March 1, 2007 | David F. Coppedge

Dynamic Solar System Illuminated in Stunning New Images

Images both striking and beautiful continue to arrive on Earth from remote corners of the solar system.  Arriving as streams of binary digits with energies mere quadrillionths of a watt, received by giant radio dishes then amplified and processed, the results are nothing short of amazing.  Here’s a glimpse of what turned up this week:

  1. Volcanic fury:  Imagine a volcano going off in Texas and covering the entire state with ash.  That’s what happens often on a moon of Jupiter, Io, not much bigger than our moon.  The New Horizons spacecraft is approaching Jupiter on its express ticket to Pluto.  Seven years ago, the Galileo spacecraft snapped amazing pictures of one of Io’s active volcanoes, Tvashtar Catena (see Planetary Photojournal), with fire fountains, lava lakes up to 2400 °F, and plumes a mile high.  Not much has changed.  New Horizons snapped these images (see BBC News) of the plume still spouting 150 miles above the surface.  The caption states, “The volcano … is surrounded by a dark patch the size of Texas consisting of the fallout from the eruption.”
  2. Glory rings:  The Cassini spacecraft assembled its data bits into some of the most stunning images of Saturn’s rings yet seen since its arrival in 2004.  Now riding high over Saturn during its “180 Transfer” maneuver, it looked up at the dark side of the rings, capturing the entire ring system in a mosaic of 36 images.  The primary mosaic exposed for the dark rings makes the planet blindingly bright, so image processors digitally removed Saturn for this ring composite of 27 images, taken from a million miles above Saturn at 60° inclination.  Browsing the image at high resolution reveals the clumpy F ring beyond the bright main rings.  Studies have shown the “shepherd moons” Pandora and Prometheus stealing material from the rings as they move nearer then farther from the band of orbiting ice.  Saturn’s rings are turning out to be much more dynamic and complex than previously realized.  A movie of Cassini’s ring plane crossing was posted to add a bit of a thrill ride to visitors.  It really gives a sense of how thin the rings are compared to their breadth.
  3. Titan dune buggy:  The latest radar images from Titan (T25, Feb 22) clarified some previously-known wonders.  Image no. PIA09181 shows some of the icy sand dunes in stark relief.  A newly released slide presentation by Ralph Lorenz (Johns Hopkins U) explains current thinking about these dunes, what they are made of, and how they form and move.  About 20% of Titan’s surface is covered in these dunes.  They exist primarily at equatorial latitudes and rise up to 100 meters high.  The presentation shows analogies with Earth sand dunes and says Titan’s dunes can form in about 1,000 years.  Material from methane rain runoff or from particles drifting down from the atmosphere are most likely candidates for the “sand” grains.  The estimated energy of Titan’s winds sets constraints on the size and mass of the particles.  One scientist counted 10,000 individual dunes on Titan—don’t ask her how or why.  You might ask her, though, “watch a dune?”
  4. Titan great lakes:  Investors might want to snatch up the prime lakefront property in Titan’s northern latitudes, as seen in this stunning radar image from the T25 flyby on Feb. 22.  The island shown (see this zoom image) is estimated to be the size of the big island of Hawaii.  If the dark area is indeed liquid methane or ethane, it appears to be deepest in the upper part and shallower near the island.  Finding possible lakes on Titan was exciting, but the amount falls far short of pre-Cassini predictions.
  5. Saturn gallery:  For more ooh-ahh pictures of Saturn taken recently by Cassini’s cameras, visit the Imaging Science album.
  6. Ol’ Sol has soul:  A new twin mission called STEREO is taking awe-inspiring new images of the sun (see National Geographic News).  The top image needs no drum roll.  Images like this can help scientists predict solar radiation risks for future astronauts on missions to the moon and Mars (see ICR article on space hazards).

In other space news, Rosetta just passed Mars (see Astronomy Picture of the Day) on its way to a comet 7 more years from now.  The European Space Agency’s Mars Express and Venus Express are still in operation, and the USA’s Messenger is on the way to Mercury (ESA just approved a Mercury mission, also).  JPL’s Mars program is still in high gear with two rovers and two orbiters hard at work.  And Cassini has over a year of its prime mission left with a probable two- or three-year extended mission – maybe even longer, if all continues to function.  In short, lots of great space science still ahead.

Aren’t these great days to be alive?  Each data bit coming into the giant dishes of the Deep Space Network is a treasure that scientists in earlier times would have died for.  Let’s gather it safely and not let our gold get molded into graven images for idols.

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Categories: Solar System

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