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.”
No wonder so many people eat up like lemmings the Hansen Gore mishmash, it must be the fluff cloud effect. One thing that may help is to put a small salt nugget in each ear when listening to anyone pushing climate change, aka global warming, and to discredit the lies even more repeatedly say it’s a climate cycle and it’s the sun stupid. That may help others wake up to the lies and if we keep getting hammered with cold and snow we should thank old man winter for a wake up call before the politicos drive us int an economic carbon tax and trade depression.
Bruce Cunningham (19:41:29) :
“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… Somebody email me please in a thousand years and tell me what happened to my magnet.”
Forget the magnet, how does your drawer sit there, day after day, defying gravity? If the desk weren’t there, it would fall to the floor. What holds the desk up? Or, the structure upon which it sits? Or, the ground upon which it sits? And, so on. If you work it all through, you will realize your humble magnet’s resistance to gravity is really not particularly remarkable.
I blame George Bush.
If we’re within a cloud of gas, would that not act as a “lens” through which all our observations are made — like looking through a plate of glass? And if so could that distort measurements of red-shifts and the like?
“REPLY: Why does it have to? Science for its own sake is enough don’t you think? – A”
I would like to see more of this, and other new exciting stuff, than the endless climate wars.
The answer is obviouse, Galactic warming!
Leif Svalgaard (15:59:44) :
tallbloke (14:44:45) :
So this wikipedia entry is incorrect?
“the electric and magnetic fields are not completely separate phenomena; what one observer perceives as an electric field, another observer in a different frame of reference perceives as a mixture of electric and magnetic fields. For this reason, one speaks of electromagnetism or electromagnetic fields.”
No, but must be interpreted correctly. The solar wind has a magnetic field B and speed V relative to the Earth, so the Earth sees an electric field E = B x V. An observer moving with the solar wind has V = 0 and thus sees E = 0. The correct statement is that ‘there is no electric field in the rest frame of the solar wind plasma’. So there is no electric current flowing in the solar wind as a result of this zero electric field. This is intuitively trivial to understand: the conductivity is almost infinite [the wind is so thin that a charge has to traverse many millions of km to meet another one]. So, if you had a collection of positive charges at point A and a collection of negative charges at point B, there will be a very strong [10^40 times the strength of gravity] electric field between them and they would attract each other with tremendous force and accelerate towards each other at enormous speed and short out the field.
Hi Leif, thanks for the informative reply.
Since some parts of the solar wind are moving faster then other parts due to the solar rotation effect you mentioned, currents will be generated due to the differing relative velocities of the plasmas won’t they?.
Also, incoming GCR’s are moving in the opposite direction to the solar wind, so won’t they will experience a strong electric field due to the high relative velocity?
Regarding magnetic fields puzzle:
http://www.vukcevic.co.uk/SSN-GMF.gif
– Earth magnetic field is contained within magnetosphere; hence can not influence the Sun’s output.
– Solar wind field is continuously variable in strength and polarity (at the Earth’s orbit, as is direct field of the solar dynamo) to affect strength of the Earth’s dynamo at the North Pole.
And yet appears that there is some loose ‘correlation’ between two, looks as that the Sun is lagging by about 3-4 cycles, although year 1800 is a big miss.
If there is some kind of Galactic effect (?!) than the Earth’s mass being smaller would react faster.
Any ideas? Just coincidence?
Vinny (13:01:52) :
I’m not a scientist but am fascinated by science. Can anyone discuss what has allowed these two tiny spacecrafts to exceed their life expectancy so spectacularly and when will they enter interstellar space.? Why has the extreme cold not affected their ability to transmit the data we still receive from them.
They use RTG for power. RTG = Radioisotope Thermal Generator. That’s a politically corrected retronym for what they were originally called – SNAP. That’s System for Nuclear Auxiliary Power.
How they work is a chunk of some radioactive metal is surrounded by layers of stacked Peltier elements. They’re like the elements used in 12 volt coolers, but operated “backwards” to generate electricity from the temperature differential across them instead of using electricity to create a temperature differential.
As long as there’s enough radioactive decay going on to keep the core metal above ambient temperature, an RTG will generate some electricity. Once the core temp drops to the same as the space outside, the Voyager probes will be completely dead.
The Viking landers on Mars used RTGs, which is why one of them so dramatically exceeded its design life. Had the first Mars rover used an RTG it might still be going. (It used a battery pack and didn’t have any way to recharge it. Most expensive RC car ever and a very long trip to Radio Shack for new batteries!)
RTG’s have been used in terrestrial applications, most notably in some Soviet era lighthouses and remote navigation beacons. Some idiot campers and hunters have died or been severely injured by stripping the shielding from those RTGs and using them instead of a campfire to keep warm.
American built RTGs are constructed extremely tough. One went into the Atlantic ocean from a failed satellite launch, was recovered, refitted and launched again in the replacement satellite.
Anon (23:40:33) :
If we’re within a cloud of gas, would that not act as a “lens” through which all our observations are made — like looking through a plate of glass? And if so could that distort measurements of red-shifts and the like?
“Cloud” may be a good term for astronomers, but it’s still pretty empty out there. This is like you were doing a satellite survey of the surface of an empty parking lot at a mega-mall. Then you find out approximately five pennies have been scattered throughout the area. How much is that going to affect your measurements? And five to a parking lot is actually far denser than this “cloud” really is, plus the instruments being used don’t have the resolution to notice them anyway.
These particles are out there, but they are pretty much not interacting with anything so we don’t notice them. If we were looking at something at high resolution through a lot of this “cloud space” it might fuzz up the image a bit, but we likely won’t notice it for just about everything.
“No, but must be interpreted correctly. The solar wind has a magnetic field B and speed V relative to the Earth, so the Earth sees an electric field E = B x V.”
[But] “An observer moving with the solar wind has V = 0 and thus sees E = 0.”
This sounds a bit like Schrödinger’s cat thought experiment, often described as a paradox: The cat can not be both dead and alive at the same time.
A physical force is either present or not.
An electric field is either physically present or not — it can’t be both.
Positing a physical analysis where a force is either present or not depending on relative motion is a first slippery step into pseudo-science.
James F. Evans (17:21:30) :
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.
I started a thread about the fundamentals of magnetism here:
http://www.bautforum.com/space-astronomy-questions-answers/97944-fundamentals-magnetism.html
Some of the replies are interesting.
James F. Evans (02:56:55) :
It is evident you have not had much education in physics.
Special relativity is not quantum mechanics and does not display the ambiguities .
Actually special relativity transformations are inherent in the theory of Maxwell’s formulation of electromagnetism (Lorenz transforations). The out of the box thinking of Einstein was in extending them to massive objects.
The electromagnetic field itself, for example the light that you use to read this, has varying electric and magnetic fields as it propagates into space and reaches your eye: the change in the electric field generates a magnetic field ahead which changes and generates an electric field ahead and the light ray travels like a centipede at the speed of light :).
It is OK not to know physics. One can live one’s whole life without knowing the definitions of force and energy and coordinate systems. What is not OK is to think that one’s ignorance should be imposed on the thinking of others. Like the fox whose tail was cut and wanted to set the fashion of cut tails.
I
Martin B (12:10:05) :
“Sure we’ve learned alot from the Voyager probes, and the Pioneer probes before them, but, good God, think of their carbon footprint! Imagine how much carbon-dioxide was released in launching them. The Horror!
Better if we had never launched them at all. Or any rockets, ever. And that we had ever emerged from our caves”.
What’s holding you from living in a cave? I’m not stopping you!
Ya, anna, just like the Man-made global warming scientists who tried to impose their pseudo-science on all the rest of us.
Leaving the science up to the scientists failed humanity.
Those days are over.
Better, yet, explain to the readers how Schrödinger’s cat can be both dead and alive at the same time?
>>Kaboom (13:18:30) :
>>Don’t forget the obscene, war-like message in 55 languages
>>attached to the Voyager craft, on a 33 1/3 r.pm. phonograph
>>record (whatever that might be!)
Que???
The message says something like “greetings from the people of Earth”. What is your bitch with that?
My only criticism is that, to make things easier for an alien interpreter, all the messages should have been the same. But they are not. Some languages get two sentences, some just say “shalom”. I’m not sure how Hittite got in there either – not many of those around nowadays.
http://voyager.jpl.nasa.gov/spacecraft/languages/background.html
tallbloke (01:02:58) :
Since some parts of the solar wind are moving faster then other parts due to the solar rotation effect you mentioned, currents will be generated due to the differing relative velocities of the plasmas won’t they?.
No, because the plasma is not moving across the magnetic field, the latter being frozen into the plasma and moving with it.
Also, incoming GCR’s are moving in the opposite direction to the solar wind, so won’t they experience a strong electric field due to the high relative velocity?
The electric field does not arise from particles moving relative to each other, but from charges moving across magnetic field lines. The force on a cosmic ray proton is F = q(E + v x B). See http://en.wikipedia.org/wiki/Lorentz_force . Since E is zero in space plasmas, the magnetic field B will deflect the cosmic ray [part of the modulation process].
vukcevic (01:13:11) :
And yet appears that there is some loose ‘correlation’ between two, looks as that the Sun is lagging by about 3-4 cycles
The solar dynamo does not have any influence on the Earth’s dynamo [the ‘North Pole’ bit is just nonsense] so no ideas are needed.
James F. Evans (02:56:55) :
An electric field is either physically present or not — it can’t be both.
The field depends on the frame of reference so can be both present and not depending on the frame. For more:
http://en.wikipedia.org/wiki/Moving_magnet_and_conductor_problem
Positing a physical analysis where a force is either present or not depending on relative motion is a first slippery step into pseudo-science.
pseudo-science depends on the [often willful] ignorance of its believers.
par5 (00:18:35) :
“REPLY: Why does it have to? Science for its own sake is enough don’t you think? – A”
I would like to see more of this, and other new exciting stuff, than the endless climate wars.
Read these articles:
http://www.biocab.org/Cosmic_Rays_Graph.html
http://www.biocab.org/Coplanarity_Solar_System_and_Galaxy.html
The next graph shows the correlation between ICR and variability of temperature:
http://www.biocab.org/Anomaly_ICR_and_Change_T.jpg
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Leif Svalgaard (08:28:19) :
vukcevic (01:13:11) :
“….The solar dynamo does not have any influence on the Earth’s dynamo [the ‘North Pole’ bit is just nonsense] so no ideas are needed”.
I think I knew that (did not experience an Earth’s MF reversal, but did few solar ones), there is always a remote possibility of a common cause.
If man declared many of natural riddles ‘nonsense’, the humanity would not be what it is; individuals’ curiosity and enterprise are forces moving us forward!
http://www.vukcevic.talktalk.net/LOD-GMF.gif
http://www.vukcevic.co.uk/SSN-GMF.gif
I hope you had good Christmas, the season of good will to all.
vukcevic (09:27:44) :
there is always a remote possibility of a common cause.
There is some loose ‘correlation’ between the emotional agitation of inmates of lunatic asylums and crossing of the heliospheric current sheet two days later. There is always a remote possibility of a common cause, but this subject is generally not seen as worthy of pursuit. The notion that progress is brought about by treating all wild ideas on an equal footing is not part of the scientific method and cannot be taken as a priori justification for pursuing such ideas. There are well-established ways of separating the wheat from the chaff. Of course, if one is peddling chaff, those methods are discarded out of hand. I can understand that, and that is quite OK as amusement as long as you know it is chaff.
James F. Evans (07:41:35) :
Ya, anna, just like the Man-made global warming scientists who tried to impose their pseudo-science on all the rest of us.
Leaving the science up to the scientists failed humanity.
Those days are over.
Better, yet, explain to the readers how Schrödinger’s cat can be both dead and alive at the same time?
If you want those days to be over, then everybody has to study science to the level of Maxwell’s and Schrodinger’s equations and get at least a C+.
Paradoxes arise when there is confusion between different systems of describing the world.
Quantum mechanics mainly describes well the microcosm which is dominated by the size of hbar, i.e. small numbers . The exception is coherent states, like crystals, superconductivity etc, where macroscopic quantum mechanical effects can manifest.
A cat is neather crystal not coherent in any mathematical way and cannot be described by a pure quantum mechanical state function. i.e. you cannot write a quantum mechanical formula for the probability of seeing a cat or not.
The paradox of Schrodinger’s cat comes about because of the mixing of philosophical concepts ( a different system of describing the world) and quantum mechanical concepts.
It is an analogy which is vaguely connected to what happens in the microcosm, where truly experiments have proven that an electron, for example, is both a wave and a particle, and before you do the two slit experiment you cannot know from which slit it will pass or whether it will pass through both ( which is what the experiment shows).
By your logic, society, instead of adopting the heliocentric system, when it was proven that the geocentric one was wrong, should have rejected all astronomy and science of the time.
Leif Svalgaard (09:42:57) :
“There is some loose ‘correlation’ between the emotional agitation of inmates of lunatic asylums and crossing of the heliospheric current sheet two days later.”
Your idea of lunatics’ agitation by solar events could be of some interest to psychiatrists (classic opinion relates it to the Moon cycle– russian ‘Luna’).
The prettier half of humanity is also thought to suffer from Luna related cyclomania; perhaps this also could be related to the 27 days and 43 min “heartbeat” of the Sun, which Dr. Jane Feynman announced at her pres conference on February 1, 2000.
She however, omitted to tacknowledge hat two brilliant solar scientist from the Institute for Plasma Research, some quarter of century earlier, discovered and graphically recorded the same “heartbeat” of the Sun:
latest:
2009 11 21 2406 XXX……..*..*XXXX*XX.XXXX
2009 12 18 2407 *XX…….
vukcevic (09:27:44):
http://www.vukcevic.talktalk.net/LOD-GMF.gif
http://www.vukcevic.co.uk/SSN-GMF.gif
From your graphs one can deduce that small changes in sunspots number have imperceptible effects in the geomagnetic field, present over there, however; larger changes, i.e. the Maunder Minimum, have without doubt measurable fluctuations in the geomagnetic field.
Gregg E;
Thank you from taking the time to explain voyagers electrical system in an understandable way. I don’t profess to understand what the heck everyone is saying but you can pick up pieces to understand some of it any way.
Thanks again for your help.
Leif Svalgaard (08:28:19) :
tallbloke (01:02:58) :
Since some parts of the solar wind are moving faster then other parts due to the solar rotation effect you mentioned, currents will be generated due to the differing relative velocities of the plasmas won’t they?.
No, because the plasma is not moving across the magnetic field, the latter being frozen into the plasma and moving with it.
Thanks for your patience. What I’m trying to understand is how this fits with your earlier comments about fast solar wind from coronal holes catching up with slow moving solar wind, slamming into it from behind, and causing a pile up wherein the magnetic field lines get all tangled up and form a ‘mirror’ which deflects incoming GCR’s.
If the magnetic fields of these different velocity plasmas get tangled up and force each other around, that’s going to generate quite big perturbance in the electric field isn’t it?