News from Space: Titan’s Seas Mapped in Detail

titan_cassiniIt’s been an eventful year for NASA, thanks to the ongoing efforts of its many space probes and landers. In addition to some breathtaking discoveries made on Mars (proof of the existence of water and an atmosphere in the past), the MESSENGER probe discovered ice around the poles of Mercury, captured impressive footage of the surface, and mapped out the planet for the first time.

And while all this was happening in the Inner Solar System, the Cassini space probe was doing some rather impressive things in the Outer Solar System. In addition to taking part in the “Smile at Saturn” event, surveying the Jovian satellite of Europa, and unlocking the strange secrets of Saturn’s moons, Cassini also provided the most detailed map yet of the Saturnalian giant known as Titan.

titan_surfaceAnd now, using the data provided by NASA’s spacecraft, scientists have created this beautiful mosaic mapping the northern hemisphere of Titan, which is full of rivers, lakes, and seas. Ever since Cassini started mapping the world in 2004, it has been known that Titan boasts natural bodies of water that are composed not of water, but liquid hydrocarbons.

However, Cassini’s scans missed the true extent of some seas, including the biggest one of all: Kraken Mare. This new map fills in almost all the area of Titan’s north pole and provides scientists with important answers to some of their questions. These include how the geographic distribution of these natural bodies of water came to be.

titan_surface1For instance, while the northern hemisphere is dotted all over with hundreds of tiny lakes, the large seas seem confined to a specific area (see the lower right side of the image above). As geophysicist Randolph Kirk of the U.S. Geological Survey pointed out during a press conference at the American Geophysical Union conference, geological forces are most likely at work here.

Basically, the team thinks that Titan’s crust has fractured here when active tectonics created almost straight lines of parallel mountain chains. The low-lying areas are what gets filled with liquid, creating Kraken Mare and its smaller neighbor, Ligeia Mare. The scientists think the process may be analogous to the flooding which created large bodies of water in Nevada some 12,000 years ago.

titan_lakesOther tectonic processes are probably behind the smaller dotted lakes too, though scientists don’t yet know precisely what. Some of the lakes could be the infilled calderas of former active volcanoes, which would spew molten water instead of lava. But there isn’t enough volcanic activity on the moon to account for all of them.

Instead, many were probably created when liquid hydrocarbons dissolved the frozen ice, in the same way that water on Earth dissolves limestone to create features like the Bottomless Lakes in New Mexico. According to Kirk, “this creates a kind of exciting prospect that under the northern pole of Titan is a network of caves.” Such caves on Earth are often filled with all manner of life, so these ones could be as well.

Moons_of_Saturn_2007Other radar data has shown the depth and volume of Ligeia Mare, the second largest sea in the northern hemisphere. According to NASA scientists, the sea has a maximum depth of about 170 meters, as deep as Lake Michigan, and about twice its volume. Alas, beyond the comparative size of these bodies of water, Titan’s liquid bodies could not be more different than those on Earth.

As already noted, Titan’s lakes, rivers and seas are composed of liquid hydrocarbons, most likely ethane and methane. Ordinarily, these exist in gaseous form. But given Titan’s surface conditions, where the average temperatures is -180 degrees Celsius (-292 Fahrenheit), these hydrocarbons are able to exist in liquid form.

TitanNevertheless, finding evidence of such chemicals on planets beyond Earth is a rare and impressive find. Combined with the discovery of propelyne in Titan’s atmosphere – an organic compound that is a byproduct of oil refining, fossil fuel extraction, and thought not to exist beyond Earth – this moon is proving to be full of surprises!

And be sure to enjoy this video which simulates a flyover of Titan, as complied by NASA from the data provided by the Cassini space probe:


Nile-Like River Spotted on Titan

titan_nileOut in the far reaches of the Solar System, the Cassini Space Probe continues to send us mind-bogging images of Saturn and it’s moons. This latest was released by NASA just two days ago, a photograph which shows a massive river on Titan, Saturn’s appropriately-named largest moon. Already, Cassini confirmed the existence of a large, methane lake in Titan’s “tropical” region. But this latest find would seem to indicate the Titan is even more Earth-like than previously thought.

For example, the river is not only comparable in relative size and shape to the Nile here on Earth, it is also filled with a cold, hydrocarbon liquid (most likely ethane or methane). This is a historic find, since it is the first time images have revealed a river system this vast and in such high resolution anywhere beyond Earth. But of course, it’s what the river implies that has many scientists especially excited. For example, Jani Radebaugh, a Cassini radar team associate at Brigham Young University, USA, claims that the river may be an indication of plate tectonics:

“Though there are some short, local meanders, the relative straightness of the river valley suggests it follows the trace of at least one fault, similar to other large rivers running into the southern margin of this same Titan sea. Such faults – fractures in Titan’s bedrock – may not imply plate tectonics, like on Earth, but still lead to the opening of basins and perhaps to the formation of the giant seas themselves.”

In short, the river is another indication that Titan may be an early version of Earth. At one time, it is believed Earth’s own surface was covered with lakes that were much different in chemical composition than the one’s we know today. The process of change is what may have given rise to certain colonies of cell bacteria, which in turn created more complex organisms and eventually vertebrates. Intrinsic to all of this were shifts in the planet’s plates, which corresponded to several life-creating epochs in Earth’s history – the most notable being the “Cambrian Explosion”.

Naturally, there are plenty of difference between this “alien” river and it’s Earth-bound cousin too. For one, the Nile extends for a whopping 6,650 kilometers (4,132 miles), whereas Titan’s big river is roughly 400 km long. What’s more, Titan cycles hydrocarbons instead of water, as our life-friendly planet does. On top of all that, Titan is able to maintain these hydrocarbons in a liquid state because of its cold temperatures, much colder than what we enjoy here on the comparatively balmy Earth.

nileStill, I think you’ll agree, the resemblance is quite startling 😉 Stay tuned for more news from our Solar System. It becomes more exciting every day!

Source: Universe

Titan’s Tropical Methane Lakes!

Recently, NASA’s Cassini spacecraft did a fly-by of Saturn and noticed something unexpected on its largest moon of Titan. In the so-called tropical area of the moon, where temperatures rise to a high point of −179 °C (or −290 °F), it appears that there are lakes of liquid methane. This is a surprise to scientists who previously assumed that liquid bodies could only exist near the poles.

Appropriately, this region is known as Shangri La, which appears to have some dark areas which showed up on Cassini’s visual and infrared mapping spectrometer. One of the tropical lakes appears to be the size of Utah’s Great Salt Lake, and features a depth of at least one meter. When asked where these lakes came from, Caitlin Griffith – a Cassini team associate at the University of Arizona – speculated that the lake is being fed from an underground aquifer. “In essence,” she says, “Titan may have oases.”

Knowing about these lakes and where they come from is an important step to understand how weather works on Titan. Whereas the Earth has a “hydrological cycle” (aka. a water cycle), Titan has a “methane” cycle, where methane is circulating rather than water. What’s more, ultraviolet light is able to pierce through Titan’s atmosphere, causing it to break the methane apart on contact. This in turn results in a complicated chain of organic chemical reactions.

These finds are significant for two reasons. For one, it means that life might actually exist on Saturn’s largest moon. The chemical reactions in question involving UV light and methane gas might very well be able to produce organic molecules such as amino acids, the building blocks of life. And second, it could mean the planet would be a suitable candidate for terraforming some day. Liquid methane might not be suitable for humans, but with the right kind of equipment and chemical know-how, it could be converted into water and water vapor without much trouble.

Or we could simply use it as is, pumping it out as fuel. On the other hand, who’s to say we shouldn’t just sit back and watch the life grow. In a few million years, assuming humanity is still alive, Titan may very well join other moons like Europe is producing native life that will emerge from the primordial soups and look out at the stars. And if they then reach out, they might just find us in the mood to share with them. Who knows? It’s the prospects that are exciting!

Source: I09 Magazine.