The orbits of Jupiter's four tiny inner moons -- Amalthea, Adrastea, Metis, and Thebe -- are seen in an artist's cutaway view of the gas giant's ring system. These moons are thought to be the sources of the dust that forms Jupiter's faint rings.
The orbits of Jupiter's four tiny inner moons -- Amalthea, Adrastea, Metis, and Thebe -- are seen in an artist's cutaway view of the gas giant's ring system. These moons are thought to be the sources of the dust that forms Jupiter's faint rings.
More Climate Change — on Jupiter
National Geographic News | 9 Oct 2007 | Anne Minard
Posted on 10/10/2007 2:09:55 PM EDT by docbnj
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Have Jupiter's smallest moons been obliterated?The Long Range Reconnaissance Imager (LORRI) camera on New Horizons should have been able to spot moons down to a diameter of about 1 kilometre. But it saw nothing smaller than Adrastea, a 16-kilometre-wide resident of Jupiter's faint ring system (see image at right). This is puzzling, because scientists expected the number of objects to increase at smaller size scales, as they do in the rings of Saturn. The missing moons may have been eroded away by micrometeoroids, say researchers led by Mark Showalter of the SETI Institute in Mountainview, California, US. A steady rain of small objects - probably between the sizes of a grain of sand and a pebble - would destroy small moons while leaving larger ones mostly intact, they say. For example, a 27-kilometre-wide moon could survive having its outer 5 km worn away over time, whereas an object just 5 km across would be eroded away to nothing in the same time period... But why did this process spare Saturn's small moons? Showalter thinks the answer has to do with the fact that Saturn is simply less massive than Jupiter.
by David Shiga
New Scientist
October 9, 2007
