From NASA Science News January 15, 2010: Last year, when NASA’s IBEX (Interstellar Boundary Explorer) spacecraft discovered a giant ribbon at the edge of the solar system, researchers were mystified. They called it a “shocking result” and puzzled over its origin.
Now the mystery may have been solved.
“We believe the ribbon is a reflection,” says Jacob Heerikhuisen, a NASA Heliophysics Guest Investigator from the University of Alabama in Huntsville. “It is where solar wind particles heading out into interstellar space are reflected back into the solar system by a galactic magnetic field.”
Heerikhuisen is the lead author of a paper reporting the results in the Jan. 10th edition of the Astrophysical Journal Letters.
“This is an important finding,” says Arik Posner, IBEX program scientist at NASA Headquarters. “Interstellar space just beyond the edge of the solar system is mostly unexplored territory. Now we know, there could be a strong, well-organized magnetic field sitting right on our doorstep.”
The IBEX data fit in nicely with recent results from Voyager. Voyager 1 and 2 are near the edge of the solar system and they also have sensed strong* magnetism nearby. Voyager measurements are relatively local to the spacecraft, however. IBEX is filling in the “big picture.” The ribbon it sees is vast and stretches almost all the way across the sky, suggesting that the magnetic field behind it must be equally vast.
Although maps of the ribbon (see below) seem to show a luminous body, the ribbon emits no light. Instead, it makes itself known via particles called “energetic neutral atoms” (ENAs)–mainly garden-variety hydrogen atoms. The ribbon emits these particles, which are picked up by IBEX in Earth orbit.
Above: A comparison of IBEX observations (left) with a 3D magnetic reflection model (right). More images: data, model.
The reflection process posited by Heerikhuisen et al. is a bit complicated, involving multiple “charge exchange” reactions between protons and hydrogen atoms. The upshot, however, is simple. Particles from the solar wind that escape the solar system are met ~100 astronomical units (~15 billion kilometers) away by an interstellar magnetic field. Magnetic forces intercept the escaping particles and sling them right back where they came from.
“If this mechanism is correct–and not everyone agrees–then the shape of the ribbon is telling us a lot about the orientation of the magnetic field in our corner of the Milky Way galaxy,” notes Heerikhuisen.
And upon this field, the future may hinge.
The solar system is passing through a region of the Milky Way filled with cosmic rays and interstellar clouds. The magnetic field of our own sun, inflated by the solar wind into a bubble called the “heliosphere,” substantially protects us from these things. However, the bubble itself is vulnerable to external fields. A strong magnetic field just outside the solar system could press against the heliosphere and interact with it in unknown ways. Will this strengthen our natural shielding—or weaken it? No one can say.
Right: An artist’s concept of interstellar clouds in the galactic neighborhood of the sun. [more]
“IBEX will monitor the ribbon closely in the months and years ahead,” says Posner. “We could see the shape of the ribbon change—and that would show us how we are interacting with the galaxy beyond.”
It seems we can learn a lot by looking in the mirror. Stay tuned to Science@NASA for updates.
h/t to Leif Svalgaard
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Astonishing.
Believe it or not Leif, other matters do occasionally call us away from the screen.
Cheers for your information.
And boos for your insults.
Now, this is not good enough for a six-year old [or for you or Vuk], but each term used can be explained in simpler terms and those, in turn, by yet simpler terms until it is simple enough. All that is required is immense patience on the part of both teacher and six-year old [the latter is the hard part].
Well, game on then, let’s hear you break it down into simpler terms.
Why and how does the Sun’s equator rotate faster than it’s polar latitudes?
tallbloke (10:06:03) asked Dr. Svalgaard: “Why and how does the Sun’s equator rotate faster than it’s polar latitudes?”
In way of a possible answer.
The beginning of a hypothesis: A hypothetical where a body of plasma is gravitationally bound and motionless in space.
Enthropy will cause the plasma to dissipate away from the gravitationally bound body of plasma into the vacuum of space from high pressure and high temperature to low pressure and low temperature, “an equalization process”, this possibly could take the form of a toroidal outward spin away from the body of plasma.
This outward toroidal spin will cause in effect: “The moving plasma, i.e., charged particles flows, are currents that produce self-magnetic fields, however weak.” — A. L. Peratt
tallbloke, the Sun’s equator possibly spins faster than the higher latitudes because of the toroidal spin effect (which would manifest itself to Man’s observation as the Sun’s equator spinning faster than higher latitudes) .
Mind you, it’s just the bare bones of a possible hypothesis (and there is a whole other half of the possible hypothesis).
But considering all the contradictions between observation & measurement of the Sun’s processes and the Standard Solar Model, it might be a good place to start.
tallbloke (10:06:03) :
Cheers for your information.
And boos for your insults.
And where are the insults? I’m not aware of any. I carefully lay out the arguments. I patiently point out what I see as pseudo-science and why? I recognize when I get the equivalent of a blank stare, so lower the aim accordingly, etc.
Well, game on then, let’s hear you break it down into simpler terms. Why and how does the Sun’s equator rotate faster than it’s polar latitudes?
The ‘why’ is a bit misplaced. We can get to the ‘how’, possibly.
The game may go on for several thousand posts depending on your ignorance. Are you [and Anthony] ready for that?
So we start: Do you know what angular momentum is? Or perhaps let us first explore what ‘angular’ is? This is a term I might have to explain to a six-year old. How about you?
P.S. A typical problem with pseudo-science is the lack of sense of proportions. The Heliosphere is vast. If you compare it in size to the Superdome football stadium, the Sun is like a pea somewhere in the middle and Jupiter is a grain of sand.
From your mouth to God’s ears, as they say. (Enjoyed the rest of the post thoroughly, too.)
But I would like to have a look at those future textbooks! It seems to me that there is more power input into the earth’s weather systems from space that need to be examined. And then we need to understand the paths that that power takes through the magnetosphere, the atmosphere, and down to the surface where we all live. There are some steps in that direction; but perhaps our thinking should go beyond even what Svensmark has demonstrated.
I have wondered if the Madden-Julian oscillation is a clue that power is coming in, building up, and releasing. It’s all so interesting, and the truth about what drives climate and how could change our lives. I wish Science would get on with it!
Leif Svalgaard (11:04:29) :
The game may go on for several thousand posts depending on your ignorance. Are you [and Anthony] ready for that?
So we start: Do you know what angular momentum is? Or perhaps let us first explore what ‘angular’ is? This is a term I might have to explain to a six-year old. How about you?
I hold a UK qualification (Higher National Certificate) in Mechanical Science, which included a module on fluid dynamics, and another in higher level Applied Mathematics.
I’ve read the wikipedia pages on differential stellar rotation, and they boil down to
“We don’t know, and we don’t have enough computer power to get our hypothetical models to work.”
The empirical results from GONG appear to have undercut some of the previous ideas about convection from below the tachocline.
But please do enlighten me with your simple terms explanation.
“So we start: Do you know what angular momentum is? ”
Let me have a go. Angular momentum is a property of a rotating body such that it will continue to rotate until a force is applied to stop it. The size of this momentum is proportional to angular velocity and the radius of rotation, and of course its mass. Like linear momentum, angular momentum is conserved, so that if you change either radial velocity or radius, the other will change to keep the product constant.
tallbloke (12:01:58) :
I’ve read the wikipedia pages on differential stellar rotation, and they boil down to
“We don’t know, and we don’t have enough computer power to get our hypothetical models to work.”
But you, apparently, did not bother to read [or look at] section 4.3 of http://solarphysics.livingreviews.org/Articles/lrsp-2005-1/
And you tried to play games in
tallbloke (07:39:45) :
In terms a six year old can understand please
Now you come up with degree here and degree there. Show me a six-year old with that.
What I suggested was that you look at the link I supplied and then tell me where you get stuck and we’ll go from there.
But please do enlighten me with your simple terms explanation
Vincent (12:10:09) :
Let me have a go.
And that was correct. The problem still exists how to explain that to a six-year old. Take ‘mass’ for example. A six-year old may have some idea of ‘weight’, i.e. heavy and light. If not you can show him by giving him something heavy to hold and then something light. He’ll get that ‘weight’ is something that presses down on your hand when hold hold something. But ‘mass’ as different from weight? Here is what I would do: suspend something heavy by a thread and then by another thread something much lighter [e.g. a brick and a feather]. Now ask him to put his hand underneath those two objects and have him realize that they no longer press down his hand. Now have him try to push the suspended brick and then the suspended feather and you can make him understand that they must have a property that makes it easy to push the feather, but harder to to push the brick, and that is ‘mass’. And so it goes.
Maybe this will move things along and elicit an exec summary of the new theory form Leif.
“Until the advent of helioseismology, the study of wave oscillations in the Sun, very little was known about the internal rotation of the Sun. The differential profile of the surface was thought to be extending into the solar inertia as rotating cylinders of constant angular momentum [3]. Through helioseismology this is now known not to be the case and the rotation profile of the Sun has been found. On the surface the Sun rotates slowly at the poles and quickly at the equator. This profile extends on roughly radial lines through the solar convection zone to the interior. At the tachocline the rotation abruptly changes to solid body rotation in the solar radiation zone [4].”
http://en.wikipedia.org/wiki/Solar_rotation
tallbloke (12:55:04) :
Maybe this will move things along and elicit an exec summary of the new theory from Leif.
What happened to the facetious ‘six-year old, please’ remark?
I can try to give a summary but I’m [as I said] unsure of at what technical level to keep it. I don’t play games. I’m a very literal person. If I feel someone is serious, I’ll invest my time in teaching. With some people, that time is wasted: I explain the same thing many times over and the response I get is that my explanation was ‘misleading’. I offer to do it thoroughly and that is seen as an insult.
So, again, read the link and tell me about your first stumbling block and we’ll go from there [now, how many times have I said that?]
Leif Svalgaard (12:26:04) wrote: “Of more interest is my first question: ‘what generates the currents?’ and in realistic environments, e.g in the Galaxy.”
Yes.
Questions about “what happened in the beginning” are a distraction.
The pertinent question: “What is happening now?”
Hannes Alfven understood that and realized “beginning” type questions were likely to lead scientists astray and often were used to distract from the truly pertinent question: What is happening now?
To the post: The hypothesis put forward can be tested by in situ observation & measurement. This is an exciting challenge for astrophysical science and one that can be falsified as opposed to so many astronomical hypothesis that can’t be falsified.
But whether it is a “reflection” from the inside or an “impingement” from the outside, there is a “curtain” seperating the inside from the outside.
Magnetic fields are inherently bound up in this “curtain” effect.
The solar wind is a stream of charged particles and the “curtain” is a magnetic field.
An electromotive force [mathematical equation] giving rise to electrical currents in conducting media is produced wherever a relative perpendicular motion of plasma and magnetic fields exists.” — Dr. Anthony L. Peratt, Los Alamos National Laboratory
Dr. Svalgaard: “Yes, the electric current is created by the neutral plasma moving through a magnetic field.”
At the point where the solar wind moves through a magnetic field an Electrical Double Layer, aka “magnetic reconnection”, occurs resulting in electric fields and electric currents.
So, I humbly suggest that Science, and NASA more specifically, develop and launch additional in situ satellite probes that can make observations & measurements which can test the various hypothesis and either confirm or falsify such hypothesis.
Such is the business of science.
Embrace the future.
Leif,
“The problem still exists how to explain that to a six-year old.”
Have the six year old sit on the edge of a rotating disc of about 6 foot radius. Then tell him to crawl slowly towards the centre. As he does so, the rotation will speed up. On second thoughts, could be a bit dangerous.
James F. Evans (13:07:10) :
The solar wind is a stream of charged particles and the “curtain” is a magnetic field.
A neutral stream, and there is no ‘curtain’ separating anything from anything. The solar wind is everywhere permeated by a magnetic field.
An electromotive force [mathematical equation] giving rise to electrical currents in conducting media is produced wherever a relative perpendicular motion of plasma and magnetic fields exists.”
In the solar wind the magnetic field moves with the plasma so there is no emf.
So, I humbly suggest that Science, and NASA more specifically, develop and launch additional in situ satellite probes that can make observations & measurements which can test the various hypothesis and either confirm or falsify such hypothesis.
That is wjat they have been doing the past 40+ years and the result is the picture of the solar wind that we have today, not picture Birkeland or Alfven were having.
Such is the business of science.
Embrace the future.
Accept today’s [and the past many years of] observations.
Vincent (13:19:14) :
On second thoughts, could be a bit dangerous.
And he would not gain any understanding. Perhaps an experience, but he would not know why things are the way they are. With the hindsight that hundreds of years of experimenting and thinking about how Nature works, we can make him understand how it works. This is the miracle of memory, culture, and science that past generations toil can be transmitted to the future.
Leif Svalgaard (13:04:51) :
So, again, read the link
There’s sevral weeks worth there Leif. You just trying to keep me quiet? 🙂
I’ve made a quick review of sections 4.3 and 6.3 and so far, I’m not getting the impression of a nearly sorted theory which is having it’s i’s dotted and t’s crossed.
tallbloke (14:15:20) :
There’s several weeks worth there Leif. You just trying to keep me quiet? 🙂
No [and I did see the smiley], and it may be worth it [and I’ll help as is my wont]. After all, angular momentum is part of the story 🙂
I’ve made a quick review of sections 4.3 and 6.3 and so far, I’m not getting the impression of a nearly sorted theory which is having it’s i’s dotted and t’s crossed.
Of course not. The theory is very data driven [observations with SDO will help a lot] in the sense that we need to know where the flows go and what the sound speed is.
There are very few theories that a polished. But that is not important. I think we know what goes into the theory [the equations], but we don’t know all the boundary conditions. As we learn from observations, we ‘constrain’ the theory [pruning away wrong assumptions].
I wanted you to see that the subject is not a complete mystery and that we have good reasons for optimism. In VERY broad terms [way beyond any six-year old], the differential rotation is the result of the interaction between meridional circulation [now what drives that one? temperature differences? and how do they arise? etc], Reynolds Stresses [turbulent fluctuations as you should know], and [to a minor extent] Lorentz forces [magnetic effects]. It is very hard to give a hand-waving explanation, because these things are complicated and our common day-to-day intuition does not measure up to such phenomena that we usually do not experience in our daily lives.
Nice reply, thanks Leif.
It’s getting late here, and I’ve had a couple of glasses of very nice red wine, so I’m going to sleep on it before I give a fuller response. In the meantime, enjoy the rest of your day.
Cheers
Rog Tallbloke
@ur momisugly anna v (01:33:45) :
Number 2 can be seen in the action of a normal coil. When using direct current, the magnetic field builds logarithmically to saturation. The atoms involved will only take so much magnetization. When the current is cut the field collapses rapidly. Across the terminals of the coil there will be a high voltage pulse. This property is used in an ignition coil for a car. Without something tapping the current, the energy stored in the field (mainly in the temporarily-magnetized core) becomes heat. Atoms do not like to be magnetized, and will get rid of a magnetic charge as soon as possible. Even “permanent” magnets, where the atoms are held in a magnetism-producing orientation within a matrix, will lose their charge over time.
But in space, if an isolated atom acquires a magnetic charge, what’s it going to do? Like the 6000 deg C atoms in that interstellar cloud, they have nothing to interact with, no way to shed the energy, so they stay magnetized. Thus these weak magnetic fields in space persist, even with nothing actively generating them. The energy is not being lost, therefore there is no need to replenish it to maintain the field.
As to magnetic fields and black holes, well… The magnetism is arising from moving charges within the star. When the black hole consumes the star, the star becomes… something else. Thus what caused the magnetism is gone, so the field should be gone. If the star magnetized any matter around it on the way in, leaving behind any residual magnetic fields, eh, the black hole will take care of that matter in time.
kadaka (15:17:28) :
But in space, if an isolated atom acquires a magnetic charge, what’s it going to do?
This is not quite how it works. Consider a coil in space. If the magnetic field through the coil were to change a current would be induced in the coil which would restore the field, so it cannot change. Now, if the coil is made of copper or some other normal conductor, the current will suffer some ohmic dissipation and the magnetic field would not be completely restored and over time would disappear. If the coil was made of a space plasma, there would be no resistance and no ohmic dissipation, hence the field is maintained.
Leif Svalgaard (13:49:19) :
Evans (13:07:10) wrote: “The solar wind is a stream of charged particles and the “curtain” is a magnetic field.”
Dr. Svalgaard responded: “A neutral stream, and there is no ‘curtain’ separating anything from anything. The solar wind is everywhere permeated by a magnetic field.”
“A neutral stream” is a stream of charged particles in a state of quasi-neutrality, plasma, and, yes, this has a magnetic field because:
“The moving plasma, i.e., charged particles flows, are currents that produce self-magnetic fields, however weak.” — A. L. Peratt
You are confused Dr. Svalgaard, when I referred to “curtain”, I was referring to the magnetic field perpendicular to the solar wind, also known as the heliosheath. This is where and what the image of the ribbon was observed & measured from.
You know, that nearly spherical magnetic bubble the solar system resides in.
“An electromotive force [mathematical equation] giving rise to electrical currents in conducting media is produced wherever a relative perpendicular motion of plasma and magnetic fields exists.” A. L. Peratt
Dr. Svalgaard wrote: ‘In the solar wind the magnetic field moves with the plasma so there is no emf.’
Generally so, however the helio current sheet can develop Electric Double Layers, aka “magnetic reconnection”, and where this happens, Electromotive Force is present.
Also, the helio current sheet, where and when the magnetic field changes polarity, should give rise to Electromotive Force.
Dr. Svalgaard wrote: “That is what they have been doing the past 40+ years and the result is the picture of the solar wind that we have today, not picture Birkeland or Alfven were having.”
“…the realization of the need to apply plasma physics and electromagnetic forces to the understanding of the dynamical properties, evolution, and radiation to astrophysical data was lost with the death of Kristian Birkeland (1867 – 1917) and not to be resurrected until tow decades later by Hannes Alfven (1908 – 1995).” –Dr. Anthony L. Peratt, Los Alamos National Laboratory
“Hannes Alfven supported the concept of Birkeland currents and developed a theory for the generation of these currents by the solar wind. This half-century long dispute was decided in Birkeland’s favor in 1967 with the discovery of Birkeland currents by the U.S. Navy navigation satellite 1963 – 38C at ~1100 km altitude (Potemra, 1988 Laser and Particle Beams 6, 503).” — Dr. Anthony L. Peratt, Los Alamos National Laboratory
Birkeland currents are named in honor of Kristian Birkeland (1867 – 1917).
(Sydney Chapman was proven wrong in the dispute.)
Yes, there already have been many useful observations & measurements for sure, and there is room for many more useful observations & measurements in the scientific quest to understand the Universe around humanity stretching to Man’s farthest ability to makes observations & measurements of the Universe.
James F. Evans (15:56:17) :
“The moving plasma, i.e., charged particles flows, are currents that produce self-magnetic fields, however weak.” — A. L. Peratt
This is however not what produces the magnetic field of the solar wind. That field comes out of the Sun and is generated there.
Generally so, however the helio current sheet can develop Electric Double Layers, aka “magnetic reconnection”, and where this happens, Electromotive Force is present.
It can, but does it rarely and only intermittently, which is why the HCS exists at all [otherwise it would reconnect away]. And magnetic reconnection is not the same as double layers.
Also, the helio current sheet, where and when the magnetic field changes polarity, should give rise to Electromotive Force.
No, the HCS current is a drift current. No emf there.
Birkeland currents are named in honor of Kristian Birkeland
(Sydney Chapman was proven wrong in the dispute.)
And the Svalgaard vortex current system in the polar caps is named after me. Chapman argued that the currents were in the ionosphere and, of course, they were not. But that has nothing to do with our modern view of matters.
James F. Evans (15:56:17) :
Also, the helio current sheet, where and when the magnetic field changes polarity, should give rise to Electromotive Force.
No, the HCS current is a drift current. No emf there.
Here is a short reference to what a drift current is:
Google (drift current magnetic heliospheric sheet kallenrode)
and click on the first entry: Space physics: an introduction to plasmas and particles in the … – Google Books Result
by May-Britt Kallenrode – 2004 – Science – 482 pages
This phenomenon was discovered by Alfven and was one of the discoveries that brought him the Nobel prize. See also:
http://en.wikipedia.org/wiki/Guiding_center [note the reference at the bottom]
Please see additional Information that helps the discussion groups
Star Keeps Magnetic Lock on Its Big Brother — Berardelli… – sciencemag [dot] org – Jan 17
[Magnetic Universe, Binary state, COsmic Alignment, Cosmic Pot Universe – Sub:MAGNETIC UNIVERSE- COSMIC ALIGNMENT See:www [dot] earthportals [dot] com/Portal_Messenger/nanduri3 [dot] html Your Ref:Star Keeps Magnetic Lock on Its Big Brother Information:images of the magnetic field generated by one of Binary stars in the Algol system, located about 93 light-years away. The two stars in the system–one about three times more massive than the sun and the other a little less massive–are so close to each other that one orbit takes only 3 days. The smaller star is the source of the magnetic field, and even though that field is about 1000 times stronger than the sun’s, The resulting images show a giant magnetic loop extending from the north and south poles of the smaller star all the way to its larger partner, located about 9 million kilometers away. The loop persisted for all 6 months of observations, instead of flaring up and quieting down, like our sun’s field. It’s a mystery why the loop seems to be permanent, COMMENTS: Magnetic Fields Spread need to be understood as part of – SOURCE,FIELDS,FLOWS and REFLECTOR CONCEPTS clearly mentioned in COSMIC POT ENERGY UNIVERSE. See:scribd [dot] com/doc/21526401/Cosmic-Pot-Universe-2003 My projection links to Cosmic Alignment Vidyardhi Nanduri Cosmology Vedas Interlinks ]
Leif Svalgaard (16:22:39) :
Evans (15:56:17) wrote: “The moving plasma, i.e., charged particles flows, are currents that produce self-magnetic fields, however weak.” — A. L. Peratt
Dr. Svalgaard responded: “This is however not what produces the magnetic field of the solar wind. That field comes out of the Sun and is generated there.”
Does the Sun have a dipole magnetic field? If so, the solar wind’s magnetic field would be in addition to this dipole magnetic field. If the Sun does not have a dipole magnetic field, where is the magnetic field emanating from besides the solar wind’s plasma flow?
Dr. Svalgaard wrote: “And magnetic reconnection is not the same as double layers.”
Please distinguish the physical differences between “double layers” and “magnetic reconnection”.
Dr. Svalgaard, I appreciate that “the Svalgaard vortex current system in the polar caps” is named in your honor.
Birkeland currents are named in Kristian Birkeland’s honor.
Each person should have his accomplishments recognized not disparaged.
James F. Evans (08:20:43) :
Leif Svalgaard (16:22:39) :
Does the Sun have a dipole magnetic field? If so, the solar wind’s magnetic field would be in addition to this dipole magnetic field.
No, the solar wind magnetic field IS the Sun’s dipole field dragged out into interplanetary space.
If the Sun does not have a dipole magnetic field, where is the magnetic field emanating from besides the solar wind’s plasma flow?
There is no magnetic field from the ‘plasma flow’. There are additional magnetic fields from decaying sunspots that are also dragged into space. It will be good for you to read a book about space physics instead of misinformation gleaned on the internet. The book I linked to is a good choice. Another [very good one] is Kenneth R. Lang “The Sun from Space” 2nd ed.ISBN 978-3-540-76952-1
Please distinguish the physical differences between “double layers” and “magnetic reconnection”.
Wikipedia does that well:
http://en.wikipedia.org/wiki/Double_layer_(plasma)
http://en.wikipedia.org/wiki/Magnetic_reconnection
As you can see from these, they don’t mention each other for the good reason that they describe different processes.
Each person should have his accomplishments recognized not disparaged.</i?
Indeed, so we should appropriately honor Sydney Chapman for his discovery of the Chapman-Ferraro current on the magnetopause. There is probably also one on the heliopause, caused by the same physics [a neutral plasma moving towards a stronger magnetic field].
James F. Evans (08:20:43) :
Each person should have his accomplishments recognized not disparaged.
Indeed, so we should appropriately honor Sydney Chapman for his discovery of the Chapman-Ferraro current on the magnetopause, rather than disparage him for ‘losing the debate’. There is probably also a Chapman-current on the heliopause, caused by the same physics [a neutral plasma moving towards a stronger magnetic field].