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NASA Space Science

Probe Shows Jupiter Moon 'Puking' Into Space 152

Tablizer writes "The New Horizons probe caught the moon Io in the act of 'barfing' into space. A five-frame sequence from the New Horizons probe captured a beautiful plume of ash from Io's Tvashtar volcano. "Snapped by the probe's Long Range Reconnaissance Imager (LORRI) as the spacecraft flew past Jupiter earlier this year, this first-ever "movie" of an Io plume clearly shows motion in the cloud of volcanic debris, which extends 330 kilometers (200 miles) above the moon's surface ... The appearance and motion of the plume is remarkably similar to an ornamental fountain on Earth, replicated on a gigantic scale.""
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Probe Shows Jupiter Moon 'Puking' Into Space

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  • by mikael ( 484 ) on Sunday June 10, 2007 @04:35PM (#19460055)
  • Re:Dizzy (Score:5, Informative)

    by DiamondGeezer ( 872237 ) on Sunday June 10, 2007 @05:16PM (#19460277) Homepage
    Since its tidally locked to Jupiter (just like the Moon is to the Earth), then there's not much spinning to be concerned about.

    Io is heated continually by tidal friction, leaving its core molten and its surface full of lava lakes and the vents and calderas of active volcanoes. The tide raising force of Jupiter raises the surface of Io in some places by several meters.
  • Re:Dizzy (Score:3, Informative)

    by KingArthur10 ( 679328 ) <> on Sunday June 10, 2007 @05:33PM (#19460377)
    Tidal locking means that the same face is always facing the planet (or the sun, in the case of a planet). This means that the moon is rotating at the same speed as it orbits the planet. Since Io orbits Jupiter every 1.769 earth days, it also makes a complete rotation every 1.769 days, also. There is definitely plenty of spinning going on for that moon.
  • by dkf ( 304284 ) <> on Sunday June 10, 2007 @06:03PM (#19460553) Homepage

    Step 3: Write it up. Hello, interwebz. Let's move some ads!
    Except the only link in the whole story (including the "Tablizer writes:" preamble) is to an ad-free site and there's no link concealing or other sorts of nefarious stuff either. Nice theory of yours, but the facts don't support it. Looks instead exactly like a good story spoilt by a potty-mouthed submitter. Like that's never happened before...
  • Re:Amazing pics (Score:5, Informative)

    by phulegart ( 997083 ) on Sunday June 10, 2007 @08:56PM (#19461423)
    Not sure where you read what you read, but it is obvious that you did not RTFA, since from the article we learn...

    "Boosaule Mons, which at 18 kilometers (11 miles) is the highest mountain on Io and one of the highest mountains in the solar system, pokes above the edge of the disk on the right side." ... and although this is not the height of the volcano that is erupting, it points to structures on Io that are larger than anything here on earth.

    You might have read this...

    "Unlike most moons, Io has a "young" surface. Because there is so much volcanic activity, the surface is almost free of craters. Also, its volcanoes are quite unusual. Instead of erupting like a normal volcano, they erupt more like geysers do on earth." ...from em/Jupiter/Io [] ...or you might have read this though...

    "Io has lots of thermal areas just like Yellowstone," says JPL's Bill Smythe. "The volcanic plumes get most of the attention but there are probably also things like fumeroles and geysers. On a previous flyby the Particles and Fields instruments saw a deficit of energetic particles over Io where gas was probably coming out of the surface -- but no plumes were seen. We call this the 'stealth plume hypothesis.' The closest Earthly analog to what's happening would be a water geyser like Old Faithful. In fact, if you put Old Faithful on Io it would be about 37 km high!" ...which came from 99_1.htm [] and only indicates that due to conditions on Io, a familiar geyser on earth would eject matter quite high. However, with this data from the article...

    "the cloud of volcanic debris, which extends 330 kilometers (200 miles) above the moon's surface. Only the upper part of the plume is visible from this vantage point - the plume's source is 130 kilometers (80 miles) below the edge of Io's disk, on the far side of the moon." ... we can safely infer that the volcanoes erupting on Io are not similar to earth geysers in size, rather only in how they erupt.

    Volcanoes on Io are rather different in general from their Earth cousins. From Wikipedia...

    "Io's surface is dotted with volcanic depressions known as paterae. Paterae generally have flat floors bounded by steep walls. These features resemble terrestrial calderas, but it is unknown if they are produced through collapse over an emptied lava chamber as with their terrestrial cousins. One hypothesis suggests that these features are produced through the exhumation of volcanic sills, with the overlying material either being blasted out or integrated into the sill. Unlike similar features on Earth and Mars, these depressions generally do not lie at the peak of shield volcanoes and are normally larger, with an average diameter of 41 km (25½ mi), the largest being Loki Patera at 202 km (125½ mi)." ... in other words flat holes in the ground slightly similar to sinkholes. So personally, I wouldn't look forward to an eruption from the still active Loki, at a diameter of 125 miles. I mean, I wouldn't look forward to sitting ringside to that.
  • Re:puke stuff (Score:3, Informative)

    by volcanopele ( 537152 ) on Sunday June 10, 2007 @09:05PM (#19461469)
    What you are seeing in this image is mostly sulfur and sulfur dioxide that has condensed out of the gas in the plume. There is also a mix of basaltic ash. The plume consists of gas and dust that escapes from an erupting lava curtain on the surface.
  • Re:Amazing pics (Score:2, Informative)

    by volcanopele ( 537152 ) on Sunday June 10, 2007 @09:20PM (#19461531)
    I think the Wikijunior article on Io's volcanism is being a bit simplistic. Basically, Io's volcanoes erupt like Kilauea in Hawaii, except the lava is a little less viscous (similar in viscosity to olive oil) so they don't build up large shield volcanoes like on Earth or Mars. The output also tends to be much greater. The plumes we are see on Io are not themselves the volcano, but are byproducts of Io's volcanism. Their size is a combination of the lack of a substantial atmosphere on Io and that moon's low gravity. Volatiles, like sulfur and sulfur dioxide exsolve from Io's lava as it erupts, carrying small, dust-sized particles from the lava along with it. This gas and dust is what you see in this movie (actually, you are only looking at the dust, the gas is invisible in images like this). In this case, the gas and dust is exsolving from a 1-km tall fire fountain. Smaller plumes, like the one at Prometheus, form slightly differently. At these volcanoes, lava flows over terrain covered in sulfur and sulfur dioxide. The underlying sulfur dioxide heats up, and once reaching a critical pressure, bursts through the overlying lava. So these are not like geysers. These volcanoes erupt much like volcanoes on Earth, but the interplay between volatiles and lava, the near-vacumn environment, and the slightly less-viscous lava, help make spectacular displays like you see here at Tvashtar.
  • Re:mass (Score:2, Informative)

    by volcanopele ( 537152 ) on Sunday June 10, 2007 @11:57PM (#19462243)
    Nearly all of the material that is ejected in this plume returns to the surface and forms a giant red ring surrounding Tvashtar. Here is an image that shows the effects of a similar eruption in 2000 and 2001: [] As far as what it would look like, we don't have a higher resolution image of the plume, but the plume source was well imaged by Galileo during several encounters in 1999, 2000, and 2001. The source is a curtain of lava, very similar to what you might see at Kilauea in Hawaii. Here is a graphic showing two views taken during those Galileo encounters: [] The image on the left shows the fire fountain eruption from 1999 (the actually fire fountain is a drawing of what it would have looked like if the eruption weren't so bright, it saturated the detector, see [] for the original image). During the New Horizons encounter, a similar fire fountain event occurred at the same site (as evidenced by the glow from the lava being visible, during daytime, at visible wavelengths, from a spacecraft 2.5 million km away!) and was the source of the plume linked in the article above. Jupiter's rings are formed through micrometeorite impacts on the surfaces of its inner satellites, particularly Metis and Adrastea. There is a torus of plasma (mostly sulfur and oxygen ions) sharing Io's orbit, but the material for that ring, if you can call it that, comes from Io's atmosphere, not from Io's volcanoes directly. Only 1% of the material ejected by Io's volcanoes reaches escape velocity, while most of the material is ejected at a maximum of 1 km/sec. (compared to Io's escape velocity of 2.6 km/sec.)
  • Re:Dizzy (Score:3, Informative)

    by ari_j ( 90255 ) on Monday June 11, 2007 @12:37AM (#19462395)
    While someone else pointed out that Io rotates on the same period as its orbit, don't forget that the photos were taken by a probe as it flew past Jupiter - in other words, the camera was far from stationary. I don't know the path that the probe took, but regardless of that, flying past a sphere gives the impression that the sphere is rotating. In summary:
    1. Io is rotating, contrary to the comment that asserted that tidal locking == no rotation (even though that's clearly not what he meant, it is what he started out saying
    2. The appearance of rotation in the animated GIF in TFA is due to a combination of Io's rotation and the probe's movement relative to it; either one on its own would be sufficient to make it look like that
  • by asninn ( 1071320 ) on Monday June 11, 2007 @05:43AM (#19463333)
    In any grade where people still have a sense of humour left.

"Don't worry about people stealing your ideas. If your ideas are any good, you'll have to ram them down people's throats." -- Howard Aiken