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.”
Geoff Sharp (15:45:45) :
I would like to know how does it maintain a 6000C temperature with no apparent heat source?
Ask another question: ‘how could it cool?’
Hints: things cool by conduction, expansion, and radiation.
Really interesting, thanks for posting this! The Voyagers have fascinated me since I was a teenager. My interest started with some issue of National Geographic I read as a kid, which showed the first images of Jupiter from Pioneer 10 & 11. I think the Pioneer and Voyager spacecraft are still the most impressing pieces of technology ever made (although those long-lived rovers on Mars are pretty impressing too).
Leif Svalgaard (16:04:03) :
Ask another question: ‘how could it cool?’
Hints: things cool by conduction, expansion, and radiation.
Thus the insulation on space suits is more comparable to a light winter coat than what is needed for the dark times in Antarctica. There are high grade metal alloys being processed in vacuum environments in a molten state. It is hard to overstate the insulating properties of a vacuum.
“They [magnetic fields] have always been there.”
Hmmm?
The magnetic fields exist independently from the flow and organization of the plasma?
In the course of Electric Double Layers, aka, “magnetic reconnection”, electric fields participate with magnetic fields to constrain the flow and direction of free electrons and ions, plus accelerate and energize the electrons and ions resulting in generation of electric currents.
James F. Evans (16:24:59) :
The magnetic fields exist independently from the flow and organization of the plasma?
They can easily do that. There is no plasma near the magnets on my refrigerator.
In the course of Electric Double Layers, aka, “magnetic reconnection”, etc.
As usual you have this backwards. The process is as follows: when magnetic fields with opposite polarity are frozen into a plasma and by movements of parcels of the plasma are pressed together, an electric field is created and the frozen-in condition can break down in a very thin interface layers, allowing reconnection to take place, and accelerating particles away from the reconnection region. Electric currents are the cause of all interesting phenomena involving plasmas and are created locally by movement of said plasma across an existing magnetic field.
As Saint Gore (“Al Baby”) would say: You must believe! Science is settled!. Our Holy Inquisition will take care of you non believers!
There is no plasma near the magnets on my refrigerator
There is a potential difference in it between FeO and Fe2O3, and these magnets are “started” at fatory by an electric field (Oersted).
Leif Svalgaard (16:04:03) :
Ask another question: ‘how could it cool?’
Hints: things cool by conduction, expansion, and radiation.
Hadnt thought of it that way…amazing. So we can expect some sort of heat transfer when the collision occurs.
Who’d have thunk, when launching the Voyager deep-space probes, that they could tell us something about what makes the weather on Earth?
And a magnet generates its magnetic field by — take your pick — electron spin, magnetic moment, electron flow within the magnet’s lattice, all rely on electron “something”, principly movement of some kind.
Yes, “Electric currents are the cause of all interesting phenomena involving plasmas and are created locally by movement of said plasma across an existing magnetic field.”
“They [magnetic fields] have always been there.”
Science has more to learn & understand.
James F. Evans (17:21:30) :
Science has more to learn & understand.
From your postings it is clear that you have a lot yet to learn and understand. I fear, however, that this will not happen, seeing how learning-resistant you have been in the past.
The same happens with:
Iron 26.000000 55.847000 2 3
cobalt 27.000000 58.933000 2 3
nickel 28.000000 58.710000 2 3
Having valence 2/3 (jumping electrons to satisfy both), notably with Iron in OUR PLASMA (in hemoglobin). This is why these are magnetizable materials.
Carl Bussjaeger (11:45:00) :
“…creating magnetic fields orders of magnitude greater in strength than gravity.”
These are two different things, and the statement is meaningless. Perhaps you mean “creating magnetic fields which induce forces orders of magnitude greater in strength than those due to gravity”? If so, that is not generally correct either.
Magnetic fields only exert force on moving charges according to the Lorentz force equation. Furthermore, both fields create singularities (event horizons) where they become theoretically infinite, but the field from a dipole falls off as R cubed, whereas that from a monopole falls off only as R squared, and there are no magnetic monopoles. So, gravity has more influence over long distances. Moreover, gravity affects both charge biased and neutrally charged particles alike.
Gravity has been measured to many significant digits between neutrally charged masses via torsion balance. It is not an electromagnetic phenomenon. And, the equivalence of gravitational and inertial mass has been demonstrated to many, many significant digits as well, which puts gravity in a special class all its own among the forces of nature.
There is a disturbing tinge of pseudoscience emerging on this thread. That is what I have feared most would happen when the magnitude of the politicization of climate science became starkly obvious to all. Let me state plainly to those who are searching for answers: Special Relativity is beyond question. That science really is settled. Time dilation in particular has been confirmed beyond a shadow of any doubt in decay rates of particles traveling at relativistic speeds.
General Relativity has been demonstrated to accurately describe many phenomena with potent predictive power. It is not settled completely, but we can say it is settled to the extent that any more advanced theory will have to include it as a special case in a specific domain.
The defeat of the pseudoscience behind CAGW would be pyrrhic indeed if it opens the floodgates to even less sophisticated pseudoscience.
The Voyagers. The most successfull little space crafts and program in space exploration ever…….. and still goin’ strong!
I find it amazing that they are still working and giving us insight into the cosmos.
JonesII (16:56:38) :
There is no plasma near the magnets on my refrigerator
There is a potential difference in it between FeO and Fe2O3, and these magnets are “started” at fatory by an electric field (Oersted).
There were likely primordial magnetic fields in the Universe [and we can discuss how they arose], but may I ask where the electric field you mentioned came from? Perhaps generated by a power station by rotating copper coils in a magnetic field?
Geoff Sharp (17:06:55) :
Hadnt thought of it that way…amazing. So we can expect some sort of heat transfer when the collision occurs.
No, as there is no collision between particles.
The cloud cannot cool by conduction because of no collisions, cannot cool be expansion because it is held in place by its magnetic field, and cannot cool by radiation because it is fully ionized [so the electrons cannot jump from from bound state to a lower one, emitting a photon in the process]. Now, some clouds are dusty [ours doesn’t have much since it is hot]. If there is a lot of dust, then particles can collide with the dust [dust particles have a much larger cross section than protons] and transfer heat to it, which the dust then can radiate away because it is not ionized. In that way the dust can slowly cool the cloud, in fact the interior of thick dusty clouds are the coldest places in the universe [except from some places made by intelligent beings to measure weak radio waves].
Bart (17:32:46) :
The defeat of the pseudoscience behind CAGW would be pyrrhic indeed if it opens the floodgates to even less sophisticated pseudoscience.
Indeed.
Unbelievable such a belief system! So redox reactions now are impossible and we do not breath!
Well, well, anyway life is nature´s way of overcoming entropy…..
John (10:09:06) :
“Interesting, but how does this have any bearing on our climate and ice age cycle?
REPLY: Why does it have to? Science for its own sake is enough don’t you think? – A”
According to the scientists that published the first report about this Interstellar Cloud in 1978, this cloud could trigger an ice age.
You can download the entire report and read their conclusions here:
http://adsabs.harvard.edu/abs/1978ApJ…223..589V
Svensmark and Nir Shaviv (http://www.sciencebits.com/CosmicRaysClimate) think clouds like this will influence our terrestrial climate and so does NASA.
So, I have absolutely no doubt that this report belongs at WUWT.
@ur momisugly kadaka (11:36:21)
Thanks!
I believe the article’s citation of a 6000C temperature relates only to the helium atoms themselves and is not indicative of an “ambient” temperature of that magnitude. A thermometer out there will measure near absolute zero as the actual density of hot atoms is extremely low compared to the frame of reference of earth’s atmosphere. The same phenomena occurs in our upper atmosphere. The low density gas atoms in the remnants of our atmosphere at 30,000m are whizzing around pretty fast and are quite hot. Nevertheless, the total kinetic energy per unit volume is minuscule compared to sea level.
I think I would prefer to stick to Earth, and I’m pretty sure the stray cat we’ve been tending feels the same way these recent December nights. We’re close enough to space in the Mile High City. Still, I do enjoy looking up on a summer’s evening.
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.
Mirco (14:20:54) :
There is a project that could give us fast interplanetary drives (days to weeks) and, with a bit of luck, interstellar travel drives. Woodward, Mach and Breakthrough Propulsion
I tend to be suspicious of things that try to cheat around doing work. It takes a lot of effort to get off this rock and I don’t see how a Mach-Lorentz thruster would be up to the task. I followed your link, read some stuff on Woodward’s home page, googled some more info.
In this idea of “thrust without ejecting mass,” Woodward’s test device as described, and based on his descriptions of how it functions, it is like a box with a mechanism that slams a weight against one side of the box’s interior, slowly moves the weight back (perhaps with a spring return), then repeats the motions. On a flat tabletop slamming upwards it might dance but go nowhere. On a frictionless slope it would have net no movement upwards, just slide to the bottom of the slope no matter how fast the mechanism cycled.
But Woodward then goes into how all particles are somehow linked together. Which is technically true, a particle on Earth has a gravitational attraction to a particle 35 light years away. Roughly speaking, this makes the device’s operation like the box was dropped into a container of frictionless sand, with all the grains attracted to each other as well as the box. When the weight slams the box moves forward, but it does not move backwards while the weight is reset as the sand has moved, the space where the box was is now filled with the grains which resist the backwards motion.
There are numerous problems though with the concept, provided my “thought experiment” model is really following the described effect. For one, imagining all the particles connected together with little springs, I would expect the particles to take the shock and then “spring back” into position, leaving the box where it was. Moreover, this has too much of a “cosmic aether” feel to it, more like you were describing how something could move through water by getting the water molecules to move relative to the object.
And, the forces involved sound incredibly weak. I do not see how they could possibly get an object away from Earth orbit, let alone off the ground. There is the pull of millions of eligible women trying to draw a man away from the house, but the firm hand of his wife on his arm keeps him inside.
Moreover, I read that the device creates a great deal of heat. That sets off alarm bells for me, as numerous issues such as expansion of materials and changes in conductivity of the wiring can affect test readings. Plus there has not been replication of results by different experimenters, some see no effect, some see far more, some see it when the capacitor alone is energized (see Woodward’s Mach’s Principle” presentation) but not the piezoelectric force transducer.
It sounds iffy, too sci-fi and working with forces that seem too weak to move through space, let alone get off the planet. For the foreseeable future we will still be using chemical rockets to get off this rock, the “space elevator” looking like the next most-likely improvement. And once we are in space, there are already several promising engine designs to move us around, even between stars, with several highly-efficient ones proposed and in development. All of which look far closer to reality than Woodward’s concept might ever be.
“Voyager data show that the Fluff is much more strongly magnetized than anyone had previously suspected—between 4 and 5 microgauss*,”
Actually Van Allen conjectured and Frith 2003 gave us a pretty accurate prediction of this figure.
Projected disappearance of the 11-year cyclic minimum of galactic cosmic ray intensity in the antapex direction within the outer heliosphere
James A. Van Allen Bruce A. Randall GRL 2005
This paper reports observed galactic cosmic ray (GCR) intensity (kinetic energy T > 80 MeV/nucleon) by the University of Iowa instrument on the interplanetary spacecraft Pioneer 10 (P10) for the thirty-year period, 1972–2002, during which it moved outward from 1 to 80 AU heliocentric radial distance (r). The trajectory of P10 since 1976 was in the approximate direction of the solar antapex. Comparable data for nearly the same time period from the Applied Physics Laboratory/Johns Hopkins University instrument on the Earth-orbiting satellite Interplanetary Monitoring Platform – 8 (IMP-8), as corrected (Van Allen and Randall, 1997), have been adopted as the 1 AU reference. An important new finding is that the solar modulation of GCR intensity had dwindled markedly at P10 during the most recent (2001) cyclic intensity minimum at r ∼ 78 AU relative to that at the two previous 11-year cyclic minima in 1981 and 1991. A plausible projection of the trend established by the 1991 and 2001 values of a modulation index predicts the disappearance of direct solar modulation at r = 106 (±10) AU in the antapex direction. A similar finding from Voyager 1 and Voyager 2 data (Webber and Lockwood, 2004a and b) in the approximate apex direction confirms the previously noted absence of a apex/antapex asymmetry (Van Allen and Webber, 2002). Several heuristic comments of a general nature are included.
in the comments…
We wish to revive an earlier conjecture [Van Allen
and Webber, 2002] that unmodulated interstellar GCR may
have at least partial access to the outer heliosphere along
lines of force that interconnect the interplanetary magnetic
field with the magnetic field in the nearby interstellar
medium. Frisch [2003] adopts B = 5 microgauss as the
magnetic field strength in the nearby interstellar medium, a
value that is about an order of magnitude greater than that
measured by V1 at 75 AU – a remarkable fact, if true, and
one that may contribute some plausibility to our intercon-
nection conjecture.
Very good theoretical prediction by Priscilla
Carl Bussjaeger (11:45:00) :
“James F. Evans (10:54:59) :
Why doesn’t the article touch on these known and established principles?”
That was probably a rhetorical question, but for the sake of folks who may not know I’ll answer: Astronomers gradually built their models before eectricity and plasmas were known. They now have suchge investment in gravity-only models that they are reluctant to admit that the “hot gas” they keep seeing is plasma, because plasma is conductive, which means current can flow, creating magnetic fields orders of magnitude greater in strength than gravity.
Maybe it is the time for my swallow story again. Half knowledge is an undesirable stage.
People think that saying: “orders of magnitude larger than gravity” we should be amazed and bow low. Do you know that there are magnetic fields within all solids that are huge, order of magnitude larger than gravity or anything? I know, because I studied a bit on the idea ( of Tom Ypsilantis) of using these fields for a different type of particle accelerator.
So what if the fields are huge? can one use a crystal to power a car? It is all in the energy and the boundary conditions that have to enter the problem to solve for what is happening in large bodies. It is not enough to have orders of magnitude larger than this or that. It is energy and momentum and angular momentum that determines what the real solutions for given boundary conditions will be.
That these interstellar plasmas with their magnetic field have tiny energies with respect to the gravitational potential energies, is all one needs to know . The only orthodoxy is energy momentum and angular momentum conservation laws.