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Spacecraft Detects Mysterious “Ribbon” at Edge of Solar System

Accurate timing of the incoming ENAs allows the IBEX team to obtain a higher resolution in the latitudinal direction. The inset at right shows some of the fine detail of the ribbon.  Credit: Southwest Research Institute (SwRI)

Accurate timing of the incoming ENAs allows the IBEX team to obtain a higher resolution in the latitudinal direction. The inset at right shows some of the fine detail of the ribbon. Credit: Southwest Research Institute (SwRI)

Since it launched a year ago, the Interstellar Boundary Explorer (IBEX) has been monitoring heliosphere and how our Sun interacts with and the local interstellar medium — the gas and dust trapped in the vacuum of space. The first results from the mission, combined with data from the Cassini mission, are showing the heliosphere to be different from what researchers have previously thought. Data show an unexpected bright band or ribbon of surprisingly high-energy emissions. “We knew there would be energetic neutral atoms coming in from the very edge of the heliosphere, and our theories said there would be small variations in their emissions,” said David McComas, IBEX Principal Investigator at a press conference on Thursday. “But instead we are seeing two-to-three hundred percent variations, and this is not entirely understood. Whatever we thought about this before is definitely not right.”

The energies IBEX has observed range from 0.2 to 6.0 kiloelectron volts, and the scientists said its flux is two to three times greater than the ENA activity throughout the rest of the heliosphere. McComas and his colleagues said that no existing model can explain all the dominant features of this “ribbon.” Instead, they suggest that these new findings will prompt a change in our understanding of the heliosphere and the processes that shape it.

This image illustrates one possible explanation for the bright ribbon of emission seen in the IBEX map. The galactic magnetic field shapes the heliosphere as it drapes over it. The ribbon appears to trace the area where the magnetic field is most parallel to the surface of the heliosphere (the heliopause).  Credit:  Southwest Research institute

This image illustrates one possible explanation for the bright ribbon of emission seen in the IBEX map. The galactic magnetic field shapes the heliosphere as it drapes over it. The ribbon appears to trace the area where the magnetic field is most parallel to the surface of the heliosphere (the heliopause). Credit: Southwest Research institute


McComas suggested that the energetic neutral atom (ENA) ribbon could be caused by interactions between the heliosphere and the local interstellar magnetic field. “The local interstellar magnetic field is oriented in such a way that it correlates with the ribbon. If you ‘paint’ the ribbon on the boundary of the heliosphere, the magnetic field is like big bungie cords that pushing in along the sides and at southern part of the heliosphere. Somehow the magnetic field seems to be playing a dominant roll in these interactions, but we don’t know it could produced these higher fluxes. We have to figure out what physics were are missing.”

The solar wind streaks away from the sun in all directions at over a millions kilometers per hour. It creates a bubble in space around our solar system.

For the first ten billion kilometers of its radius, the solar wind travels at over a million kilometers per hour. It slows as it begins to collide with the interstellar medium, and the point where the solar wind slows down is the termination shock; the point where the interstellar medium and solar wind pressures balance is called the heliopause; the point where the interstellar medium, traveling in the opposite direction, slows down as it collides with the heliosphere is the bow shock.

The heliosphere. Credit: NASA

The heliosphere. Credit: NASA


The Voyager spacecraft have explored this region, but didn’t detect the ribbon. Team member Eric Christian said the ribbon wound in between the location of Voyager 1 and 2, and they couldn’t detect it in their immediate areas. Voyager 1 spacecraft encountered the helioshock in 2004 when it reached the region where the charged particles streaming off the sun hit the neutral gas from interstellar space. Voyager 2 followed into the solar system’s edge in 2007. While these spacecraft made the first explorations of this region, IBEX is now revealing a a more complete picture, filling in where the Voyagers couldn’t. Christian compared Voyager 1 and 2 to be like weather stations while IBEX is first weather satellite to provide more complete coverage.

McComas said his first reaction when the data started coming in was that of terror because he thought something must be wrong with the spacecraft. But as more data kept coming back each week, the team realized that they were wrong, and the spacecraft was right.

“Our next steps will be to go through all the detailed observations and rack them up against the various models and go find what it is that we are missing, what we’ve been leaving out,” he said.

For more information and visuals, see this NASA webpage.

About 

Nancy Atkinson is Universe Today's Senior Editor. She also works with Astronomy Cast, and is a NASA/JPL Solar System Ambassador.

Comments on this entry are closed.

  • Lawrence B. Crowell October 19, 2009, 5:50 AM

    This problem does involve plasma physics. So on the face of it Anaconda is not completely off the mark. He just illustrates some strange thinking. He seems to feel that NASA is making a ground breaking statement by saying “Magnetic fields are caused by electric currents,” when this really was found in the mid 19th century by Michael Faraday.

    To lay down the cards, this does involve plasma physics. It involves the magnetohydrodynamics of the interstellar medium and the region of the heliopause, which is much smaller. The heliopause is in motion relative to the interstellar ionized MHD region and there is a complicated interaction.

    I might suggest a simple way to look at this and how this might be modelled. The galactic magnetic field has a certain energy density. The heliopause is moving through it and lines of magnetization are being pulled apart along a region where the galactic magnetic field is tangent to the heliopause. See the picture above. This requires energy, so the motion of the heliopause is reducing the magnetic flux in these tangential regions. The energy or work the heliopause exerts on the galactic magnetic field then has to go somewhere. That energy then appears to be going into the motion of charged particles in the KeV domain of energy.

    Lawrence B. Crowell

  • Aqua October 19, 2009, 12:39 PM

    Have you heard? Monopole magnetic fields have been created in the lab… nice! ‘The other side of the coin’ has been flipped. A challenge to understand the implications? Mirror matter anyone?

  • Lawrence B. Crowell October 20, 2009, 10:07 AM

    This is a sort of pseudo-magnetic monopole. Quantum Hall effects with certain materials can result in a magnetic dipole, but where one of the poles is topologically removed by the matieral in a way which gives the appearance of a magnetic monopole.

    LC

  • Paul Eaton-Jones October 23, 2009, 2:31 AM

    I’ve just had a quick look at the Wattsup…. site. Man, I’m gobsmacked. According to one poster the sun is a clothed neutron star which accounts for the low neutrino count and the ribbon at the edge of the solar system is apparently the debris left over from when the sun went supernova but only along its equator.

  • Homme du Sud October 23, 2009, 1:07 PM

    Paul Eaton-Jones, I never thought about it that way. Could be on to something there!!! ;)

  • Nereid October 27, 2009, 5:31 PM

    Two things.

    First: Anaconda is an utterly unreliable commenter … he is on record as defining “current” (as in electrical current) in a way that is not only non-standard and idiosyncratic, but also so different from the way the term is used by his heroes (Alfvén, Peratt, etc) that his loud proclamations of support for them become fatal blows to his very own words (reference available upon request).

    Second: not one EU cult member has taken the cult leader, Don Scott, to task over his prominent, unambiguous declaration that astronomy, as a science, is impossible (certainly not a peep from Anaconda). This is a truly extraordinary state of affairs, not least because almost everything EU cult members quote – from NASA PRs say – is based upon the validity of astronomy, as a science.

    To remind readers of cult-leader Scott’s astonishing fatwa: “There is no way that a measurement taken at only one end of a transmission channel can reveal changes that have occurred farther up the channel.” In other words, to take just one example, unless you can check out the photons as they leave the Sun’s photosphere (say), merely detecting them here on Earth tells you nothing whatsoever about what has happened to those photons on their journey from Sun to Earth (and hence nothing about their state at origin).

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