Interstellar winds buffeting our solar system have shifted direction

Sep 05, 2013
This image shows the nearest interstellar gas clouds around the solar system, including the Local Interstellar Cloud (LIC) and G Cloud, along with positions of neighboring stars in the plane of our Milky Way galaxy. The arrow shows the sun's motion relative to neighboring stars. Image courtesy of P.C. Frisch, University of Chicago

Scientists, including University of New Hampshire astrophysicists involved in NASA's Interstellar Boundary Explorer (IBEX) mission, have discovered that the particles streaming into the solar system from interstellar space have likely changed direction over the last 40 years.

The finding helps scientists map our location within the Milky Way galaxy and is crucial for understanding our place in the cosmos through the vast sweep of time—where we've come from, where we're currently located, and where we're going in our journey through the galaxy.

Additionally, scientists now gain deeper insight into the dynamic nature of the interstellar winds, which has major implications on the size, structure, and nature of our sun's —the gigantic bubble that surrounds our solar system and helps shield us from dangerous incoming galactic radiation.

The results, based on data spanning four decades from 11 different spacecraft, including IBEX, were published in the journal Science September 5, 2013.

"It was very surprising to find that changes in the interstellar flow show up on such short time scales because are astronomically large," says Eberhard Möbius, UNH principal scientist for the IBEX mission and co-author on the Science paper. Adds Möbius, "However, this finding may teach us about the dynamics at the edges of these clouds—while clouds in the sky may drift along slowly, the edges often are quite fuzzy and dynamic. What we see could be the expression of such behavior."

The data from the IBEX spacecraft show that neutral interstellar atoms are flowing into the solar system from a different direction than previously observed. Interstellar atoms flow past the Earth as the interstellar cloud surrounding the solar system passes the sun at 23 kilometers per second (50,000 miles per hour).

Pictorial view of the Earth's orbit and the interstellar flow, as seen from far above the North Pole. During the wind's journey through the Sun's gravitation, it is bent like a soccer ball that is pulled back to Earth in a curve. Slower wind (dark blue) is bent stronger than faster wind. Thus, during the month of February, when the Earth moves into the interstellar flow, the Interstellar Boundary Explorer (IBEX) observes slower wind earlier on Earth's orbit than faster wind. To determine the flow speed, the IBEX team has taken advantage of this "speedometer" that Mother Nature freely provides. Credit: NASA/GSFC/UNH

The latest IBEX measurements of the interstellar differed from those made by the Ulysses spacecraft in the 1990s. That difference led the IBEX team to compare the IBEX measurements to data gathered by 11 spacecraft between 1972 and 2011. The scientists wanted to gather as much evidence from as many sources as possible to determine whether the newer instruments simply provided more accurate results, or whether the wind direction itself changed over the years.

The various sets of observations relied on three different methods to measure the incoming interstellar wind. IBEX and Ulysses directly measured neutral helium atoms as they coursed through the inner . IBEX's measurements are close to Earth, while Ulysses' measurements were taken between 1.3 and 2 times further from the sun.

In the final analysis, the direction of the wind obtained most recently by IBEX data differs from the direction obtained from the earlier measurements, which strongly suggests the wind itself has changed over time.

"Prior to this study, we were struggling to understand why our current measurements from IBEX differed from those of the past," says co-author Nathan Schwadron, lead scientist for the IBEX Science Operations Center at UNH. "We are finally able to resolve why these fundamental measurements have been changing with time: we are moving through a changing interstellar medium."

The paper, "Decades-long Changes of the Interstellar Wind Through our Solar System," includes IBEX team members from the University of Chicago, the Space Research Centre of the Polish Academy of Sciences, the Southwest Research Institute, the University of Texas in San Antonio, UNH, Dartmouth College, Central Arizona College, the University of California at Berkeley, and NASA's Jet Propulsion Laboratory.

IBEX is part of NASA's series of low-cost, rapidly developed Small Explorer space missions. Southwest Research Institute in San Antonio leads the IBEX mission with teams of national and international partners. NASA's Goddard Space Flight Center in Greenbelt, Md., manages the Explorers Program for NASA's Science Mission Directorate in Washington.

Explore further: SDO captures images of two mid-level flares

More information: "Decades-Long Changes of the Interstellar Wind Through Our Solar System," by P.C. Frisch et al Science, 2013.

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User comments : 14

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tadchem
2.3 / 5 (19) Sep 05, 2013
The real question is this: "How can we use this to support the existence of an earth-threatening problem that can only be fixed with HUGE amounts of government research funds being directed immediately to astronomical climate research?"
Benni
1.5 / 5 (16) Sep 05, 2013
The real question is this: "How can we use this to support the existence of an earth-threatening problem that can only be fixed with HUGE amounts of government research funds being directed immediately to astronomical climate research?"


Really mister big statist government guy? You think some government grant will fix this kind of a problem? You come off sounding more like someone with your hands already in the pork barrel looking for still more job security when your present government research grant expires. Yeah, "HUGE" amounts you say, donated to your paycheck.
Kiwini
2.5 / 5 (19) Sep 05, 2013
The real question is this: "How can we use this to support the existence of an earth-threatening problem that can only be fixed with HUGE amounts of government research funds being directed immediately to astronomical climate research?"


Really mister big statist government guy? You think some government grant will fix this kind of a problem? You come off sounding more like someone with your hands already in the pork barrel looking for still more job security when your present government research grant expires. Yeah, "HUGE" amounts you say, donated to your paycheck.


Since you appear to not recognize it when it's in front of your face, look here for enlightenment: http://en.wikiped.../Sarcasm
Gmr
3 / 5 (10) Sep 05, 2013
Okay, now I'm confused - was that a meta-sarcasm followed by a Poe's law, or are we seriously looking at one sarcasm, and two Poe's, or a sarcasm-Poe-sarcasm sandwich?
DonGateley
1.5 / 5 (8) Sep 05, 2013
My thoughts run immediately to the effect this might have on Earth's climate. So perhaps some expenditure is justifiable to ask if and what.
MRBlizzard
1.8 / 5 (10) Sep 05, 2013
One of the points of the 2012, end of the world brouhaha was that the Solar System was passing through the plane of the Milky Way's equator. If that is true, then a change in galactic wind flow might be an interesting (unsuspected) effect.
obama_socks
1.4 / 5 (10) Sep 06, 2013
Let not your heart be troubled. The Solar wind will keep it at bay.
m(%)m
Neinsense99
2 / 5 (10) Sep 06, 2013
Okay, now I'm confused - was that a meta-sarcasm followed by a Poe's law, or are we seriously looking at one sarcasm, and two Poe's, or a sarcasm-Poe-sarcasm sandwich?

I'm starting to think the entire thread is a clear case of Poe judgment.
obama_socks
1.4 / 5 (9) Sep 06, 2013
One of the things which I've had no need to be concerned about was what the effects would be on the Earth if our Solar system was swallowed up by a thick cloud of interstellar gas. It turns out that it is nothing to worry about unless stars begin to form in our immediate vicinity. I searched for it, but all I could find was this from 2008:
http://www.newsci...eReAdWc8
GSwift7
4 / 5 (4) Sep 06, 2013
Interstellar gas outside our solar system is so thin that it's barely there. It is extremely difficult to measure, and this is an important thing to keep in mind regarding the story above.

Notice the story says that the wind "may" have changed direction. The result is based on two different devices which were located at different locations in the solar system. There could be a number of reasons for different results between the two instruments. The above work is a statistical analysis to determine the chance that the result is real. That hardly counts as proof.

In response to this, I would suggest including a neutral atom detector on another future spacecraft headed out of earth orbit. Then they can verify if it gets the same result as IBEX or not. Even then, it doesn't rule out the source of the change being something inside our own solar system.

How do we know the interstellar wind doesn't swirl around inside our solar system like wind in your car with windows open?
obama_socks
1 / 5 (7) Sep 06, 2013
Such as a maelstrom of whirls and eddys when it comes in contact with the Solar wind? There certainly is enough space between planets and such where a maelstrom could occur. But nobody has ever seen one, as far as I know. Our high technology is still in its infancy, taking baby steps. So it will take a while.
Q-Star
4 / 5 (4) Sep 06, 2013
It turns out that it is nothing to worry about unless stars begin to form in our immediate vicinity. I searched for it, but all I could find was this from 2008:


Ya have about 4 or 5 billions years before that COULD "maybe" happen. And even then it will be only a possibility, not even likely. But ya might as well begin prepare, eh?
Q-Star
4.2 / 5 (5) Sep 06, 2013
Such as a maelstrom of whirls and eddys when it comes in contact with the Solar wind? There certainly is enough space between planets and such where a maelstrom could occur.


GSwift was pointing out that such a maelstrom would be material which is several BILLIONS of times less dense than the air ya are breathing.

We do have the tools to see a "maelstrom" (even as rarefied as that) very well. The solar system's heliosphere would provide very ample protection from such a "maelstrom".
cantdrive85
1 / 5 (9) Sep 08, 2013
One needs to ask where the measurements are taking place. Interstellar birkeland currents are coaxial, depending upon where the measurements are being made may only indictate the flow of that region.

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