A big surprise from the edge of the solar system: magnetic bubbles (w/ video)

Jun 09, 2011 by Dr. Tony Phillips
Old and new views of the heliosheath. Red and blue spirals are the gracefully curving magnetic field lines of orthodox models. New data from Voyager add a magnetic froth (inset) to the mix. Credit: NASA

(PhysOrg.com) -- NASA's Voyager probes are truly going where no one has gone before. Gliding silently toward the stars, 9 billion miles from Earth, they are beaming back news from the most distant, unexplored reaches of the solar system.

Mission scientists say the probes have just sent back some very big news indeed.

It's bubbly out there.

According to computer models, the bubbles are large, about 100 million miles wide, so it would take the speedy probes weeks to cross just one of them. entered the "foam-zone" around 2007, and followed about a year later. At first researchers didn't understand what the Voyagers were sensing--but now they have a good idea.

"The sun's magnetic field extends all the way to the edge of the solar system," explains Opher. "Because the sun spins, its magnetic field becomes twisted and wrinkled, a bit like a ballerina's skirt. Far, far away from the sun, where the Voyagers are now, the folds of the skirt bunch up."

When a magnetic field gets severely folded like this, interesting things can happen. Lines of magnetic force criss-cross, and "reconnect". ( is the same energetic process underlying .) The crowded folds of the skirt reorganize themselves, sometimes explosively, into foamy magnetic bubbles.

"We never expected to find such a foam at the edge of the solar system, but there it is!" says Opher's colleague, University of Maryland physicist Jim Drake.

This video is not supported by your browser at this time.
Using a computer model based on Voyager data, scientists have shown that the sun's magnetic field becomes bubbly in the heliosheath due to reconnection. Credit: NASA/Goddard Space Flight Center

Theories dating back to the 1950s had predicted a very different scenario: The distant magnetic field of the sun was supposed to curve around in relatively graceful arcs, eventually folding back to rejoin the sun. The actual bubbles appear to be self-contained and substantially disconnected from the broader solar magnetic field.

Energetic particle sensor readings suggest that the Voyagers are occasionally dipping in and out of the foam—so there might be regions where the old ideas still hold. But there is no question that old models alone cannot explain what the Voyagers have found.

Says Drake: "We are still trying to wrap our minds around the implications of these findings."

Magnetic bubbles at the edge of the solar system are aboout 100 million miles wide--similar to the distance between Earth and the Sun. Credit: NASA

The structure of the sun's distant magnetic field—foam vs. no-foam—is of acute scientific importance because it defines how we interact with the rest of the galaxy. Researchers call the region where the Voyagers are now "the heliosheath." It is essentially the border crossing between the Solar System and the rest of the Milky Way. Lots of things try to get across—interstellar clouds, knots of galactic magnetism, cosmic rays and so on. Will these intruders encounter a riot of bubbly magnetism (the new view) or graceful lines of leading back to the sun (the old view)?

The case of cosmic rays is illustrative. Galactic cosmic rays are subatomic particles accelerated to near-light speed by distant black holes and supernova explosions. When these microscopic cannonballs try to enter the , they have to fight through the sun's magnetic field to reach the inner planets.

This video is not supported by your browser at this time.
Computer simulation of the magnetic reconnection in the heliosheath.

"The magnetic bubbles appear to be our first line of defense against cosmic rays," points out Opher. "We haven't figured out yet if this is a good thing or not."

On one hand, the bubbles would seem to be a very porous shield, allowing many cosmic rays through the gaps. On the other hand, could get trapped inside the bubbles, which would make the froth a very good shield indeed.

So far, much of the evidence for the bubbles comes from the Voyager energetic particle and flow measurements. Proof can also be obtained from the Voyager magnetic field observations and some of this data is also very suggestive. However, because the is so weak, the data takes much longer to analyze with the appropriate care. Thus, unraveling the magnetic signatures of bubbles in the Voyager data is ongoing.

"We'll probably discover which is correct as the Voyagers proceed deeper into the froth and learn more about its organization," says Opher. "This is just the beginning, and I predict more surprises ahead."

Explore further: After Rosetta, Japanese mission aims for an asteroid in search of origins of Earth's water

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User comments : 25

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Atoyota
3 / 5 (4) Jun 09, 2011
Awesome!
I saw this earlier today from another physic.org tweet, but this article is much better.
I'm very interested in magnetic/gravitational waves emanating by the black hole at the center of our galaxy (that and other objects in line with the center) and that energy transfer.
Dipole fields are warped by the motion and spin of the black hole and I feel concentrated. Further data from voyagers may see this.
Sanescience
5 / 5 (7) Jun 09, 2011
Neato! Go plutonium thermal gradient power cells!
gwrede
4.8 / 5 (17) Jun 09, 2011
Spacecraft sending us profoundly new and valuable data, even when they were sent there before most of PhysOrg readers were even born! And others, half a dozen years beyond their designed life, sending us unique data from Mars.

Now, that is something I didn't anticipate in the sixties, when I tried to imagine life beyond the year 2000.

I just took a web tour of 1977 tech (the year the Voyagers were sent), and the technology and computers were just primitive and ancient. These spacecraft were designed with pencil, pocket calculators, and paper.

Not to mention, these things still work!! Can you buy *any* gadget today that would work after 35 years????
SemiNerd
3 / 5 (1) Jun 09, 2011
If the froth is a shield, its a very small one in connection to cosmic rays. The froth described here really only covers the side of the solar system in the direction of the suns travel in its orbit around the center of the galaxy. The rest would be unprotected (at least in terms of cosmic rays).
_nigmatic10
4.2 / 5 (5) Jun 09, 2011
makes sense. spin something in the water, and you get ripples and bubbles.. a froth. same principle seems to exist here.
Ober
3 / 5 (6) Jun 09, 2011
Cosmic rays must be far more plentiful than I ever thought. If our star has this kind of shield around it, then what about all other stars?? Surely the Milky Way must be a massive foam of magnetic fields, so how do cosmic rays penetrate all the way through this??? The central black hole, may also form some kind of bizarre magnetic foam further out as well????
Perhaps, as some have suggested, that cosmic rays might originate from microscopic black holes. Purely conjecture there!!!!
I wonder what a galaxy map of all the twisted and knotted magnetic fields would look like. I bet this map would be of significant importance in understanding the nature of our galaxy and local space.
Gilbert
2.8 / 5 (4) Jun 09, 2011
I wonder how that would effect the perceived distance of interstellar objects, as this would mean that it actually takes longer for rays to get to us, does that mean that many/some/all are closer than it seems?

also does that mean that when you're outside the solar system space would appear to be bright white, rather than black? or at least alot brighter than it is from here?

or am I mistaken ?
finitesolutions
4.7 / 5 (3) Jun 10, 2011
I can only imagine the next century spacecrafts flying past by Voyager on their way to explore Alpha Centauri .
We are still primitive people.
antialias_physorg
2.3 / 5 (3) Jun 10, 2011
can only imagine the next century spacecrafts flying past by Voyager on their way to explore Alpha Centauri .

Unlikely (unless navigation software will become worse in the future than it currently is in my car) - as Voyager isn't heading anywher near the direction of Alpha Centauri.
LKD
1 / 5 (1) Jun 10, 2011
The question that comes to my mind is how does this area of the Helio compare to the boundary if you were to follow the Sun's pole? There should be a far greater effect, much like the Auroras.
RealScience
5 / 5 (4) Jun 10, 2011
Gilbert - this only affects cosmic rays (charged particles). It does not affect light, so it does not affect the measurements of distances to stars and galaxies.

gwrede - the space program had computers back in 1977. I'd been programming computers for over a decade when Voyagers were launched (including for Goddard Institute of Space Studies), and the computers of 1977 were great! (Of course we didn't have bloatware to slow them down).
But you are spot on regarding the incredible lifespan of the voyagers.
Gilbert
4 / 5 (2) Jun 10, 2011
I was thinking along the lines of the Faraday effect, Faraday rotation in the interstellar medium, if you take this new find and assume that the rest of interstellar space between everything is filled with this magnetic ( independent ) energy, wouldn't it be logical that cosmic rays being affected would in turn effect the refraction of radiation, as it interacts with these charged particles, ( as it is of course over enormous distances )thus effecting the readings we receive here, (and effecting infra red, microwaves more-so, which lately have been a basis for interstellar pictorials.)

and on my second point, don't these charged particles (especially the ones with high energy) create electromagnetic radiation when interacting with other matter, and with each other, so when in this area, visually there would be some kind of background brightness/ aura, and the extent of which would change as you traveled through each "bubble"? This would be especially true if, as they ask,
Gilbert
3.5 / 5 (2) Jun 10, 2011
the rays become trapped orbiting these bubbles, if that happened there would most definitely be interaction between them right?
RealScience
5 / 5 (2) Jun 10, 2011
Gilbert - you could indeed end up some Faraday rotation. If the bubbles are fine-grained this would tend to cancel from bubble to bubble with polarization, but some effect would remain. Some smart grad student will probably get a PhD for figuring out how to use this to map the bubbles.

However this would not noticeably affect distance measurements based on Cepheid variables. The change in index of refraction is minuscule and it is the intensity rather than the timing that is measured anyway. Even for light red-shifted well into the infrared the effect would be tiny.

Cosmic background folks, who study polarization and at longer wavelengths, should at least double-check the magnitude of this, but I suspect that it is only well into radio wavelengths that this will even be measurable.
MarkyMark
1 / 5 (1) Jun 11, 2011
I wonder how that would effect the perceived distance of interstellar objects, as this would mean that it actually takes longer for rays to get to us, does that mean that many/some/all are closer than it seems?

also does that mean that when you're outside the solar system space would appear to be bright white, rather than black? or at least alot brighter than it is from here?

or am I mistaken ?
Sniff Sniff, i smell creationism in this post! ( mostly joking of course ).
avafeas
3.5 / 5 (2) Jun 11, 2011
Forgive me because I'm not educated about this - but at a large enough distance from the Sun, shouldn't the magnetic field of the Sun be able to be modelled as if it were a point charge; why does it have a magnetic field at all, when we are far away? Do all the negative charges in the sun have positive companions, is the sun electrically neutral?

Is there an analogous magnetic "foam" surrounding very small spinning charges, then? Around atoms or molecules? I'm not sure if atoms or molecules can be said to "spin" in a classical sense. Could an analogous "foam" effect exist around a larger (but still microscopic) object then? A nanoparticle?

I am genuinely curious and appreciate any responses, even if they're critical.
RealScience
4.7 / 5 (3) Jun 11, 2011
avafeas - the magnetic fields at that distance are not from the sun being a spinning charge.
The negative and positive charges in the sun are well matched, so compared to an electron or a proton the sun as a whole is neutral. But the electrons and protons are separated into a plasma, which can conduct electricity, so the churning gasses create a dynamo that builds a magnetic field (much like the earth's liquid iron outer core).

The sun is constantly sending out charged particles (mostly protons and electrons) in the solar wind, and occasionally blasting out huge masses of plasma (coronal mass ejections). This plasma is launched by the sun's magnetic field, and carries the magnetic field with it.

An atom or molecule or proton or electron is not emitting a magnetized conductive plasma, so it would not have a similar foam around it.

(Electron spin does interact with a magnetic field - see the Zeeman effect.)
avafeas
3 / 5 (1) Jun 11, 2011
Thanks, that was really helpful. I'm sure that the "wind" of electromagnetic particles flying past our solar system plays a part in the interaction that produces these magnetic bubbles too, so the chances of seeing something similar in a smaller (microscopic) system are basically zero - there is no plasma, there is no "ether" wind on such a small scale.

Thanks for the quick explanation about plasmas as well; the charge separation in plasmas hadn't occurred to me but is completely logical, that's what happens when you don't try (very much) to answer your own questions before posting.
RealScience
not rated yet Jun 11, 2011
avafeas - Exactly. It is an interaction between the "wind" from our sun and the interstellar "wind". Amazingly enough, these behave much like wind, even though their densities are so many orders of magnitude lower (the magnetic fields do add another layer of complexity, though).
Wulfgar
not rated yet Jun 11, 2011
Aren't these magnetic bubbles also known as plasmoids? Are these bubbles aligned along the same plane as the planets in our solar system as the graphic is suggesting?
Johannes414
1 / 5 (5) Jun 13, 2011
Man can dream about travelling beyond the starts, but that will never happen. More important to every individual is the question of what happens after we die. Eternity is a long time.
RichPea
not rated yet Jun 13, 2011
I couldn't imagine Man not moving beyond the stars...we're just taking our baby steps and need to create bigger and better ways to move about in a vacuum, or enhance our knowledge of deep hibernation sleep for long treks between stars. If you had a traveling, functioning society in space, there would be no need to worry about death when your children can take over after you die. Multiple societies in space habitats would be even better. Gotta block that radiation above all things though.
martinwolf
not rated yet Jun 13, 2011
Amazing..the more time passess/the more individuals are involved in research of all kinds/the more amazing the understanding of this magical universe we all call home...Kind of makes one smile with joy that humankinds knowledge bank has no frontiers but continues to be added to and refined..the future looks exciting from an early sexagerians timeline and life experience following the scientific enterprise as much as possible:)...thanks to all the governments/business/philanthropists and amateurs supporting this exploding progress in virtually every field of science and philosophy(including the arts in this declination)...
EWH
1 / 5 (1) Jun 13, 2011
I wish the astrophysicists would stop using the sloppy term "magnetic reconnection". The field lines are no more real than lines of longitude, merely a convenient but often misleading visualization. The supposed reconnection only takes place where there is no field, hence different field lines never touch, and since field lines are always closed loops, therefore there can be no reconnection of field lines. It's a tempting shorthand, but like saying "the sun rose" it is just plain wrong.
nickelsworth
not rated yet Jun 15, 2011
Faraday was the first thought that burst forth inside my beleaguered brainpan. Could our heliosheath be related to any of Faraday's laws of optics, electromagnetics, or even physical chemistries? Perhaps a mix of all three? I'm a dreamer.. that's for sure! But, I love mysteries and ultimate truths. We are in this Universe and sometimes I can't help but feel that this Universe is inside us.

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