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When Voyager 1 passed into the heliosheath in 2004, it became the first man-made object to explore the remote edge of the Sun’s magnetic influence. Launched by NASA on September 5, 1977, the probe was designed to study the outer Solar System and eventually interstellar space. One of its missions was to look for the heliopause – the boundary at which the solar wind transitions into the interstellar medium. What it found was mayhem…
According to NASA, Voyager 1 has crossed into an area where the velocity of the hot ionized gas, or plasma, emanating directly outward from the sun has slowed to zero. Scientists suspect the solar wind has been turned sideways by the pressure from the interstellar wind in the region between stars. “The solar wind has turned the corner,” said Ed Stone, Voyager project scientist based at the California Institute of Technology in Pasadena, Calif. “Voyager 1 is getting close to interstellar space.”
Now it has entered the heliosheath, an area ranging from 1.5 to 15 billion kilometers thick (930 million to 9.3 billion miles) and starting roughly 14 billion km (8.7 billion mi) from the Sun. But there’s nothing quiet here. This is the area where outgoing flows of solar wind begin to be repelled by interstellar particles and magnetic fields pushing towards the solar system. While passing through the heliosheath, Voyager 1 experienced many sudden and drastic changes in the surrounding magnetic field driven by structures called current sheets.
The team of L. F. Burlaga: Geospace Physics Laboratory, NASA Goddard Space Flight Center and N. F. Ness of the Institute for Astrophysics and Computational Sciences have been studying the ongoing results sent back by Voyager and have come to a new conclusion – there are three distinct types of current sheets.
“The structures, appearing as proton boundary layers (PBLs), magnetic holes or humps, or sector boundaries, were identified by characteristic fluctuations in either magnetic field strength or direction as the spacecraft crossed nearly 500 million km (310 million mi) of heliosheath in 2009. PBLs are defined by a rapid jump in magnetic field strength, with one observed event resulting in a doubling of the field strength in just half an hour.” said the team. “Passing through a sector boundary led to a sudden change in direction of the magnetic field. Magnetic holes saw the field strength drop to near zero before returning to the original background strength. Magnetic humps consisted of a sudden spike in strength and then a return to initial levels.”
But this isn’t the first time the Voyager has returned zero readings. In December 2004 the intrepid probe broke the barrier of the termination shock and data from Voyager 1’s Low-Energy Charged Particle Instrument was used to deduce the solar wind’s velocity. When the speed of the particles matched the speed of the spacecraft, scientists knew they had a null number on their records. “When I realized that we were getting solid zeroes, I was amazed,” said Rob Decker, a Voyager Low-Energy Charged Particle Instrument co-investigator and senior staff scientist at the Johns Hopkins University Applied Physics Laboratory in Laurel, Md. “Here was Voyager, a spacecraft that has been a workhorse for 33 years, showing us something completely new again.”
And new is what we need to continue our understanding of what lay at the furthest reaches of our now explorable space. Says Burlaga, “The firsthand detections made by Voyager 1 are likely to be extremely important for researchers trying to decide between current leading theories for the source and structure of current sheets.”
Story source: Journal of Geophysical Research – Space Physics.
Awesome, more data!
I’ll be happy if the probe makes it past the Bow Shock without disintegrating completely or something else unforeseen that would negatively impact human space travel beyond the solar system. It would add quite a lot of time to have to toss people-laden space craft away from the bow shock and have to go around it to get anywhere in that direction.
There appears to be a f…f…f…fluctuation at the second paragraph, in the second line.
got it. thanks!
“changes in the surrounding magnetic field driven by structures called current sheets.”
Are they now saying the magnetic fields are generated and sustained by current sheets(I assume they mean ELECTRIC CURRENT) or are these more of those funky “frozen” magnetic fields?
Sector boundries?? Why not just call them double layers?
Great data lending more weight to the EU paradigm!
if you really value what science is all about, go read for yourself the two competing thoeries on the structure of the heliosphere.
Mainstream=Mechanical interaction
Electric Universe=Plasma interactions
one adds up the other….
[(2 + zebra)2 ÷ glockenspiel] = ELECTRIC UNIVERSE!!!1!1!1!
Oh don’t be absurd. You can’t divide by glockenspiel or the universe implodes. You MUST divide by ukulele.
Yes, but in the limit as glockenspiel approaches hula-hoop you can take marmoset to the power of tangerine and purple it.
Unless you’re working in regimes where Soditon nebulosity approaches translucent, in which case it becomes more approriate to take Tamarin to the power of chartreuse and beige it.
Thanks for clearing that up those other guys were way off,Thanx
Pure gold.
The EU “paradigm” is useless. I’d call it junk science, except that would be grossly disrespectful to science. And junk. It is so hopelessly vague that whenever anything happens involving the words “magnetic”, or “plasma”, or “electric” you EU promoters can stand around nodding sagely and going “Aha! I knew it!”
Of course, it’s as easy as it is pointless to do this after the fact. I’d be impressed if the EU idea had predicted this beforehand, but it didn’t. In fact, I have never known the illogical muddle of handwaving vagueness that is EU to make ANY testable prediction at all.
In real science, we generate hypotheses to explain observed facts and TEST them by making predictions that can be checked. In this way we refine our ideas, and expand our knowledge. EU doesn’t work this way at all. Never has. Never will. Why? Because it’s STUPID.
Really? The EU hasn’t dusted off old technology like Orion either..
Usually you shouldn’t encourage trolls, but this is too simplistic even for “cracks for brain case”:
All you do with your comments is to show the world that you know nothing about physics and isn’t suited to proclaim on it.
“I assume they mean”
Of course they mean electric charged current sheets, since we are discussing EM forces.
“Why not just call them double layers?”
Because there is no double layer here. What would form them in the absence of dense plasma?
Sector boundaries are boundaries between sectors of different magnetic polarity, i.e. magnetic “domains” if this was solid matter. Domain walls are _not_ double layers of opposite charges in plasmas. It is merely a change in magnetic orientation in “empty” space.
This is basic electric, magnetic and plasma theory. Go study instead of throwing out incessant chatter!
“the two competing thoeries on the structure of the heliosphere.”
There is no competing different theory to the ongoing theory building which relies on physics.
What you are referring to is a known pseudoscience crackpot “theory”, which shouldn’t be discussed on a science blog. (Unless the topic is pseudoscience and crackpottism.)
Even a crackpot should be aware of the marginal status of his “theory”, unless he/she is completely without touch with reality. Marginalization = no serious “competition”.
“Mainstream=Mechanical interaction”
??? It is mainly solar system physics with EM effects.
Historically you can make a case for that as long Maxwell used “gears and cogs” to portray the EM field it was a mechanical theory. Even he himself rejected that early on.
And today of course it is a quantum field theory, with no classical mechanics at all at the basis.
It’s not necessary to feed the trolls anymore. They’ve outworn their welcome here at Universe Today.
His comments have been removed and for violating UT policy. He’s done.
Before certain individuals start wetting their knickers over this article, it should be pointed out that the magnetic field strength of ‘potholes’ in the heliosheath are only about
1.0×10-11 T (10 picoteslas); the magnetic field strength in the heliosphere is between 1.0×10-10 T to 1.0×10-8 T (0.1 to 10 nanoteslas); whereas, in comparison, the magnetic field strength of magnetic tape near a tape head is about 2.4×10-5 T (24 microteslas).
Its not the strength of the ‘bloody magnetic field’ that’s important… its the size. Think in terms of a giga-parsec lever… a little push here, a little push there, rotation everywhere…
@ Aqua
These are a few facts which seem to have overshot your perceptions.
The various field(s) in the area in question are the remnants–
a) of the solar wind, the dominator of this – our system
b) the interaction of the solar wind on those bodies within our system
c) any wandering fields generated independent of the solar wind by any bodies capable, strike that, there is not a chance that the solar wind does not dominate even here. These pseudo independent fields are actually interactions with the solar wind and bodies within our system we have yet to explain via some mechanism of interaction.
The fields these aforementioned quantiles interact with/and at any boundary of –or local section of interest, are also remnants cast to the interstellar medium by other stellar systems (not just the closest ones to us you understand) within our sphere of affect and influence. As our stellar wind pushes its way into the void between bubbles of stellar bounty just so have other stellar systems existing now and in the past, all leaving some remnant of their passage and location and dwelling time.
They might be huge but that is all they have to recommend them to your biases within the Electric Universe. They are more depleted than they stared out being and will continue the road of debilitation until equilibrium matches in that local area.
On another level all of this interaction takes place within the galactic fields and contributes to the huge current sheets but these too are spread over vast distances and do not dominate at any of these bounding areas. There is no spooky action taking place, there is no general current which powers the universe, and there is not a chance you will grasp these simple facts until you actually study these many interrelated subjects as they relate to each other and repeat any of those experiments which indicate several of these facts yourself I am guessing
Your faith in the EU/PU is just that, faith –since there are more reasons to see these pseudo sciences in the poor light they provide for illumination of the darkest reaches of the universe, your faith is shown for what it is. It is not a reasoned grasp of facts but belief which rules your arguments and your railing against mainstream science.
There is no vast guiding hand here shifting dense plasmas, jolting the cosmos via titanic current flows, magnetically forcing whole worlds into orbits they would not take due to gravity, and certainly there is no super-science space opera tale being told. If you wish to tell us such a tale then please dress it in a better costume, the one it is wearing now is rather thread bare.
Bird on a wire…
Mary
Try this.. Our solar system’s magnetic field, as generated by Sol, is propagated by charged particles in the solar wind. Voyager 1 passed thru a boundary where Sol’s field interfaces with the IGM’s mag. field. At that radii, of approximately 8.7 billion miles. The surface area of a sphere @ 4pr^2 = 9.5114^20 sq. miles, whereas the volume is 4/3p^3 = 2.7583 ^30 cu. miles. While an area of 951,140,000,000,000,000,000 sq. miles may not be easy to imagine, 2,758,300,000,000,000,000,000,000,000,000 cubic miles is even more difficult to visualize? That whole volume is encompassed and influenced by the IGM’s mag. field…. Which is a BIG lever….
@ Aqua
You seem to think it is size that matters in these interactions. Your imagined mechanistic bias is ‘plane’ to see.
The amount or value of any large number in this example is not a determinate factor when the real world, determining factor is the micro tesla.
Would you say that more air will exit your lungs than you take in on average?
The increased CO2 is slightly heavier so many would say yes but experimental values show a different story being told, just as your story does not match observed data. Density, mass, volume, and content all contribute to the stories being told. What does MORE mean in this example… just some thoughts to guide your study.
Some further words now:
The breath of our star is more than just ionized plasmas. The recombining of the discarded portions at the fringes of our cubic of stellar influence does not power the galactic current.
I feel math might be less helpful in your training than analogies and syllogistic images suggesting the direction your minds eye veer.
These few words may, hopefully, penetrate and percolate.
Mary
That sounds to me like homeopathy — the greater the dilution, the more potent it is!
Then again.. this says nothing of the actual shape(s) or polarities of those fields. Sol’s field most likely resembles a flattened toroidal disk?
@ Aqua
Do the study needed to know what you talk about please.
A donut is a poor example even when you flatten it for effect.
Mary
Threadbare… hmmm. Sorry, I seem to have lost my ‘economy’ somewhere? Wash your window for a quarter Lady?
@ Aqua
Now you attempt to turn the conversation away from the details I presented (and asked you to learn more about via self study since your belief was showing) –by posing as a homeless person offering to wash my ‘window’ at this intersection in your life. Pulleeasse!
Next you’ll have us on by relating of a tornado of cyclonic potential with an origination at the edge of our Van Allen Belts.
“And the vacuum rushes in…” — early PC game’s response when an air machine was blasted by an errant bolt from your blaster.
Mary
A gigantic lever? You do realize that we are talking about a gas in space, not a solid bar and a fixed point where we can push on?
But tell me, how much force are was talking about? Give us some numbers?
And how much mass does this sheet represents?
Think inductive motor… a very, very big one.
Inductive motor?
And where exactly in space do you see solid material to hold the magnets in place?
When I was working at Space Camp we had a display of the solar system with Voyager in it, and back in 1990 or so the narrator was talking about reaching the heliopause, and I thought that was about the coolest thing ever. I guess I still do. Thanks for the updates!
PS: Is the scale on the drawing correct? Figuring 35 years for Voyager to get where it is now, are we really only 70 years from Alpha Centauri? Please forgive me if I am making a fool of myself with this question.
Er… no, the scale is logarithmic; i.e., each unit increase on the logarithmic scale represents an exponential increase in the underlying quantity for the given base — 10, in this case.
Yep, I had to look at diagram several times, its very confusing.
Yep, I had to look at diagram several times, its very confusing.
@ Grimbold
“Passing through a sector boundary led to a sudden change in direction of the magnetic field.”
In mainstream non woo science please quantify this statement. i.e. What causes the magnetic field direction to change when passing thru a sector boundry?
Regards
Sol889
“Of course, it’s as easy as it is pointless to do this after the fact. I’d be impressed if the EU idea had predicted this beforehand, but it didn’t. In fact, I have never known the illogical muddle of handwaving vagueness that is EU to make ANY testable prediction at all.”
How’s 2006 after the fact??? Go see that crack woo bunk’m science site by that complete nutter Wal Thornhill – He made predictions about what V1 may find when passing thru the heliopause and low and behold…he was correct!!! Fancy that.
Now lets do that dance again were you cry about the lack of math to back up such wild claims and we claim you are building a strawman.
But on paper looks like the EU explination sans your math, is a little more correct from the math we knew about over 150 years ago
That ‘prediction’ by Thornhill is known as the Texas sharpshooter fallacy; the name comes from a joke about a Texan who fires some shots at the side of a barn, then paints a target centered on the biggest cluster of hits and claims to be a sharpshooter.
Sol says: In mainstream non woo science please quantify this statement. i.e. What causes the magnetic field direction to change when passing thru a sector boundry?
Please, do the research yourself Sol as this is a very specialized subset of a very specialized branch of a very esoteric portion of basic physic and any broad overview such as this does it no justice. I have reason to think the word sector is the hangup for you here, clear your mind of any prior conceptions.
Read on if you must..
Containment without coalescence is the basic solution here. All the forms of the observed effect(s) match a great deal of past speculation and require a great deal of refinement and review before additional testing of any predictions formed by any new postulates can occur.
Think of the many magnetic moments which must exist in the solar charged micro gravity environ, now visualize entering a fairly large area of one at any angle on the generalized spherical field, does this help you? As you enter the field and leave the field the direction of the field will be changed in relation to your static line of travel.
For just ONE of the sources there are Coronal Mass Ejections, those CME which are not absorbed or dissipated, are sometimes rearranged by and guided by the magnetic sheaths interactions with those of planetary strength near to the line of travel. Any portion of that CME we are considering here which survives to reach the area under discussion will contribute to the –pause for it, heliopause.
Levity aside though, consult an encyclopedic source for any real details as what I provide is a very broad overview which does not cover many of the interactions expected or known, nor the inclusion of other facts and surmises.
Using a broad brush to paint this picture for you, if we could see, in 4d, these very large cubic but tiny magnetic field strength bubble’s interactions we would see the slow movement and occasional coalescence of the bubbles, as well as the fissioning and sub fissioning, calving and extreme interference from time to time which is the major problem with domain of opposition in any small field strength with large cubic solutions. There are a lot of factors which need to become a part of the problem’s solution. Time frames can be rather long as the energy is small and mass, cubic and environ are dominate, there is a lot of time for accumulation and change at the heliopause and the ever varying cubic it contains. There might even be micro traces of the initial birth pulse from our primary’s first light trapped in a local eddy of magnetic moment although it is very unlikely to be discovered or even looked for by anyone.
This ‘work’ being done via exchanges of MM by the many and varied sources does not diminish the very real presence of a slightly ionic, slightly charged, very tenuous but loosely grouped plasma which changes “affiliation” from time to time as conditions warrant — such as those cumulative charges and additions ramping up the change in direction or field strength, etc. At times it will not take much to effect such a minor change within this pseudo-turbulent non-uniform media made of many and varied forms both charged and uncharged.
Our arm of the Milky Way is but an eddy, at times, in the lee of the galaxy’s march around the local group. If what has been at this location has left any ‘mark’ or trace of itself then that too will interact in some fashion with our present passage. There is a lot we do not know, a lot we hope to surmise correctly and much more to test. Buckle your seat belts, you are in for a bumpy ride –Bette Davis.
Mary
“What causes the magnetic field direction to change when passing thru a sector boundry?”
See my comment to you below.
Btw, that math you claim is, according to Ivan3Man below, humorously the fallacy of mistaking a priori probability for a posteriori likelihood. A cute but boring trick used by religious minded people over the world through time. Makes it no less a fallacy.
Why did I think there would be this type of discussion?
These magnetic field are very small. The solar wind sends charged particles outwards and this is an extremely diffuse plasma which carries a magnetic field. The reversal of the magnetic field may reflection some transport property issues or tny currents associated with th heliopause. So this may really be no more mysterious than the fact as one passes a Hall probe through the magnetic field of a solenoid and through a gap in the coil that the field reverses.
LC
It would be interesting to send a fleet of probes along the Suns north-south poles, its the only way to build a more complete picture. Perhaps the Solar systems Magnetosphere is similar to Earth’s with field lines converging on the sun’s poles?
The RTGs on Voyager 1 are only going to last till around 2025 (wikipedia). Shame really, the next ones have to last for a few hundred years at least. (or go faster) or both. 🙂
No, it isn’t the only way to achieve a more complete picture. The large scale structure of the heliosphere has already been determined, and presented here on UT a couple of times.
They used another observatory, the aptly named Interstellar Boundary Explorer (IBEX).
If you need long term power generation, a nuclear reactor would be the way to go. It could last centuries by starting from lesser active material (if the design allows it).
At least one probe has flown around the solar poles: the European probe Ulysses which was launched on a space shuttle. This poor thing is already frozen to death, but it send quite unique data.
@Torbjörn Larsson
IBEX is revealing results of interactions with the heliosphere and the local interstellar medium. It doesn’t necessarily paint a good picture of our suns magnetic moment. Its results * Quote: David McComas, IBEX Principal Investigator; “suggest that these new findings will prompt a change in our understanding of the heliosphere and the processes that shape it.”
Regarding RTGs, there has been much advancement in thermoelectric’s to date, using Selenium as the semiconductor results in a much higher efficiency. Nuclear needs to be in the mix somehow however for such long missions.
@ DrFlimmer
I have forgotten about Ulysses, but you know, it didn’t provide us with any kind of magnetic map of the suns poles. (that I know of). Seems we learned more about Jupiter from it then we did about the sun. And comets.
A fleet of small micro-satellites sent out in all directions could “map” the Heliospheric current sheet, if they are sent fast enough and with enough fuel to exit the solar system. An innovative solution might be to actually let them be carried by the solar wind.
http://en.wikipedia.org/wiki/Heliospheric_current_sheet
One can hope.
A magnetic field is a dipole field. For a magnetic dipole moment m this field is
B(m,r) = (?/4?r^3)(3(m*r)r – m)
Where the * indicates an inner product. Along the equatorial plane of the sun this is zero as m*is directed along the poles and r is in the plane of the equator. The point then is the field strength drops off as ~ 1/r^3. The solar magnetic field is only about a .1 microtesla at the solar surface, or about that of the Earth. Of course it is huge in its extent. The solar radius is 4×10^{5}km and the heliopause is out around 10^2 AU or 1.5×10^9km out. So taking the ratio (4×10^{5}/1.5×10^9)^3 = 1.9×10^{-11} and so the magnetic field is this much smaller than at the photosphere. So the solar magnetic field is about 10^{-11} Gauss or 10^{-15)T.
This is fairly small. The field strengths are too small to dynamically move the extremely diffuse plasma of the solar wind.
LC
My impression now is that you are moving the goal posts. Well, the more complete picture and the resulting “change in our understanding of the heliosphere” will include a more thorough understanding of the magnetosphere. Indeed it already has, as the link shows.
Sure one can wish for more observatories. I was mostly pointing out that your claim of “only way” was erroneous as stated.
As for RTGs, increased efficiency is good; I get ~ 2xinitial efficiency gets you ~ 70 % longer time due to the exponential die off of radioactivity; but surely it won’t make the time factor 2-8 you speak of (100 – 300 years).
@Torbjörn Larsson
Actually, your correct; IBEX is providing exciting information, and my statement (its the only way) is a turn of phrase. I will happily retract it. Indeed, Probes such as New Horizons and others that (will) travel through our solar system are providing new point measurements that continue to build a bigger picture. So while I wish for a more direct exploration, over time the data will grow anyway.
I’m not trying to move the Goalposts, perhaps I didn’t explain it properly to begin with;
It seems counterintuitive to assess that the Solar Plasma Sheath and the Heliosphere are not connected entities. While the Solar Magnetic Field is too weak to have an effect on the solar wind, it extends all the way throughout the solar system. Indeed what the IBEX and Cassini results suggest is that the Heliopause is: quote:
“Rather than being dominated by the collisions between the solar wind and the interstellar medium, the INCA (ENA) maps suggest that the interaction is controlled more by particle pressure and magnetic field energy density.[1]”
http://en.wikipedia.org/wiki/Heliopause#Heliopause
Thus my interest in the Solar Plasma Sheath as logically the Heliosphere is the boundary of its effects. If its not the Solar Wind alone that creates the boundary then logically the Solar Dynamo becomes the next best contender based on these new observations. It is at least a plausible connection in ‘my opinion’. But Im no scientist, so shall eagerly await any new research and observation.
Regarding Nuclear power, well, its an interesting conversation, but there are two facets. Propulsion or Power generation. Both apply for space travel, but apart from RTGs, all nuclear space studies seem to concentrate more on propulsion. The Soviet Thermionic ‘TOPAZ’ reactors are at the leading edge of study for space borne power generation. However most civilian study in this field seems to have stalled in the 1970’s.
http://en.wikipedia.org/wiki/Thermionic_converter
Induced Gamma Emission batteries also sound promising for their ability to be (re-charged). Also Look up: Hafnium controversy
http://en.wikipedia.org/wiki/Induced_gamma_emission
Sorry for the late reply, its been a fun conversation, I tend to learn a lot from them. 🙂
At least one probe has flown around the solar poles: the European probe Ulysses which was launched on a space shuttle. This poor thing is already frozen to death, but it send quite unique data.
At least one probe has flown around the solar poles: the European probe Ulysses which was launched on a space shuttle. This poor thing is already frozen to death, but it send quite unique data.
At least one probe has flown around the solar poles: the European probe Ulysses which was launched on a space shuttle. This poor thing is already frozen to death, but it send quite unique data.
Where is Uranus in NASA’s Illustration
Maybe it’s on the other side of the sun, hanging out with mercury and venus
Basically at the back!? =D
My hypothesis is that it is the log scale, for ease of visualization, that forced some omission.
I have read that twice, but I still don’t get it!? Space is _vast_.
Would you worry about hitting a drifting derelict on our oceans, even? Now multiply that unlikely event with 10^15 (the ratio between a 100 au volume vs Earth volume).
And, since the probes (2 of them) are traveling outwards, the risk diminishes with every year.
Uranus is at the top of your legs and just below the tailbone
Wow, that is _a lot_ of physics out of one ~ 700 kg observatory.
So I need to orient myself in that figure. It is logarithmic, but Voyager 1 is at ~ 116 AU so basically at the heliopause “You Are Here” arrow.
But what is the “G Cloud”? NASA’s Rosetta page: “Another theory is that comets originally formed in dense molecular clouds of interstellar space and were captured by the sun to form the Oort Cloud. (A similar interstellar cloud, the G Cloud,”
So it is a peculiar local molecular cloud (that we will run into in some 10 000 years, according to less certain sites) and have little to do with the general physics here.
IVAN3MAN-picking:
“A new is what we need to continue our understanding of what lay at the furthest reaches of our now explorable space.”
A new what!? (A new probe would be good.)
LOL-picking:
“Says Burlaga, “The firsthand detections made by Voyager 1 are likely to be extremely important for researchers trying to decide between current leading theories for the source and structure of current sheets.””
Burlaga made a funny.
You MUST divide by ukulele…. LOL!!
The Voyagers are awesome!! I know the Moon missions (Apollo) were special, but I grew up in the 70’s and there was no manned missions. 🙁 There were Pioneers, Voyagers, and Vikings.
Voyager has returned SO much scientific data — places we knew nothing about till they flew there.
Still my favorite NASA missions.
You MUST divide by ukulele…. LOL!!
The Voyagers are awesome!! I know the Moon missions (Apollo) were special, but I grew up in the 70’s and there was no manned missions. 🙁 There were Pioneers, Voyagers, and Vikings.
Voyager has returned SO much scientific data — places we knew nothing about till they flew there.
Still my favorite NASA missions.
Best work done! by the Voager 1,I am happy regarding the Information sent by this Instrument.But it gives best results regarding certain event at the boundry of Oort cloud.At the boundry this Instrument may or may not show defunction properties.