Strange new worlds such as Pan remind us that there are still bizarre, unexplored corners of the solar system. NASA / JPL-Caltech / Space Science Institute. Get those 3-D glasses out for this fine anaglyph of Pan. Next month, Cassini prepares for the climax, a series of Grand Finale orbits that will end with the demise of the spacecraft on September 15, 2017, at 8:07 AM EDT (12:07 Universal Time), when it burns up in Saturn's atmosphere. Cassini is currently finishing up a series of twenty ring-grazing orbits, swooping in through the ring plane of Saturn once every seven days. Launched on October 15, 1997, Cassini arrived at Saturn on July 1, 2004. Pan in Saturn's rings as witnessed by Cassini in 2006. We'll get a good look at that moonlet next month, when Cassini flies just 13,000 kilometers past Atlas on April 12th. Cassini, once again, delivered us a wonderful gift!”Ĭassini's distant images of Saturn's moon Atlas indicate it's probably similar to Pan. But the thrill of discovery is why we do this. “It looked so alien and 'well executed,' so to speak, that I didn't think it was real. “My first impression when I saw the first image? That it was an artist's depiction of what Pan might look like,” says Porco. Space fans saw in the moon's bizarre shape anything from a filled pasta, to a space cabbage, to an empanada, perhaps reflecting a true “hunger” out there for space exploration. The release of the images also sparked a flurry of commentary across social media last week. Is it rock hard, or soft as newly fallen snow? Or is pasta-shaped Pan just filled with cheesy goodness all the way through? One can only wonder what sort of alien sky an observer standing next to it would see, with glorious Saturn and the edge-on rings filling the view beyond the frozen wall. The skirt of ice towers several kilometers above the surface. “During the last stages the rings were very thin and so the material falling onto Pan at this time came down on its equator and built the ridge you see.” “Pan got its distinctive “skirt” because of the last stages of its formation (continued even in slow motion today) in which it accreted material from the rings it's embedded within,” says Porco. ![]() How did Pan get its strange shape? The leading idea is that the flange of ice around its equatorial bulge is ring material swept up and collected by the moon as it cruises through the Encke Gap. Brave Little Moonįor a while now, scientists have had a hunch that there's something askew about Pan and Atlas, based on distant views obtained by Cassini in 2007. While the Daphnis is slightly inclined to the plane of Saturn's rings by 0.0036 degrees and kicks up vertical waves in its wake, the orbit of Pan is nearly flat with an inclination of only 0.0001 degrees, and it induces spiral density waves in the ring plane. Unlike the narrow 35-kilometer-wide Keeler gap occupied by the tiny moonlet Daphnis, the wider 325-kilometer Encke Gap also hosts a tenuous ringlet that Pan braids and modifies. The moon has an albedo (or reflectance) of 50%, equivalent to dirty snow. On Earth, Pan would just barely fit inside Tampa Bay. The moon orbits Saturn every 13.8 hours from an average distance of 134,000 kilometers (80,150 miles), equivalent to about one-third the Earth-Moon distance, and just 73,000 miles from the Saturnian cloud tops), the 34x31x21-kilometer moon carves out the Encke Gap in Saturn's outermost bright A Ring. After accurately predicting the moon's orbit, Pan was found in 11 images taken by Voyager 2 during its August 1981 flyby. Showalter and colleagues first inferred the tiny moon's presence by the waves it kicked up in the wake of its passage through the Encke Gap. Mark Showalter (then at Stanford University) discovered Pan on July 16, 1990. “Here is 35-km Pan in mind-blowing detail with its unmistakable accretionary equatorial bulge.” Cassini's flyby of Pan, frame by frame. ![]() “Nearing its end, Cassini delights again,” says Carolyn Porco (Space Science Institute) on Twitter. NASA's Cassini spacecraft flew just 15,268 miles past the moonlet (closer than the distance to the geosynchronous satellites from Earth) on March 7th. ![]() Appropriately named after the half-man, half-goat satyr from Greek mythology, Pan is nestled in the Encke (pronounced EN-key) Gap within Saturn's A ring. Who ordered that? The universe served up a piece of astro-pareidolia last week, when humanity got its first closeup look at Saturn's tiny moon Pan. NASA / JPL-Caltech / Space Science Institute Cassini gave us a good look a Saturn's moon Pan last week.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |