Physicists produce black hole plasma in the lab

Nov 04, 2010
Exotic structure: There is a lot of turbulence in the vicinity of a black hole. What exactly is happening there? Image: NASA/Dana Berry, SkyWorks Digital

(PhysOrg.com) -- Black holes are voracious: They devour large amounts of matter from gas clouds or stars in their neighbourhood. As the incoming "food" spirals faster and faster into the abyss, it becomes denser and denser, and heats up to temperatures of many millions of degrees Celsius. Before the matter finally disappears, it emits extraordinarily intense X-rays into space. This "last cry" originates from iron, one of the elements contained in this matter. Researchers at the Max Planck Institute for Nuclear Physics in Heidelberg have collaborated with colleagues at the Helmholtz Zentrum Berlin and used the BESSY II synchrotron X-ray source to investigate what happens in this process.

In order to understand the nature of black holes, it is best to watch them feeding. The most interesting part is just before the matter disappears behind the event horizon - that is, the distance at which the mass attraction of the black hole becomes so strong that not even light can escape. This turbulent process generates X-rays, which in turn excite various in the cloud of matter to emit X-rays themselves with characteristic lines ("colours"). An analysis of the lines provides information on the density, velocity and composition of the plasmas near the event horizon.

During this process iron plays an important role. Although it is not as abundant in the universe as lighter elements - mainly hydrogen and helium - it is much better at absorbing and reemitting X-rays. The emitted thereby also have a higher energy, respectively a shorter wavelength (a different "colour"), than that of the lighter atoms.

They therefore leave behind clear fingerprints in the rainbow of the dispersed radiation: in the spectrum they reveal themselves as strong lines. The so-called K-alpha line of iron is the final visible spectral signature of matter, its "last cry", before it disappears behind the of a black hole, never to be seen again.

The X-rays emitted are also absorbed as they pass through the medium surrounding the black hole at larger distances. And here iron again leaves behind clear fingerprints in the spectra. The radiation ionises the atoms several times and so-called photoionisation typically strips away more than half of the 26 electrons which the iron atoms usually contain. This produces ions with positive charge states that correspond to the number of stripped electrons. The end result is highly charged ions produced not by collisions but by radiation.

It is precisely this process, the stripping of further electrons from highly charged ions by incident X-rays, which researchers at the Max Planck Institute for have reproduced in the laboratory in collaboration with colleagues at BESSY II - the Berlin synchrotron X-ray source. The heart of the experiment was the EBIT electron beam ion trap designed at the Max-Planck institute. Inside the trap, iron atoms were heated up with the aid of an intense electron beam as they would be deep inside the sun or, as in this case, in the vicinity of a black hole.

Under such conditions, iron exists, for example, as the Fe14+ ion, ionised fourteen times as it were. The experiment proceeds as follows: A cloud of these ions, only a few centimetres long and thin as a hair, is kept suspended in an ultra-high vacuum with the help of magnetic and electric fields. X-rays from the synchrotron then impact on this cloud; the photon energy of the is selected by a "monochromator" with extreme precision and directed onto the ions as a thin, focused beam.

The researchers use EBIT, the electron beam ion trap, to reconstruct processes in the laboratory as they occur in the matter around black holes. Image: MPI for Nuclear Physics

The spectral lines measured in this experiment can be directly and easily compared with the most recent observations made by X-ray observatories, like Chandra and XMM-Newton. It turns out that most of the theoretical calculation methods used do not predict the line positions accurately enough. This is a big problem for the astrophysicists, because without accurate knowledge of the wavelengths there is no accurate determination of the so-called Doppler effect of these lines.

The Doppler effect describes the change in frequency (energy or wavelength) of the emitted light as a function of the velocity of the source (the ions in the plasma.). Anyone who listens to the siren of a passing ambulance experiences this phenomenon: as long as the vehicle approaches, the perceived pitch of the sound is higher; as it moves away, it is lower. If the frequency in the system at rest is known (ambulance is stationary), measuring the pitch makes it possible to determine the velocity of the source - in astronomy this is the plasma.

This left the scientists puzzled over the interpretation of NGC 3783, one of the active galactic nuclei which have been under investigation for the longest time. The error bars in the frequency in a rest frame calculated with the aid of different theoretical models led to such large uncertainties in the derived velocity of the emitting plasma that reliable statements on the flows were no longer possible.

The laboratory measurements of the Heidelberg-based Max-Planck researchers have now identified one theoretical method among several model calculations that provides the most accurate predictions. They also achieved the highest spectral resolution to date in this wavelength range. It had previously not been possible to experimentally check the different theories in this energy range with such high accuracy.

The novel combination of a trap for highly charged ions and bright radiation sources thus represents an important step and a new approach for understanding the physics in the plasmas around or active galactic nuclei. The researchers expect the combination of EBIT spectroscopy and brighter and brighter X-ray sources of the third (PETRA III at DESY) and fourth generation (free-electron laser XFEL, Hamburg/Germany; LCLS, Stanford, USA; SCSS, Tsukuba, Japan) to bring fresh drive to this field.

Explore further: Timely arrival of Pharao space clock

More information: Physical Review Letters, Vol. 105, p. 183001, October 29, 2010. The article in Physical Review Letters - link.aps.org/doi/10.1103/PhysRevLett.105.183001

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User comments : 39

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tkjtkj
1 / 5 (3) Nov 04, 2010
I still can't understand why x-rays are allowed to escape.

Are not x-rays affected by enormous gravitational forces?

ThatOneGuy
5 / 5 (12) Nov 04, 2010
I still can't understand why x-rays are allowed to escape.

Are not x-rays affected by enormous gravitational forces?



The X-Rays are coming from outside the event horizon. Outside the event horizon, anything with enough velocity can escape a black hole. These signatures are from just outside that radius.
Pyle
5 / 5 (9) Nov 04, 2010
The x-rays don't "escape". They are a result of matter falling into the black hole. They are emitted outside the event horizon.

http://en.wikiped...f_matter

I must say the headline is more than a little misleading. No planets teeming with life were harmed during the reported experiment.
Parsec
5 / 5 (9) Nov 04, 2010
I still can't understand why x-rays are allowed to escape.

Are not x-rays affected by enormous gravitational forces?


As ThatOneGuy points out, the x-rays are coming from outside the event horizon. One the important pieces of information conveyed by these x-rays is the intensity of the gravity effects that they encounter. This allows calculations involving their location relative to the event horizon among other things.
Slotin
1 / 5 (12) Nov 04, 2010
The X-Rays are coming from outside the event horizon. Outside the event horizon, anything with enough velocity can escape a black hole. These signatures are from just outside that radius.
In my assumption the black hole jets are analogy of gravitational brightening, which can be observed at the case of giant rotating stars and they're really formed inside of black hole with matter, which is evaporating from collapsar, not from outside of it. The fast rotation makes event horizon transparent for light of shorter wavelengths and lightweight particles like the neutrinos in these places. Such singularity has a shape of torus - so there is actually a hole inside of black hole, which makes black hole partially "white" or "naked singularity".

I hope, I didn't confuse this subject a lot...
Sanescience
5 / 5 (1) Nov 05, 2010
I wonder if the energies and "pressure" in the accretion disk become high enough for fusion and the production of iron.
tkjtkj
1 / 5 (3) Nov 05, 2010
Thanks , guys and girls .. So, the x-rays are not from the BH itself ..
But anyone examining the photo..the 'artist's rendition' should conclude that the artist needs some input! It seems clear there that the x-rays are emanating from the core of the BH itself ... axial, they are. .. clearly ..
but clearly wrong?
Ravenrant
5 / 5 (4) Nov 05, 2010
The black hole itself is small, any artists rendition will show the jets as if they are coming from it because the black hole is relatively microscopic in comparison. The jets are measured in light years, the black hole is measured in miles.
mysticshakra
1.3 / 5 (15) Nov 05, 2010
You can't start a sentence with the words "blacks holes are" when they haven't been shown to exist in the first place and likely don't exist at all. That a theory says they should or must says nothing about the reality of the matter.

The only things we do know is that x rays are being emitted from the galactic core and that gravitational models of astromechanics are completely inadequate to explain our observations. Beyond that its all just speculation and steering of public opinion in favor of theories that require ad hoc miracles to make them work.

If your theory doesn't fit the observational data, scrap it and start over. A good theory doesn't require willful suspension itf disbelief or and endless of array of counterintuitive and implausible band-aids to fix it.
Skeptic_Heretic
4.2 / 5 (11) Nov 05, 2010
You can't start a sentence with the words "blacks holes are" when they haven't been shown to exist in the first place and likely don't exist at all. That a theory says they should or must says nothing about the reality of the matter.
Sorry, Black holes exist, we've observed them indirectly in over the next decade we may actually observe them directly if the radio telescope project works.
mysticshakra
1.6 / 5 (18) Nov 05, 2010
Observed them indirectly is exactly the.kind of faulty reasoning and lack of proof to which I refer. The observations being made could have a variety of different interpretations. While this one is still the flavor.of the day it probably wont be once physicists start being honest again and restore evidence to its proper place at the top and remote theory to where it.belongs. theories are cute, but observations are king.
tkjtkj
3.9 / 5 (12) Nov 05, 2010
Observed them indirectly is exactly the.kind of faulty reasoning and lack of proof to which I refer. The observations being made could have a variety of different interpretations. While this one is still the flavor.of the day it probably wont be once physicists start being honest again and restore evidence to its proper place at the top and remote theory to where it.belongs. theories are cute, but observations are king.


you are actually stating that you require an unobservable object to be observed, it order to prove its (unobservable) existence??

You must be joking ... right??
TELL me you're joking ... maybe a teeenyweeenie joke?? a grab for a chuckle??

You do get a smirk, but not for the reason you might assume ..

or am i not smirking?? apparently i cant, unless it's right in front of you..

Yes, 'evidence' is a king, with logic as its partner.

genastropsychicallst
1 / 5 (12) Nov 06, 2010
Around ´a´ black hole is NO as through light, shortest answer of Hawkings his thinking. Through a ´as´ is her longest YES on Einsteins dark false question, as unknowing.
genastropsychicallst
1 / 5 (12) Nov 06, 2010
Mean, Einstein wanted to geth further then anybody else. Hawkings want to get closer then himself.
Blakut
5 / 5 (8) Nov 06, 2010
Hey misticshaka, have you ever observed an electron directly? I mean, shine some light on it and see where it is?...

I sure haven't observed you directly either.
Shootist
1 / 5 (3) Nov 06, 2010
All of this, and no one wonders, or else they take the observations for granted?

time should be extremely contracted close in to the event horizon. to an outside observer, time should appear, to stop at this limit.

why isn't the light emitted by the in-falling matter not significantly red-shifted?
fmfbrestel
1 / 5 (1) Nov 06, 2010
I wonder, is it possible for a toroidal black hole to have a diameter so large such that it's event horizon would also be toroidal? Anyone with the requisite knowledge want to answer that for me? Thanks.
fmfbrestel
1 / 5 (1) Nov 06, 2010
I mean, some of these galactic core black holes should be absolutely gargantuan. Maybe hawking radiation comes from matter stuck in the center of a toroidal event horizon?

Wild speculation from these two posts, but if someone could offer an informed opinion them, I would appreciate it.
ekim
not rated yet Nov 07, 2010
My question concerning black holes is ,why is a singularity needed? Hawking shows that all matter falling in eventually becomes energy in the form of Hawking radiation. Due to the time dilation at the Swartzchild radius this conversion could seem instantaneous to a particle falling into the hole. However an observer at a distance might perceive this conversion as taking much longer depending on the mass of the hole. Also the uncertainty present at the radius would lead to the particle existing as both energy and matter. The mass of the particle could contribute to the hole without needing it to be forced into an infinite dense singularity. I would like to know if this sounds plausible.
tkjtkj
5 / 5 (1) Nov 07, 2010
Ekim says: "...Also the uncertainty present at the radius would lead to the particle existing as both energy and matter.."


I don't see where Heisenberg's Uncertainty Principle has anything to do with being 'uncertain' about whether or not a thing is energy or matter or both ...
The principle is about the uncertainty in knowing all features of a particle at a given instant .. its momentum and its position .. One can not know both at the same time. Unless, of course, some accepted theory mod exists of which I am not aware ..
ekim
1 / 5 (1) Nov 07, 2010
I don't see where Heisenberg's Uncertainty Principle has anything to do with being 'uncertain' about whether or not a thing is energy or matter or both ...

I'm thinking the uncertainty of the position of the particle near the radius. If the particle is past the radius it contributes to mass and size of the radius ,however if it doesn't pass the radius stays. So the radius also becomes uncertain on atomic scales. This fuzzy radius blurs the transition of the particle from being matter (and having mass) to becoming radiation (not having mass) and escaping the gravity of the hole.
fmfbrestel
not rated yet Nov 07, 2010
The uncertainty would lie in how we can observe the particle not in where the particle actually is. The particle has a very definite momentum and position at all times.
ekim
1 / 5 (2) Nov 07, 2010
The uncertainty would lie in how we can observe the particle not in where the particle actually is. The particle has a very definite momentum and position at all times.

Yet even the hole can't measure both. If it could we could also measure both. That's the uncertainty. Either the position (mass) is known or the momentum (energy)is known. A mass measurement places the particle past the radius by adding to the mass of the hole. A momentum measurement causes the radius to shrink because the particle is not contributing mass to the hole. If it were contributing mass ,the hole would know and the uncertainty would be violated.(I know black holes aren't aware.)
fmfbrestel
5 / 5 (1) Nov 07, 2010
Yet even the hole can't measure both. If it could we could also measure both. That's the uncertainty. Either the position (mass) is known or the momentum (energy)is known.


No, the hole is not measuring anything. The reason there is uncertainty in measurements is due to the effect the measuring stick has on the particle. But because there is no such thing as a quantum of gravity, the particle is constantly adding to the local gravity field regardless of its position. There is absolutely no uncertainty being violated. The black hole doesn't need to measure the particle, and it doesn't need to know anything about the particle.

Besides, the uncertainty principle says you cant know momentum and position PERFECTLY at the same time. We are talking VERY small scales before the uncertainty principle would affect the reliability of measurements.
fmfbrestel
1 / 5 (1) Nov 07, 2010
But seriously people, can anyone tell me if it is hypothetically possible for an event horizon to be toroidal given a large toroidal black hole? It would obviously need to be supper massive to be large enough, but im talking galactic core black holes here.
tkjtkj
5 / 5 (1) Nov 07, 2010
But seriously people, can anyone tell me if it is hypothetically possible for an event horizon to be toroidal given a large toroidal black hole? It would obviously need to be supper massive to be large enough, but im talking galactic core black holes here.

It might be any thing you imagine it to be, and have the cahungas to propose, with an explanation as to your logic.
Can 'anything be' ? i think that's been answered with a resounding 'yes'.
But we still require reasoned evidence if our feeble minds have any chance at all of understanding these unimaginable concepts.
daywalk3r
3.3 / 5 (16) Nov 07, 2010
But seriously people, can anyone tell me if it is hypothetically possible for an event horizon to be toroidal given a large toroidal black hole? It would obviously need to be supper massive to be large enough, but im talking galactic core black holes here.
If the BH is considered as being a singularity (independent on the frame of refference), then NO.

But if the BH is treated as mass with density just "approaching" infinity, then it would be actually (theoreticaly) possible - given the rotation speed of the BH (relative to its mass) is high enough to affect its shape / density distribution, up until the density in the middle is low enough to cause a "hole" in the center of the (normally very close to spherical) horizon, essentially resembling it to be of a torus/ring shape.

But given the density and horizon diameter of a SMB, it would possibly require rotational speeds approaching infinity for such a severe deformation of the horizon to actually happen..
fmfbrestel
not rated yet Nov 08, 2010
But given the density and horizon diameter of a SMB, it would possibly require rotational speeds approaching infinity for such a severe deformation of the horizon to actually happen..


Yeah, that was what i was afraid someone would say. Makes sense. Thanks.
Sanescience
4 / 5 (4) Nov 08, 2010
I understand where doubters of BH comes from, and perhaps two features of a BH should be separated. The idea of an event horizon and the state of matter/energy/space creating the event horizon.

Observations of objects circling the galactic center allow us to calculate that there is "something" there creating a gravity well strong enough to be an event horizon.

As to the structure question, our models fail us and we should keep an open mind that the "singularity" indicated by the failed models is probably a lack of understanding that would let us describe what it actually is.

It is too bad the term "gravistar" never caught on, as BH turn out to be anything but "black".
ekim
not rated yet Nov 08, 2010
fmfbrestel
The theoretical Higgs particle is thought to be the mediator of mass. An Anti-Higgs particle source could in theory prop up the gravity well of a black hole. If you find a source of Anti-Higgs let me know ,I need some for the flux capacitor of the DeLorean.
Ravenrant
not rated yet Nov 09, 2010
The black hole itself is small, any artists rendition will show the jets as if they are coming from it because the black hole is relatively microscopic in comparison. The jets are measured in light years, the black hole is measured in miles.


We can see these monstrous jets of energy coming from a relative point source and there is nothing there at the source, you think magic is a more likely explanation? If black holes don't exist an even more strange explanation is required.

Also, like infinity, don't expect singularities to actually exist. Just because we can come up with concepts like infinity and a dimensionless point doesn't mean they exist in nature. And probably don't.
MIDASAW
not rated yet Nov 09, 2010
Strange!!Even today, there is no satisfactory theory for what happens at and beyond the singularity>
MIDASAW
1 / 5 (1) Nov 09, 2010
We theorise that a black hole is a region of space from which "nothing", not even light can escape. Yet Quantum Mechanics predicts that black holes also emit many variations of radiation including X-ray's. That suggests X-rays are a by-product of the extreme gravitational forces on other matter. therefore will and do escape.
JCR
1 / 5 (4) Nov 10, 2010
I agree with Hawkins There are no event horizons or black holes. If there is a singularity, why would gravitational pull be unidirectional ? if there were black holes and only one event horizon then go to the back side where there is no gravitational pull and go inside and take a look.
BillFox
not rated yet Nov 10, 2010
if there were black holes and only one event horizon then go to the back side where there is no gravitational pull and go inside and take a look.


Did you think that through quite much?
peter09
1 / 5 (1) Nov 11, 2010
While I am open to the existence of Black Holes I always remember the Skeptic mantra (to which I agree) which is levelled at those making claims of strange things.

- Extraordinary Claims require extraordinary evidence -
frajo
3.7 / 5 (3) Nov 12, 2010
While I am open to the existence of Black Holes I always remember the Skeptic mantra (to which I agree) which is levelled at those making claims of strange things.

- Extraordinary Claims require extraordinary evidence -
Do you just question the existence of Black Holes or do you have qualified objections?
IMHO only the latter case is truly skeptical.
peter09
not rated yet Nov 14, 2010
Hi,
bit difficult to follow this in the limited format we have, however, firstly, while I have an engineering degree, I do not consider myself anymore that a layman in these things. I guess my main worry about blackholes is the way these ideas came about. My understanding is that somewhere in the 60's-70's someone projected mathematically that stars could collapse to a dense state of matter so the idea of the neutron star was borne, this was followed by scaling this idea up to blackholes -> bigger stars etc. The trouble is that nowhere in this mathematical model was there any physical object which required these explanations and indeed the final model involves an infinity --- and indeed the concept gets more esoteric every month with new strange mathematical projections.

Today we use these mathematical models to explain all sorts of phenomena and call them blackholes etc.
denijane
2 / 5 (3) Nov 26, 2010
Don't know if anyone already said it but black holes in the sense that theoretical physics puts in them are NOT observed. What is observed are BH in the astronomical sense - namely dark massive compact object. But for such an object to be a BH in the other sense, it must posses an event horizon (or two). And since there is no definitive evidence of event horizon, we haven't observed a BH. What we see are heavy objects, that according to our theory of the evolution of the stars should be black holes. But I don't know of observation of a theoretical black hole as described by Schwarzchild or Kerr metrics.
And something more - those metrics are good only on the outside of the object. Inside, it's every unclear what happens. So, don't take the idea for black holes so absolutely. It's only a model of an object that so far fits some of our observation. But then, any compact massive object will do that. Because we see only the mass and the rotation. Not the horizons.