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.”
Discover more from Watts Up With That?
Subscribe to get the latest posts sent to your email.
tallbloke (09:02:35) :
Hey Carla. Who are ‘THEY’ and what is your source of information about what ‘THEY’ know?
Well, bad choice of a word, (they) on my part. LOTS does that help?
THE STRUCTURE OF THE LOCAL INTERSTELLAR MEDIUM IV: DYNAMICS, MORPHOLOGY, PHYSICAL PROPERTIES, AND IMPLICATIONS OF CLOUD-CLOUD INTERACTIONS1 Redfield & Linsky
http://arxiv.org/PS_cache/arxiv/pdf/0709/0709.4480v1.pdf
The above names two. Rosine Lallement (3) part of IBEX team. One IBEXer knows well you can guess the rest. Rosine thought the ribbon discovered by IBEX was well part of a “Shock,” due to the cloud, cloud interactions at first when she saw the IBEX data because she is fully aware of where the solar system is located and going to.
I feel like a the kid in the back seat that keeps asking, “Are we there yet?” Meaning are we in G cloud yet.
Started the day a half hour late, finish fifteen minutes late. (1:15pm) don’t ask. Can I turn my cell phone off so the dispatcher can’t locate me? hee hee
Tallbloke, was last years sudden stratospheric warming due to a shock wave through the solar system? Was that the last of the shocks, if it was a shock?
Are we there yet?
Carla (12:08:17) :
THE STRUCTURE OF THE LOCAL INTERSTELLAR MEDIUM IV: DYNAMICS, MORPHOLOGY, PHYSICAL PROPERTIES, AND IMPLICATIONS OF CLOUD-CLOUD INTERACTIONS1 Redfield & Linsky
http://arxiv.org/PS_cache/arxiv/pdf/0709/0709.4480v1.pdf
Thanks. Read through that, but I’m none the wiser with regard to timescales and projected effects. The latter I can appreciate nobody knows yet, but I would have thought someone might have a go at the timescale for transition between the Local Interstellar Cloud and the G cloud.
tallbloke (13:14:00) :
but I would have thought someone might have a go at the timescale for transition between the Local Interstellar Cloud and the G cloud.
“Contrary to previous claims the sun appears to be located between LIC and G.”
Which means we have been in MIC and any day now or next year, sooner rather than much much later we will enter G cloud proper. Signatures of both have been found in the heliosphere. AS we get closer, we would expect an increase of the G cloud signature within and without. IMHO
She hasn’t found me yet, almost off the hook. ssshhh
Carla (07:02:46) :
Meet “fluffy?”
Local interstellar cloud 7500K+-1500K (LIC)
Micro interstellar cloud 9900K (MIC)
G cloud 5500K +-400K (G)
What kind of terrestrial effects would we have seen while the heliosphere was moving through a 9900K slim and slender MIC cloud. (don’t answer that.)
What kind of terrestrial effects would we begin to realize when the heliosphere enters 5500K cloud? (don’t answer that)
Hi Carla….do you think the temperature of these clouds can have any terrestrial effects? Someone pointed out here a couple of days ago that the cloud as a whole cant be measured but instead the temperature reading was at the particle level, a little like what we see in our outer atmosphere where there is no measurable difference in the outer atmosphere, but the particles can have very high temps.
The density of the cosmic rays in each cloud and the magnetic strength could be a different matter.
Hmm, well, maybe it took a decade to get as far as we have through the MIC, starting with a warm shock (’98 el nino) and maybe ending with a cool shock (2009 SSW), so who knows. Speculation on a postcard, from somewhere warm…
But maybe it won’t be so bad in the G cloud. If going from the LIC to MIC raised temp 0.2C, maybe plunging into the G cloud will drop it by 0.5C. This will make UK winter sports climbing a renewed option.
@Carla…
Indeed, we are already into the interstellar cosmic cloud. We have tasted it a bit since 2003, or perhaps before 2003; worst is for coming through the next ~10000 years. NASA scientists and Vidal Madjar refer to climate changes due to the interactions between particles and atmospheric molecules.
Geoff Sharp (13:50:21) :
Hi Carla….do you think the temperature of these clouds can have any terrestrial effects?
~
Yes IMHO, but hey I drive a van for living. Multiple shocks going out (solar) multiple shocks coming in MIC. Did you start to feel toasty for a while?
Then what, we hit G proper and no more incoming shocks.
tallbloke (13:59:44)
But maybe it won’t be so bad in the G cloud. If going from the LIC to MIC raised temp 0.2C, maybe plunging into the G cloud will drop it by 0.5C. This will make UK winter sports climbing a renewed option.
~
Maybe it won’t be so bad tallbloke, but at my age I will need some padding to get the ice skates going again. Do you think Al G. will start telling us about the little froggy slowly freezing to death?
Nasif Nahle (15:01:16) :
NASA scientists and Vidal Madjar refer to climate changes due to the interactions between particles and atmospheric molecules.
~
Particles from…..?
Carla (16:39:40):
Nasif Nahle (15:01:16) :
NASA scientists and Vidal Madjar refer to climate changes due to the interactions between particles and atmospheric molecules.
~
Particles from…..?
From the interstellar cosmic cloud, i.e. He and H nucleons and electrons.
Geoff Sharp (13:50:21) :
>i>like what we see in our outer atmosphere where there is no measurable difference in the outer atmosphere, but the particles can have very high temps.
The density of the cosmic rays in each cloud and the magnetic strength could be a different matter.
I don’t think there will be any measurable effects of any kind.
Nasif Nahle (17:03:22) :
Carla (16:39:40):
Nasif Nahle (15:01:16) :
NASA scientists and Vidal Madjar refer to climate changes due to the interactions between particles and atmospheric molecules.
~
Particles from…..?
From the interstellar cosmic cloud, i.e. He and H nucleons and electrons.
~
Oh…yeah, like from the interstellar inflow into the heliosphere up to 1AU, that well established stream of H, He particles, along with dust and GCR, that varies over the solar cycle, that Earth is continually orbiting inside this density field, sometimes even the flows themselves.
Sorry, you said “cosmic” and I got all weird.
Nasif Nahle (15:01:16) :
NASA scientists and Vidal Madjar refer to climate changes due to the interactions between particles and atmospheric molecules.
~
But, just one thing, the solar cycle of late hasn’t varied much, so what does that do to the density field Earth is continually orbiting?
Carla (18:36:26) :
Nasif Nahle (15:01:16) :
NASA scientists and Vidal Madjar refer to climate changes due to the interactions between particles and atmospheric molecules.
~
But, just one thing, the solar cycle of late hasn’t varied much, so what does that do to the density field Earth is continually orbiting?
We are not sure on any effect on the intensity of the density field in the Solar periphery. The only thing I can say for sure is that if the GCR waves bump over a high energy density front, massive particles would accelerate, that is, would be more energetic so they would be able to overcome upstream the planetary density field being cooled again. It’s the mechanism by which they reach the upper layers of the Earth’s atmosphere. The end (?) of this process is explained in the article you provided some posts above.
Gregg E. (00:39:55) :
What? Super*sonic* speed in space? Isn’t supersonic defined as a velocity faster than the speed of sound in a given medium?
Sound can’t travel in the vacuum of space, therefore there’s no such thing as a supersonic velocity in space.
Or is the solar corona supposed to be thick enough to transmit sound?
The interplanetary space is not a perfect vacuum. There are particles there, including simple organic molecules. Then sound can travel in the interplanetary space.
On the other hand, the unfortunate expression “supersonic velocities” is applied just to describe the velocity of particles in the interplanetary space, which surpasses the magnitude of the velocity of sound over the dense Earth’s atmospheric space; the velocity of sound is used only like a point of reference.
Cosmic particles can reach speeds up to 400 km/s. The speed of sound in the atmosphere averages 340 m/s. Conversely, the velocity of sound in the outer space is irrelevant and often described like “minuscule vibrations”.
@Greg…
Sorry for not providing a link in support of the arguments exposed above. I had problems to find the link. I found it finally:
http://science.nasa.gov/headlines/y2003/09sep_blackholesounds.htm?list143936
Those weak vibrations in the outer space are not given into consistent oscillations due to the existing gaps between the outer space particles, so we cannot say that any steady sound can be detected in the outer space, but only isolated weak vibrations that NASA scientists understood by real sound.
Nasif Nahle (19:27:30) :
We are not sure on any effect on the intensity of the density field in the Solar periphery. The only thing I can say for sure is that if the GCR waves bump over a high energy density front, massive particles would accelerate, that is, would be more energetic so they would be able to overcome upstream the planetary density field being cooled again. It’s the mechanism by which they reach the upper layers of the Earth’s atmosphere.
~
Mr Wizard??
Carla (20:45:52) :
Nasif Nahle (19:27:30) :
We are not sure on any effect on the intensity of the density field in the Solar periphery. The only thing I can say for sure is that if the GCR waves bump over a high energy density front, massive particles would accelerate, that is, would be more energetic so they would be able to overcome upstream the planetary density field being cooled again. It’s the mechanism by which they reach the upper layers of the Earth’s atmosphere.
~
Mr Wizard??
Yes… Elementary astrophysics for kids. 🙂
Nasif Nahle (17:03:22) :
Carla (16:39:40):
Nasif Nahle (15:01:16) :
NASA scientists and Vidal Madjar refer to climate changes due to the interactions between particles and atmospheric molecules.
~
Particles from…..?
From the interstellar cosmic cloud, i.e. He and H nucleons and electrons.
Astrophysicists seems to concentrate on the H atom because it is detectable. What about H2 molecules, which are invisible to our telescopes? Hydrogen atoms readily combine to form the H2 molecule, and there are probably a lot more H2 molecules in the clouds than singleton H atoms. This will increase the density of the clouds by an order of magnitude or more. Could it be that the neglect of a discussion of H2 has skewed the estimates of the strength of the magnetic field in the fluffy cloud?
tallbloke (00:52:26) :
Nasif Nahle (17:03:22) :
Carla (16:39:40):
Nasif Nahle (15:01:16) :
NASA scientists and Vidal Madjar refer to climate changes due to the interactions between particles and atmospheric molecules.
~
Particles from…..?
From the interstellar cosmic cloud, i.e. He and H nucleons and electrons.
Astrophysicists seems to concentrate on the H atom because it is detectable. What about H2 molecules, which are invisible to our telescopes? Hydrogen atoms readily combine to form the H2 molecule, and there are probably a lot more H2 molecules in the clouds than singleton H atoms. This will increase the density of the clouds by an order of magnitude or more. Could it be that the neglect of a discussion of H2 has skewed the estimates of the strength of the magnetic field in the fluffy cloud?
Indeed, some authors, like Maoz for example, consign heavier than H+ nuclei and molecules of all the elements in GCC. (Maoz. 2007. Page 148, Line 8th).
Anyway, the current immersion of the solar system into this “fluffy” interstellar cloud is not something to be afraid on because it has occurred about 20 times in the life of our solar system. Besides, the current GC cloud is trapped by the magnetic field of the MW’s disk.
By the way, I think this cloud is of galactic origin, i.e. it was produced by supernova explosions. It’s not probable it is of extragalactic origin. We could expect to find a neutron star giving support to the strong magnetic field of the cloud, so perhaps we should include it as an explanation on the cohesion of the components of the cloud. It could be. 🙂
Nasif Nahle (08:05:59) :
Anyway, the current immersion of the solar system into this “fluffy” interstellar cloud is not something to be afraid on because it has occurred about 20 times in the life of our solar system. Besides, the current GC cloud is trapped by the magnetic field of the MW’s disk.
Hmmm, and did it get warmer or colder? 🙂
tallbloke (09:51:02) :
Nasif Nahle (08:05:59) :
Anyway, the current immersion of the solar system into this “fluffy” interstellar cloud is not something to be afraid on because it has occurred about 20 times in the life of our solar system. Besides, the current GC cloud is trapped by the magnetic field of the MW’s disk.
Hmmm, and did it get warmer or colder? 🙂
Interesting question… If muons production overwhelms statistical projections, it would be colder. If muons production remains constant or increases slightly (above 1000 muons/s), but slow particles with high energy density form a continuous flow towards our atmosphere, it would be warmer. I would like it gets colder, but it is dangerous for every living form. 🙂
Nasif Nahle (11:08:43) :
tallbloke (09:51:02) :
I hate to spoil your fun, but this is totally nuts.
Leif Svalgaard (11:45:15) :
Nasif Nahle (11:08:43) :
tallbloke (09:51:02) :
I hate to spoil your fun, but this is totally nuts.
~
Pick self up off floor, dust off, re-gain composure. (mostly)
Just wondering about those muons. Are these muons being produced by GCR striking particles or some other muons.
Out the door for a lab spec. run.
Carla (13:03:07) :
Nasif Nahle (11:08:43) :
tallbloke (09:51:02) :
Pick self up off floor, dust off, re-gain composure. (mostly)
Just wondering about those muons. Are these muons being produced by GCR striking particles or some other muons.
Out the door for a lab spec. run.
Protons of cosmic rays in general (around 90% of CR particles); local CR, GCR and IGCR. However, we are now in a special situation after ~200 million years, I guess. Perhaps the solar system has gone through other cosmic clouds in the interim.
Hurry up! Have a good job at the lab! 🙂