December 23, 2009: The solar system is passing through an interstellar cloud that physics says should not exist. In the Dec. 24th issue of Nature, a team of scientists reveal how NASA’s Voyager spacecraft have solved the mystery.
“Using data from Voyager, we have discovered a strong magnetic field just outside the solar system,” explains lead author Merav Opher, a NASA Heliophysics Guest Investigator from George Mason University. “This magnetic field holds the interstellar cloud together and solves the long-standing puzzle of how it can exist at all.”
Right: Voyager flies through the outer bounds of the heliosphere en route to interstellar space. A strong magnetic field reported by Opher et al in the Dec. 24, 2009, issue of Nature is delineated in yellow. Image copyright 2009, The American Museum of Natural History. [larger image]
The discovery has implications for the future when the solar system will eventually bump into other, similar clouds in our arm of the Milky Way galaxy.
Astronomers call the cloud we’re running into now the Local Interstellar Cloud or “Local Fluff” for short. It’s about 30 light years wide and contains a wispy mixture of hydrogen and helium atoms at a temperature of 6000 C. The existential mystery of the Fluff has to do with its surroundings. About 10 million years ago, a cluster of supernovas exploded nearby, creating a giant bubble of million-degree gas. The Fluff is completely surrounded by this high-pressure supernova exhaust and should be crushed or dispersed by it.
“The observed temperature and density of the local cloud do not provide enough pressure to resist the ‘crushing action’ of the hot gas around it,” says Opher.
So how does the Fluff survive? The Voyagers have found an answer.
“Voyager data show that the Fluff is much more strongly magnetized than anyone had previously suspected—between 4 and 5 microgauss*,” says Opher. “This magnetic field can provide the extra pressure required to resist destruction.”
Above: An artist’s concept of the Local Interstellar Cloud, also known as the “Local Fluff.” Credit: Linda Huff (American Scientist) and Priscilla Frisch (University of Chicago) [more]
NASA’s two Voyager probes have been racing out of the solar system for more than 30 years. They are now beyond the orbit of Pluto and on the verge of entering interstellar space—but they are not there yet.
“The Voyagers are not actually inside the Local Fluff,” says Opher. “But they are getting close and can sense what the cloud is like as they approach it.”
The Fluff is held at bay just beyond the edge of the solar system by the sun’s magnetic field, which is inflated by solar wind into a magnetic bubble more than 10 billion km wide. Called the “heliosphere,” this bubble acts as a shield that helps protect the inner solar system from galactic cosmic rays and interstellar clouds. The two Voyagers are located in the outermost layer of the heliosphere, or “heliosheath,” where the solar wind is slowed by the pressure of interstellar gas.
Voyager 1 entered the heliosheath in Dec. 2004; Voyager 2 followed almost 3 years later in Aug. 2007. These crossings were key to Opher et al‘s discovery.
Right: The anatomy of the heliosphere. Since this illustration was made, Voyager 2 has joined Voyager 1 inside the heliosheath, a thick outer layer where the solar wind is slowed by the pressure of interstellar gas. Credit: NASA/Walt Feimer. [larger image]
The size of the heliosphere is determined by a balance of forces: Solar wind inflates the bubble from the inside while the Local Fluff compresses it from the outside. Voyager’s crossings into the heliosheath revealed the approximate size of the heliosphere and, thus, how much pressure the Local Fluff exerts. A portion of that pressure is magnetic and corresponds to the ~5 microgauss Opher’s team has reported in Nature.
The fact that the Fluff is strongly magnetized means that other clouds in the galactic neighborhood could be, too. Eventually, the solar system will run into some of them, and their strong magnetic fields could compress the heliosphere even more than it is compressed now. Additional compression could allow more cosmic rays to reach the inner solar system, possibly affecting terrestrial climate and the ability of astronauts to travel safely through space. On the other hand, astronauts wouldn’t have to travel so far because interstellar space would be closer than ever. These events would play out on time scales of tens to hundreds of thousands of years, which is how long it takes for the solar system to move from one cloud to the next.
“There could be interesting times ahead!” says Opher.
To read the original research, look in the Dec. 24, 2009, issue of Nature for Opher et al’s article, “A strong, highly-tilted interstellar magnetic field near the Solar System.”
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Quote:”It’s about 30 light years wide and contains a wispy mixture of hydrogen and helium atoms at a temperature of 6000 C.”
Having worked with a Inert Gas Plasma Generator in a laboratory setting, and having experience with the noble gases Argon (Ar) and Helium (He), I can tell you that in addition to generating its own light, that Helium in plasma form DOES partially occlude visible light. In the Plasma Generator, the inert gas is electromagnetically excited inside a clear quartz glass chamber at high vacuum, typically less than 100 millitorr. I have no experience with hydrogen in that respect. It’s interesting that nobody seems to be talking about the possible effect that this interstellar cloud may have on the level of solar irradiance that will reach the earth and other planets, once the cloud moves between us and the sun, if not already.
And I was always taught in school that outer space is a vacuum!
30 years and still operating. I wish I could get that sort of life out of my batteries, but you get what you pay for I suppose. Alternatively, alien life forms have destroyed the Voyagers and replaced the signals with their own, which are sending misinformation to distract us from CO2. Al Gore would be fully supportive of this theory.
Bart (13:01:02) :
anna v (10:27:07) :
“…an electron, for example, is both a wave and a particle…”
No, it is a particle which moves with apparent wavelike properties in common experience, just like photons.
We knew about particles from the days of Demokritos and the atom.
We studied light after the enlightenment as first, rays, and then waves with the brilliant theories of Maxwell.
It is quantum mechanics that tied up the two formulations for photons/electromagnetic-waves and posited that depending on the experiment electromagnetism manifested as particles or waves, and the same with quantum mechanics which dictated experiments that showed that particles could manifest as waves, depending on the experiment.
Actually the cat in the box analogue was generated to demonstrate that unless one did an experiment ( observed) one did not know if it would manifest as a particle or a wave: all matter, photons and electrons and….
Even the word “photon” to describe an electromagnetic transfer of energy was invented when the photoelectric effect was observed in the beginning of the twentieth century.
RE: ‘Nasif Nahle (08:34:06) :’
Thankyou- very much.
Leif Svalgaard (13:43:54) :
The spiral is an illusion, just like the seeming spiral of water drops from a rotating lawn sprinkler.
True, but the next water drop leaves the sprinkler head just after the previous one, so the effect is like a wavefront of faster moving particles which will form a spiral leaving the sun. Not that it matters much fo Earth, since it is in a ‘line of sight’ to the sun and will collect a cross section of this succession of ‘peaks and troughs’.
The faster particles does not move ‘through’ the slower ones, but scoops them up into a compression region. The magnetic field acts as the shields preventing the two regions from interpenetrate.
Hence the tangling and mirror forming as the magnetic fields jumble at the interface. Thanks, I have a better visualisation of this process now.
The distance between the ‘waves’ will be 600 km*24(hours)*3600[secs)*25(days) = 1.3 billion km = 9 AU. Since there often are 4 high speed streams per solar rotation, the distance between compression regions will be 9/4 = 2 AU. If the the heliopause is 80 AU distant, there will be 80/2 = 40 such ‘mirrors’ between the Sun and an incoming cosmic ray.
Ah yes, I was thinking Km/h instead of Km/s. So we would have these successive waves of compression/rarefaction washing past us on a frequency of around 68 hours if I got my sums right this time :o)
vukcevic (13:33:46) :
http://www.vukcevic.talktalk.net/LOD-GMF.gif
(tallbloke might comment)
It’s very similar to the correlation between LOD and the rate of change of the declination of the north magnetic pole. I put a post up on my blog about it a week ago, please click on my name and drop by to comment on that thread.
Carla (17:48:51) :
Tallbloke, one more link for you.
Links to the movie of IMF in the ecliptic for Oct. 2003 when multiple solar events were occurring. Pretty cool to compare the then and now. You can see, I think the compression Leif was talking about.
http://gse.gi.alaska.edu/index.html
Forecasts during the Halloween Events period:
Real-time forecast of ecliptic plane IMF during the October, 2003 swarm of solar events:
AVI zipped movie: 10 AU (6-hr time step, includes locations of Ulysses and Cassini spacecraft)
Fascinating animations, thanks for the links.
I enjoyed the U2 as well. Cheers.
Leif Svalgaard (14:12:46) :
“I normally don’t look at your links [ 🙂 ], but apart from the cherry picking of the location and the fact that lately the two curves diverge, it is quite possible that the LOD is influenced by the same movements inside the Earth that are driving the geomagnetic dynamo.”
That is probably why you may have declared the obvious as ‘nonsense’.
http://www.vukcevic.talktalk.net/SSN-GMF.gif
You already (as some other prominent scientists of the past) have used the ‘East component’ of the GMF as a reliable pointer of the solar activity in past, so the link may not be that tenuous or even less a ‘nonsense’, it would be fine if you declare it ‘coincidence’ for time being.
Temporary divergence for LOD has happened before (1990) possibly due to ‘inertia’ within the different layers within the terrestrial ‘spin dryer’.
http://www.vukcevic.talktalk.net/LOD-GMF.gif
but trend was re-established.
The Earth’s magnetic field still has many secrets. ‘Cherry picking’ is not, geographically there are only two main references, N and S poles.
Two poles are behaving in somewhat different manner. Amplitude oscillations in the South have been largely negligible, with a steady decline in the total intensity. I put this down to huge and constant Circumpolar Current, maintaining stability, via negative feedback, result: far less likely to be shaken by the external input. North has numbers of small gyres but they not particularly effective. Rise in the central Siberian pole during the last 200 years and corresponding weakness in the Hudson Bay’s pole adds to complexity of the North’s GMF behaviour.
To stray away from matters terrestrial, here is what doc Hathaway had to say before he got tangled into SC24 forecasting:
“When we apply the theory and scaling parameters for the reversal period of the magnetic field of the Sun to Jupiter and Saturn, we derive an estimate for the time interval between magnetic reversals to be on the order of centuries. This time scale is consistent with observed changes in Jupiter’s magnetic field over the last 2 decades.”
Man is obviously talking ‘nonsense’, how possibly could solar activity have 105-7 year cycle, unless there is some kind of electro-magnetic (not to be confused with electromagnetic) feedback loop as proposed by elements of the lunatic fringe.
Nasif Nahle (18:17:09) :
Galaxy is something I used to marvel about in my childhood, now even nearer home is a big enigma, at least for me, currently I am down to earth, mystified by Nastapoka, an obscure area of the North East Canada.
Carla (17:31:55) :
“Could be some other indictators (2) big ones that I am thinking of, that are implicating “fluffy” as well. I’m going to try to keep my foot out of mouth now, so don’t ask.”
I have already done it by quoting dr. Hathaway [ vukcevic (02:00:26): ], still look regularly at your posts elsewhere, e.g. ‘fluffy clouds’.
tallbloke (23:18:27) :
Thanks for the invite, I will look in.
vukcevic (02:00:26) :
You already (as some other prominent scientists of the past) have used the ‘East component’ of the GMF as a reliable pointer of the solar activity in past, so the link may not be that tenuous or even less a ‘nonsense’, it would be fine if you declare it ‘coincidence’ for time being.
What makes it nonsense is that the GMF as observed consists of two parts, an internal part [which you have plotted] that is 99% to 99.9% of the whole, and a tiny external part which is controlled by the Sun. We don’t use the East Component as a measure of solar activity, but the tiny solar-caused variation that sits on top of the internal part.
The scaling law makes sense because the same process [dynamo] is generating the fields, but this does not mean that one internal field is controlled by another. Your arguments remind me of Voltaire’s proof that you are a stone: “a stone cannot fly, you cannot fly, ergo you are a stone”. It is a pity for the scientific integrity of this blog that it be marred by your nonsense.
Leif Svalgaard (05:50:03) :
“…..The scaling law makes sense because…..”
Thanks for the guidance, which I do appreciate.
It may be time for me to take a very long New Year break from the matters solar.
To Anthony, the moderators, the other contributors and readers and especially to you to be a VERY HAPPY YEAR.
When all that is knowable is known there will still be one question, “Why?”
Pascvaks (07:28:37) : Be careful, HE could have the answer to that question too.☺
Pascvaks (07:28:37) :
When all that is knowable is known there will still be one question, “Why?”
When lightning hits a tree in the forest, there is no “Why?”, so ‘whys’ are not needed.
Leif Svalgaard (19:14:57) :
“But once they have left the sprinkler, they don’t continue to curve in a spiral. The spiral effect comes from the sprinkler head rotating.”
True enough. I was just pointing out that the momentum is not radially directed. Why I was pointing this out, I’m not sure. It was late and I was getting a little punchy.
anna v (21:55:58) :
The old “wave-particle” duality is a relic of pre-QED quantum physics. I highly recommend Feynman’s book to which I linked.
Bart (08:04:51) :
I was just pointing out that the momentum is not radially directed. Why I was pointing this out, I’m not sure. It was late and I was getting a little punchy.
The solar wind has a very small transverse component [due to solar rotation], but is essentially radial because once it has left the inner corona, the wind is continually accelerated outwards. All analogies eventually fail when we come to the fine print 🙂
“…the [solar] wind is continually accelerated outwards.”
What causes the continual acceleration of the charged particles in the solar wind?
Hmmm?
Well, Science does know an electric field causes charged particle acceleration.
James F. Evans (09:22:59) :
What causes the continual acceleration of the charged particles in the solar wind?
The solar wind accelerates because it is being heated and [somewhat counter-intuitively] because its outflow is being restricted by gravity [see deLaval nozzle http://en.wikipedia.org/wiki/De_Laval_nozzle ].
Well, Science does know an electric field causes charged particle acceleration.
solar wind expansion has nothing to do with electric fields [which BTW can’t exist in a space plasma, as you have been told numerous times].
Leif Svalgaard (07:44:47) :
Pascvaks (07:28:37) :
When all that is knowable is known there will still be one question, “Why?”
When lightning hits a tree in the forest, there is no “Why?”, so ‘whys’ are not needed.
Why?
A one word question gets a one word answer:
Because.
tallbloke (10:14:46) :
Why?
A one word question gets a one word answer:
Because.
Which are both meaningless in this context.
Bruce Cunningham (19:41:29) :
So the science is settled after all, just like Enstien he could never reconcile the so-called unified field theory. While differintial equations get us closer and closer there is always the very small possibility that things will go awry as time extends out. My fascination has always been, how does magnatism work and why is it always there. My toolbox at the place where I toil at has a very strong magnet attached to one of my drawers, it sits there day after day defying gravity. I would assume after a few thouand years my humble toolbox and its contents will return to the earth, Somebody email me please in a thousand years and tell me what happened to my magnet.
This Bruce Cunningham has no magnets on a toolbox drawer where I work. The toolbox I use at work has only computer programs such as Mathcad, Nastran, etc. And I know how to spell differential equations and magnetism, among other things.
Leif Svalgaard (09:30:34) :
solar wind expansion has nothing to do with electric fields [which BTW can’t exist in a space plasma, as you have been told numerous times].
Electric fields in space plasma are currently being studied.
http://ham.space.umn.edu/efasc.html
Electric fields DO exist in space plasmas, as you have been told numerous times, and they are being studied right now.
Catch up, man. You sit there and belittle anyone who mentions electric fields in space plasmas, while there is a specific area of research devoted to those very same electric fields you say don’t exist in space. WUWT?
Even with “current free” double layers between two different (density and/or temp) plasma regions, an electric field will develop at the boundary.
Don’t so called anomalous cosmic rays originate in the heliosheath? Might the causation be an electric field in what is actually a plasma double layer that we call the heliosheath?
…Astronomers call the cloud we’re running into now the Local Interstellar Cloud or “Local Fluff” for short. It’s about 30 light years wide and contains a wispy mixture of hydrogen and helium atoms at a temperature of 6000 C. The existential mystery of the Fluff has to do with its surroundings. About 10 million years ago, a cluster of supernovas exploded nearby, creating a giant bubble of million-degree gas. The Fluff is completely surrounded by this high-pressure supernova exhaust and should be crushed or dispersed by it.
“The observed temperature and density of the local cloud do not provide enough pressure to resist the ‘crushing action’ of the hot gas around it,” says Opher.
So how does the Fluff survive? The Voyagers have found an answer.
“Voyager data show that the Fluff is much more strongly magnetized than anyone had previously suspected—between 4 and 5 microgauss*,” says Opher. “This magnetic field can provide the extra pressure required to resist destruction.”
~
Opher’s statement, “This magnetic field can provide the extra pressure required to resist destruction.”
Well seems now I have a little confusion about that statement. (what’s life without some confusion heh, life goes on and time goes by)
solrey (12:05:55) :
Electric fields in space plasma are currently being studied.
Even with “current free” double layers between two different (density and/or temp) plasma regions, an electric field will develop at the boundary.
As I have said many times, electric fields can build up as the result of conductors moving across magnetic fields and are results of plasma movements, not causes of them. The energy is in the magnetic field and in the bulk movements of the plasma, not in the electric fields. Characteristic for pseudo-science is that there is a grain of truth in it, being misappropriated.
The issue is what causes what. Almost all interesting phenomena in plasmas are caused by electric currents, as I have said so many times. The electric fields driving these currents are generated locally and are not large-scale, long-lived properties of the plasma.
Leif (05:50:03): “Your arguments remind me of Voltaire’s proof that you are a stone: “a stone cannot fly, you cannot fly, ergo you are a stone”.
Is that Voltaire? I thought it was my countryman – and your excountryman – Ludvig Holberg. He lets his main character Erasmus Montanus, alias Rasmus Berg, use this line of argument to mock or impress the simple people of his village as he returns from studies in Copenhagen. Erasmus Montanus is a brilliant comedy from 1731:
http://www2.kb.dk/elib/lit//dan/holberg/komedier/erasmus.dkl/a2.htm