The Sun's ripple effect

Jul 30, 2013
Image of sun courtesy of NASA.

A new study co-authored by Boston University astronomers indicates that a bow shock (a dynamic boundary between the Sun's heliosphere and the interstellar medium) is highly likely. These findings challenge recent predictions that no such bow shock would be encountered.

The researchers base their expectation of finding a on a new magneto-hydrodynamic simulation that confirmed a theoretically expected slow bow shock (SBS) ahead of the . The new research supports the idea that the sun, like a boat moving through water, forms a crescent-shaped shockwave as it moves through interstellar gas. The study, titled "A slow bow shock ahead of the heliosphere," was published recently in the journal Geophysical Research Letters.

In the current study, Bertalan Zieger, lead author and research scientist at BU's Center for Space Physics, and colleagues predict that a slow bow shock should exist ahead of the heliosphere. This challenges some recent models that argued no bow shock at all would be found. Those studies, which used the Interstellar Boundary Explorer (IBEX) satellite to measure the speed of interstellar particles entering the solar system near the edge of the heliosphere, suggested that the sun was moving too slowly through interstellar space (at 52,000 miles an hour) to create a bow shock.

However, the bow shock that they refer to is what is called a fast bow shock. The new study shows that a slow type is possible: IBEX observations also indicate that the interstellar wind is slower than the fast and the intermediate wave, but faster than the slow wave. Using these observations, the researchers conducted a magneto-hydrodynamic simulation that predicts a slow bow shock should exist in front of the heliosphere.

These projections could soon be confirmed by actual data: Voyager 1 is heading toward the slow bow shock, while Voyager 2 is not, which means that the two spacecraft are expected to encounter different interstellar plasma populations beyond the heliopause. Confirmation of the existence of a bow shock could have important implications for our understanding of the nature of the interstellar magnetic field that the Voyagers will encounter ahead of the heliopshere, including whether the slow bow shock filters the influx of high-energy cosmic rays into the heliosphere.

Explore further: Amazing raw Cassini images from this week

More information: Geophysical Research Letters, Vol. 40, 1–6, doi: 10.1002/grl.50576, 2013

Related Stories

Voyager observes magnetic field fluctuations in heliosheath

Oct 29, 2012

As they near the outer reaches of the solar system, for the past several years the two Voyager spacecraft have been sending back observations that challenge scientists' views of the physics at the edge of the heliosphere, ...

Interstellar dust and the sun

Nov 12, 2012

(Phys.org)—The space between stars is not empty. It contains copious but diffuse amounts of gas and dust; in fact about 5-10% of the total mass of our Milky Way galaxy is in interstellar gas. About 1% of ...

Runaway star plows through space

Jan 25, 2011

(PhysOrg.com) -- A massive star flung away from its former companion is plowing through space dust. The result is a brilliant bow shock, seen here as a yellow arc in a new image from NASA's Wide-field Infrared ...

Wind mission encounters 'SLAMS' waves

Apr 16, 2013

(Phys.org) —As Earth moves around the sun, it travels surrounded by a giant bubble created by its own magnetic fields, called the magnetosphere. As the magnetosphere plows through space, it sets up a standing ...

Recommended for you

Amazing raw Cassini images from this week

6 hours ago

When Saturn is at its closest to Earth, it's three-quarters of a billion miles away—or more than a billion kilometers! That makes these raw images from the ringed planet all the more remarkable.

Europe launches two navigation satellites

6 hours ago

Two satellites for Europe's rival to GPS were lifted into space on Friday to boost the Galileo constellation to six orbiters of a final 30, the European Space Agency (ESA) said.

SpaceX gets 10-year tax exemption for Texas site

7 hours ago

Cameron County commissioners have agreed to waive 10 years of county taxes as part of an agreement bringing the world's first commercial site for orbital rocket launches to the southernmost tip of Texas.

Voyager map details Neptune's strange moon Triton

8 hours ago

(Phys.org) —NASA's Voyager 2 spacecraft gave humanity its first close-up look at Neptune and its moon Triton in the summer of 1989. Like an old film, Voyager's historic footage of Triton has been "restored" ...

How the sun caused an aurora this week

9 hours ago

On the evening of Aug. 20, 2014, the International Space Station was flying past North America when it flew over the dazzling, green blue lights of an aurora. On board, astronaut Reid Wiseman captured this ...

User comments : 10

Adjust slider to filter visible comments by rank

Display comments: newest first

cantdrive85
1 / 5 (8) Jul 30, 2013
new magneto-hydrodynamic simulation


"A century ago, James Clerk Maxwell, in his monumental Treatise on Electricity and Magnetism, wrote these prophetic words: "The phenomena of electrical discharge are exceedingly important, and when they are better understood they will probably throw great light on the nature of electricity as well as on the nature of gases and of the medium pervading space.""

"For the next 50 years, studies of the electrical discharge were pursued with considerable vigor, and the world was led into the age of electronics. After that, however, as Professor Hannes Alfvén reminded us when he accepted the 1970 Nobel Prize in Physics (26), "most theoretical physicists looked down on this field, which was complicated and awkward ... not at all suited for mathematically elegant theories." The theorists, says Alfvén, preferred to approach plasma physics by way of the kinetic theory of gases, which led to "mathematically elegant" theories."

(con't)
cantdrive85
1 / 5 (8) Jul 30, 2013
(con't)

"In Alfvén's estimation, "the cosmical plasma physics of today ... is to some extent the playground of theoreticians who have never seen a plasma in a laboratory. Many of them still believe in formulas which we know from laboratory experiments to be wrong ... several of the basic concepts on which theories of cosmical plasmas are founded are not applicable to the condition prevailing in the cosmos. They are 'generally accepted' by most theoreticians, they are developed with the most sophisticated mathematical methods; and it is only the plasma itself which does not 'understand' how beautiful the theories are and absolutely refuses to obey them...""

"The implication of Alfvén's remarks is clear enough: astrophysicists must bone up on the neglected field of electrical discharge phenomena. I, for one, believe that when they do so the new lines of inquiry will rather quickly lead to the rejection of the idea that stars are thermonuclearly powered."

Ralph Jurgens, 1972
barakn
2.8 / 5 (4) Jul 30, 2013
Do you mean Ralph Juergens, the guy who never bothered to get a PhD? Wow, was he ever proved wrong. Neutrino studies have nailed the lid to that coffin.
no fate
not rated yet Aug 02, 2013
Do you mean Ralph Juergens, the guy who never bothered to get a PhD? Wow, was he ever proved wrong. Neutrino studies have nailed the lid to that coffin.


They certainly didn't. The assumption that all of the neutrinos of each type detected in sudbury were produced by the fusion process would nail the lid if it could be proven that is the case. Since we know Neutrino production has several sources this is more of a "fingers crossed" assumption than anything. The only place the proton-proton fusion chain produces more power than it requires would be the core of the sun....everywhere else it requires more energy than it produces.

So far experiment cannot verify the suns fusion core.
GSwift7
5 / 5 (1) Aug 02, 2013
Yeah, he means Ralph Jurgens, the Velikovsky proponent, who thinks the planets were in different orbits during the times of the roman and greek empires.

As cantdrive himself is fond of saying; garbage in, garbage out.

Quoting an idiot about a subject you yourself don't understand is not a good debate tactic.

Try consulting modern astronomy sources, rather than outdated work from the first half of last century, prior to the space age.
cantdrive85
1 / 5 (3) Aug 02, 2013
Your claim of neutrino studies as being the end of the story is false, a red herring. First, the electric model doesn't disallow fusion occurring on the sun, as a matter of fact fusion is well supported by the electric model. Any fusion taking place on the Sun is probably occurring in the double layer (DL) at the top of the photosphere (not deep within the core). Also, from 'The Electric Sky' from Dr. Don Scott;
" It has reportedly been observed that the neutrino flux from the Sun varies inversely with sunspot number. This is expected in the ES hypothesis because the source of those neutrinos is probably z-pinch produced fusion which is occurring in the double layer - and sunspots are locations where there is no DL in which this process can occur. The greater the number of sunspots, the fewer the number of observed solar neutrinos."

Seems as if the data match the model, unlike the standard model which has absolutely ZERO predictive ability.
cantdrive85
1 / 5 (3) Aug 02, 2013
Try consulting modern astronomy sources, rather than outdated work from the first half of last century, prior to the space age.


Magnetohydrodynamic theoretical models of plasma which were proven false 50 years ago? From Alfven's Nobel speech, OVER 40 YEARS AGO, "the cosmical plasma physics of today ... is to some extent the playground of theoreticians who have never seen a plasma in a laboratory. Many of them still believe in formulas which we know from laboratory experiments to be wrong ... several of the basic concepts on which theories of cosmical plasmas are founded are not applicable to the condition prevailing in the cosmos. They are 'generally accepted' by most theoreticians, they are developed with the most sophisticated mathematical methods; and it is only the plasma itself which does not 'understand' how beautiful the theories are and absolutely refuses to obey them..."

The idiocy is by those who insist on support of theoretical models in spite of observation.
GSwift7
not rated yet Aug 02, 2013
From Alfven's Nobel speech, OVER 40 YEARS AGO


Yep, there you go again. 40 YEARS AGO.

Try using stuff that isn't outdated. Recent work from KOBE, STEREO and the like have far surpassed anything Alfven ever dreamed of. His work was a good starting point, but we have a much better understanding of it now than anything he would have been able to come up with. He just didn't have the observations and computer power needed to fill in the missing pieces and rule out some of the things he claimed might be possible. MHD actually counters some of the things he proposed, and do play an important part, in addition to MHD. You cannot discard the rules of MHD, gravity, Maxwell, Gauss, etc. You must account for all of the forces interacting with each other in order to understand the complete picture. We are just beginning to get to that point.
cantdrive85
1 / 5 (4) Aug 02, 2013
Just because we have greatly improved our observational abilities does not imply that astronomers have changed their models. MHD models are still used, what Alfven was saying 40 years ago still applies as the authors of the study used "new" MHD models. He was clear the MHD models used are incorrect and were proven so by nuclear scientists. A plasma "networking" or particle and circuit model MUST be used to describe cosmic/solar plasma phenomena.
http://www-pub.ia...p_17.pdf

Empirical data always trumps theoretical belief and there is ZERO empirical data which supports the theoretical MHD plasma. As Alfven stated, the field of astrophysics has yet to experience the revolution nuclear scientists experienced due to the failed theoretical models.
axemaster
not rated yet Aug 04, 2013
Any fusion taking place on the Sun is probably occurring in the double layer (DL) at the top of the photosphere (not deep within the core).

If that were the case we would easily detect the gamma radiation generated by the fusion reactions. We don't detect them, so your idea is wrong.

NOTE: By definition the photosphere is the region where visible light can escape without further interactions. Obviously this holds true for shorter wavelengths as well.