APOD: Mysterious Changing feature on Titan (2014 Oct 15)

[APOD Robot]

Mysterious Changing feature on Titan

Explanation: What is that changing object in a cold hydrocarbon sea of Titan? Radar images from the robotic Cassini spacecraft orbiting Saturn have been recording the surface of the cloud-engulfed moon Titan for years. When imaging the flat -- and hence radar dark -- surface of the methane and ethane lake called Ligeia Mare, an object appeared in 2013 just was not there in 2007. Subsequent observations in 2014 found the object remained -- but had changed! The featured image shows how the 20-km long object has appeared and evolved. Current origin speculative explanations include bubbling foam and floating solids, but no one is sure. Future observations may either resolve the enigma or open up more speculation.

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[bystander]

http://asterisk.apod.com/viewtopic.php?p=232565#p232565

[Nitpicker]

I've no idea what the changing feature might be on this strange world. But with Titan's axis very closely aligned with Saturn's axis, I should think that in 2007, Titan's northern polar region would have been on its way out from a long spell of darkness, whereas it is now in the beginning of a long spell of sunshine, admittedly only 1% of the sunshine Earth receives. So, I suppose it's tempting to call it a mysterious seasonal change.

[madtom1999]

Is it not possible to get some 3d type images of this.
Wondering if it could be tidal.

[ems57fcva]

Look carefully at the overall image. There appears to be a line of demarcation in first two images running from the center of the top of teh frame towards the bottom near the lower left corner. There is more "stuff" to the right of that line than to the left. In the last picture, the line is still there, but it has moved to the right, and more so at the bottom than the top. Also the "stuff" on the right side of the line is brighter which I take to mean that it is denser.

I assume that the change in the location of the line is due to a change of current in Ligeia Mare. This in turn indicates that the "stuff" is floating.

Conclusion: The changing bright feature may be hydrocarbon "icebergs" getting caught on some shallows and then breaking up and/or moving on. That would explain why the feature was not observed in pictures between 7/13 and last August.

[Guest]

If you look carefully at the image, you will see a 'bay' to the right of the inscribed circle. And then a ridge that separates the next structure that looks like a fiord. Carefully compare the three images and you will see changes in the three images. Assuming these are fixed features of the 'landscape', then the logical conclusion is that the surface level of the lake has dropped over the two year period. Evaporation could account for that, but what of the process and timeframes?

[Tszabeau]

There appears to be some craters, on the right side of the most recent image that are not so apparent in the earlier pics... or are my eyes playing tricks again?

[Marv the obvious]

Based on how the shoreline changes at the objects to the right of the object in question, I'd say some how the fluid level changed in the time span between the images, either by loss or tide.

[Marvtheobvious]

Based on how the shoreline changes at the objects to the right of the object in question, I'd say some how the fluid level changed in the time span between the images, either by loss or tide.

[julianm3]

Thar be whales on Titan!

[MarkBour]

I'm suspecting the third image may have a focal difference from the other two. If not, then the changes are happening much more rapidly than in the first 6 years. 'Tis a great set of images. Hopefully over time we'll learn about dissolution/condensation processes on very cold methane seas.

[Boomer12k]

Looks to me like there are LOTS of changes from left to right....too numerous to point out....

So...the place changes...it has a sea...an atmosphere...it is bound to be somewhat Dynamic....not the Static Universe some would suppose....

:---[===] *

[dlw]

There seem to be quite a few changes. The most dramatic is, of course, the "island" but there are many others. I assume, since this is radar, that changes in lighting is not an explanation. Very interesting.

[kindness]

Maybe this 'lake' has a tide.

[Kasuha]

Looks like a tidal effect to me with some feature very close to the liquid surface appearing and disappearing periodically. The shoreline appears lower in the (bottom right part of) second image (since upper left is copied from first image), then it is back up in the third image.

I wonder how was the feature oriented relative to Saturn in either of the three cases.

[Startreader]

Current origin speculative explanations include bubbling foam and floating solids, but no one is sure. Future observations may either resolve the enigma or open up more speculation.

The explanation is obvious: this is an image of a man driving a construction crane with his wiry little doggie in the left-hand seat. He has been bringing sand and stones and stuff to build a castle at the sea-shore. He's cold, so he's slow.

I say "man" not to be sexist but because most crane drives are male and "man" would include aliens. The shape is definitely a biped with two arms and a sensor stalk topped by a floppy cap. Possibly named "Bob".

[Maxim]

It's in a hydrocarbon SEA. The tides come in....the tides go out. Shallows cover up.....shallows appear.

[Nitpicker]

Note that the upper part of the middle image -- above what I assume is the black "stitching" line on an angle -- is identical to the upper part of the left image. Looks like they didn't capture the full field of view in 2013. Most of the differences in the images can probably be explained away as noise, but not the mysterious feature inside the ellipse. (North is to the image bottom-left, by the way.)

[Ann]

Startreader wrote:
I say "man" not to be sexist but because most crane drives are male and "man" would include aliens.

Hey, I have no problem with your assumption that a crane driver would usually be a man, but... aren't there female aliens?

As Mr Spock once said, It is a well-known fact that we Vulcans propagate our race by mail.

Ann

[Perk Cartel]

I'm guessing "seasonal" ethane/methane cycle and/or tidal event affecting lake surface level relative to the lake edge terrain...

[Beyond]

As Mr Spock once said, It is a well-known fact that we Vulcans propagate our race by mail.

I must have missed that episode.

[Ann]

As Mr Spock once said, It is a well-known fact that we Vulcans propagate our race by mail.

I must have missed that episode.

The Spock quote might have been in a Star Trek novel. I read tons of them in the 1980s.

Ann

[Nitpicker]

Startreader wrote:
I say "man" not to be sexist but because most crane drives are male and "man" would include aliens.

Hey, I have no problem with your assumption that a crane driver would usually be a man, but... aren't there female aliens?

As Mr Spock once said, It is a well-known fact that we Vulcans propagate our race by mail.

Ann

Not logical, Ann. Startreader's comment does not rule out the possibility of female aliens. And I'm sure it's just a coincidence that the interval over which this APOD was recorded -- seven years -- is the same interval experienced by Vulcans, in between bouts of their mating cycle hormone imbalance, pon farr.

[DavidLeodis]

Seeing the image brought up through the "Future observations" link made me .

[DavidLeodis]

Note that the upper part of the middle image -- above what I assume is the black "stitching" line on an angle -- is identical to the upper part of the left image. Looks like they didn't capture the full field of view in 2013. Most of the differences in the images can probably be explained away as noise, but not the mysterious feature inside the ellipse. (North is to the image bottom-left, by the way.)

Hi Nitpicker.

In the information brought up through the 'featured image' link it states "The upper half of the middle image uses data from the April 26, 2007 Titan flyby. That area did not receive SAR coverage during the July 10, 2013 encounter, so the earlier data was used to fill-in the scene."