APOD: Saturn's Iapetus: Painted Moon (2018 Jun 03)

Comments and questions about the APOD on the main view screen.
User avatar
APOD Robot
Otto Posterman
Posts: 3212
Joined: Fri Dec 04, 2009 3:27 am

APOD: Saturn's Iapetus: Painted Moon (2018 Jun 03)

Post by APOD Robot » Sun Jun 03, 2018 4:06 am

Image 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.

<< Previous APOD This Day in APOD Next APOD >>

Boomer12k
:---[===] *
Posts: 2243
Joined: Sun Apr 22, 2007 12:07 am

Re: APOD: Saturn's Iapetus: Painted Moon (2018 Jun 03)

Post by Boomer12k » Sun Jun 03, 2018 9:28 am

"Sugar frosted Doughnut Ball...."

Great Image...

:---[===] *

Agent Buchwald

Re: APOD: Saturn's Iapetus: Painted Moon (2018 Jun 03)

Post by Agent Buchwald » Sun Jun 03, 2018 10:21 am

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

Alietr
Asternaut
Posts: 6
Joined: Mon Jul 09, 2007 11:26 am

Re: APOD: Saturn's Iapetus: Painted Moon (2018 Jun 03)

Post by Alietr » 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.

User avatar
neufer
Vacationer at Tralfamadore
Posts: 15050
Joined: Mon Jan 21, 2008 1:57 pm
Location: Alexandria, Virginia

Re: APOD: Saturn's Iapetus: Painted Moon (2018 Jun 03)

Post by neufer » Sun Jun 03, 2018 11:08 am

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...
Art Neuendorffer

User avatar
orin stepanek
Plutopian
Posts: 4558
Joined: Wed Jul 27, 2005 3:41 pm
Location: Nebraska

Re: APOD: Saturn's Iapetus: Painted Moon (2018 Jun 03)

Post by orin stepanek » Sun Jun 03, 2018 11:41 am

If the white is Ice; then there is a lot of water on this little moon! :ssmile:
Orin

Smile today; tomorrow's another day!

Tszabeau

Re: APOD: Saturn's Iapetus: Painted Moon (2018 Jun 03)

Post by Tszabeau » Sun Jun 03, 2018 12:49 pm

To me... “the man in this moon” looks to be saying, “OH NO... not another Moon Pie joke”.

User avatar
neufer
Vacationer at Tralfamadore
Posts: 15050
Joined: Mon Jan 21, 2008 1:57 pm
Location: Alexandria, Virginia

Re: APOD: Saturn's Iapetus: Painted Moon (2018 Jun 03)

Post by neufer » Sun Jun 03, 2018 12:57 pm

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! :ssmile:
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.>>
Art Neuendorffer

Matt Terry

Re: APOD: Saturn's Iapetus: Painted Moon (2018 Jun 03)

Post by Matt Terry » 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?

User avatar
neufer
Vacationer at Tralfamadore
Posts: 15050
Joined: Mon Jan 21, 2008 1:57 pm
Location: Alexandria, Virginia

Re: APOD: Saturn's Iapetus: Painted Moon (2018 Jun 03)

Post by neufer » Thu Jun 07, 2018 1:40 pm


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?

:arrow: Perhaps it is a tea stain.
Art Neuendorffer

User avatar
Chris Peterson
Abominable Snowman
Posts: 13805
Joined: Wed Jan 31, 2007 11:13 pm
Location: Guffey, Colorado, USA

Re: APOD: Saturn's Iapetus: Painted Moon (2018 Jun 03)

Post by Chris Peterson » Fri Jun 08, 2018 12:31 am

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.
Chris

*****************************************
Chris L Peterson
Cloudbait Observatory
http://www.cloudbait.com