Inside the Milky Way: One step closer to figuring out the mysteries of our galaxy's core

October 14, 2014 by Julie Cohen
This composite of Sagittarius A-Star combines radio images from the NRAO Very Large Array (green), BIMA (red) and the NASA Spitzer Space Telescope (blue). Credit: NRAO/AUI

Is matter falling into the massive black hole at the center of the Milky Way or being ejected from it? No one knows for sure, but a UC Santa Barbara astrophysicist is searching for an answer.

Carl Gwinn, a professor in UCSB's Department of Physics, and colleagues have analyzed images collected by the Russian spacecraft RadioAstron. Their findings appear in the current issue of The Astrophysical Journal Letters.

RadioAstron was launched into orbit from Baikonur, Kazakhstan, in July 2011 with several missions, one of which was to investigate the scattering of pulsars—the cores of dead stars—by interstellar gas. What the team found led them to examine additional observations of Sagittarius A-Star (A*), the source that marks the Milky Way's central black hole. Sagittarius A* is visible at radio, infrared and X-ray wavelengths.

This —which contains 4 million solar masses—does not emit radiation but is visible from the gas around it. The gas is being acted upon by the black hole's very strong gravitational field. The wavelengths that make Sagittarius A* visible are scattered by interstellar gas along the line of sight in the same way that light is scattered by fog on Earth.

Gwinn and his colleagues found that the images taken by RadioAstron contained small spots. "I was quite surprised to find that the effect of scattering produced images with small lumps in the overall smooth image," explained Gwinn. "We call these substructure. Some previous theories had predicted similar effects in the 1980s, and a quite controversial observation in the 1970s had hinted at their presence."

The rocket carrying RadioAstron lifts off from the Cosmodrome in Baikonur, Kazakhstan. Credit: UCSB

In order to better understand the substructure, Michael Johnson, Gwinn's former graduate student now at the Harvard-Smithsonian Center for Astrophysics, conducted theoretical research. He realized that the anomalies could be used to infer the actual size of the underlying source.

Additional observations made using the Very Long Baseline Array—an interferometer consisting of 10 identical antennas distributed across the United States—and the 100-meter Green Bank Telescope in West Virginia showed the presence of lumps in the image of Sagittarius A*. Recent upgrades have greatly increased the sensitivity of these telescopes. Even so, evidence of the lumps, or substructure, remained extremely faint.

"The theory and observations allow us to make statements about the interstellar gas responsible for the scattering, and about the emission region around the black hole," Johnson said. "It turns out that the size of that emission region is only 20 times the diameter of the event horizon as it would be seen from Earth. With additional observations, we can begin to understand the behavior in this extreme environment."

While no scientific team has been able to produce a complete image of the black hole's emission, astronomers have drawn inferences about scattering properties from observations at longer wavelengths. "From these they can extrapolate those properties to 1 centimeter and use that to make a rough estimate of the size of the source," Gwinn said. "We seem to agree quite well with that estimate."

Not only did Gwinn and his colleagues directly confirm these indirect inferences about the size of Sagittarius A*, they were also able to provide new information about fluctuations in the that cause scattering. Their work shows that the spectrum of interstellar turbulence is shallow.

"There are different ways of interpreting observations of the scattering, and we showed that one of them is right and the others are wrong," said co-investigator Yuri Kovalev, the RadioAstron project scientist. "This will be important for future research on the gas near this black hole. This work is a good example of the synergy between different modern research infrastructures, technologies and science ideas."

A friendly international race is going on to see who will be the first to image the black hole's emissions and thereby determine whether gas falls into the black hole or is being ejected in the form of a jet.

"The character of the substructure seems to be random, so we are keen to go back and confirm the statistics of our sample with more data," Gwinn said. "We're also interested in looking at shorter wavelengths where we think the emission region may be smaller and we can get closer to the black hole. We may be able to extract more information than just the size of the emission region. We might possibly be able to make a simple image of how matter falls into a black hole or is ejected from it. It would be very exciting to produce such an image."

Explore further: Researchers offer possible explanation for lack of radiation flash from gas cloud interaction with Milky Way black hole

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Tuxford
1 / 5 (7) Oct 14, 2014
Matter ejected from a Black (grey) hole ? I wonder who has been talking about that?
Da Schneib
4.5 / 5 (8) Oct 14, 2014
The matter gets sucked into the black hole, or it gets thrown out of the accretion disk and since it's plasma, it responds to the electromagnetic field of the rest of the accretion disk and is ejected at the poles.

How much of which? That's the question.
Top Taciturn
2.6 / 5 (5) Oct 14, 2014
It shouldn't surprize anyone that, while not being a physicist, I'm at a loss. Do, or do not , black holes swallow up matter. That they do not permit anything to escape? Yet I'm finding contridiction here. So how can anything be permitted to "emit?"
movementiseternal
Oct 15, 2014
This comment has been removed by a moderator.
movementiseternal
Oct 15, 2014
This comment has been removed by a moderator.
jsdarkdestruction
3.9 / 5 (7) Oct 15, 2014
It shouldn't surprize anyone that, while not being a physicist, I'm at a loss. Do, or do not , black holes swallow up matter. That they do not permit anything to escape? Yet I'm finding contridiction here. So how can anything be permitted to "emit?"

The radiation they are talking about here is from the accretion disk and not inside the actual event horizon itsef which is the point of no return where it can never escape.
no fate
1 / 5 (7) Oct 15, 2014
The matter gets sucked into the black hole, or it gets thrown out of the accretion disk and since it's plasma, it responds to the electromagnetic field of the rest of the accretion disk and is ejected at the poles.

How much of which? That's the question.


Not the only one I'm afraid...

So the magnetic field of an accretion disk is focused at the poles of black holes and is responsible for accelerating particles away from the black hole. Has any mainstream scientist ever managed to produce a particle jet? No. Has any mainstream experiment ever reproduced an accretion disk? No. Is this purely theoretical with the only evidence observed not reproducable using mainstream techniques? yes...as usual.

There is no way for an accretion disk to produce a magnetic field capable of doing of what is claimed. (Hint, charged particles moving in directional unison at the same velocity do not generate an external magnetic field) there is no double layer in the disk.

Try again.
pugphan
1 / 5 (7) Oct 15, 2014
There are no lil green men, however ETs and ALFs are and have been here...see: www.weliveamonyoucom
Da Schneib
4.4 / 5 (7) Oct 16, 2014
It shouldn't surprize anyone that, while not being a physicist, I'm at a loss. Do, or do not , black holes swallow up matter. That they do not permit anything to escape? Yet I'm finding contridiction here. So how can anything be permitted to "emit?"
Black holes form an "accretion disk," caused by the rotational momentum of the matter they pull into their neighborhood, *outside* the event horizon. It goes into a decaying orbit, getting hotter and hotter the more it is compressed (this is standard thermodynamics, and is caused by the gas molecules and dust particles colliding with one another; as pressure increases, so does temperature, by the Ideal Gas Law q.v.). Eventually it gets hot enough that it ejects some of the gas and particles from the accretion disk (not the black hole itself).

contd
Da Schneib
4.4 / 5 (7) Oct 16, 2014
When this happens, because this gas and dust has been reduced to plasma by the very high temperatures, it is electrically charged (as is some of the gas and dust in the accretion disk, mostly in close to the black hole's event horizon), and is affected by the electric charge and its associated magnetic field in the accretion disk near the horizon, so it is repelled, and curled by the magnetic field into a jet that emerges from the rotational poles of the accretion disk (which is also, not coincidentally, the axis of rotation of the black hole).

On the other hand, some of the matter also falls into the black hole.

As I said, the question is, how much gets ejected from the accretion disk *before* it gets sucked in, and how much gets sucked in?

So there's the explanation of your apparent contradiction: the matter was never *in* the black hole, it was just swirling around it.

Good question. I gave 5 stars.
Da Schneib
4.4 / 5 (7) Oct 16, 2014
Not the only one I'm afraid...

So the magnetic field of an accretion disk is focused at the poles of black holes
No. It exists everywhere in the disk, but in varying amounts depending upon the temperature at that distance from the black hole, in the disk.

It is strongest over the inside edge of the disk, nearest the horizon. It's not "focused." It's just strongest there.

Reading comprehension fail.
no fate
1 / 5 (7) Oct 17, 2014
No. It exists everywhere in the disk, but in varying amounts depending upon the temperature at that distance from the black hole, in the disk.

It is strongest over the inside edge of the disk, nearest the horizon. It's not "focused." It's just strongest there.

Reading comprehension fail.


At least it isn't a physics comprehension fail like you seem to repeatedly demonstrate. Try starting with what is required for magnetic field generation by particles, specifically what motion is required from the particles to accomplish this. Are those conditions possible at the inner disk boundary according to the mainstream BH model? Amusingly not. Yet another example of real physics trumping theoretical fairy tales.
Da Schneib
5 / 5 (6) Oct 20, 2014
Ummmm, the heat strips electrons off the atoms in the accretion disk, resulting in a positively charged plasma, which is rotating around the black hole.

I see moving charges.

Physics says moving charges make magnetic fields. Maybe you forgot.

Magnetic fields accelerate charged particles. Like in generators. Maybe you forgot.

Ummm, overall looks like I'm not the one who doesn't comprehend physics.
no fate
1 / 5 (7) Oct 21, 2014
Ummmm, the heat strips electrons off the atoms in the accretion disk, resulting in a positively charged plasma, which is rotating around the black hole.

I see moving charges.

Physics says moving charges make magnetic fields. Maybe you forgot.

Magnetic fields accelerate charged particles. Like in generators. Maybe you forgot.

Ummm, overall looks like I'm not the one who doesn't comprehend physics.


Well...it still does, more than ever actually...but now it is also a reading comprehension fail, you are on quite a roll in our little talks. See above where I specified "what particle motion is required". (Hint, particles cannot be moving in the same direction and still generate a field...which is what the MS model shows as taking place in this inner region) You may also want to look at field directionality in relation to the particle motion. That whole perpendicular to current thing may not reconcile very well with the axis of emission.
Ummm, maybe try knitting?

cantdrive85
1 / 5 (7) Oct 21, 2014
Physics says moving charges make magnetic fields. Maybe you forgot.


Fate will not grasp this fact, he believes in magical preexisting magnetic fields. Oh, and those moving charges must be in a complete circuit for magnetism to occur.
BTW, black holes are as real as unicorns and well...preexisting magnetic fields.
no fate
1 / 5 (6) Oct 21, 2014
Physics says moving charges make magnetic fields. Maybe you forgot.


Fate will not grasp this fact, he believes in magical preexisting magnetic fields. Oh, and those moving charges must be in a complete circuit for magnetism to occur.
BTW, black holes are as real as unicorns and well...preexisting magnetic fields.


The word elation is an understatement when describing how I feel about you and I being directly opposed regarding how the fundamentals work. That said I have never once disagreed with the fact that moving charges generate a magnetic field, they just cant be moving in the same direction like Da Putz thinks.

You get that lab time so you can finish proving your theory to the rest of the world yet?
cantdrive85
1 / 5 (7) Oct 21, 2014
The word elation is an understatement when describing how I feel about you and I being directly opposed regarding how the fundamentals work.


It's not you and I that differ as much as you and 200+ years of empirical science which is the basis of our modern electronic society.
Da Schneib
5 / 5 (4) Oct 21, 2014
Now THIS is ironic.

It's not you and I that differ as much as you and 200+ years of empirical science which is the basis of our modern electronic society.
Weren't you last seen pretending that electric charge cannot exist without a closed connection?
cantdrive85
1 / 5 (5) Oct 22, 2014
Now THIS is ironic.

It's not you and I that differ as much as you and 200+ years of empirical science which is the basis of our modern electronic society.
Weren't you last seen pretending that electric charge cannot exist without a closed connection?

Please point that out, I have never made such a claim. All that was mentioned was that an electric current (moving electric charges) and it's resultant magnetism cannot happen without a complete circuit.
That's typical of your obfuscation and/or misunderstanding though.

If it's any consolation, both you and fate are pissing into the wind here. Black holes and magical magnetic fields are both fiction!

no fate
1 / 5 (4) Oct 22, 2014
If it's any consolation, both you and fate are pissing into the wind here. Black holes and magical magnetic fields are both fiction!


When you can form an electrical current without a magnetic field you win. Everyone will have to eat crow, you will be king of the mountain and will be entitled to wed the virgin of your choice. Until then, keep dancing around the fact that you cant do it. I like reruns.
cantdrive85
1 / 5 (6) Oct 22, 2014
From EU website;
"Electricity- "The physical phenomenon arising from the behavior of electrons and protons (electric charges) that is caused by the attraction of particles with opposite charges and the repulsion of particles with the same charge." An electric charge produces around itself an electric field, the means by which it transmits force to other nearby charges. It does this even when it is not moving. When the charge does move, it creates in addition a magnetic field. So an electric current is a continuous stream of charged particles in a magnetic field."

Magnetism is a result of the movement of electric charges, it is not an intrinsic phenomena. An electric field is however intrinsic to an electric charge. This is what you and Lapoint can't seem to grasp.

no fate
1 / 5 (4) Oct 22, 2014
Tappity tappity tap...with a spin and a cane bounce. Ta dahh!

You should probably keep dancing to draw attention away from your opaque plasma chamber full of charged particles NOT aligning when there is no applied magnetic field.

Are you the plasma whisperer?
Da Schneib
5 / 5 (2) Oct 22, 2014
I don't see any difference between what you said and what I said, cd. And it's wrong. We detect free protons in the solar wind all the time, and they don't go back to the Sun.
cantdrive85
1 / 5 (3) Oct 23, 2014
Tappity tappity tap...with a spin and a cane bounce. Ta dahh!

You should probably keep dancing to draw attention away from your opaque plasma chamber full of charged particles NOT aligning when there is no applied magnetic field.

Are you the plasma whisperer?

So now it's only opaque, it's not glowing anymore? You do understand there will be a cathode and anode in your chamber, there is already a current flowing through your "glowing opaque plasma". That electric current is the reason the glow and the diffuse nature of the plasma. If you want to describe what is happening in hot plasmas you've got to up the power, like these guys.

http://www.sandia...machine/

no fate
1 / 5 (1) Oct 23, 2014
You do understand there will be a cathode and anode in your chamber, there is already a current flowing through your "glowing opaque plasma". That electric current is the reason the glow and the diffuse nature of the plasma.


You know nothing. Your lack of experience with the actual mediums you comment on is blatant. The glow is particle vibration due to an APPLIED ionizing voltage (this is what turns atoms into a plasma), not because the particles flow as they do in electrical current,but because they are heated by the applied current which creates and sustains the plasma (you should click on the "how it works" tab in your link). This is why there is no magnetic field present in the chamber, despite the presence of glowing plasma and why, in order to structure the plasma you have to apply a magnetic field. Without applied voltage the plasma cools and recombines into atoms (the only particle interaction possible in the absence of a magnetic field).
no fate
1 / 5 (1) Oct 23, 2014
You have no idea how completely stupid you look when you make claims about Birkeland currents when " A Birkeland current usually refers to the electric currents in a planet's ionosphere that follows magnetic field lines (ie field-aligned currents), and sometimes used to described any field-aligned electric current in a space plasma"

Why do you think Birkeland had to insert a solenoid into his globe to create them?

http://www.plasma..._current

Once aligned they can form their own fields and various energetic phenomena may occur, but a field aligned current doesn't generate the field that aligns it and the fields it generates cause the initial structure to dissipate (sometimes violently as in solar flares).

The unsupported, fantastic claims you make on a daily basis here only serve to further invalidate the EU theory.... and annoy people, whereas they hate me because I am sarcastic, arrogant and really antagonistic when antagonized.
cantdrive85
1 / 5 (3) Oct 23, 2014
You know nothing. Your lack of experience with the actual mediums you comment on is blatant. The glow is particle vibration due to an APPLIED ionizing voltage (this is what turns atoms into a plasma), not because the particles flow as they do in electrical current,but because they are heated by the applied current which creates and sustains the plasma (you should click on the "how it works" tab in your link).


Right back at you, dude. I think a 'Primer on Gas Discharges' will do you good, you've got much to learn Danielson.
http://electric-c...utGD.pdf
cantdrive85
1 / 5 (2) Oct 23, 2014
Why do you think Birkeland had to insert a solenoid into his globe to create them?


Because he knew it would produce a magnetic field to replicate the Earth's magnetic field AFTER he applied an electric current through it.

http://en.wikiped...Solenoid

the field that aligns it and the fields it generates cause the initial structure to dissipate (sometimes violently as in solar flares).

Actually, it can be a stable structure, as Alfven pointed out;
"Plasma cables seem to be reasonably stable formations which can be considered as structures important for the understanding of plasma phenomena."

Sometimes they can create a Bennett pinch (real science and unrealized basis for "Primer Fields" pseudoscience) which can cause instabilities, double layers, among other characteristics and the circuits they reside along can be disrupted and explode as you point out.
cantdrive85
1 / 5 (2) Oct 24, 2014
no fate
4 / 5 (1) Oct 24, 2014
I think a 'Primer on Gas Discharges' will do you good, you've got much to learn Danielson.
http://electric-c...utGD.pdf


LMAO...not from you, or the quack that wrote the first paper you linked.
A "virtual anode"....priceless.

Like everything else you post, high in entertainment value thanks to the twisted perception of how things work ( opposite to practical physics that are experimentally validated) but void of truth. Scotts theory is no better than a shitty dark matter postulate because he also has a "virtual" component performing an actual physical function.

Seriously, it's fun watching you dipsy doodle around the physical impossibilities of the EU's claims but it is also very clear what those impossibilities are. You don't even understand the physics of a Z-pinch enough to not claim the universe produces stable ones...or that Birkeland currents can only ever exist when the magnetic field precedes the particles which form the current.

Wax off.
no fate
not rated yet Oct 24, 2014
You think particles align to form a current without a magnetic field, you don't even fathom "potential" when you talk about the sun being part of a galactic circuit (hence the requirement for a "virtual" anode) and on the quantum scale you curl up in ball and suck your thumb because that is all you can do. Your theory is destroyed by a fridge magnet and when that is pointed out you retreat into your own fantasies of how that magnet does what it does with no voltage or current present.

I find it funny, I have encountered alot of people who, through mindless arrogance/ignorance, plough their way through their beliefs en route to the biggest let down of their lives...when you're theory is just soooo bad that, despite having access to all apparatus required to prove your theory is valid if it is, you still haven't done a single experiment to try.

Maybe if you post about enough that will make up for it....but at least you understand that Black holes can't exist.
cantdrive85
1 / 5 (2) Oct 24, 2014
LMAO...not from you, or the quack that wrote the first paper you linked.
A "virtual anode"....priceless.


You must have stopped reading? Maybe you have an explanation for the glow discharge known as St. Elmo's Fire. Here we have a natural plasma phenomena without an actual cathode, how can that be? His "virtual cathode" has a natural counterpart, and he explains it as such;
"Their electric paths spread out and end on negative charges located at remote distances – at virtual cathodes."

Unless you can identify the real metal cathodes that allows this type of phenomena then your argument falls apart once again. Fail!

You don't even understand the physics of a Z-pinch enough to not claim the universe produces stable ones.

That was Alfven which made the claim, not I. I'll trust his opinion before a physics challenged, magic dependent online neophyte any day.

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