Satellite Imagination: Ravioli, Anyone?

The advent of orbiter missions to the giant planets Jupiter and Saturn have enabled astronomers to get detailed looks at moons that, in the view of earthbound telescopes, look like little white dots. When a white dot gets too close to a planet, it gets washed out in the glare.

However, the Cassini mission (for example) could get pretty near those close-in moons and get images that were not washed out in the reflected sunlight from Saturn’s clouds and rings. When Cassini cameras were aimed at the small moons there, what interesting pictures they sent back to Earth. 

PIA21436.jpgTo the right is Pan. (Image credit: By NASA, Matúš Motlo – National Aeronautics and Space Administration, Public Domain, https://commons.wikimedia.org/w/index.php?curid=57190751) Strange thing about the discovery: it was first predicted by mathematics. In the 1980s, astronomers noticed waves at the edge of one of Saturn’s rings. The irregularities suggested that perhaps a moon was raising tides. The known laws of gravity were applied, numbers crunched, and after checking old images from 1981, astronomer Mark Showalter located white dots in 11 pictures snapped by Voyager 2. Discovery was verified in 1990.

How do you miss a moon like that? It’s small compared to our moon–only 20 miles wide and 13 miles from one short end to the other. Maybe NASA wasn’t moonstruck as much as it was “ring-struck” as it studied the Saturnian neighborhood.

Pan is considered a “shepherd moon.” It seems to keep a 200-mile gap open in the middle of Saturn’s rings. And since the mythical Pan was a shepherd, we have the name.

Atlas 2017-04-12 raw preview.jpg

Atlas didn’t get missed by NASA; it was identified in 1980, a find of the earlier Voyager 1 mission. Cassini captured this image, left, as it did the one of Pan, above.

Atlas orbits on the outer edge of Saturn’s A ring. Maybe that’s why it was named for the titan of Greek pagan religion; it kind of “holds up” the whole ring system. It’s a bit bigger and a titch more flat than Pan, measuring 24 miles wide and almost 12 miles from one short end to the other.

Put your imagination to work. What do these moons resemble? Pierogies? Ravioli? Flying saucers? Those flattened “ridges” are probably ice dust deposited from ring particles. Think of a world-girdling snow drift deeper than Mount Everest. If you had a snowblower and a spacesuit, it’s only a few miles to cut through those ridges. 

Even when humans manage to make it to Saturn, these moons will likely be admired from afar. Any ship that tried to land would find itself buried. There may not even be a solid surface deep inside–the overall density of these moons is similar to fresh snow, slightly packed. I wouldn’t want to ski on them either. 

 

 

About catholicsensibility

Todd lives in Minnesota, serving a Catholic parish as a lay minister.
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