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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No one is sure exactly what this means. But it does mean we have a lot to learn. The political oligarchy that tells us that the science is settled on climate is laughable.
This is but one example of the many forces that dwarf us and yet ultimately affect us in ways we do not understand. And quite obviously some of these forces impact climate.
The sheer arrogance of the Gores and Hansens is breathtaking.
“John
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
”
I agree with you and appreciate such articles A.
John, if you want to know the possible relation between Earth’s climate and extra solarsystem factors, you might get Henrik Svensmark and Nigel Calder’s book “The Chilling Stars” as there is a discussion there concerning the possibility of nearby supernovae being involved in specific cooling episodes that the Earth underwent.
Leif Svalgaard (10:28:05) :
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
I don’t think this is correct. Cosmic rays are scattered away from the inner solar system by compression regions in the solar wind including the big one at the edge of the heliosphere, so I think that a more compressed heliosphere would mean less cosmic rays.
Could the scattering effect be more a function of the amount or inhomogenaity across the solar system, rather than the average density? i.e. the variations caused by ‘buffeting’ might have more effect on the scattering of the incoming rays than slight changes in overall density.
James F. Evans (10:54:59) The astrophysics new age church has forbidden to name what causes a magnetic field…because that apostate theory of an electric universe would mean an eternal universe and that they think it would undermine social order and tranquility.
On the other hand, astronauts wouldn’t have to travel so far because interstellar space would be closer than ever.
Maybe it has to do with the 2D presentation of the second picture, but it sure looks like we are getting further away from three stars while moving only somewhat closer to one. Locally speaking, how are we closer?
Of course they appear to be talking about the heliosphere determining where “interstellar space” starts and are using that for their statement. Which may be of great interest to a few, but dang it, people want to get to other worlds! “Interstellar space” is what is between us and them. And not only do we seem no closer to crossing that gap, now it looks like the trip will be even harder. If we do end up using automated sleeper ships, what additional micro-damage can we expect from 6000 deg C particles? It’ll be a long trip, likely at a very high fraction of c (speed of light), these impacts will add up. And it sure seems likely humanity will not want to wait 50-100 years to find out how successful the first ship was before sending more.
We need more info. Soon.
If the Voyagers probes are the only monuments to humankind, they are a pretty good one. They are amazing and continue to delight and reward us.
So much for the “science is settled” school of thought. There’s much yet to be discovered and our knowledge is measured in grains of sand while our ignorance can be measured by the size of the universe.
I’ve found the above artist’s concept of the Local Interstellar Cloud, also known as the “Local Fluff”, fasinating since reading the recent article by Linda Huff and Priscilla Frisch. For some reason I thought it might help explain the ups and downs of Earth’s climate variations as the Sun orbited around the Milky Way. (Simple minds look for simple answers:-) Nice to see it again and in this context.
“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.”
The NASA remark about possible terrestrial climate effects seems to acknowledge Henrik Svensmark’s theory of low cloud formation from ionizing radiation caused by cosmic rays entering Earth’s atmosphere.
JonesII (11:10:51) :
James F. Evans (10:54:59) The astrophysics new age church has forbidden to name what causes a magnetic field
According to the unreliable wikipedia
http://en.wikipedia.org/wiki/Electric_field
“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.”
“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)”
The sketch shows our sun moving at significantly less than 90 degree angle with respect the direction toward the galactic center (?of mass?). So does this mean the sun’s orbit around the galactic center is highly eliptical? Or is this just an artifact of the artists concept drawing?
John
These guys got to keep this thing funded. Not because my wife works at MIT on the Voyager 2 data, but because this thing is still sending back information that will be hard to collect for many, many years. If GCR has something to do with climate, knowing what is out there is vital.
Bart (10:50:50) :
The stuff built today is generally more capable, but that added capability can also be a liability. Older discrete components tend to hold up better in a high radiation environment.
The following info should be of interest. From here:
A seminal microprocessor in the world of spaceflight was RCA’s RCA 1802 (aka CDP1802, RCA COSMAC) (introduced in 1976) which was used in NASA’s Voyager and Viking spaceprobes of the 1970s, and onboard the Galileo probe to Jupiter (launched 1989, arrived 1995). RCA COSMAC was the first to implement C-MOS technology. The CDP1802 was used because it could be run at very low power, and because its production process (Silicon on Sapphire) ensured much better protection against cosmic radiation and electrostatic discharges than that of any other processor of the era. Thus, the 1802 is said to be the first radiation-hardened microprocessor.
The RCA 1802 had what is called a static design, meaning that the clock frequency could be made arbitrarily low, even to 0 Hz, a total stop condition. This let the Voyager/Viking/Galileo spacecraft use minimum electric power for long uneventful stretches of a voyage. Timers and/or sensors would awaken/improve the performance of the processor in time for important tasks, such as navigation updates, attitude control, data acquisition, and radio communication.
I’m more interested in what is causing these magnetic fields and where they extend to
I guess since the fluff does exist the science wasn’t all that settled.
James F. Evans (10:54:59) :
But more important is what causes the magnetic field in the first place and what determines its strength?
The magnetic fields in space are caused by dynamo processes where electrically neutral [but conducting] plasma moves across existing magnetic fields, creating currents that amplify the magnetic field and keeps them from dissipating. All this is amply demonstrated by laboratory experiments and from Maxwell’s equations combined with Newton’s laws.
Clive (10:56:24) :
Pretty cool information. We don’t know a lot do we?
Scientific progress is learning what we didn’t know we didn’t know.
tallbloke (11:08:52) :
Could the scattering effect be more a function of the amount or inhomogenaity across the solar system, rather than the average density? i.e. the variations caused by ‘buffeting’ might have more effect on the scattering of the incoming rays than slight changes in overall density.
As I have said many times, the scattering is due to the inhomogeneities in the solar wind and at the heliopause, and does not depend strongly on average density or magnetic field strength.
Leon Brozyna (11:17:13) :
The solar system is passing through an interstellar cloud that physics says should not exist.
So much for the “science is settled” school of thought.
The interstellar cloud was predicted 30 years ago…
Clive (10:56:24) :
Pretty cool information. We don’t know a lot do we?
Scientific progress is learning what we didn’t know we didn’t know.
“JonesII (11:10:51) :
James F. Evans (10:54:59) The astrophysics new age church has forbidden to name what causes a magnetic field…because that apostate theory of an electric universe would mean an eternal universe and that they think it would undermine social order and tranquility.”
Are you referring to neutron repulsion here?
Yes, certainly does seem to be a back handed confirmation of Svensmark’s theory.
Mars has also recently been warming up at proportionately the same rate as Earth was doing up to recently.
So much so that 20C is not unknown on this allegedly frozen world, but of course Mars has a 95% C02 atmosphere.
But even then, NASA has to over egg the pudding by claiming that the excess warmth comes from an extra greenhouse effect caused by giant dust storms.
Even on Mars, they cant bring themselves to admit that this warmth is primarly due to increased solar activity
“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.
I was pleased to see L. Gardy LaRoche mention Donald Scott’s _The Electric Sky_. It’s a great introduction to Electric Universe concepts. There’s a lot in EU theory that I’m dubious of, but several EU modellers have eliminated the need for “dark matter” and “dark energy” (30 years on still inconveniently unobserved) to account for observed movement by including electromagnetic effects.
I’ve loved this kind of stuff since I was a kid. Thanks, Anthony.
tallbloke (11:08:52) : “Could the scattering effect be more a function of the amount or inhomogenaity across the solar system, rather than the average density? i.e. the variations caused by ‘buffeting’ might have more effect on the scattering of the incoming rays than slight changes in overall density.”
Could be the “scattering effect” is caused by interactions of plasma at their boundary contact with other bodies of plasma.
And what has been observed & measured in the plasma laboratory by repeated experiments is that Electric Double Layers develope between plasma bodies with different physical properties such as density, temperature, magnetic field strength, relative motion and velocity.
Electric Double Layers cause dynamic changes to the flow and organization of the plasma supporting the process.
James F. Evans (11:58:59) :
And what has been observed & measured in the plasma laboratory by repeated experiments is that Electric Double Layers develops between plasma bodies with different physical properties such as density, temperature, magnetic field strength, relative motion and velocity.
And precisely those double layers carry no current. They are known as ‘current-free double layers’. Even wikipedia has this correct:
“Current-free double layers occur at the boundary between plasma regions with different plasma properties”
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.
Another interstellar “fluff” piece! I love it! More fluff please. Can’t get enough of this interstellar fluff. How much fluff is enough fluff? Some fine stuff this fluff…
Seriously, interesting article.
Cheers!