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The ‘death star’ crater up close

At first glance, it looks uncannily like the Death Star.

NASA has released this incredible image of the gigantic Odysseus crater on Saturn’s icy moon Tethys.

An enormous impact created the crater, which is about 280 miles (450 kilometers) across, with its ring of steep cliffs and the mountains that rise at its center.

 

An enormous impact created the Odysseus crater, which is about 280 miles (450 kilometers) across, with its ring of steep cliffs and the mountains that rise at its center.

WHAT DOES THE IMAGE SHOW? 

Odysseus is on the leading hemisphere of Tethys (1,071 kilometers, or 665 miles across). 

In this image, north on Tethys is up.

This view is a composite of several images taken in visible light with the Cassini spacecraft narrow-angle camera on Aug. 17, 2015, at a distance of about 28,000 miles (44,500 kilometers) from Tethys.

The Cassini spacecraft ended its mission on Sept. 15, 2017.

 

Odysseus is on the leading hemisphere of Tethys (1,071 kilometers, or 665 miles across).  

The image was created by combining several images taken in visible light with the Cassini spacecraft narrow-angle camera on Aug. 17, 2015, before it ended its mission on Sept. 15, 2017 by crashing into the surface of Saturn.  

The images were taken at a distance of about 28,000 miles (44,500 kilometers) from Tethys.    

According to NASA, Tethys has two overpowering features, a giant impact crater and a great valley. 

Odysseus Crater (named for a Greek warrior king in Homer’s two great works, “The Iliad” and “The Odyssey”) is pictured here, and dominates the Tethyan western hemisphere. 

Odysseus Crater is 250 miles (400 kilometers) in diameter, nearly two-fifths of Tethys itself. 

‘Such an impact could have shattered a solid body, which suggests that the internal composition of Tethys was still partially molten,’ NASA said.

The crater’s rim and central peak have largely collapsed, leaving a shallow crater, and this also suggests a terrain that was elastic enough to change shape. 

Spot the moon! It’s one of 53 named moons known to be circling Saturn – but, in a stunning new image, the icy moon Tethys appears to be the planet’s only companion, bathed in ‘Saturnshine.’ In this view, Cassini is roughly 930,000 miles (1.5 million kilometers) from Tethys

Spot the moon! It’s one of 53 named moons known to be circling Saturn – but, in a stunning new image, the icy moon Tethys appears to be the planet’s only companion, bathed in ‘Saturnshine.’ In this view, Cassini is roughly 930,000 miles (1.5 million kilometers) from Tethys

THE SCALE OF SATURN 

When it comes to space, it isn’t always easy to understand how big objects really are.

To put things into perspective, if Earth was the size of a tennis ball, the moon would be the size of a marble.

Saturn would be the size of a beach ball and the sun would be the length of seven football fields away from Earth. 

The subdued features of Odysseus Crater are in contrast to the many steep cliffs found elsewhere on the moon, which again suggests that the ancient terrain was still elastic enough to change shape.  

The second major feature, a valley called Ithaca Chasma (named for the country ruled by Odysseus), runs roughly from the Tethyan north pole to its south pole. 

It is 62 miles wide, 2 to 3 miles deep, and extends 1,200 miles (100 kilometers, 3 to 5 kilometers, and 2,000 kilometers, respectively). 

Thethy is one of of 53 named moons known to be circling Saturn – and in a recent image, the icy moon Tethys appears to be the planet’s only companion, bathed in ‘Saturnshine.’

The image, captured by the Cassini spacecraft at roughly 750,000 miles (1.2 million kilometers) from Saturn, shows the mid-sized moon illuminated by sunlight reflected off the ringed planet, bringing its night side into full view. 

The new view of Tethys was captured in visible light by Cassini’s wide-angle camera on May 13, 2017.

Sitting roughly 930,000 miles (1.5 million kilometers) from the spacecraft at the time the photo was taken, Tethys is just a speck in the dark sky far beyond the massive figure of Saturn and its rings. 

But, thanks to sunlight bouncing off Saturn, Cassini was able to view the moon from its night side.

‘Tethys was on the far side of Saturn with respect to Cassini here; an observer looking upward from the moon’s surface toward Cassini would see Saturn’s illuminated disk filling the sky,’ NASA explains.

‘Tethys was brightened by a factor of two in this image to increase its visibility. A sliver of the moon’s sunlit northern hemisphere is seen at top.

‘A bright wedge of Saturn’s sunlit side is seen at lower left.’ 

Earlier this month, NASA released a stunning view of Saturn that reveals the waves of clouds swirling above the planet, like ‘strokes from a cosmic brush.’

The image, captured by the Cassini spacecraft from roughly 750,000 miles (1.2 million kilometers) above the surface, shows the turbulent essence of Saturn’s clouds, which move as bands in different speeds and directions. 

COULD PRIMITIVE LIFE EXIST ON TITAN? 

Using data collected as Cassini flew through the upper atmosphere, at about 950–1,300 km (590-807 miles) above the surface, researchers have identified what are known as ‘carbon chain anions.’

These are thought to be the building blocks of more complex molecules.

Researchers say the data from Cassini’s plasma spectrometer (CAPS), suggest the carbon chains ‘seeded’ larger molecules at Titan, as they were found to dwindle closer to the moon, while precursors to larger aerosols underwent rapid growth.

Not only does the discovery suggest Titan may contain molecules that drive prebiotic chemistry, but it could also help to explain how life sprung up on Earth, according to ESA.

While early images of Titan taken by Cassini were spotty, every encounter has built upon the previous one.

And over the course of the entire mission, Cassini’s radar investigation imaged approximately 67 per cent of Titan’s surface.

Views from Cassini have slowly added details, building up a more complete picture of Titan.

Steve Wall, deputy lead of Cassini’s radar team at Nasa’s Jet Propulsion Laboratory, said: ‘Now that we’ve completed Cassini’s investigation of Titan, we have enough detail to really see what Titan is like as a world, globally.’

Scientists now have enough data to understand the distribution of Titan’s surface features and the behaviour of its atmosphere over time.

During its latest close brush with Titan as it heads into its Grand Finale, Cassini imaged a long area of the surface that included terrain seen on the very first Titan flyby in 2004.

Mr Wall said: ‘It’s pretty remarkable that we ended up close to where we started.

‘The difference is how richly our understanding has grown, and how the questions we’re asking about Titan have evolved.’  

 

 

 

 



Read more at DailyMail.co.uk


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