Cassini finds flooded canyons on Titan

Cassini finds flooded canyons on Titan
NASA's Cassini spacecraft pinged the surface of Titan with microwaves, finding that some channels are deep, steep-sided canyons filled with liquid hydrocarbons. One such feature is Vid Flumina, the branching network of narrow lines in the upper-left quadrant of the image. Credit: NASA/JPL-Caltech/ASI

NASA's Cassini spacecraft has found deep, steep-sided canyons on Saturn's moon Titan that are flooded with liquid hydrocarbons. The finding represents the first direct evidence of the presence of liquid-filled channels on Titan, as well as the first observation of canyons hundreds of meters deep.

A new paper in the journal Geophysical Research Letters describes how scientists analyzed Cassini data from a close pass the spacecraft made over Titan in May 2013. During the flyby, Cassini's radar instrument focused on channels that branch out from the large, northern sea Ligeia Mare.

The Cassini observations reveal that the channels—in particular, a network of them named Vid Flumina—are narrow canyons, generally less than half a mile (a bit less than a kilometer) wide, with slopes steeper than 40 degrees. The canyons also are quite deep—those measured are 790 to 1,870 feet (240 to 570 meters) from top to bottom.

The branching channels appear dark in radar images, much like Titan's methane-rich seas. This suggested to scientists that the channels might also be filled with liquid, but a direct detection had not been made until now. Previously it wasn't clear if the dark material was liquid or merely saturated sediment—which at Titan's frigid temperatures would be made of ice, not rock.

Cassini's radar is often used as an imager, providing a window to peer through the dense haze that surrounds Titan to reveal the surface below. But during this pass, the radar was used as an altimeter, sending pings of radio waves to the moon's surface to measure the height of features there. The researchers combined the altimetry data with previous radar images of the region to make their discovery.

Key to understanding the nature of the channels was the way Cassini's radar signal reflected off the bottoms of the features. The radar instrument observed a glint, indicating an extremely smooth surface like that observed from Titan's hydrocarbon seas. The timing of the radar echoes, as they bounced off the canyons' edges and floors, provided a direct measure of their depths.

The presence of such deep cuts in the landscape indicates that whatever process created them was active for a long time or eroded down much faster than other areas on Titan's surface. The researchers' proposed scenarios include uplift of the terrain and changes in sea level, or perhaps both.

"It's likely that a combination of these forces contributed to the formation of the deep canyons, but at present it's not clear to what degree each was involved. What is clear is that any description of Titan's geological evolution needs to be able to explain how the canyons got there," said Valerio Poggiali of the University of Rome, a Cassini radar team associate and lead author of the study.

Earthly examples of both of these types of canyon-carving processes are found along the Colorado River in Arizona. An example of uplift powering erosion is the Grand Canyon, where the terrain's rising altitude caused the river to cut deeply downward into the landscape over the course of several million years. For canyon formation driven by variations in water level, look to Lake Powell. When the water level in the reservoir drops, it increases the river's rate of erosion.

"Earth is warm and rocky, with rivers of water, while Titan is cold and icy, with rivers of methane. And yet it's remarkable that we find such similar features on both worlds," said Alex Hayes, a Cassini radar team associate at Cornell University, Ithaca, New York, and a co-author of the study.

While the altimeter data also showed that the liquid in some of the canyons around Ligeia Mare is at sea level—the same altitude as the liquid in the sea itself—in others it sits tens to hundreds of feet (tens of meters) higher in elevation. The researchers interpret the latter to be tributaries that drain into the main channels below.

Future work will extend the methods used in this study to all other channels Cassini's radar altimeter has observed on Titan. The researchers expect their continued work to produce a more comprehensive understanding of forces that have shaped the Saturnian moon's landscape.


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Journal information: Geophysical Research Letters

Provided by JPL/NASA
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Aug 10, 2016
All that hydrogen and carbon and oxygen....
Bound to be, at least, one or two amines floatin' around in there...:-)

Aug 10, 2016
Why turn the metric information given into foot pounds and all that crap. The sort of slobs who use feet and pounds are all Trump suporters who want NASA shut down.

Aug 10, 2016
Why turn the metric information given into foot pounds and all that crap. The sort of slobs who use feet and pounds are all Trump suporters who want NASA shut down.


In my experience, NASA always give their press releases with both metric and ancient measurement systems. Usually with metric in parentheses. I can see their point. I'm sure, as scientists, they'd prefer to just give measurements in metric, but you could imagine the rednecks who would like them closed down, kicking up a storm about goddamn foreign measurements bein' used by a goddamn gov'ment agency that the Amurrcan people have goddamn paid for.
Politics, I suspect.

Aug 10, 2016
Silly. Giving measurements in feet and miles, as well as meters and kilometers is intended to help the reader in several ways. First, even if you use meters everyday, if you grew up with feet and inches, having both numbers can give you a better "feel" for the data.

But there is a more subtle point that is quite intentional. If I tell you that some distance is 1 kilometer, you would have no idea of the accuracy of the measurement. If I say one kilometer or 11 hundred yards, I am telling you that the measurement error is about 20 feet (or 6 meters) you choose. ;-)

Incidentally, yes I can flip those numbers around in my head. The handy numbers to know are 2.54 centimeters to one inch. A meter is almost exactly 39.37 inches, but the 2.54 number is by definition. For the above a kilometer is 1,093.61 yards, 3,280.84 feet, or 0.6214 miles, but for rough measurements, like when giving driving directions, 11 hundred yards, 3300 feet or 5/8 of a mile will get you close enough.

Aug 11, 2016
An example of uplift powering erosion is the Grand Canyon, where the terrain's rising altitude caused the river to cut deeply downward into the landscape over the course of several million years.

This is questionable. Measurements of current erosion rates shows that erosion is so fast that millions of years is not an option. In that kind of time period most mountains would have eroded down to plains with nary an indication of their once having existed.
Furthermore, just how does "erosion" occur over such a large area as the width of the Grand Canyon yet for hundreds of square kilometers underneath and in between the different rock layers there is ZERO sign of ANY erosion?
Quite clearly this type of speculation is unscientific. It is NOT supported by the observational evidence and FAILS on every point of verification.

Aug 11, 2016
Why turn the metric information given into foot pounds and all that crap.

Because the press releases are aimed at the general public - not at scientists (scientists read the papers, direct). And the general public in the US isn't literate in metric units.

Aug 11, 2016
An example of uplift powering erosion is the Grand Canyon, where the terrain's rising altitude caused the river to cut deeply downward into the landscape over the course of several million years.

This is questionable. Measurements of current erosion rates shows that erosion is so fast that millions of years is not an option. In that kind of time period most mountains would have eroded down to plains with nary an indication of their once having existed.
Furthermore, just how does "erosion" occur over such a large area as the width of the Grand Canyon yet for hundreds of square kilometers underneath and in between the different rock layers there is ZERO sign of ANY erosion?
Quite clearly this type of speculation is unscientific. It is NOT supported by the observational evidence and FAILS on every point of verification.


Links to back any of that up? Other than Answers in Genesis?

Aug 11, 2016
Why turn the metric information given into foot pounds and all that crap.

Because the press releases are aimed at the general public - not at scientists (scientists read the papers, direct). And the general public in the US isn't literate in metric units.


As shown by the fact that they managed to lose a Mars mission due to confusion over what units were being used. In 3 years, it'll be 50 years since New Zealand went metric. It isn't rocket science.

Aug 11, 2016
it'll be 50 years since New Zealand went metric. It isn't rocket science.

Unfortunately anything in the US that is not native 'murican' immediately turns into a political issue. And when it comes to politics the US aren't exactly what one would call 'sane'.

Aug 12, 2016
it'll be 50 years since New Zealand went metric. It isn't rocket science.

Unfortunately anything in the US that is not native 'murican' immediately turns into a political issue. And when it comes to politics the US aren't exactly what one would call 'sane'.

Couldn't we spread the rumor that Franklin invented metric and the europeans stole it? I bet most 'muricans' would buy it. Who cares for facts anyway. ;-)

Aug 13, 2016
Couldn't we spread the rumor that Franklin invented metric and the europeans stole it? I bet most 'muricans' would buy it

The sad thing is this: Would probably work.

Aug 13, 2016
So let's get cracking.


Shall we get cracking in U.S. gallons, imperial gallons, or (like the rest of the sane world) in litres?

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