* Astronomy

Blobrana · L

RE: Iapetus

Blobrana · L

Saturn's two-faced moon Iapetus appears to have flaking paintwork.
The moon was known to have one black half and one white half, but when the Cassini spacecraft flew within 1000 kilometres of the moon on 10 September, it saw much more complicated patterns.
Iapetus has a landscape unlike anything else in the solar system: sharp-edged islands of dark material within pale regions, and patches of white ice on the dark mountainsides.

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Credit: NASA

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Blobrana · L

Scientists on the Cassini mission to Saturn are poring through hundreds of images returned from the Sept. 10 flyby of Saturn's two-toned moon Iapetus. Pictures returned late Tuesday and early Wednesday show the moon's yin and yang--a white hemisphere resembling snow, and the other as black as tar.
Images show a surface that is heavily cratered, along with the mountain ridge that runs along the moon's equator. Many of the close-up observations focused on studying the strange 20-kilometre high mountain ridge that gives the moon a walnut-shaped appearance.

"The images are really stunning. Every new picture contained its own charm. I was most pleased about the images showing huge mountains rising over the horizon. I knew about this scenic viewing opportunity for more than seven years, and now the real images suddenly materialised" - Tilmann Denk, Cassini imaging scientist at the Free University in Berlin, Germany, who was responsible for the imaging observation planning.

This flyby was nearly 100 times closer to Iapetus than Cassini's 2004 flyby, bringing the spacecraft to about 1,640 kilometres from the surface. The moon's irregular walnut shape, the mountain ridge that lies almost directly on the equator and Iapetus' brightness contrast are among the key mysteries scientists are trying to solve.

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Blobrana · L

Cassini completed its closest flyby of the odd moon Iapetus on Sept. 10, 2007. The spacecraft flew about 1,640 kilometres from Iapetus' surface and is returning amazing views of the bizarre moon.
All the data were successfully recorded on the spacecraft. Twenty-one minutes into the first post-flyby data downlink, the spacecraft went into a precautionary condition called "safe mode. The cause has been determined to be a solid state power switch that was tripped due to a galactic cosmic ray hit.
While in safe mode, the spacecraft turns off all unnecessary activities and transmits only essential engineering telemetry at a low data rate, while it awaits commands from Earth.
Tuesday morning, Sept. 11, commands were sent to the spacecraft to resume high rate science and engineering data playback. The project expects all data on the spacecraft will be returned to Earth during downlinks on Tuesday and Wednesday, with no impact on the Iapetus science data return beyond a brief delay.
Due to the safing event, the sequence executing on the spacecraft was halted, and Cassini's instruments will not be turned back on for three or four days. The last time Cassini was in safe mode was over four years ago.

Source NASA

Blobrana · L

This image of Iapetus was taken by the Cassini spaceprobe on September 10, 2007, when it was approximately 1,478 kilometres away.

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Credit: NASA

The image was taken using the CL1 and CL2 filters.

Blobrana · L

This image of Iapetus was taken by the Cassini spaceprobe on September 10, 2007, when it was approximately 1,316 kilometres away.

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Credit: NASA

The image was taken using the CL1 and CL2 filters.

Blobrana · L

This image of Iapetus was taken by the Cassini spaceprobe on September 10, 2007, when it was approximately 8,732 kilometres away.

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Credit: NASA

The image was taken using the CL1 and GRN filters.

Blobrana · L

This image of Iapetus was taken by the Cassini spaceprobe on September 10, 2007, when it was approximately 8,594 kilometres away.

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Credit: NASA

The image was taken using the CL1 and CL2 filters.

Blobrana · L

This image of the darkside of Iapetus was taken by the Cassini spaceprobe on January 01, 2005, when it was approximately 55,218 kilometres away.

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Credit NASA

The image was taken using the CL1 and CL2 filters.

Blobrana · L

Raw and unprocessed composite image of the Iapetus taken on September 10th

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Credit NASA