Cassini finds new evidence for subsurface ocean on Titan

Artist’s conception of Titan’s interior based on the new findings. Credit: A. Tavani / NASA / JPL

Titan, the largest moon of Saturn and one of the most fascinating places in the solar system, is a world of rain, rivers, lakes and seas. Unlike Earth though, this alien hydrological cycle is composed of liquid methane rather than water, since the temperatures on Titan are far colder than even at the poles of our own planet.

It had long been theorized, however, that liquid water could actually exist on Titan – underground. Gravitational tugging from Saturn could create enough heat inside Titan to maintain a layer of water, similar to that on another Saturn moon, Enceladus and one of Jupiter’s moons, Europa (and possibly others as well). Literally, an underground ocean.

Now, new evidence from the Cassini orbiter has indicated that there most likely is indeed a Titanian ocean.

See for the full article.

Smooth sailing ahead – on Titan

Artist's conception of the TiME probe floating in the Ligeia Mare sea on Titan. Credit: JHU APL / Lockheed Martin

What would it be like to go sailing on one of Titan’s lakes or seas? Apart from the fact that they are composed of liquid methane/ethane instead of water in the much colder environment, they share a lot of physical similarities to their earthly counterparts. Radar images taken by the Cassini orbiter (to see through the thick, perpetually hazy atmosphere) show that they look just like lakes and seas on Earth, although they are concentrated near the moon’s poles, the north pole in particular.

If you were able to go out in a boat, it would also be a similar experience to sailing on Earth, other than the intense cold and smoggy-looking orangish sky overhead. It might also be safer though, in terms of “rough waters” – the lakes and seas on Titan have so far been found to be smoother than those on Earth, with much less wave activity, according to a new study to be published in Icarus.

With typically weak surface winds on Titan, it was determined that waves on Ligeia Mare, a large sea about 400 kilometres (250 miles) wide, wouldn’t reach any more than about a foot high under normal conditions. According to Ralph Lorenz at Johns Hopkins University Applied Physics Laboratory, “You’d notice 0.2-meter waves if you were in a rowboat, but they wouldn’t get surfers excited.”

As it turns out, we may not have to wait too long to go sailing there – a new mission, the Titan Mare Explorer (TiME), is being planned for a possible landing in Ligeia Mare in 2023. The robotic probe would drift around while taking measurement and photographs of this Titanian sea. The previous, and only probe to land on Titan so far was Huygens, which touched down in a desert region near the equator in 2005.

TiME is one of three Discovery missions being considered by NASA, with final selection scheduled for later this year. The other two are Comet Hopper, which would land on a comet multiple times and InSight, which would study the interior of Mars. Both are interesting in themselves, but if I had to choose, I’d rather go sailing on Titan; I mean how often do you get a chance to explore an alien sea?

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Cassini takes a closer look at Titan’s sand dunes

Cassini radar image of sand dunes on Titan. Credit: NASA/JPL–Caltech/ASI/ESA and USGS/ESA

Titan is a world that is amazingly Earth-like in some ways, with rain, rivers, lakes and seas. Mind you, the liquid in this case is methane/ethane instead of water, at the bitterly cold conditions on the surface. Also like Earth, Titan has vast sand dune fields, covering about 10 million square kilometres (39 million square miles), or 13% of Titan’s surface. The Cassini spacecraft has been studying these dunes with its radar (in order to see through the perpetually smog-like atmosphere), with interesting results…

See Universe Today for the full article.

Titan’s layered atmosphere is surprisingly Earth-like

Titan's thick, smog-like upper atmosphere obscures our view of the lower atmosphere and surface. The much smaller moon Enceladus is also seen in this image. Credit: NASA/JPL

Titan, the largest moon of Saturn, is in some ways the most Earth-like world in the solar system, with a thick nitrogen atmosphere, rain, rivers, lakes and seas. Albeit it is much colder, and liquid methane/ethane takes the place of water, but the hydrological processes are quite similar to those here. There may however also be a liquid water-ammonia ocean below the surface. Now, new research suggests that Titan is Earth-like in another way as well, with a layered lower atmosphere similar to ours

See Universe Today for the full article.

Is there a methane habitable zone?

A sunlight glint off a methane lake near Titan’s north pole (infrared image). Credit: NASA/JPL/University of Arizona/DLR

For a long time now, we have heard the mantra “follow the water” when it comes to searching for life elsewhere. Life as we know it here on Earth requires liquid water, whether it is tiny microbes or elephants. It has thus been assumed that carbon-based life somewhere else that is basically similar to ours in its chemical makeup (another assumption) would also require water for its survival and growth. But is that necessarily true? In recent years, more consideration has been given to the possibility that life could develop in other mediums as well, besides water. A liquid is still ideal, for allowing the necessary molecules to bond together. So what are the alternatives? Well, one of the most interesting possibilities is something we have already seen now elsewhere in our solar system – liquid methane…

See Universe Today for the full article.

A Tale of Three Moons: Is There Life in the Outer Solar System?

Until fairly recently, the search for life elsewhere in the solar system has focused primarily on Mars, as it is the most Earth-like of all the other planets in the solar system. The possibility of finding any kind of life farther out in the outer solar system was considered very unlikely at best; too cold, too little sunlight, no solid surfaces on the gas giants and no atmospheres to speak of on any of the moons apart from Titan…

See Universe Today for the full article.

(Note: this and future articles written for Universe Today are exclusive, therefore only a summary is posted here, which will link to the full article on UT).

Poll: which Discovery mission would you vote for?

As a follow-on to the previous post, which newly proposed mission for NASA’s Discovery program would you like to see happen? Only one will be selected next year, to launch in 2016…


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