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

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."

Comments

If you see a black hole

[Anonymous Coward]

Isn't it already too late?

Burp

[onyxruby]

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

Re:Burp

[macraig]

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

The title makes me weep for science journalism

[Ziggitz]

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

Re:The title makes me weep for science journalism

[mark-t]

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:The title makes me weep for science journalism

[dan_in_dublin]

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 increases correspondingly, the electroncs go to higher orbits around the atom and they drop back to lower orbits by releasing photons. so maybe they can measure the temperature of the atom at the point where the electron was released by looking at the wavelength / other properties of the photon ? wasnt the temperature of the big bang measured via the universal background radiation which is the photons released by the matter in the universe about 300,000 years after the big bang (the point at which temperatures had cooled sufficiently for electrons to get into stable orbits around atoms ?

Re:The title makes me weep for science journalism

[amRadioHed]

At that temperature the scale is fairly irrelevant. It's less than an order of magnitude difference either way.

Re:The title makes me weep for science journalism

[Chris Burke]

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 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 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.

Re:The title makes me weep for science journalism

[dido]

It's clearly a reference to Wien's displacement law. 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.

Re:The title makes me weep for science journalism

[Chris Burke]

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.

I hate this

[PopeRatzo]

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.

Re:How does something escape a black hole?

[geekoid]

Hawking radiation escapes.

Hundred-Million Degrees?

[The_Rook]

is that Fahrenheit or Celsius?

Re:Upper Limit

[Neil Boekend]

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 at 4 trillion degrees C. What it is at even hotter temperatures is unknown to me (and a quick Google/wikipedia).