Underground Oceans Discovered on Titan

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With each flyby, NASA’s Cassini spacecraft has been building up the case that there are lakes and seas of liquid hydrocarbons on the surface of Saturn’s moon Titan. But now we get the stunning news that the planet might have vast oceans of water and ammonia underneath its surface as well.

Over the course of 19 separate Cassini Titan flybys, members on the mission science team carefully established the position of 50 unique landmarks on the surface of the moon. After each flyby, they located the landmarks again, and marked their positions.

During nearly 2 years of flybys, from October 2005 to May 2007, surface features had moved from their original positions by up to 30 km (19 miles). The only way the surface could be shifting like this is if the moon’s icy crust is floating atop an internal ocean.

“We believe that about 62 miles beneath the ice and organic-rich surface is an internal ocean of liquid water mixed with ammonia,” said Bryan Stiles of NASA’s Jet Propulsion Laboratory (JPL) in, Pasadena, Calif.

Since Titan has an incredibly thick atmosphere, 1.5 times more dense than the Earth, it’s possible that powerful winds are rocking the moon back and forth around its axis. It might be speeding the rotation up at one point in the year, and then slowing it back down again. But this would only be possible if there’s an ocean underneath the surface that the entire crust floats on top of.

“The combination of an organic-rich environment and liquid water is very appealing to astrobiologists,” said Ralph Lorenz, lead author of the paper and Cassini radar scientist at the Johns Hopkins Applied Physics Laboratory in Laurel, Md. “Further study of Titan’s rotation will let us understand the watery interior better, and because the spin of the crust and the winds in the atmosphere are linked, we might see seasonal variation in the spin in the next few years.”

Researchers will get another chance to test their theories shortly. Cassini is due to make another Titan flyby on March 25th, at an altitude of only 1,000 km (620 miles).

The research will be published in the March 21st issue of the journal Science.

Original Source: NASA News Release

Titan has “Hundreds of Times More” Liquid Hydrocarbons Than Earth

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According to new Cassini data, Saturns largest moon, Titan, has “hundreds” times more liquid hydrocarbons than all the liquid fossil fuel deposits on Earth. This is impressive as Titan’s 5150 km diameter is only about 50% larger than Earth’s Moon and only a little larger than the planet Mercury. Titan’s hydrocarbons cycle into the atmosphere, fall as rain and collect in lakes creating massive lakes and dunes.

Titan is a planet-sized hydrocarbon factory. Instead of water, vast quantities of organic chemicals rain down on the moon’s surface, pooling in huge reservoirs of liquid methane and ethane. Solid carbon-based molecules are also present in the dune region around the equator, dwarfing Earth’s total coal supplies. Carl Sagan coined the term “tholins” to describe prebiotic chemicals, and the dunes of Titan are expected to be teeming with them. Tholins are essential for the beginning of carbon-based organisms, so these new observations by Cassini will stir massive amounts of excitement for planetary physicists and biologists alike.

The cold -179°C (-290°F) landscape of Titan is currently being mapped by the Cassini probe as it orbits the ringed gas giant, Saturn. Some 20% of the moons surface has been catalogued and so far several hundred hydrocarbon seas and lakes have been discovered. These lakes, individually, have enough methane/ethane energy to fuel the whole of the US for 300 years.

These new findings have been published in the January 29th issue of the Geophysical Research Letters by Ralph Lorenz from the Cassini radar team (Johns Hopkins University Applied Physics Laboratory, USA). Lorenz said on reviewing the Cassini data that, “we know that some lakes are more than 10 m or so deep because they appear literally pitch-black to the radar. If they were shallow we’d see the bottom, and we don’t.” He also steps into the life-beyond-Earth debate by pointing out: “We are carbon-based life, and understanding how far along the chain of complexity towards life that chemistry can go in an environment like Titan will be important in understanding the origins of life throughout the universe.”

The ESA Huygens probe separated from Cassini and dropped slowly through the Titan atmosphere in January 2005 analyzing the atmospheric composition and taking some breathtaking images of the surrounding landscape. To complement the huge amount of data assembled from Huygens decent, Cassini will flyby the moon again on February 22nd to take radar data of the Huygens landing site.

Source: Physorg.com

Titan has Drizzling Methane Rain

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If you’re planning a visit to Saturn’s moon Titan, make sure you bring an umbrella. You’ll need it. Not to protect you from water raining down; on frigid Titan, where temperatures dip below 180-degrees Celsius, all the water is completely frozen. No, according to scientists, there’s a steady drizzle of liquid methane coming down in the mornings.

New infrared images gathered by Hawaii’s W.M. Keck Observatory and Chile’s Very Large Telescope show that Titan’s Xanadu region experiences a steady drizzle of methane during its lengthy morning. The concept of morning is a little misleading, since Titan takes about 16 Earth days to complete one rotation. So, the “morning” drizzle actually lasts around 3 Earth days, dissipating around 10:30 a.m. local time.

Astronomers aren’t actually sure if this is a moon-wide phenomenon, or just localized around the Xanadu region of Titan. Even though large lakes and seas have been discovered around the moon’s poles, no process had been discovered that fills them with liquid… until now.

Reporting their findings in the latest issue of the online journal Science Express, researchers from UC Berkeley note that, “widespread and persistent drizzle may be the dominant mechanism for returning methane to the surface from the atmosphere and closing the methane cycle.”

The new Keck/VLT images show a widespread cloud cover of frozen methane at a height of 25 to 35 kilometres. And then there are liquid methane clouds below 20 kilometres, and finally rain falling at the lowest elevations.

The droplets of liquid methane in the rain clouds are 1,000 times larger than water vapour here on Earth, and this surprisingly makes them harder to detect. Since the droplets are larger, but still carry the same amount of moisture, they’re much more spread out, making the clouds extremely diffuse, and nearly invisible.

How much liquid is trapped in the clouds? If you squeezed them all out and spread the liquid across the surface of Titan, it would coat the entire moon to a depth of about 1.5 cm. And that’s actually the same amount as we’d get if you did the same thing with the Earth’s clouds.

Original Source: UC Berkeley News Release

Coastal Scene on Titan

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Take a look at the image attached to this story. If you didn’t know any better, you’d think you were looking at a rugged coastline somewhere on Earth. Maybe some island in the Mediterranean, or Norwegian fjord. Nope, you’re looking at a completely alien world: Titan.

NASA’s Cassini spacecraft took this image on May 12, 2007 during its most recent flyby of Saturn’s largest moon. During the flyby, its radar instrument captured this image using its radar instrument. Smooth surfaces, like liquid are seen as black, while the textured regions are land.

While other bodies of liquid such as lakes have been seen on Titan before, nothing has had these kinds of features: channels, islands, bays, and other terrain you’d see on Earth. But instead of water, this liquid is probably a mixture of ethane and methane. Since there are no brighter regions in the liquid regions of the image, scientists are assuming the ocean exceeds tens of metres deep.

The image is about 160 kilometers (100 miles) by 270 kilometers (170 miles) across.

Original Source: NASA/JPL/SSI/ESA News Release

Organic Chemicals Discovered in Titan’s High Atmosphere

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Since the twin Voyager spacecraft flew past Saturn’s moon Titan, Scientists have been excited about what its hazy atmosphere can tell us about the earliest days of our own planet. The Voyagers discovered that Titan’s atmosphere is swirling with hydrocarbons and other complex organic molecules that could be the building blocks of life. The latest findings from NASA’s Cassini spacecraft have uncovered these organic molecules floating higher in Titan’s atmosphere than scientists originally thought possible.

This latest research has been published in the May 11, 2007 edition of the Journal Science. It shows that these organic aerosols, called tholins, have been found in altitudes higher than 1,000 kilometres (620 miles) above the surface of Titan. And these molecules are formed differently than how scientists originally believed.

This inquiry is important because the Titan’s environment is thought to be very similar to the Earth’s early history, before the first life formed. A similar process could have happened here.

Original Source: SwRI News Release

Massive Mountain Range Seen on Titan

Mountain range on Titan. Image credit: NASA/JPL/SSINew images of Titan sent back by NASA’s Cassini spacecraft show a large mountain range, extending about 150 km (93 miles) long. The mountains were seen on Cassini’s most recently flyby on October 25, 2006, where the spacecraft captured the highest resolution infrared views of Saturn’s largest moon. They reach about 1.5 km (almost 1 mile) high, and they’re probably made of icy material, and coated with many layers of organic material.
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The Early Earth’s Atmosphere was Similar to Titan

The thick organic haze that shrouds Titan is similar to what we had here on Earth billions of years ago; an environment that might have helped early life get a foothold. NASA researchers set up several experiments that reproduced the atmosphere in the early Earth and Titan today. The Earth experiments produced tremendous amounts of organic material, which could have been one of the ways life first appeared.
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Twin Lakes on Titan

This incredible photograph taken by NASA’s Cassini spacecraft shows two lakes on the surface of Saturn’s moon Titan, attached by a thin channel. The image was taken during Cassini’s most recent flyby, when it passed by on September 23, 2006. On Earth, they’d be filled with water, but it’s just too cold on Titan; so these lakes contain a mixture of methane and ethane.
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Evidence of Lakes on Titan

NASA’s Cassini spacecraft has found new evidence of hydrocarbon lakes in Titan’s northern latitudes. In a new set of images, the dark patches – thought to be liquid methane or ethane – seem to have channels leading in and out, like rivers. Under Cassini’s radar view, they’re completely black, which means they don’t reflect any radar signals back. This leads scientists to believe they’re very smooth, liquid surfaces.
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