical Units, or 32.8 Lightyears, or about the distance from Sol to the Cepheids. Dang.
Too bad they don't specify how far out (radially) from the event horizon the last leg starts. Or even loosely define what 'last leg' means in this case.
"Trolls they were, but filled with the evil will of their master: a fell race..." -- J.R.R. Tolkien on Olog-hai
What makes you think it is in orbit in the first place?
It's just basic gravity. Things fall down. Even gas. Just look at Earth.
In fact, circular motion around a black hole would require v>c if the radius of the orbit is less than 1.5 R, where R is the black hole radius, and such motion is unstable at distances below 3.0 R.
And, of course, don't forget that an object travelling around the black hole emits gravitation waves and loses energy (but that applies to our Solar system too).
So, if there is a "googling" action, also is there a wikipedin action? :)
The Wikipedia entry about Event Horizon has an interesting "faq" about, orbitig the event horizon and sticking you hand into the event...
Also the wikipedia companion, talks about Stephen Hawking saying that no "event horizon" can be formed at a black hole... This article needs edition...
Good reading before a good sleep...
Btw, there is a neat animation about a neutron star X-ray burst
enough of karma whoring...
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Pulling facts out of black holes?
I don't see what the big deal is. The marketing department of (insert company name here) seems to do this all the time.
~The Anadromous Cowherd
Wait...I'm confused. Is this another John Dvorak article, or what?
You'd be messing with the Phantom Zone, and we'd perish under the rule of the great General Zod!
Task Mangler
...if you pull the facts out quickly.
Sheesh, evil *and* a jerk. -- Jade
The article isn't very clear on why matter traveling rapidly toward a black hole would still take a long time to fall in. I assume they are refering to the gravitational time dilation effect. For someone looking from far away, clocks near the black hole appear to run slower, and in fact to stop at the event horizon. Conversely, someone falling into the black hole (ignoring for the moment that he would in fact be ripped apart by tidal forces) would see the entire history of the universe played out above himself as he fell in.
This is a bit off topic, so my karmas' probably going to take a hit for saying this..
But what I don't understand is how anyone can claim that light slows down as it travels in near proximity to the even horizon.
Light is an immutable substance, that's one of lights unique property's.
For example: If you travel in a space ship towards Pluto at near the speed of light and someone travels in another ship from Pluto to earth at the same speed, and if as they travel towards one another they each flick on a powerful light, when each of them measures the speed of the light coming from the other ship they will find that although the speed of the lights transmitter is incredibly high the light itself is still travelling at "the speed of light" 186,000 miles per second. Weird, but true, the speed of light just isnt affected by anything, including gravity, or perhaps I was away that day in school.
Please correct me if I'm wrong.
There are way too many jokes to make about reaching the "point of no return" while being in a "black hole" to choose just one.
What makes you so certain Atoms really do exist?
Oh sure, we have mathematical formulas that prove that "something" does exist and we can even do some manipulation, but what if it turns out that all this stuff thats so tiny that we can't see it isnt at all what we think it is even though it does respond in predictable ways that we can understand and measure.
Its like an old programming analogy I once read, picture a man in a box who only understands english, but has a big book on Chinese. Now programmers feed the box instructions written in chinese and the man inside is able to look up words in his book, and then he is also able to write chinese replys using the book, but he doesnt actually understand the chinese language itself. The people on the outside would think he understands chinese because they send in chinese messages and get chinese replys in return.
Maybe atoms are like that as well. We poke atoms, and they respond in a predictable fasion, but since we cant actually see them how do we really know what we're poking?
Ummm wasn't Event Horizon a movie about a ship being lost in deep space, where it came back abandoned but it did not come back..........alone!!
That's a classic defense of dualism you're quoting, and the fatal flaw is only considering the programmer as an individual. If the book contains enough information to trick outsiders into thinking a chinese speaking person is inside, the book itself can be considered an individual, living of course only in the environment created by the actions of the programmer, but an individual none the less.
So, essentially, even if the atoms are only emulating on something more complex or different, we are still working with what we conceive of as atoms, simply at a lower level. The intermediate stage may be interesting or it may not, especially if it remains undetectable. For instance, assume a perfect simulation of the universe on a computer, the inhabitants of the universe are, philosophically, no less real than we are, they see the same phenomena as we do and think they live in a universe of atoms despite the fact that they're just data structures and algorithms emulating what our atoms would do.
..if someone tried to steer a spaceship into a black hole, from their perspective? Would the rest of the universe seem to freeze to them until they died of old age? Or would they actually be destroyed by some force inside the hole itself?
It's hard to resolve the event horizon of a black hole spatially in X-rays, but NASA has one or two R&D dedicated to address such issues. Note that the angular resolution required to "see" such small angular size is far better than what the HST can achieve today (although such comparison may not be so prudent).
So THAT'S what the goatse guy is doing!
"The one-way journey from the heart of a galaxy into the oblivion of a black hole probably takes about 200,000 years..."
"...scientists figured that material moving at 177 000km an hour would still take eons to cross into a black hole."
Eons are the largest division of geologic time. There have been just four of them since the formation of the Earth. In rough terms, that's a billion years each.
Maybe the reporter can get a job working on unit conversion for the next Mars probe. (*cough*)
Things that were predicted about atomic interaction were proved true much later. I assure you that scientists do not assume something is completely true without rigorous attempts at discounting its nature, and atomic theory as it is presented today is generally fully accepted worldwide. Of course, there are still things we don't understand, but we wouldn't try to slap a name on them and call it factual at the first sign. That's medieval.
Scientists don't prove anything. Ever. Please. That is not the nature of science. Every claim that 'scienctists have proven...' is simply false. Science works differently. Less likely theories are distinguished from more likely ones, and the most likely theory is typically taken as the working hypothesis of the day. This isn't nitpicking. Any paragraph that begins 'scientists have proven...' consigns itself to the bin of tabloid nonsense immediately.
hey dudes, that's alot! ... ... wormholes and stuff ... is there a .. whitehole
so, is it just like a small super duper dense dot, or
might it lead somewhere
too? "100 million times the mass of the sun." doesn't that like eh? have
a space-time weather influence on me too?
Im was not trying to suggest that scientists are guessing, obviously they do real scientific studys and check and recheck data and the results.
Maybe this example will help to clarify what I'm talking about, and this is also in reply to the parent poster who said that the programmers chinese book would have to be thought of as an individual.
Every human cell contains enough DNA information to make a complete copy of the entire human being. A cell with its DNA can be thought of as a chinese book.
Now what if every atom has atomic DNA and we just dont know it? What if there is something internal to every atom that is even smaller than electrons. This atomic DNA would be to an atom what regular DNA is to a human cell.
Perhaps this atomic DNA is even more complex than cellular DNA. Perhaps there is enough information in the Atomic DNA of a single atom to make a perfect copy of the entire universe.
Ok, pretty far out on the limb with that one, but hey, just trying to say that we really dont know and there's a chance we never will know, but meh.. uh, what was my point again?
Please, it's km/h
not Km/Hr
not kph
not Km/H
not anything else...
Please get it right, it's not *that* hard!
Nope. You are confusing black holes with black bodies. A "black body" is an object which reflects no light, but it emits its own radiation. A "black hole" is an object which emits no radiation at all.
A black body emits radiation unless its temperature is absolute zero. It need not be black to the human eye, black bodies used in laboratories often are glowing red hot. Black bodies used in labs are usually formed by a cavity with a very small hole. The energy emitted by the hole is the black body radiation. It's simple to see why that body is black. Make a small hole in a big cardboard box and shine a flashlight on the hole. Seen from the outside, the light from the flashlight will be lost inside the big box and the hole will still be seen as black. Confusing names, yes, because a hole in a black body is not a "black hole"...
The study of black body radiation was one of the problems that started the science of quantum physics. The spectrum a black body emits does not follow the shape that classical physics predicted. The German scientist Max Planck created a theory that correctly predicted the black body spectrum by postulating that energy is not emitted in a continuous way, but in lumps which he called "quanta".
Black holes, OTOH, emit no radiation at all, no light can escape from it because its escape velocity is the speed of light. However, since no material body can accelerate all the way to the speed of light, the stuff that falls into the black hole will take forever, as seen from our external referential. Since we see that stuff going away from us at a very high speed, any radiation it emits is redshifted. But the blakc hole itself emits no radiation, it's the matter falling into it that emits radiation.
The evaporation of black holes is a different thing. In our universe, due to Heinsenberg's uncertainty principle, pairs of particles and anti-particles may be created spontaneously and recombine a very short time after. But if that happens very close to a black hole, the pair may not have time to recombine because one of the particles will be caught by the black hole. In this way, the anti-particles will be going into the black hole, slowly cancelling its mass while the particle radiates away. Given enough time, the black hole disappears completely.
I don't really understand the chinese book riddle, because anyone who learns a foreign language knows that you cannot form proper replies from a dictionary alone (you need a grammar reference, list of exceptions and current slang etc.). So it seems to depend on how you define the dictionary.
Now what if every atom has atomic DNA and we just dont know it?
I think most scientists would agree with you that this is even likely (strings vibrating at certain frequencies are thought to be electrons at one frequency and protons at another etc.).
just trying to say that we really dont know and there's a chance we never will know, but meh.. uh, what was my point again?
I think your point was that we should not say that atoms are 'proven' without also adding that their make-up is still being researched at smaller scales.
You can now take pictures of atoms with a scanning tunneling microscope.
Researchers at IBM even move individual atoms around to create artwork.
More here: http://www.almaden.ibm.com/vis/stm/corral.html
cat
Spoiler warning: If you are a Heechee then black holes make great hiding places. You could take your spaceship in and out as well as rescue your girlfriend trapped in the event horizon. -- IV
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... Uranus!
Oh wait....
Even anti-particles still have a positive mass. They cannot cancel out anything. The black hole loses mass by what is radiating away, not by what is dropping back into it.
You guys could totally go back and rescue those guys from season 1! heck, you'll even be able to wait till season 12.
The gravity around the "hole" of a black hole is so strong that NOTHING can make its way back out after a critical distance.
I believe you meant "NOTHING, except for Chuck Norris, can make its way back".
Defining Statistics and Social Research
Don't get stuck on the details, or the analogy breaks down. The book is simply an large, imaginary tome on the Chinese language, containing everything needed to translate to/from English within.
True confidence comes not from realising you are as good as your peers, but that your peers are as bad as you are.
That makes no sense. Ordinary objects radiate heat via infrared rays travelling at the speed of light, and you can certainly feel their heat. (Also, heat is not restricted to IR radiation; all forms of EM radiation transmit heat.)
Black holes emit heat due to Hawking radiation which, roughly speaking, is produced at the event horizon. (It is actually not completely possible to "localize" the source of the radiation, and you can equivalently describe it in terms of the popular particle-antiparticle pair production near the horizon, or quantum tunnelling through the horizon.)
The inside of a black hole is a vacuum, with the possible exception of the central singularity. (We don't know whether anything still exists there.) Plus of course any transient matter that may happen to be in the process of falling to the singularity, although that doesn't last long. The interior of a black hole bears no resemblance to the core of a star.
The book doesn't translate from Chinese, it just magically has the appropriate response to any inquiry. The thought experiment is actually designed to pose questions about artificial intelligence.
http://en.wikipedia.org/wiki/Chinese_room
Black Holes are just that, holes in space-time. While, to an outside observer, time appears to stop at the event horizon that doesn't mean that time stops for the person going into the black hole. All it means is at that point the object is no longer moving forward in time with the rest of us. The person/object could just as easily be moving backwards in time or broken free of time, both of which are plausible explainations if you look at the structure of space-time in an Einsteinian manner.
You are who you are, let no one tell you different. But, never close your mind to a new point of view.
The GP probably means you can't measure the temp of the black hole itself (as a balck body) like you can do for stars, because no radiation from the black hole itself would come out. At best what you measure is the black body temp of the acretion disk or hawking radiation which is NOT the BB temp of a black hole.
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Is the scientific reason that gas can take 200,000 years to be pulled in by the most gravitationally massive type of object possible in the universe.
It is for two reasons; first off, gravitational time dilation - time gets slower the closer you get. The gas is orbitting the black hole, which also adds relativistic time dilation.
The gas, in fact, probably orbits at just under escape velocity - thanks to a fun little effect called (IANAA) relativistic frame dragging - basically the black hole drags the fabric of spacetime around itself - and objects within about 1.5 radii of the event horizon start feeling the effect - effectively locking them into a particular path. One way to look at this is to say that time is swallowed by the black hole same as mass - and therefore objects in the vicinity of the black hole fall in because their time arrow points to its dark, dark heart.
This frame dragging should happen at speeds approaching the speed of light - and require comparable amounts of energy to change your frame. There's even some theory that infalling matter will follow gravitational field lines, like you get around a magnet - but I'm not sure how much I believe that...
I am disrespectful to dirt! Can you see that I am serious?!
The Hawking radiation temperature is the blackbody temperature of the black hole. For very deep reasons in the quantum field theory of curved spacetimes, horizons themselves do have a blackbody temperature, and that temperature is equal to that of the radiation (Hawking for a black hole event horizon, Unruh for a Rindler horizon) emitted from that horizon. See, for instance, chapter 4 (IIRC) of the text by Birrell and Davies.
I didn't think people pulling facts out of (their) "black holes" was anything new :)
Some scientists belive that Black Holes are infact a gateway, that bend space and time. As most /. ers know id imagine all objects with mass have an effect on the universe, black holes have so much gravity they may actually bend space time. Creating a wormhole effect. Now this cannot be proved at our current stage of technology but one day we may be able to prove this. Some scientists also belive that as energy can never be destroyed and black holes would seem to do this as they "eat things" that there must be a so called white hole, pushing stuff back into the universe, although one has never been observed.
Still after reading that link I get stuck on the first line, where he introduces a magic dictionary/program into the room that somehow outputs correctly formed replies. Such a dictionary does not exist and if it did then it really would describe the language entirely.
So as I see it, Searle invents a hypothetical program which, if it actually existed, would prove him exactly wrong! (prove that AI is possible, i.e. the program would pass the turing test). I don't get it.
I think you do get it! Turing's test is just a better way of stating the problem than the Chinese Room.
The often overlooked and very insightful aspect of Turing's test is that it doesn't just apply to "artificial" intelligence. In his formulation, by communicating with an unknown entity, you can determine by conversation whether or not it is at least as intelligent as you.
While that's an interesting test for an AI (though many AI researchers have problems with it today) it also makes a very different point: given two people, both smarter than you, you can't tell which of the two is the smartest through direct interaction! Much of the scientific method and the culture of science can be understood from this simple observation.
Socialism: a lie told by totalitarians and believed by fools.
Within a boundary of about 50 miles from the black hole center, gravity is so strong that not even light can escape its pull
:) Just food for thought...well my thought.
I found this to be the most interesting...and here I always thought if you were anywhere near (as in hundreds of thousands, if not millions of miles) of a black hole you would be screwed...but apparantly, it is only on the 50 mile marker that you are totally hosed...I mean with our technology we would be hosed at much farther distances...but if we ever have a chance to travel at just below the speed of light then we could get within say 75 miles of a black hole?
I mod down so you can mod up. Your welcome.
As I understand it (which is not well :), an orbit is when something falls, but keeps missing what it's falling towards, because of their different speeds/directions.
An orbit is not just things falling down, it also requires a tangential velocity within a specific range. Gas spiraling into a black hole does have a tangential velocity, but it's not within the range create a orbit. In other words, yes, it was never in orbit.
Build a man a fire, he's warm for one night. Set him on fire, and he's warm for the rest of his life.
Maybe someone could answer this for me please. I'm not much into this sort of thing but now I think about it I'm curious.
If you did get stuck in a black hole (I know you can't, you'd be dead from the tidal forces), how would time seem to you? For example if time slowed down to next to nothing would you notice it had slowed or would just everything speed up around you?
Thanks for any help guys.
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The HST doesn't really do too much x-ray observations as far as I know- the Chandra telescope has amazing x-ray resolution on the other hand.
Do we "know" this, or is it simply possible that we can more easily find those black holes that emit X-rays?
"The urge to save humanity is almost always a false front for the urge to rule it."
- H. L. Mencken
The HST cannot do any X-ray observation; and my point is that the spatial resolution of an X-ray telescope must be a few order of magnitude better than that of Chandra.
i see - my bad
Same thing with Earth, if Earth was in the middle of a cloud of gas that could eat away at very large amounts of the Earth's momentum, then the Earth could spiral into the Sun. Since that gas isn't there our Earth keeps revolving around the Sun, which is good for us.
It's not the earth's energy, but rather its velocity in orbit that keeps it from free falling into the sun.
In fact, everything in orbit around earth is in free fall. The reason it does go straight towards the earth is because of its velocity in the horizontal direction which makes it fall vertically really slow.
Yes, this velocity does require a great deal of energy (aka rocket fuel) to get something in orbit, but you don't have to constantly generate it once you are up there.
Gas and various other objects would affect the earths velocity so it would crash into the sun sooner, but as all things in the orbit, the Earth is on a death spiral towards the sun as we speak.
But don't worry, it will be a couple thousand million years and by then the sun will have burt off enough fuel to expand itself way past our present location so it would be a moot point regardless.
"I am the king of the Romans, and am superior to rules of grammar!"
-Sigismund, Holy Roman Emperor (1368-1437)
In a classical sense, energy = 1/2 mv^2. So orbital velocity and energy are equivalent. I think the point you're trying to make is that you don't have to do work to remain in orbit.
> Astronomers have proven the existence of the event horizon
You keep using that word. I do not think it means what you think it means.
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As falling, but missing the ground.
If the black hole is sucking gas from a neighboring star, why isn't the velocity vector of the gas stream pointing towards the center of the black hole instead of tangential to it?
No, you have to go as faster than 'c' below the 'event horizon'. The escape volocity AT the event horizon is 'c' according to current theory. Now to orbit at the event horizon requires faster speeds yet. The idea that it would take '200K years' to cross the horizon once so close is preposterous. More probably that is what the 'observer from outside the system would see as 'time dilation' is witnessed by only the outsider as events slowly catch up to what has happened long, long ago. I won't go into the math as most slashdotters seem to be of a lower brow as witnessed by all the asenine posts that I have read on serious subjects. Rest assured that vector calculus in three dimensions is involved for the simple de-orbit calcs. The other time dilation crap I will leave in the hands of the successors to Dr Heim to whom the world will one day owe a debt of gratitude for handing mankind the keys to interstellar travel and trade.
I'd imagine there being a lot of very useful stuff in those compact spheres. Is it theoretically possible to mine these things?
Getting even a small bit off is going to be very hard, of course, but if the light can escape, it should still be possible, no?
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...of the star in question.
can be produced by immense electrical stress. No need for exotic physics, or even black holes. Feed matter through a massive plasma "pinch" and see what happens.
Who would have thoughe the words Condensed Matter Physicist and Girlfriend would be used in the same post. Go Dude!
I'm afraid you aren't going to find any physicists out there arguing that GR doesn't claim that gravitational mass and inertial mass are equal. It has nothing to do with what any experiment proves. The theory is the theory.
n /works/1910s/relative/ch19.htm
Anyone claiming that General Relativity does not purport that Gravitational Mass and Inertial mass are the same, simply doesn't know the theory.
Here is a direct quote from Albert Einstein (the guy who discovered GR, and widely respected by scientists):
"The gravitational mass of a body is equal to its inertial law"
- source: Relativity: The Special And General Theory, chapter 19.
I just googled that exact phrase and found it at http://www.marxists.org/reference/archive/einstei
I wonder what Chapter 20 is called....
"The Equality of Inertial and Gravitational Mass as an argument for the General Postule of Relativity"
do you think its part of the theory?
No one has a right to their *own* opinion. They have a right to the TRUTH.