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Space Science

NASA Satellite Sees Black Hole Belching Out Hundred-Million-Degree X-rays 74

Posted by Soulskill
from the TSA-working-on-bringing-them-to-airports dept.
The Bad Astronomer writes "NASA's NuSTAR satellite, designed to detect cosmic X-rays, detected a flare of high-energy emission coming from the Milky Way galaxy's central supermassive black hole. The X-rays were the dying gasp of a small gas cloud being torn apart, heated to a hundred million degrees, and then falling into the black hole itself. Events like this are relatively uncommon, so it's fortunate NuSTAR happened to be observing the black hole when it flared."
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NASA Satellite Sees Black Hole Belching Out Hundred-Million-Degree X-rays

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  • by Anonymous Coward

    Isn't it already too late?

    • by Jeng (926980)

      Would it even be possible to see in the first place though.

      Not as in detecting that it exists, but photons are only going one way, and that is the same direction you are going.

    • by ackthpt (218170)

      Isn't it already too late?

      You'd know it was too late if your spirit was watching your body being irradiated and distorted by the intense magnetic (and other radiation) fields and gravity. You'd be rather amazed while the chap in black, with the scythe rode up on his white horse, Binky and said YOU DON'T SEE THAT EVERY DAY. FIGURATIVELY AND LITERALLY.

    • You should look for a precursor, such as glaciers melting in the dead of night.

  • Burp (Score:5, Funny)

    by onyxruby (118189) <onyxruby AT comcast DOT net> on Tuesday October 23, 2012 @05:02PM (#41745207)

    That's taking belching to a very uncivilized level. Someone ought to teach that black hole some table manners.

    • by macraig (621737)

      Or teach the table how to lighten up and just hold its breath for a moment until it passes.

  • Oh shit, the infinite improbability drive is on the fritz again.

    • by ackthpt (218170)

      Oh shit, the infinite improbability drive is on the fritz again.

      Someone just tipped the waiter a penny aboard The Bistromath.

  • by Ziggitz (2637281) on Tuesday October 23, 2012 @05:16PM (#41745367)
    X-Rays have no temperature, they are EM radiation, not matter.
    • by Synerg1y (2169962)

      Yep, sure enough: http://science.howstuffworks.com/x-ray2.htm [howstuffworks.com]

    • by mark-t (151149)
      I suppose it depends how you read the sentence, but I understood that they were talking about the gas being heated to those temperatures, and the x-rays were the accompanying emitted EM radiation as a result, not the x-rays themselves being that temperature.
    • Re: (Score:3, Interesting)

      by dan_in_dublin (833271)
      dont photons have an energy that is inversely proportional to the wavelength (shorter wavelenths = photons at higher energy).. i'm no particle physicist but something emitted the photon which is the particle by which the xrays and all em propagate.. then photons get released when electrons drop to lower energy levels in their atomic orbits.. so as the matter of the cloud compresesd in the effect of the black hole's gravitational pull, the temperature of the matter incresaes, the energy of the electrons
    • That's just the Slashdot headline, not from TFA. So, yeah, no big surprise for facepalm-inducing editing. Meanwhile, TFA gets Extra, Extra, Extra Credit for the "Click to schwarzschildenate" caption.
    • It's very common for astronomers to refer to stars by their temperature.... red stars are cold and blue stars are hot. Betelgeuse for instance is 3500k.
    • by Anonymous Coward

      It's a common, but somewhat sloppy, convention in physics to refer a collection of photons whose energies are the same as the Planck distribution for a black-body radiator of temperature T as "T-degree photons".

      Whether or not that's reasonable, whether Slashdot titles count as science journalism, whether photons count as matter, and all sorts of other minor points are certainly arguable, but the use of that phrase is hardly the fault of "science journalism".

    • by Chris Burke (6130) on Tuesday October 23, 2012 @06:25PM (#41746017) Homepage

      X-Rays have no temperature, they are EM radiation, not matter.

      I weep for whoever told you a collection of photons can't have a temperature in the same way a collection of particles can. Who was it? Was it... no one?

      Black body radiation has a characteristic temperature just like the black body that produced it, however in the case of the photon gas [wikipedia.org] it's the Plank's Law distribution of energy in photons rather than the Maxwellâ"Boltzmann distribution which describes the matter.

      If there's any sloppiness in the title at all it's specifying just the X-rays when you'd technically have to include all photon energies to get the correct temperature, just like you would include all the particles in a gas or solid. However I think it's pretty much in the noise [wolframalpha.com] as far as inaccuracy goes. Unlike your statement. Sorry.

      P.S. Such radiation has a temperature and *also entropy*, which is inversely proportional to temperature. So for example if you assume the earth is more or less in equilibrium with the sun, that means the total energy received is equal to the total energy output, but the temperature of the received radiation is much higher, meaning less energy, meaning the earth is emitting a net-positive amount of entropy. In case you've ever wondered how exactly the whole "the earth is not a closed system; it's powered by the sun" thing worked in terms of entropy.

      • by tragedy (27079)

        I weep for whoever told you a collection of photons can't have a temperature in the same way a collection of particles can. Who was it? Was it... no one?

        It's pefectly reasonable to think that collections of photons don't have a temperature. It's also perfectly reasonable to think that not everything other than hydrogen and helium is a "metal". Some other posters

        • by Chris Burke (6130)

          Sure, it's reasonable to think that, just incorrect. Happens all the time. Don't confuse unusual nomenclature with aspects of thermodynamic theory that you weren't familiar with. Don't go complaining about a perfectly correct statement because it doesn't match the high school notion of what temperature means.

          • by tragedy (27079)

            The point I was making is that the definition being used is fairly specialized to the context, just as the definition of "metal" differs from one context to another. Consider how context sensitive mathematical symbols can be. Is it a cross product or a cartesian product or a standard product? Is it a dot product or a logical and? Don't even get me started on the overloading of the greek alphabet. If someone is familiar with a term in one context, confusion is natural when they encounter it in another and it

            • by Chris Burke (6130)

              The point I was making is that the definition being used is fairly specialized to the context

              There is no context in modern science where "only matter can have temperature" is correct.

              In short, you can educate someone about the meanings of terms in context without needing to be arrogant jerk about it.

              When the someone is sincerely questioning or just confused, then I make every effort not to be. When the someone is themselves being an arrogant jerk, calling a PhD in astronomy stupid because of their own ignorance, I see no reason to be anything else.

              If the subject of this thread was "How can X-Rays have temperature?" or similar then you would have seen that reflected in my post.

              But it isn't.

              • by tragedy (27079)

                There is no context in modern science where "only matter can have temperature" is correct.

                Common definitions of temperature typically define it as a property of matter. Given those kinds of definitions being presented, believing that "only matter can have temperature" is perfectly reasonable. Referring to the temperature of electromagnetic radiation is a convention and not everyone is going to be familiar with this convention.

                Remember, not all science is physics. Well, ok, everything actually is ultimately physics, but many other sciences don't focus that way. Medical science, for example, mostl

    • X-Rays have no temperature, they are EM radiation, not matter.

      I love how people who didn't bother to RTFA get modded insightful. The summary is bad but the article clearly states that the gas creating the X-ray emissions is what is heated.

    • If the X-rays have a spectrum that looks at all like a blackbody then temperature is a reasonable way to describe them. If you have a box of material at some temperature, the inside of that box will be filled with electromagnetic radiation who's spectrum matches that temperature and it is reasonable to describe that radiation as having a temperature (even from a technical thermodynamic point if view). As a very rough guide, you get radiation with photon energies in the range of 1eV for 10,000 degrees Kelv

      • by Ziggitz (2637281)

        The energy of a photon at any given frequency is constant. That means that every gamma ray on earth is more energetic than any X-Ray in space. To describe the temperature of a photon is meaningless and gives the false impression that temperature can vary for a given fixed frequency of light. When describing EM Radiation it makes much more sense to consider the energy of the photons in eV or to describe the entire energy amount of a discharge in joules.

        The attributing of temperature of light was the aut

        • by Chris Burke (6130)

          To describe the temperature of a photon is meaningless

          To describe the temperature of a massive particle is meaningless.

          Only by having a collection of particles (whether massive or not) that follow a particular statistical distribution can temperature be meaningfully talked about. Those distributions are different for different types of collections of particles. The one that describes ideal gasses is not the only one.

          and gives the false impression that temperature can vary for a given fixed frequency of light

          I suppose if you assume that X-ray is a single fixed frequency and that they were talking about single photons, but that would be as silly as th

    • by dido (9125)

      It's clearly a reference to Wien's displacement law [wikipedia.org]. At 100 million kelvins, the peak blackbody emission frequency by the Wien displacement law would be somewhere in the region of 6e18 Hz (0.05 nm), which is well into the hard X ray region, almost energetic enough to be called low-energy gamma rays.

    • Hows the view from mount stupid? [smbc-comics.com]

      Others have explained the physics, but yes, talking about the temperature of an EM emission is perfectly acceptable, even common, in physics. You could nitpick and say that any particular X-ray photon does not tell you the temperature of what emitted it, but in order to discuss complex matters you need a shorthand, and one of those is to say that a collection of photons has a temperature (whilst really meaning "this collection of photons is consistent with black body emissio

  • In order to be detected, something must escape a black hole. Since my understanding is that not even photons could escape a black hole, how does these X-Rays manage to do it?

    • by PaulBu (473180)

      It was emitted before, not after cloud was absorbed into the black hole...

      My favourite lines from TFA:

      So maybe saying this was a belch is a bit misleading, since you do that after you eat something. This is more like your food screaming loudly and incoherently and flailing around while you’re actually eating it. Is that better?

      Paul B.

    • by geekoid (135745)

      Hawking radiation escapes.

      • This isn't Hawking radiation.
      • Not only is TFA not talking about Hawking radiation, Hawking radiation doesn't even technically escape. Hawking radiation particles are actually formerly virtual particles that are generated just outside of the event horizon. Virtual particles are created in particle-antiparticle pairs which then instantly self-annihilate before the universe notices. But when the pair appears just outside of a black hole, sometimes one particle falls into the hole allowing the other to continue existing. This produces the i

    • by dido (9125)

      It didn't escape the black hole. These photons were generated as matter was falling into the hole and being compressed by the hole's gravity before passing beyond the event horizon. More like they were never inside the hole to begin with.

  • I hate this (Score:5, Funny)

    by PopeRatzo (965947) on Tuesday October 23, 2012 @05:42PM (#41745655) Homepage Journal

    Naturally. The Bears go to 5 and 1 and look really good to go to the playoffs and here comes a high-energy X-ray cataclysm.

    This is how it always goes for me.

  • by The_Rook (136658) on Tuesday October 23, 2012 @07:11PM (#41746367)

    is that Fahrenheit or Celsius?

  • I've always been curious, but is there an upper limit on energy density for a given space, or an upper ceiling on how hot something can get?
    • Since heat is movement, the upper limit to heat would be when the atoms are moving at C. How hot that is is a bit beyond my physics education to calculate, but matter isn't transparent at that temperature. Atoms do not exist. Neither do protons or neutrons. Everything is a quark-gluon plasma [wikipedia.org] at 4 trillion degrees C. What it is at even hotter temperatures is unknown to me (and a quick Google/wikipedia).
    • Your question is equivalent to "Is there a singularity at the beginning of the universe".

      Going back through time in conventional cosmology leads you through increasing temperature and density, until conventionally you reach a point where both are infinite - the singularity. This, however, is merely a mathematical result that fits with observations later in the universe, and our theories about gravity. We have no way of directly knowing if the universe ever was a singularity.

  • or just too much fantasy has me thinking : so this expanding universe is actually literally slowly going down the drain one galaxy at a time. The big black hole, the ultimate cosmic zipfile. Where information does not get destroyed but compressed by algorithms only the ancient ones understand. So when they finally get back to check on their experiment all they need to do is collect the data about everything that happened over time.
    yap, definitely too much fantasy there
  • Events like this are relatively uncommon, so it's fortunate NuSTAR happened to be observing the black hole when it flared.

    And when nobody is looking, nothing happens?

    -
    -99 pednatic; -999 spilleng; it's the TYPOs

One man's "magic" is another man's engineering. "Supernatural" is a null word. -- Robert Heinlein

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