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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Dr. Svalgaard wrote: “No, the solar wind magnetic field IS the Sun’s dipole field dragged out into interplanetary space.”
What does the “dragging”?
And what happens to the magnetic field generated by the solar wind’s plasma flow?
Or do you maintain, “The moving plasma, i.e., charged particles flows, are currents that produce self-magnetic fields, however weak.” — A. L. Peratt, does not exist in that physical circumstance?
If so, what physical circumstance or condition would cancel the magnetic field generated by the solar wind’s plasma flow?
Dr. Svalgaard wrote: ” It will be good for you to read a book about space physics instead of misinformation gleaned on the internet.”
Are you saying Dr. Anthony L. Peratt is wrong?
And have you considered that your analytical approach is wrong?
Dr. Svalgaard wrote: “As you can see from these, they don’t mention each other for the good reason that they describe different processes.”
I’m interested in how YOU distinguish the physical differences, not how a Wikipedia article(s) state the differences.
After all, there may not be any physical differences at all, but simply each article presents a difference perspective or perception of the same physical event.
Wikipedia articles should not be taken as the final word on much of anything of controversial nature (you are bailing out and engaging in avoidance to blandly state there is no controversy).
As I stated, please, I want YOU to distinguish the physical differences between the two. That shouldn’t be hard for you, now should it?
*******
Leif Svalgaard (13:38:39) :
For your own sake, study carefully what is known today: http://www.astro.ucla.edu/~wright/cosmology_faq.html
*******
Thanks for your input on this thread & the above link. I try to keep up w/astronomy in general, but didn’t know that the distance to the CMB is ~42 billion light-years! (not 13.7 billion) Makes sense when one includes the expansion of the universe, but I hadn’t thought enough about it.
Still can’t get my head around whether the universe is truly infinite. If it was “closed”, one would eventually come back to their original starting point, but apparently it’s either flat or open, not closed.
beng (09:33:37) :
Still can’t get my head around whether the universe is truly infinite. If it was “closed”, one would eventually come back to their original starting point, but apparently it’s either flat or open, not closed.
I think that ‘flat’ is also ‘open’ [i.e. not closed]. ‘Truly infinite’ is tough. My own inclination is “what else”. But it is too early to speculate too much. Who knows what we’ll discover.
James F. Evans (09:27:17) :
Dr. Svalgaard wrote: “No, the solar wind magnetic field IS the Sun’s dipole field dragged out into interplanetary space.”
What does the “dragging”?
The magnetic field in the solar corona is frozen into the plasma because of the very high conductivity. The plasma is very hot and simply expands away from the sun because a significant part of the protons have thermal speeds exceeding the escape velocity at the altitude where the solar wind originates.
And what happens to the magnetic field generated by the solar wind’s plasma flow?
There isn’t any.
Or do you maintain, “The moving plasma, i.e., charged particles flows, are currents that produce self-magnetic fields, however weak.” — A. L. Peratt, does not exist in that physical circumstance?
There are no currents in the escaping solar wind as equal number of electrons and protons leave the Sun.
If so, what physical circumstance or condition would cancel the magnetic field generated by the solar wind’s plasma flow?
since there isn’t any, no need to cancel anything.
Are you saying Dr. Anthony L. Peratt is wrong?
I’m saying that you misunderstand/misinterpret his analytical approach.
As I stated, please, I want YOU to distinguish the physical differences between the two. That shouldn’t be hard for you, now should it?
Yes it should, because of your lack of knowledge. It makes it harder to explain something. E.g. how to explain ‘angular momentum to the proverbial six-year old. But I can try, and we’ll see if you get it: a double layer consists of two layers with opposite electrical charge, there doesn’t need to be a magnetic field. Reconnection happens between two regions with opposite magnetic polarity changing the topology of the fields, there doesn’t need to be a current. Turning a toy magnet in the air will cause a continuing change of topology without any sparks flying.
Wiki does a good job. I have carefully reviewed the material and it looks good to me.
James F. Evans (09:27:17) :
For an even more elementary explanation of reconnection, see:
http://solar-center.stanford.edu/magnetism/magnetismsun.html
there are lots of other good links at your level on that website. Try some of them.
James F. Evans (09:27:17) :
Reconnection can now be studied in the laboratory
http://mrx.pppl.gov/
I have previously directed you to this site [no analytical stuff there, just lots of coils and magnets] but to no avail. Perhaps you didn’t understand some of stuff. Review the material and ask about specific points that give you difficulties. As is my wont, I’ll try to answer to the best of your ability.
Leif,
“I think that ‘flat’ is also ‘open’ [i.e. not closed]. ‘Truly infinite’ is tough. My own inclination is “what else”.
The universe cannot be infinite imo. The universe began from the big bang rapidly expanding from a point, so it must have had a boundary. The boundary has expanded to where we can never observe, but it must still exist. So that would imply the universe has an edge. But having an edge violates the principal that there must not exist any special vantage point. How do you solve those two contradictory requirements?
Vincent (13:35:13) :
The universe began from the big bang rapidly expanding from a point
We don’t think so. You often hear that statement, but it is wrong. Our OBSERVABLE Universe was once very small and centered on us, but that is not the same as the whole thing being small [and centered on us]. The current data and our understanding of them support the view that the BB and the expansion took/takes place at every point of the universe, so there is no problem with boundaries. There never was one to begin with [if ‘begin’ has any meaning in this context].
Leif Svalgaard (14:13:54) :
The current data and our understanding of them support the view that the BB and the expansion took/takes place at every point of the universe, so there is no problem with boundaries. There never was one to begin with [if ‘begin’ has any meaning in this context].
If the luminosity/redshift of galaxies is given the alternative interpretation of being a measure of age rather than distance, this starts to look quite like a continuous creation/steady state universe theory.
Universal expansion has always seemed a strange concept to me. Expanding into what?
xe136 (14:24:53) :
this starts to look quite like a continuous creation/steady state universe theory.
study http://www.astro.ucla.edu/~wright/cosmology_faq.html
The simplest observation to show that the redshift is not sue to age is that a supernova that takes 20 days to decay takes 40 days to decay when observed at redshift z=1, so showing the time dilation that follows from the standard interpretation [see e.g. http://www.astro.ucla.edu/~wright/cosmology_faq.html#XIN ]. The ‘tired light’ hypothesis [light loses energy with age, hence the redshift] is contradicted by observations http://www.astro.ucla.edu/~wright/tiredlit.htm
Universal expansion has always seemed a strange concept to me. Expanding into what?
Eternity. Even the steady state universe does not have a boundary [or do think it does]. Here is something that may give you a feeling for infinity: Imagine a hotel with infinitely many rooms that are all occupied. Now comes a new guest and asks if he can have a room. The clerk days ‘yes, of course’ and asks every occupant to move into the room next door with a room number one higher. this leaves room #1 free for the new guest. Then infinitely many new guests show up and ask if they can have a room too. ‘Yes, of course’ answers the clerk and asks every guest already in the hotel to move to a room number twice the number of the room of the one they are now in. This leaves all the odd-numbered rooms free for the infinitely many new guests…
Inflation is a pretty concept, but laymen are likely to ask whether it operates at all scales, and affects all bonding forces. For example is a diamond slowly expanding, too? And if everything is slowly inflating even at the subatomic level, why is it not affecting light at the same rate everywhere?
But if it is not, should we be seeing different rates of inflation where bonding forces vary?
What do our cosmologists say?
Leif Svalgaard (10:35:07) :
“vukcevic (09:38:15) :
Magnetic line does not exist any more than an isobar on a weather chart or isohypse on a mountain side of a field map.
How is it possible to conduct an intelligent discourse when your concepts are so wrong-headed”…
“Now, in the polar caps of the Earth from about 100 km and up things are very different. The magnetic field of the Earth up there and beyond are connected to the solar wind and is swept into a long anti-sunward tail. The field lines in the tail have individuality, they can sometimes even be seen [as auroral streamers] and particles scuttle up and down the field lines and don’t jump to other lines. The field lines can even wiggle and wave in response to changing solar wind [and ionospheric winds too].”
Perhaps I’m picking up fag-ends here, but an interesting issue arises in connection with the earlier (rather animated) discussion on this thread about magnetic field lines – are they real or just an illustrative tool? Dr Svalgaard asserts both can be true – in most places on the earth’s surface they are an abstraction but they manifest as real entities at the poles.
I’m no specialist in astrophysics, not exactly a rocket scientist either. However expressions like “ribbon” and “auroral streamers” in the present context for me raise a flag suggesting the possible operation of a phenomenon discussed regularly on this site – chaotic nonlinear pattern formation.
The description of auroral streamers under magnetic influence caught my attention:
“The field lines in the tail have individuality, they can sometimes even be seen [as auroral streamers]”
This reminded me of some well-known examples of non-linear pattern formation. For instance, consider smoke rising from a cigarette end (memories from a mis-spent youth) in still air: the smoke rises driven by the thermal heating of the smoke particles, but initially, instead of diffusing into the air, the smoke remains concentrated and forms a ribbon pattern as it rises. Another analogy – it you slowly turn on a water tap (or “faucet” if you like), first you get only drips, then a sort of laminar flow. Then you reach the laminar-turbulent boundary, and beyond it a chaotic cascade of streams and drops. But the interesting part is just before the onset of full chaos / turbulence, where the quasi-laminar flow sometimes is deflected to one side, or partially becomes turbulent only to converge to a laminar stream going off in a different direction. (This phenomenon sometimes has nuisance value for us menfolk when relieving ourselves in a standing position.)
Both of these and examples of a strange attractor. In the case of the smoke the “phase space” is the whole volume of air that the smoke could potentially rise into and the strange attractor is the very limited ribbon-like subset of the air volume through which the smoke actually rises.
Is there something special about the air inside the ribbon to make the smoke converge into the ribbon? No. This is simply the way nonlinear pattern formation operates – all you can say is that for some reason that is beyond traditional analysis, the rising smoke system “likes” that ribbon-shaped bit of the air more than the rest of the air.
The same is true of all systems where chaotic-nonlinear pattern formation operates and attractors exist. They are called “strange” attractors precisely because it is beyond traditional mathematical-physical analysis to understand what is special about the phase space subset that the system is attracted to.
[a pedantic aside – the use of the term “chaos” in a context such as climate or emergent pattern, is not precisely correct although is used as a shorthand. What we are talking about is in a far-from-equilibrium system the transition into nonlinear behaviour at the boundary of chaos, associated with spontaneous pattern formation, but not chaos itself, which is quasi-random and less interesting.]
So you have a strong and fluctuating magnetic field at the poles, buffeted by solar wind, and auroral streamers are seen to travel in lines or ribbons along the magnetic field. Does this mean that the magnetic field itself is separating into discreet lines or ribbons? Not necessarily. All that would be required is a certain amount of resistance to the flow of the auroral particle streams (friction or damping) and all the ingredients are in place for the streamers to show non-linear pattern formation – like the rising smoke or water from the tap. The streamer seems very likely to me to be an attractor within the (locally uniform) magnetic field. But – to return to the smoke analogy – there is nothing special about the line or ribbon along which the streamer is propagating – the line represents the attractor to which the streamer is converging.
This interpretation would argue against the existence of discreet magnetic field lines (whatever they would actually be physically) but for the separation of the auroral streamers into lines and ribbons as a normal converence into a nonlinear strange attractor. Nothing special about the line. Its just the whymsical behaviour of he system.
Its also quite likely that the “space ribbon” that is the heading of this thread is also a spontaneous pattern structure, an attractor. Again the key ingredient of frictional damping (or “dissipation”) is present: solar wind pushing the particles beyond the solar system, magnetic field resisting the solar wind and pushing them back. Result? Ribbon. In fact, any ribbon structure you see forming in a volume is most likely a strange attractor.
James F. Evans (09:27:17) :
Dr. Svalgaard wrote: “No, the solar wind magnetic field IS the Sun’s dipole field dragged out into interplanetary space.”
And what happens to the magnetic field generated by the solar wind’s plasma flow?
Or do you maintain, “The moving plasma, i.e., charged particles flows, are currents that produce self-magnetic fields, however weak.” — A. L. Peratt, does not exist in that physical circumstance?
If so, what physical circumstance or condition would cancel the magnetic field generated by the solar wind’s plasma flow?
~
Not trying to bum you out Leif, nice job providing explanations for me, joe public and the millwrights. (sounds like a band of gypsies) We thank you. Thanks Leif.
Let’s re word this perhaps. I think Evans knows that the suns magnetic field is dipole generated and carried out on solar winds. Is he suggesting that another kphase is happening with the solar wind and plasma? calling it a double layer?
If so, what physical circumstance or condition would cancel the magnetic field generated (chopped off the end of Evans question here)
Vuks, one of your favorite topics. Have you gotten that new bigger, better wrecking ball installed yet?
http://www.astro.ucla.edu/~wright/cosmology_faq.html#SS
supercritical (14:46:43) :
likely to ask whether it operates at all scales, and affects all bonding forces. For example is a diamond slowly expanding, too?
Everything is not expanding, because the forces that hold e.g. the solar system together are gazillions times stronger than the expansion: http://www.astro.ucla.edu/~wright/cosmology_faq.html#SS
Only things that are large enough will show measurable expansion.
phlogiston (15:06:12) :
It is simpler than that. The ‘explosions’ that create electric sparks and aurorae are very filamentary [also being a plasma likes to bunch up – even the EU has that grain of truth], so particles are not spread out [although there are diffuse aurorae too], but ‘spiked’. Once they start moving they are stuck on whatever [fictional] field line they happen to be on and ‘light’ that one up and [this is the important bit] gives it individuality and existence.
Carla (15:21:10) :
I think Evans knows that the suns magnetic field is dipole generated and carried out on solar winds.
I don’t think he knows. [or knew; by now he should know – it would be nice if he would tell us that he has now learned that]
Dr. Svalgaard, you stated:
Leif Svalgaard (14:15:15) October 29, 2009: “…
Dr. Svalgaard presented Evans statement: “Frankly, the descriptions [of “magnetic reconnection”] are consistent with a plasma ‘double layer’”
And Dr. Svalgaard responded: “Of course, nobody doubted that for a second. These double layers are generated in currents resulting from plasma moving in a magnetic field.”
Dr. Svalgaard, the context of the above quotes is clear, back in late October you acknowledged that the names double layers and “magnetic reconnection” describe the same process.
Today, you have claimed otherwise:
So, I present a scientific paper discussing magnetic reconnection:
http://www.leif.org/EOS/2009GL040228.pdf
Dr. Svalgaard wrote: “…a double layer consists of two layers with opposite electrical charge, there doesn’t need to be a magnetic field. Reconnection happens between two regions with opposite magnetic polarity changing the topology of the fields, there doesn’t need to be a current.”
It is apparent from the paper linked above the physical process is the same thing with different names.
James F. Evans (17:34:49) :
It is apparent from the paper linked above the physical process is the same thing with different names.
What you are missing is that double layers can form during reconnection, especially in the exhaust from the reconnection site where particles can be accelerated. What is wrong with you use of the words is the ‘a.k.a’
And the distinction is completely irrelevant for the topic. But, OK, I’m always willing to clear up your confusion. I wish I now and then would see a tangible sign of the fog lifting.
Leif Svalgaard (14:13:54) :
The current data and our understanding of them support the view
Current data and the understanding of it will be different in the future.
supercritical (14:46:43) :
Inflation is a pretty concept, but laymen are likely to ask whether it operates at all scales, and affects all bonding forces.
Experience tells me you are overestimating what ‘laymen’ will ask. A layman here or there may actually imagine to ask things like this. But most will be thinking about bills they have to pay and who will win American Idol.
James F. Evans (17:34:49) :
So, I present a scientific paper discussing magnetic reconnection: http://www.leif.org/EOS/2009GL040228.pdf
which, BTW, does not a single time mention ‘double layers’. so perhaps you can show the statement or paragraph [they’re numbered for you convenience] where it is shown that double layers and reconnection are different words for the same thing.
photon without a Higgs (17:49:19) :
Current data and the understanding of it will be different in the future.
Perhaps, but we have to go with what we have got at present. And your statement is not universally valid. I don’t think our understanding that the Earth is round will be different in the future. Or that the Solar corona is hot, or that the Earth is ~4.5 billion years old, or that the Universe is expanding, or … gazillions other things.
just a general thought about this ‘debate’:
just because you can’t understand Einstein doesn’t mean you should conclude he is wrong.
But I know my admonition won’t mean much since some people in Einstein’s day thought he was wrong, including Neils Bohr—and it’s still true today.
I wonder if it’s jealousy that makes some people talk about Einstein the way they do.
btw, I won’t be debating anyone here about if light follows the curve of space, and other things Einstein said.
photon without a Higgs (18:16:14) :
since some people in Einstein’s day thought he was wrong
Even Einstein thought he was wrong [on one small point]: “My greatest blunder” …[ http://www.jb.man.ac.uk/~jpl/cosmo/blunder.html ]
Dr. Svalgaard:
It’s not the name that matters, “a rose by any other name is still a rose”; it’s the physical processes and conditions that are important. “… double layers are generated in currents resulting from plasma moving in a magnetic field.”
Yes, we agree.
“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
And this dynamic where plasma flows “through a magnetic field” is a ubiquitous occurrence in space as flows of plasma and magnetic fields now have been observed & measured as far into the Universe as man can peer with his apparatus. And this post concerns one of those processes where plasma is flowing perpendicular into a magnetic field.
James F. Evans (18:35:13) :
And this dynamic where plasma flows “through a magnetic field” is a ubiquitous occurrence in space as flows of plasma and magnetic fields now have been observed & measured as far into the Universe as man can peer with his apparatus.
Perhaps there is hope. So, you agree that electric fields and currents in space arise because electrically neutral plasma containing equal amounts of positive and negative charges is moving across existing magnetic fields.
What took you so long? And why the acrimony?
And perhaps you would be so kind to reply to a few of my questions, such as
Carla (15:21:10) :
“I think Evans knows that the suns magnetic field is dipole generated and carried out on solar winds.”
I don’t think he knows. [or knew; by now he should know – it would be nice if he would tell us that he has now learned that]