Tag Archives: magnetosphere

Back to Jupiter

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I know that I just blogged about the Jovian magnetosphere, but here I go again. And it’s another press release from SwRI, of all things. There’s a lot going on in this diagram! First off, kudos on getting the dipole to look right, but then things get a little confusing…

The profusion of orbit lines and magnetic field lines (or tubes, I guess, if I look at the high-resolution version of the image) might make sense to a well-informed viewer, but they seem confusing for the uninitiated. I’m also wondering why the faint structure that connects the moon Io to Jupiter, which indicates ionized gases trapped in Jupiter’s magnetic field, doesn’t actually follow a magnetic field line. Yeah, they got the dipole bit correct, but then garbled the message! And the Io torus, which also looks somewhat tubular in this depiction, doesn’t seem to lie in the same plane as the orbit lines. All very odd.

Here’s the image caption, BTW: “About [one] ton of volcanic gases are spewed out by Jupiter’s moon Io every second. When ionized, these gases become trapped in Jupiter’s strong magnetic field (shown in blue) and form a vast ring (shown in red) around the planet with Jupiter’s 10-hour spin period. Jupiter’s strong magnetic, rapid rotation and Io’s prodigious source of material result in a giant magnetosphere whose dynamics are very different from the Earth.” Not such a bad explanation, really, although it helps to know that the ionized material rotates along with Jupiter’s 10-hour period, whereas Io orbits more slowly, so the stuff gets smeared out along the length of the moon’s orbit.

If you’re interested in a bit more on the topic, you can also check out an actual image of the Io torus and even see its rotation with Jupiter (the latter page actually has a much better description of the torus than the above as well). Um, did I mention I almost did a Master’s project looking at the Io torus…?

Preaching to the Choir

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A press release from the Southwest Research Institute describes observations made of Jupiter’s magnetosphere by the New Horizons spacecraft. The above image (sorry, it’s quite low-res, and to take a closer look, you’ll need to open up the huge version linked from the above) summarizes some of the results. To summarize my response: it would work quite well in a scientific publication, but it just doesn’t cut it for public use.

I admit that it’s nice to see actual data represented—and nice to see an attempt at providing context for them—but the context in which the data fails to help much; furthermore, it really only conveys the context for an expert viewer—one who knows about the solar wind, magnetic fields, and such. In a previous post, I complained about depictions of Earth’s magnetosphere; I won’t bother reiterating my gripes, but they can be applied to the top portion of the above image. Honestly, some version of the schematic portion of the image would probably have sufficed for a press release, but it would have required significant work to be made more comprehensible.

Also, we’re given no hint as to how to read the spectrograms below the schematic diagram, and furthermore, they utilize opaque units such as “Energy/Q [eV/q]” and “DOY 2007 [UT].” Oh, yeah, and pseudocolor. ’Nuff said.

Making matters worse, the picture’s caption incorporates a trult impressive quantity of jargon. To call it “incomprehensible,” at least for public audiences, would be kind. The press release is better, but not by much. The only audience I can imagine picking up on this story is a quite sophistication publication such as Scientific American. I guess that’s all well and good (better than nothing), but a little more effort could make this result more accessible to broader audiences.

(I’ll just add that the New Horizons folks actually produced a spiffy press kit that describes the fly-by, with some decent diagrams, too.)

BTW, I’m in Athens attending the Communicating Astronomy with the Public conference. Fun stuff! And I finally achieved my goal of presenting a PowerPoint using no bullet point slides. A personal victory.

From Mice to Magnetospheres

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A coworker just asked me a question about the magnetosphere, and in a quick online check, I came across the above image. I tend toward the nit-picky in matters concerning space weather, in large part because I attended a graduate program in “Space Physics and Astronomy” at Rice University. I see several problems with this image… Most disconcertingly, it makes the bow shock appear like a nearly solid boundary, with the interior and exterior vastly different in their texture and color; in fact, the bow shock simply represents the location where particles slow from supersonic (yes, there is a such a thing as sound speed in space). Furthermore, the little squiggly arrows presumably indicating particle motion through the magnetosheath look nothing like the actual flow. Finally Earth’s magnetic field should look more like a dipole, so all the field lines should not converge to a single point at the poles.

For contrast, allow me to reproduce a scene from the most recent space show produced by my institution, Cosmic Collisions:

We used data from the Center for Integrated Space Weather Modeling as the basis for the sequence, so the effect is not quite so diagrammatic. The grey surface represents the bow shock; the bluish surface represents the exterior of the region dominated by Earth’s magnetic field. And note that the flow moves through the bow shock and around the Earth’s magnetic field. You can see more from the show (and more of the data) in a short piece produced for our “Science Bulletins” AstroViz segment.

Finally, speaking of alma maters, a space weather story from Cornell just appeared in my inbox. Solar flares may cause problems with GPS receivers—no great shakes if you’re driving your Lexus down I-10, but more problematic if you’re flying through dense fog on a commuter jet.