NASA / JPL / SSI
|Saturn and its rings are backlit by the sun in an image from Cassini.
A blue sunset on Mars and a backlit portrait of Saturn and its rings have taken the top spots in two photo contests celebrating NASA's most popular interplanetary missions. The Martian sunset comes from the Spirit rover, the Saturnian view comes from the Cassini orbiter - and the best thing about both those missions is that there's likely to be much, much more to come.
More than 10,000 voters selected each winner from a field of a dozen-plus contenders in separate end-of-the-year online ballots. The Mars contest was timed to coincide with Tuesday's three-Earth-year anniversary of the Opportunity rover's landing on Mars (Spirit landed three weeks earlier than Oppy, on the other side of the Red Planet). The Saturn contest commemorated the landing of the Huygens probe on Titan on Jan. 14, 2005.
NASA / JPL / Texas A&M / Cornell
|NASA's Spirit rover sent back this sunset image from Mars' Gusev Crater.
The "People's Choice" pictures shed new scientific light on our celestial neighbors:
- The full-view Saturn picture was taken while the ringed planet was eclipsing the sun last Sept. 15, from a distance of 1.3 million miles (2.2 million kilometers). The backlighting effect not only provided an ethereal view of Saturn itself, but also illuminated the rings - including the pale G and E rings and two newly discovered circlets. As a bonus, Earth is visible as a pale blue dot within the ring system.
- Spirit took its snapshot of the Martian sunset on May 19, 2005, using color filters that approximate what a human eye might see, with just a hint of exaggerated redness. The blueness of the Martian sunset is actually due to a dust-scattering effect that becomes most pronounced when the sun is near the horizon. The color scheme is the reverse of what we're used to seeing on Earth, with red sunsets in a blue twilight sky. But the principle is the same. Such sky pictures can tell scientists how dust and ice clouds are distributed in the atmosphere.
There's much, much more to explore at the Mars and Saturn Web sites. On the Mars rover portal, maintained by NASA's Jet Propulsion Laboratory, you can watch a video commemorating this month's anniversaries, download podcasts and delve into images and mission updates to your heart's content.
Meanwhile, the Cassini imaging team's Web site has just gotten an extreme makeover to highlight videos and maps from the mission to Saturn. Yet another not-to-be-missed area displays artwork inspired by Saturn and its moons - and you'll also find a "Sector 6" discussion forum for commenting on Cassini imagery.
For more winning images from the past year, check out our "Year in Pictures" roundup of space imagery. You'll find the "People's Choice" snapshot from Saturn among the top picks.
Yet another huge Saturn image - showing the planet and the rings from almost directly above - is still being readied for release by Cassini's imaging team, but at the Planetary Society's Weblog, Emily Lakdawalla provides a preview. Looks like a future "People's Choice" winner is in the works.