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APOD: Saturn's Iapetus: Painted Moon (2018 Jun 03)
Posted: Sun Jun 03, 2018 4:06 am
by APOD Robot
Saturn's Iapetus: Painted Moon
Explanation: What has happened to Saturn's moon Iapetus? Vast sections of
this strange world are dark as
coal, while others are as bright as ice. The composition of the dark material is unknown, but
infrared spectra indicate that it possibly contains some dark form of
carbon. Iapetus also has an unusual
equatorial ridge that makes it appear like a
walnut. To help better understand this seemingly painted moon,
NASA directed the
robotic Cassini spacecraft orbiting Saturn to swoop
within 2,000 kilometers in 2007.
Pictured here, from about 75,000 kilometers out, Cassini's trajectory allowed unprecedented imaging of the hemisphere of Iapetus that is
always trailing. A huge impact crater seen in the south spans a tremendous 450 kilometers and appears superposed on an
older crater of similar size. The
dark material is seen increasingly coating the easternmost part of
Iapetus, darkening craters and highlands alike.
Close inspection indicates that the dark coating typically faces the moon's equator and is less than a meter thick. A
leading hypothesis is that the dark material is mostly dirt leftover when relatively warm but dirty ice
sublimates. An initial coating of
dark material may have been effectively painted on by the accretion of meteor-liberated debris from
other moons.
Re: APOD: Saturn's Iapetus: Painted Moon (2018 Jun 03)
Posted: Sun Jun 03, 2018 9:28 am
by Boomer12k
"Sugar frosted Doughnut Ball...."
Great Image...
:---[===] *
Re: APOD: Saturn's Iapetus: Painted Moon (2018 Jun 03)
Posted: Sun Jun 03, 2018 10:21 am
by Agent Buchwald
Looking closely on the white side, right in the middle, I see a tall thin black, building? My God it's full of stars!
END TRANSMISSION
Re: APOD: Saturn's Iapetus: Painted Moon (2018 Jun 03)
Posted: Sun Jun 03, 2018 10:40 am
by Alietr
"Close inspection indicates that the dark coating typically faces the moon's equator" -- There's a wrong word in here somewhere.
Re: APOD: Saturn's Iapetus: Painted Moon (2018 Jun 03)
Posted: Sun Jun 03, 2018 11:08 am
by neufer
Alietr wrote: ↑Sun Jun 03, 2018 10:40 am
"Close inspection indicates that the dark coating typically faces the moon's equator"
-- There's a wrong word in here somewhere.
Close inspection indicates that the dark coating
is most concentrated at the moon's equator...
Re: APOD: Saturn's Iapetus: Painted Moon (2018 Jun 03)
Posted: Sun Jun 03, 2018 11:41 am
by orin stepanek
If the white is Ice; then there is a lot of water on this little moon!
Re: APOD: Saturn's Iapetus: Painted Moon (2018 Jun 03)
Posted: Sun Jun 03, 2018 12:49 pm
by Tszabeau
To me... “the man in this moon” looks to be saying, “OH NO... not another Moon Pie joke”.
Re: APOD: Saturn's Iapetus: Painted Moon (2018 Jun 03)
Posted: Sun Jun 03, 2018 12:57 pm
by neufer
orin stepanek wrote: ↑Sun Jun 03, 2018 11:41 am
If the white is Ice; then there is a lot of water on this little moon!
https://en.wikipedia.org/wiki/Iapetus_(moon) wrote:
.
<<The low density of Iapetus [1.088 g/cm³] indicates that it is mostly composed of ice, with only a small (~20%) amount of rocky materials.
The difference in colouring between the two Iapetian hemispheres is striking. The leading hemisphere and sides are dark (albedo 0.03–0.05) with a slight reddish-brown coloring, while most of the trailing hemisphere and poles are bright (albedo 0.5–0.6, almost as bright as Europa). The dark material is a very thin layer, only a few tens of centimeters thick at least in some areas, according to Cassini radar imaging and the fact that very small meteor impacts have punched through to the ice underneath. The initial dark material is thought to have been debris blasted by meteors off small outer moons in retrograde orbits and swept up by the leading hemisphere of Iapetus, but now it consists principally of lag from the sublimation of ice from the warmer areas of Iapetus's surface. It contains organic compounds similar to the substances found in primitive meteorites or on the surfaces of comets; Earth-based observations have shown it to be carbonaceous, and it probably includes cyano-compounds such as frozen hydrogen cyanide polymers.>>
Re: APOD: Saturn's Iapetus: Painted Moon (2018 Jun 03)
Posted: Thu Jun 07, 2018 11:15 am
by Matt Terry
I find Tom Van Flandern's answer MOST interesting. The dark material is debris from an exploded planet. While not generally accepted, yet, I am not aware of its falsification. If we have proof it cannot be from such, has that been published?
Re: APOD: Saturn's Iapetus: Painted Moon (2018 Jun 03)
Posted: Thu Jun 07, 2018 1:40 pm
by neufer
Matt Terry wrote: ↑Thu Jun 07, 2018 11:15 am
I find Tom Van Flandern's answer MOST interesting. The dark material is debris from an exploded planet. While not generally accepted, yet, I am not aware of its falsification.
If we have proof it cannot be from such, has that been published?
Why would the planet explode?
Why would it affect only Iapetus?
Perhaps it is a
tea stain.
Re: APOD: Saturn's Iapetus: Painted Moon (2018 Jun 03)
Posted: Fri Jun 08, 2018 12:31 am
by Chris Peterson
neufer wrote: ↑Thu Jun 07, 2018 1:40 pm
Why would the planet explode?
Maybe it was an unstable planet that was destroyed by
Dark Star.
