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
Bowshock in space always strikes me as strange….. Where particle densities are so low, it intrigues me how you can have an interaction between particles where they do not actually touch?… So therefore it must be fields of energy that are being compressed…. Which gives rise to electrified plasma…. I find it strange that magnetic fields could exist without an electic current.
… any thoughts?
J.Hansford (18:36:56) :
“… any thoughts?”
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Gravity
phlogiston (17:13:34) : There is a dicotomy always present everywhere: Entropy vs. negentropy, the tendency to extreme order, to stasis vs. the tendency to extreme movement, to dynamis, between both, a synthesis is what is found in the dynamic stability of a Birkeland´s current.
We use to take sides but the just is in the middle. Trouble is that if we follow or, worse, if we are obliged to choose the entropic path unwillingly, no matter how good intentions are, we´ll find the anthill or the beehive, if we follow the other extreme path we also find death, this time by dissolution. Our hearts can stop beating in systole or in diastole, both meaning death.
So take it cool. Interesting times bring interesting situations.
JonesII (11:22:23) :
neglecting the majority of people the human right of enlightment , knowledge and reason
Neglecting they themselves who try to do this to others – neglecting others of these same powers and facts of human potential regarding thought – is much more like what they are actually implying as the fact about themselves. For me, that’s the only thing which explains their behavior.
J.Hansford (18:36:56) :
I find it strange that magnetic fields could exist without an electric current.
… any thoughts?
Or a physicist who could walk without electricity, or breath without oxidizing his hemoglobin from Fe2 to Fe3 without electrons, there is none.
Pascvaks (18:43:07) :
J.Hansford (18:36:56) :
“… any thoughts?”
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Gravity
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No, not on particle densities this nebulous… Gravity is a weak force, all pervasive, but weak….. Electrostatic force is 36 to the power of 10 stronger. But only within a field. According to what I have read.
“They called it a “shocking result” and puzzled over its origin.”
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LoL… They aren’t making a Pun…. are they? 😉
J.Hansford (18:36:56) :
Bow shock in space always strikes me as strange….. Where particle densities are so low, it intrigues me how you can have an interaction between particles where they do not actually touch?
Particles ‘always’ interact without touching, because they are surrounded by fields. Gravitational fields for instance. But these are usually weak compared to electric forces, so in space it is the attraction/repulsion between electric charges and the magnetic fields that mediate the interaction. Now, one can get back to the ‘touching’ image by considering a field as consisting of virtual particles that are exchanged. In this way we can ‘understand’ the repulsion of two electrons: one electron emits a [virtual] photon. Since a photon has momentum, the emitting electron will experience a recoil. When the photon meets another electron it can be absorbed by the other electron. Because the photon carries momentum, the absorbing electron will be pushed in the direction of the photon’s movement which is the opposite direction of the recoil of the first electron. So, the two electrons seem to repulse each other [as they move in opposite directions] and momentum is conserved. If one works with particles or with fields are often a matter of convenience. It may be somewhat meaningless to ask what it ‘really’ is.
So charged particles moving into a magnetic field will feel forces at a distance even if nothing is ‘touching’.
“….So charged particles moving into a magnetic field will feel forces at a distance even if nothing is ‘touching’.”
Thanks Leif.
There is no such thing as a static magnetic field which persists simply because it cannot dissipate via a current. All magnetic fields are dynamic, the results of the motions of charge carriers. Any magnetic field at all is evidence of an existing current, even if it is merely a virtual and mathematical net current not corresponding in a simple way to what actual particles are doing.
Easy; it’s called a “radiating structure”, an antenna in it’s modern incarnation, and it can be demonstrate by an oft-repeated act performed by ham radio operators doing …. Moon bounce:
[youtube=http://www.youtube.com/watch?v=xWZntgLkQeA&hl=en_US&fs=1&]
A good 2 1/2 seconds later (after the ‘current’ has long ceased in the transmitting antenna) one can hear one’s own voice returning back after having effectively created an EM wave that propagates to, then is reflected back by the moon.
Nature creates propagating EM waves in the form of ‘static crashes’ (that plague (particularly) 160m and 80m bands + the AM broadcast band) long after the current ceases flowing owing to lightning discharges occurring in thunderstorms.
The movement of charges (ions/charged physical particles) will also produce mag fields; under the right circumstances propagating waves are also a possibility from those sources …
.
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Paul R (20:34:28) :
There is no such thing as a static magnetic field which persists simply because it cannot dissipate via a current.
Magnetic fields in media [like most space plasmas] with infinite [or nearly so] conductivity behave differently from magnetic fields in vacuum or other non-conductors.
Paul R (20:34:28) :
Any magnetic field at all is evidence of an existing current
The ‘existing’ word needs to be dealt with correctly. Take the example of the magnetic field between your ears [or just in front of your eyes]. This field is not evidence of an electric current between your ears [one might hope you have some electricity there, though 🙂 ]. It is evidence of a current somewhere else [in the Earth’s core where it is generated by conducting material moving relative to the already existing magnetic field there – a dynamo]. Similarly, the magnetic field in the solar wind is evidence of a dynamo current inside the Sun. Because of the [practically] infinite conductivity of the solar wind plasma, the field of the Sun is dragged out into interplanetary space by the expanding gas. A plasma trying to move across a magnetic field line will generate a current that immediately will be shorted out and thus cannot be sustained. The net result is that the magnetic field is stuck to the plasma and follows it where-ever the plasma goes. As the plasma twists and turns, the magnetic field can be amplified greatly. The magnetic field of galaxies and in intergalactic space is evidence of currents that flowed at the birth of the Universe [The Biermann battery effect, http://nedwww.ipac.caltech.edu/level5/March08/Subramanian/Subramanian3.html ].
Shades of Immanual Velicovsky. He just might have been right again, and again to the chagrin of “conventional science”.
Leif Svalgaard (21:47:44) : ……..” A plasma trying to move across a magnetic field line will generate a current that immediately will be shorted out and thus cannot be sustained.”
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Doesn’t a plasma isolate itself from shorting out by “organizing” into a “double layer” ?… It is why it is hard to measure the physical appects of Plasma… Hence the Langmuir probe was devised to do that job.
I also read this…. I don’t know how correct it is… But I’ll Paste it…. and leave it to you….
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“Now we know that there can be slight voltage differences between different points in plasmas. Plasma engineer Hannes Alfvén pointed out this fact in his acceptance speech while receiving the Nobel Prize for physics in 1970. The electrical conductivity of any material, including plasma, is determined by two factors: the density of the population of available charge carriers (the ions) in the material, and the mobility of these carriers. In any plasma, the mobility of the ions is extremely high. Electrons and ions can move around very freely in space. But the concentration (number per unit volume) of ions available to carry charge may not be at all high if the plasma is a very low pressure (diffuse) one. So, although plasmas are excellent conductors, they are not perfect conductors. Weak electric fields can exist inside plasmas. Therefore, magnetic fields are not frozen inside them. ”
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Thanks Jim….
J.Hansford (19:02:38) :
Pascvaks (18:43:07) :
Gravity is a weak force
I’ve heard this said a lot. But I’ve always wondered if it was thought through. The most common example given is EM (electromagnetism) in a magnet can pick up metal and thus is easily defeating gravity that was pulling it down. But isn’t there a concentration, so to speak, of EM in a magnet? So if gravity was concentrated, so to speak, in a black hole could the same magnet pick up the same piece of metal in the black hole?
J.Hansford (22:40:33) :
So, although plasmas are excellent conductors, they are not perfect conductors. Weak electric fields can exist inside plasmas. Therefore, magnetic fields are not frozen inside them. ”
Trying to generalize always gets one in trouble. The mobility of charges inside a dilute space plasma is not limited by collisions because there are none. The relevant quantity is called the ‘plasma parameter’ http://en.wikipedia.org/wiki/Plasma_parameter
In the solar wind and galactic space conductivity is almost infinite and no electric fields occur. In other plasmas, situations may be different. The solar photosphere is often called a plasma, but its conductivity is no higher than that of sea water, so magnetic fields are only weakly frozen in. Similarly with plasmas in magnetospheres and in the laboratory [it is hard to make the hard ‘vacuum’ of interplanetary space].
photon without a Higgs (23:14:50) :
a magnet can pick up metal and thus is easily defeating gravity that was pulling it down.
It is defeating the gravitational attraction of the entire Earth…
just what are you NASA guys doing?
Cocaine discovered in NASA shuttle hangar
http://www.presstv.ir/detail.aspx?id=116350§ionid=3510212
Leif Svalgaard (16:12:05) :
…..The Caltec image shows [a poor rendition]…..
I wonder if their rendition may be more up to date than some 20-30 years old more artistic ones. Thanks for your links, already familiar with. The rest of your comments are somewhat misleading.
– Once particles (protons & electrons) leave the sun, they travel in strait line not along a spiral, and wrapping is a relative relationship to the point of origin, but has no impact on further trajectory of the particles.
– Current sheet may be wrapped around many times, but ‘wraps’ are spaced along the path, and further away you are from the sun, more spared out they are, due to increased velocity.
– Only one portion of the apparent ‘spiral’ will hit the nose of the heliosphere at any time.
– You failed to explain how ribbon happens to be such a well focused form if the heliosphere is impacted by CRs from many directions. Even if the CRs are coming from a single source, distances are so vast that the radial dispersal would be such that possibility of narrow focusing at place of impact with a distant object would be practically zero.
– In addition you have not offered any view, however speculative, how such well formed ribbon shape could be formed and apparently acquire shape which appear to be same as the outer edge of the HCS.
Of course for time being my observations as many others are purely speculative, but at least I offer a plausible solution to a puzzle, without contradicting any laws of physics or being in conflict with the known properties of the heliosphere or the surrounding space.
http://www.vukcevic.talktalk.net/LFC3.htm
Leif Svalgaard (23:50:55) :
Really?
photon without a Higgs (23:14:50) :
“…. So if gravity was concentrated, so to speak, in a black hole could the same magnet pick up the same piece of metal in the black hole?”
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Black holes and neutrons stars are not “real” apparently…. They are hypothetical models of observed phenomenon…… Guesses of what is happening, with mathematical justifications and fudge factors to obscure the fact it is just a guess;-)
For it appears that a neutron star is comprised of only neutrons and their existence contradicts known physics. “Neutronium” doesn’t appear in the periodic table either and nor could it ever.
Matter comprised solely of neutrons is unstable. A lone neutron will decay in fourteen minutes and two or more neutrons in an atomic structure will fly apart instantaneously.
The theories are very weighty to be sure… But that is not a good thing where the principle of occam’s razor is concerned…. entia non sunt multiplicanda praeter necessitatem. “entities must not be multiplied beyond necessity”…. That the simplest explanation or strategy tends to be the best one.
Thanks Leif……
“In the solar wind and galactic space conductivity is almost infinite and no electric fields occur. In other plasmas, situations may be different. The solar photosphere is often called a plasma, but its conductivity is no higher than that of sea water, so magnetic fields are only weakly frozen in. Similarly with plasmas in magnetospheres and in the laboratory [it is hard to make the hard ‘vacuum’ of interplanetary space]
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Ah, righto. You are saying. That in deep galactic space the magnetic fields ARE frozen because the plasma IS infinite in its conductivity…. It’s the nature of very “dilute” plasma.
But where it is hotter and denser it does conduct weakly, thus the magnetic fields are “freer” within it?…
…. and that where the confusion arises is due to the inability to create the plasma conditions of deep intergalactic space within the laboratory….? Yes?
This reminds me of a website I saw some time last year but can’t find now. Something about natural electric currents and magnetic fields operating on gigantic scale, causing the pinched middle shapes of several nebulas and gas clouds that’re the remains of supernovas. Had lots of pictures from Hubble and other telescopes.
Natural “magnetic pinch” fusion process… squeezes the results out in two directions. Without some belt-like process to constrain those stellar explosions, the expanding leftovers ought to be darn near spherical, or at least randomly blob-ish.
Yet there are many that aren’t, and more of those wasp-waisted clouds are being found quite often.
(An explanation for the “Collapsing Hrung Disaster”? 😉
Re: my previous comment. Google for hourglass nebula and you’ll find some good images.