Brain teasers from space
Posted: Friday, June 12, 2009 9:12 PM by Alan Boyle
NASA / JPL / SSI |
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A natural-color image provided by the Cassini orbiter shows Saturn's southern
hemisphere and the planet's main rings. Click on the image for a larger version.
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Did you know that Saturn's rings are wavy? Which Mars probe is back in business after it ran into trouble? How many rookies are on the space shuttle Endeavour? Which Apollo 11 crew member never set foot on the moon? Test your wits - and exercise your curiosity.
We've freshened up three brain-teasing quizzes that just might boost your brain power as well. But first, let's consider some observations that are tickling the brains of the bright folks associated with the international Cassini mission to Saturn:
Waves in Saturn's rings?
Traditional views of Saturn, like the freshly released picture above, make the planet's rings look as flat as a phonographic record (remember those?). But other images from Cassini's cameras have revealed something that hasn't been seen so well before: vertical ring structures that are attributed to the gravitational effects of a 5-mile-wide (8-kilometer-wide) moon.
The findings from Cassini's imaging team were published online this week in The Astronomical Journal, and addressed as well in a news release issued Thursday.
Over most of their area, Saturn's main rings are only about 30 feet (10 meters) thick, but the ring particles (which are mostly water ice) can be perturbed along their edges by gravitational interactions with moons that circle in gaps within the rings. The latest imagery focuses on a tiny moon called Daphnis, which pushes the ring material into structures that tower as high as a mile (1.5 kilometers).
When the rings are nearly edge-on to the sun, as they are right now, the structures cast long shadows that Cassini chronicled in the imagery shown below. Such imagery can be taken only every 15 years or so, when Saturn is near its equinox.
NASA / JPL / SSI
Never-before-seen looming vertical structures created by the tiny Saturnian moon
Daphnis cast long shadows across the planet's rings in this startling image taken
by the Cassini orbiter as Saturn approaches its mid-August equinox.
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"We thought that this vertical structure was pretty neat when we first saw it in our simulations," said John Weiss, the research paper's lead author. "But it's a million times cooler to have your theory supported by such gorgeous images. It makes you suspect you might be doing something right."
Weiss' co-authors are Carolyn Porco, head of the Cassini imaging team at the Colorado-based Space Science Institute, and Cornell astronomer Matthew Tiscareno. The research paper also delves into the theory behind gap-embedded moons. During observations yet to come, Cassini's team plans to look at other gaps in hopes of finding some missing moons.
"It is one of those questions that have been nagging at us since getting into orbit: 'Why haven't we yet seen a moon in every gap?'" Porco said in the news release. "We now think they may actually be there, only a lot smaller than we expected."
Triple dose of trivia
Here's your very own opportunity to tackle some nagging scientific questions:
- Test your Sci-Q: We've updated the Science/Space news quiz with a fresh batch of brain teasers, based on the week's news.
- How's your shuttle IQ? Our space shuttle quiz has also been freshened up with a few questions about Endeavour's mission to the international space station, due for launch early Saturday.
- Apollo trivia revisited: The 40th anniversary of the Apollo 11 moon landing coming up next month, and in the weeks to come you'll be hearing a lot more about NASA's glorious past and uncertain future. Test your Apollo IQ, and if you need to refresh your memory, we have just the reading list for you.
Join the Cosmic Log corps by signing up as my Facebook friend or hooking up on Twitter. And if you really want to be friendly, ask me about my upcoming book, "The Case for Pluto."
