How Astronomers Will Take the "Image of the Century": a Black Hole 129
An anonymous reader writes with news that scientists may be close to getting the first image of a black hole. "Researchers studying the universe are ramping up to take the image of the century — the first ever image of a supermassive black hole. While the evidence for the existence of black holes is compelling, Scientists will continue to argue the contrary until physical, observational evidence is provided. Now, a dedicated team of astrophysicists armed with a global fleet of powerful telescopes is out to change that. If they succeed, they will snap the first ever picture of the monstrously massive black hole thought to live at the center of our home galaxy, the Milky Way. This ambitious project, called the Event Horizon Telescope (EHT), is incredibly tricky, but recent advances in their research are encouraging the team to push forward, now. The reason EHT needs to be so complex is because black holes, by nature, do not emit light and are, therefore, invisible. In fact, black holes survive by gobbling up light and any other matter — nearby dust, gas, and stars — that fall into their powerful clutches. The EHT team is going to zoom in on a miniscule spot on the sky toward the center of the Milky Way where they believe to be the event horizon of a supermassive black hole weighing in at 4 million times more massive than our sun. We can still see the material, however, right before it falls into eternal darkness. The EHT team is going to try and glimpse this ring of radiation that outlines the event horizon. Experts call this outline the "shadow" of a black hole, and it's this shadow that the EHT team is ultimately after to prove the existence of black holes."
Red Dwarf question (Score:5, Funny)
Well, the thing about a Black Hole, its main distinguishing feature, is it's black. And the thing about space, your basic space colour is black. So how are you supposed to see them?
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If you read the summary there is a clue.
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If you read the title of the post you were replying to, there would be another clue! [youtube.com] About 1min in.
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They thought they detected it, but in 50 years time it could well turn out to be a bit of grit.
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I just find the claim of the "picture of the century" to be arrogant in the extreme.
We're only in the second decade of the 21st century. We don't know what will happen in the next 80-someodd years. In 1914, nobody could predict the pictures from the moon.
For example, what if there's a picture of a "first contact" 50 years from now?
Lunar Imagery (Score:2)
In 1914, nobody could predict the pictures from the moon.
Except for that guy that did [wikipedia.org] and made a film [youtube.com] about it. His images aren't really that similar to the lunar terrain that we considered safe to land on, but 1914 wasn't as backwards as you seem to think. That said, your general point stands: predicting the future is hard. Likely whether or not we have more incredible images in the future, we'll say they're more incredible anyway. Especially if funding levels were commensurate with headlines.
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The larger a black hole is, the less intense its Hawking radiation. The one in the galactic centre is too big to emit any detectable Hawking radiation.
But yes, the silhouette of the black hole should be visible. Somewhat distorted, because light passing near the black hole is bent by gravity, but you can compensate for that.
Edge on perspctive (Score:3)
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enhance!
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The black hole is not a disk. But accretion disks are disks. AKA "ring of fire".
The angle of the disk matches the rotation of the hole, and the hole should roughly match the rotation of the galaxy overall, and since we're in the galaxy, we'll thus most likely be edge on to the disk.
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This is kind of expected and a good thing. The accretion disk will still be transparent to a lot of signals of interest, but now there is the added benefit of seeing stuff from both the co-rotating and counter-rotating edge of the black hole which will help confirm and measure any rotation. If we were seeing it from some place closer to the poles, it would be much more difficult to see the rotation effects, which otherwise cause a difference in the amount of light that wraps around since it is easier for
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Wiki: A black hole of one solar mass has a temperature of only 60 nanokelvin (60 billionths of a kelvin); in fact, such a black hole would absorb far more cosmic microwave background radiation than it emits. A black hole of 4.5 × 1022 kg (about the mass of the Moon) would be in equilibrium at 2.7 kelvin, absorbing as much radiation as it emits.
Black holes are not black (Score:2, Redundant)
Actually, no, it is not black. In order to have a color, light must reflect off of the object. In a black hole, light does not escape it and therefor it has no color.
In fact, you cannot see a black hole at all. You would only know it's there because of the objects orbiting the event horizon.
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This is semantics. Some people don't think of black and/or white as colors at all. Some people define black as a total absense of light (photons), others as an amount of light below the humanly visible treshold. You seem to define black as the latter, with the addition that atleast some light must be present. In the end, whether a black hole has the color black is a matter for dictionaries, not a matter of scientific fact (unless assuming a scientific definition of what the words "color" and "black" mean).
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Some people define black as a total absense of light (photons)
This is a bad definition because it cannot happen in our Universe. All you can do is compare the "brightness" of an object against another object and define the "darker" object as being "black". But no object can be completely void of emitting photons, only less and less of them, approaching zero.
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By its strictest definition, black does not reflect any light either, and so does not qualify as a color either. We can usually see so-called black objects either because they are perhaps just a very dark grey, and are thus still reflecting some amount of light that we can detect, or else in the case of something like Vantablack [scmp.com], because of objects nearby.
Nanotube/graphene based products like this Vantablack is going to be the new hotness for the next twenty years, then for the fifty years after that it's going to make generations of lawyers very wealthy due to the occupational/environmental exposure cancer claims.
Call it the 21st century asbestos.
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Transmissive: Black is %0 color
Depends on the context. As for black holes, maybe it was an unfortunate choice of nomenclature. Should we really be discussing the 'black' part of the name?
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+1, wooshie
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Leave the lens cap on, nobody will know.
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Well, the thing about a Black Hole, its main distinguishing feature, is it's black. And the thing about space, your basic space colour is black. So how are you supposed to see them?
Actually, in theory, they are not black, but have Hawking radiation that if could be detected accurately would be of some use to us confirming theory. Then there is the radiation given off by the things falling into them. Most black holes probably aren't observable because the region around them is opaque from all the energetic things going on before matter even hits the event horizon. Then, space isn't black, there is cosmic background microwaves, distant galaxies, gas clouds, etc. A black hole will obscur
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The Hawking radiation is very very tiny, and I am pretty certain is impossible to see. Hawking radiation is inversely proportional to the black hole size.
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The Hawking radiation is very very tiny, and I am pretty certain is impossible to see. Hawking radiation is inversely proportional to the black hole size.
True, which I why I stated "detected accurately". In fact, for a super massive black hole it should be less than the background radiation from the big bang. Thus, we could expect naked black holes (not singularities) to possibly be a cold spot against the CMB.
Re: Red Dwarf question (Score:2, Funny)
It's "African Stellar Person", you racist.
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White people are born in Africa too you know. Say black when you mean black.
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Except....that a black home has a bottom. There's nothing infinite about them, except in some formulas (i.e. the _mathematical_ singularity at the center). If the black hole is big enough (around 150 billion solar masses), you could even stand more or less comfortably on its surface, normal earth-like gravity, provided the radiation doesn't kill you.
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Except....that a black home has a bottom.
I seem to remember Hawking saying something of the sort recently, but I don't recall it being decided one way or the other.
If the black hole is big enough (around 150 billion solar masses), you could even stand more or less comfortably on its surface
If you can stand comfortably, couldn't you also easily escape. What do you mean by "surface"? Do you mean the event horizon, or the surface of the hypothetical 150 billion solar mass object inside the event horizon?
You can survive crossing the event horizon of a sufficiently large black hole because the tidal forces are low, but I thought you'd need approaching infinite force to remain
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Interstellar pic ? (Score:3)
Re:Interstellar pic ? (Score:5, Informative)
ah..yes, it does apparently.
http://thefilmstage.com/news/h... [thefilmstage.com]
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My question is, will the image of the black hole suck less than the 'Event Horizon' movie?
Quasars? (Score:2)
I thought the general consensus was that there was a supermassive black hole at the centre of every galaxy although only some of these were active, thus showing up as quasars.
Don't know about this image of the century hype
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We know quasars exist and involve radiation blasted out from the fucktons of matter pouring into early-universe supermassive blackholes.
What has yet to happen is someone has yet to image the black part of the black hole. The region that's quite literally so dark that light just falls into it. (depending on how thin the accretion disk is, it might not actually be black -- but it's going to be a hell of a lot less energetic than the regions near the disc/equator!).
It's already been proven. (Score:5, Informative)
> the EHT team is ultimately after to prove the existence of black holes."
It's already been proven. There is a black hole at the center of the Milky Way galaxy, and it's been named "Sagitarius A"
Using infrared telesopes, you can "see" stars orbiting the black hole at the center of the galaxy. Orbits of about 28 stars have been observed and using math, the mass of the stars and the required mass of the black hole has been calculated. Only a black hole can account for the kinds of orbits you see those stars doing.
It is a sight to behold and at first I could not believe it. Watching the stars at the frickin center of the galaxy orbit a black hole is a stunning sight once you truly grok what you are seeing.
https://www.youtube.com/watch?... [youtube.com]
Realize that this video is not an artist's intepretation, but is actual imagery of stars orbiting something of immense mass, something which can only be a black hole.
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The stars are in the range of 900 to 3300 AU and period of 11 to 93 years. They are moving at a fair clip
Re:It's already been proven. (Score:5, Informative)
Correction: It's called "Sagittarius A*" And NASA does not qualify it using terms such as "might be a black hole" or "theorised to be a black hole." They simply call it a "supermassive black hole"
http://www.nasa.gov/mission_pa... [nasa.gov]
Has it been proven? (Score:1)
Stars at the outer edge of the galaxy take the same amount of time to rotate around the galaxy as the inner stars. How can you calculate the mass of the center in this case? If you pick a closer star you will end up with a smaller mass than if you pick an outer star using the same equations.
Not sure that is proof at all, and from what I remember they recently came up with some new theory that said black holes can't exist (not that this new theory is any better). So I'm not sure there is proof they exist
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Yeah... a new theory where instead of going through a thorough peer review process first, the person who came up with it simply had a press release about it, giving the theory loads of disproportionate publicity over time-tested theories that explain what we observe far more readily.
In actuality, that recently announced theory that bla
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Unless those stars are orbiting outside the galactic plane, then I don't believe that is "actual imagery". Maybe it's a representation (based on the data) of what it would look like if you could hover above the galactic plane and look down at the black hole.
This is why this project seems strange to me. Why image our own galactic center? There's roughly 25,000 light years of dust and stars to see through. Why not image the center of a galaxy that's plane is perpendicular to us?
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> There's roughly 25,000 light years of dust and stars to see through.
You're right... it would be impossible to view those stars using the optical spectrum. However, the scientists in this case, and for the multi-year time-lapse loop I linked to used radio waves which were unaffected by dust. One might think that interposing stars would block out the view (after all, the view is sideways through the "platter" of the galaxy) but given the far separation of the stars, the view is not blocked even at such
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> Why not image the center of a galaxy that's plane is perpendicular to us?
Another factor: on that video I linked, the scale on those images is 10 light days. I don't think modern astronomy can resolve individual stars on that fine a scale, which would be required to produce the same effect while viewing another galaxy.
That's another thing that makes that image amazing to me... how close those stars are. 10 light days is nothing, cosmically speaking.
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https://www.youtube.com/watch?... [youtube.com]
Realize that this video is not an artist's intepretation, but is actual imagery of stars orbiting something of immense mass, something which can only be a black hole.
Do you know the time scale of this video? Are these stars orbiting in hours, days, years?
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Years. That is a time lapse loop, and the current year is in the upper left corner.
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Saying that radio images translated so we can view them in at a freqency visible to us are not "real" is like saying images produced using night vision goggles are not real.
The waves involved in this issue are not part of the observable spectrum for humans. Converting them to visible frequencies for our observation does not make them any less "real" except to the pedantic or to those of us who go as far as to say that observable science can't prove anything.
How can it prove it when (Score:5, Insightful)
That's nitpicking (Score:5, Insightful)
The surface will get very close to the apparent horizon very quickly though, and after that it will be so redshifted that it looks just like one of the idealized black hole solutions, and will be indistinguishable from one to any observer. It will be just as black, just as compact and just attractive, and still deserves to be called a black hole. When people say "black hole" they don't necessarily mean "Schwartzchild black hole" or "Kerr black hole".
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I'm glad this long-overlooked idea is finally being remembered. It does lead to two further conclusions of course: how can these frozen collapsing stars have spin? And how can they have magnetic fields or (detectable) electric charge?
It doesn't seem they could have either, so all the physics done on rotating and/or charged/magnetic black holes with real singularities seems to be making the rather large assumption that there are any that were formed at the birth of the universe. They can't form now so quite
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Re:How can it prove it when (Score:4, Informative)
In general your model is broken because you're not considering the metric [wikipedia.org]. The most important effect you are neglecting in this case is the time-time component of the metric, which indicates how quickly stationary local clocks tick compared to coordinate time (there is also the radius-radius component which tells you that the event horizon is much further away than you would naively think, but we'll ignore that here). It looks like this for the metric outside a nonrotating, uncharged, massive body: 1-R/r, where R is the Schwartzchild radius of that source, and r is a radial coordinate. At large distances this factor approaches 1, so coordinate time moves at the same speed as the time of a far-away observer, such as us here on earth. But as r approaches R, the factor goes to 0. So time close to the horizon moves ever more slowly as one gets closer to it, according to our far-away reference frame. That is why crossing the horizon takes an infinite amount of (our) time.
However, the frequency and intensity of light is multiplied by the same factor, and very quickly becomes almost zero. So you would not see the object hanging there forever. You would see it quickly fade to blackness, leaving an incredibly faint and ever fainter afterimage in far radio wavelengths.
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If I understand correctly, higher gravity makes time pass more slowly
Correct. Or to be more general, time passes more slowly deep down in a gravitational well
so a clock in lower gravity will register more time from its perspective than the clock in higher gravity.
Yes. Every time a clock on earth ticks 1 time a (stationary) clock near a black hole will tick 1-R/r times. For example, a clock at a distance r=10/9*R will only tick 0.1 times every time a clock on earch ticks 1 time. The same applies to all other physical processes, not just clocks. So a person on Earch could wave their arms 10 times every time a person that close to the blck hole could wave them once. Or a person on
Save the trouble and our tax dollars (Score:2)
https://www.google.com/search?site=&tbm=isch&source=hp&biw=1440&bih=811&q=black+hole&oq=black+hole&gs_l=img.3..0l10.1410.3802.0.4788.10.9.0.1.1.0.267.1084.0j2j3.5.0.msedr...0...1ac.1.58.img..4.6.1087.Tj8XnhV53ww
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Yes, fuck yeah. Science is a waste of money, build more churches.
How so? (Score:3)
What about this story makes you think Hawking radiation doesn't exist? We can't be completely sure it exists because we don't have any observations of it, but there are compelling theoretical reasons to believe it should exist. But for non-tiny black holes, it is extremely faint, so faint that we have no hope of observing it. For example, the supermassive black hole in the center of the milky way would be expected to radiate 3.6e-48 W [dyndns.org]. That's 1 with 50 zeros behind it times weaker than a light bulb!
Re:I thought that black holes don't exist?!?? (Score:5, Interesting)
It would be nice if science reported were color coded or something. Green for robust, independently verified and generally accepted stuff (general relativity, evolution, etc.), yellow for new stuff that's not yet independently verified but in line with well-tested models, and red for stuff that's exciting but very uncertain and/or likely to be wrong (faster-than-light neutrinos, string theory, dark matter annihilation observations in galaxies, etc). The sort of stuff you read about in the news is usually red or yellow, but is presented as if it were green. The article you quote falls squarely into the red category.
Business Insider? (Score:5, Informative)
I work on this project... (Score:5, Informative)
I have some questions (Score:2)
When will observations start? How long will they last? When can we expect to see results on arXiv? How well will the fourier plane be covered (will you still need telescopes in the middle of nowhere to join/be built)? What will the spatial and temporal resolution be? Are there any important astrophysical foregrounds that could mess things up (blurring by plasma sheaths is something I think I've heard mentioned)? How are they handled? Did you know from the beginning that ALMA would join? Can you expect any o
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Observations are typically done in March/April. This gives good weather at the many sites involved. The typical
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The two EHT telescopes that I work on are in Arizona, although I build some of the hardware that's being taken to the South Pole Telescope. It's getting improved to be a part of the EHT. One of the Arizona telescopes is a prototpye ALMA antenna that we just moved here from New Mexico last year, and got working a month ago.
That's intereting. I didn't know that the EHT worked at SPT-relevant frequencies. I work on data analyis for the Atacama Cosmology Telescope, a very similar telescope to SPT, and a neighbor of ALMA. So I've seen the ALMA telescopes up close several times.
Observations are typically done in March/April. This gives good weather at the many sites involved.
Isn't the weather often bad at the ALMA site in that period? In ACT we've used that period for maintenance.
The typical run is a week, and they try to get several 10-minute recordings during that time period. The data is recorded at 1 Gbyte/sec onto banks of hard drives, then shipped by FedEx to MIT for correlation. (I don't know if a FedEx truck makes it to the South Pole every day.)
That's a lot of hard drives! Is that the aggregate data rate for all the telescopes, or just for SPT?
Except, it's a Wormhole (Score:2)
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That's a fascinating article, but you won't find many astrophysicists who would bet on it being correct (this probably includes the authors). Traversable wormholes are unstable without large amounts of negative mass, and we have no reason to believe that such exotic matter even exists. And if one is willing to assume that these wormholes have been there since the beginning of the universe in order to explain the presence of compact massive bodies in the center of every galaxy, then you might as well assume
Wait.... (Score:3)
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It is possible quantum mechanics prevents formation of a black hole, instead there could be a form of degenerate or exotic matter. We don't have a useable theory of quantum gravitation yet to know what happens when the realms of GR and QM overlap
Ob. Event Horizon Quote+ (Score:2)
I created the Event Horizon to reach the stars, but she's gone much, much farther than that. She tore a hole in our universe, a gateway to another dimension. A dimension of pure chaos. Pure... evil. When she crossed over, she was just a telescope. But when she came back... she was alive! Look at her, Miller. Isn't she beautiful?
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Ads? What are you about?
If you can see ads on the Internet, you're doing it wrong.