APOD: Mystery Feature Now Disappears in... (2016 Mar 07)

Post a reply


This question is a means of preventing automated form submissions by spambots.
Smilies
:D :) :ssmile: :( :o :shock: :? 8-) :lol2: :x :P :oops: :cry: :evil: :roll: :wink: :!: :?: :idea: :arrow: :| :mrgreen:
View more smilies

BBCode is ON
[img] is ON
[url] is ON
Smilies are ON

Topic review
   

Expand view Topic review: APOD: Mystery Feature Now Disappears in... (2016 Mar 07)

Re: APOD: Mystery Feature Now Disappears in... (2016 Mar 07)

by Fred the Cat » Fri Apr 08, 2016 9:32 pm

This was fun to watch :)

Re: APOD: Mystery Feature Now Disappears in... (2016 Mar 07)

by BMAONE23 » Wed Mar 23, 2016 5:07 pm

You are correct, these are Radar Images and not dependent on visible light so no visible light shadowing effect would be possible.
Although radar shadowing can occur, this is usually manifested as missing data rather than Flat data

Re: APOD: Mystery Feature Now Disappears in... (2016 Mar 07)

by geckzilla » Wed Mar 23, 2016 3:33 pm

Thomas, the imagery was made using radar. Hence, the spacecraft itself provided the light (in the form of microwaves) in order to create the image.
http://saturn.jpl.nasa.gov/spacecraft/c ... siniradar/

edit: someone please do correct me if I am wrong here. I wrote it the best I knew how.

Re: APOD: Mystery Feature Now Disappears in... (2016 Mar 07)

by TLGr » Wed Mar 23, 2016 3:24 pm

The missing link in Titan's lake? Actually nothing is missing, it is disappearing from sight because of rotation of the Plaint casting light on the visible Hydrocarbon above the lake's level, in the top inset, point in question, is not visible because of the isthmus low profile in the umbra light of the planet.
Notice the brightness of the second inset down it is brightest in light of the four insets, the "Mysterious Missing" is very visible in this inset. The third inset has a little less light and the "Mysterious Missing" is fading out, The lowest inset has even less light and the "Mysterious Missing" has disappeared from sight or it is not showing on the surface.
Shadows of light on the Carbon 'land-scape' surface indicate the rotation of the Planet, the top inset is very little exposed with light consequently not seen by the camera , the next down shows light coming from near the Zenith, the brightest, that is why the 'Mystery' is showing, the third Inset down indicates the light coming form low in the south barley showing the Mistry island, the fourth inset the light is coming from the low north with low lighting and no exposure to our "Mysterious Missing" it's evident the photos were not taken in a direct sequence.
The april 26, 2007 Image is it not shown? that is some confusion to the dates of the other insets. I'm curious as to how this little speck of the surface was noticed missing, in the lower inset there is a large portion of the land scape missing on it's west or left side of the picture.

Thomas L Groot
TLG5719@centurylink.net

Re: APOD: Mystery Feature Now Disappears in... (2016 Mar 07)

by Fred the Cat » Wed Mar 16, 2016 5:20 pm

Are they sure those are land masses? If they were a less dense floating solid on a liquid hydrocarbon lake and the density of the liquid was fluctuating per season wouldn't they change buoyancy? Of course then the liquid hydrocarbon might expand also and rise its surface level which wasn't detected.

Still a mystery...

Re: APOD: Mystery Feature Now Disappears in... (2016 Mar 07)

by Chris Peterson » Wed Mar 16, 2016 4:05 pm

just-a-16yrold wrote:What if it is just a land form under the lake and the lake is just rising or falling in its level?
Since this is a radar image, based on ranging data, I presume that any change in the surface level would be detectable.

Re: APOD: Mystery Feature Now Disappears in... (2016 Mar 07)

by just-a-16yrold » Wed Mar 16, 2016 3:49 pm

What if it is just a landform under the lake and the lake is simply rising or falling in its level?

Re: APOD: Mystery Feature Now Disappears in... (2016 Mar 07)

by just-a-16yrold » Wed Mar 16, 2016 3:47 pm

What if it is just a land form under the lake and the lake is just rising or falling in its level?

Re: Mystery Object In Titan Lake

by Chris Peterson » Wed Mar 09, 2016 3:47 pm

neufer wrote:
Ron Parker wrote:This is my first time on deck. I would like to ask a question: Are the fluid levels on Titan lake subject to rise and fall due to tidal forces? I was curious if it was possible that the mystery object (APOD March 7 2016) has not disappeared so much as become submerged. My observation is based on apparent solid surface material gaining and then lessening.
Titan is tidally locked to Saturn so the "tides" do not change.
The tidal force on Titan from Saturn is several hundred times greater than that of the Moon on the Earth. While Titan's orbital eccentricity is quite small, it is nevertheless large enough to allow for a fair degree of tidal flexing. I doubt that tides are significantly changing the height of surface liquids, but most certainly there are changing tides on Titan.

Re: Mystery Object In Titan Lake

by neufer » Wed Mar 09, 2016 1:33 pm

Ron Parker wrote:
This is my first time on deck. I would like to ask a question: Are the fluid levels on Titan lake subject to rise and fall due to tidal forces? I was curious if it was possible that the mystery object (APOD March 7 2016) has not disappeared so much as become submerged. My observation is based on apparent solid surface material gaining and then lessening.
Titan is tidally locked to Saturn so the "tides" do not change.

Mystery Object In Titan Lake

by Ron Parker » Wed Mar 09, 2016 4:56 am

This is my first time on deck. I would like to ask a question: Are the fluid levels on Titan lake subject to rise and fall due to tidal forces? I was curious if it was possible that the mystery object (APOD March 7 2016) has not disappeared so much as become submerged. My observation is based on apparent solid surface material gaining and then lessening. -Ron Parker

Re: APOD: Mystery Feature Now Disappears in... (2016 Mar 07)

by neufer » Tue Mar 08, 2016 10:43 pm

Possesomuwi-awtossis wrote:
Maybe it’s a drop in the level of Ligeia Mare. Some of the black inlets in the featured peninsula get smaller as the mysterious object comes into view, and larger again when it disappears. Would that be possible?
They are "Radar images" so they would know exactly if the water level were changing.

Re: APOD: Mystery Feature Now Disappears in... (2016 Mar 07)

by Possesomuwi-awtossis » Tue Mar 08, 2016 9:43 pm

Maybe it’s a drop in the level of Ligeia Mare. Some of the black inlets in the featured peninsula get smaller as the mysterious object comes into view, and larger again when it disappears. Would that be possible?

Re: APOD: Mystery Feature Now Disappears in... (2016 Mar 07)

by McMud » Mon Mar 07, 2016 10:10 pm

.. so this is wherrre the oulde Nessy's gona .. :wink:

Re: APOD: Mystery Feature Now Disappears in... (2016 Mar 07)

by Tekija » Mon Mar 07, 2016 8:29 pm

Boomer12k wrote:I am wondering how much is Camera Related....2007 is very clear, the others not so...with maybe static...then in 2015 is clear again. It also, appears to be "lower", then "more full"... but is "full" in 2007.

I would like to see the "full size" lake images of the times mentioned...to see any other changes around the lake.

:---[===] *
The shore on the opposite side of the peninsula also has changed quit a bit:

http://photojournal.jpl.nasa.gov/jpeg/PIA18430.jpg

Re: APOD: Mystery Feature Now Disappears in... (2016 Mar 07)

by neufer » Mon Mar 07, 2016 7:30 pm

bluebass wrote:
Have we overlooked the perfectly circular feature at the top of the frame? We need a conspiracy theory or better, a reasonable discussion what that might be. Crater?
https://www.newscientist.com/article/dn24430-astrophile-soggy-bogs-swallow-craters-on-titan/ wrote:
Soggy bogs swallow craters on Titan
New Scientist, 18 October 2013

<<The other meteors in the solar system were so lucky. They landed on nice, hard rock like on Mars or Mercury, exploding on the surface and excavating deep craters. If I had followed their lead, I could have left my mark! But no, I headed straight for this orange haze-ball Titan and plopped down in the northern marshes. I was a mere splash in an icy puddle, and all evidence of my existence was erased.

So was the fate of many a meteorite that struck Saturn’s largest moon, according to a new analysis of Titan’s topography. The work suggests that large, crater-free bands bordering the moon’s equator are wetlands fed by subsurface springs, where any incoming meteors would have made more of a splash than a bang. Those same springs may be the source of Titan’s polar lakes, feeding the world’s unusual liquid cycle.

“The complete lack of craters near the poles… People have noticed this for a while, but nobody’s had any good explanations,” says Catherine Neish of the Florida Institute of Technology in Melbourne. She wondered if craters there are simply melting away because the meteorites are landing in vast hydrocarbon swamps.

If Titan’s craters are being swallowed by soggy ground, then the ones we do see should appear more often at higher elevations, where the ground would be drier. To test this idea, Neish and her colleague Ralph Lorenz at the Johns Hopkins University Applied Physics Lab in Laurel, Maryland, examined a new map of Titan made from radar readings by NASA’s Cassini orbiter, published earlier this year. “It’s the first global topographic map of Titan that’s ever been made,” says Neish. “This is the first chance to really explore this issue quantitatively, instead of just qualitatively.” The team found that, statistically, more craters do exist at higher elevations all across the globe, while low zones have far fewer.>>

More at: https://www.newscientist.com/article/dn ... -on-titan/

Re: APOD: Mystery Feature Now Disappears in... (2016 Mar 07)

by bluebass » Mon Mar 07, 2016 7:09 pm

Have we overlooked the perfectly circular feature at the top of the frame? We need a conspiracy theory or better, a reasonable discussion what that might be. Crater? Trampoline?

Re: APOD: Mystery Feature Now Disappears in... (2016 Mar 07)

by Guest » Mon Mar 07, 2016 7:02 pm

I know that Titan is tidally locked to the planet, but there is some variation in the orbit. Given the size of the lake/sea, is it possible for the orbital variations or other surrounding moons to be enough to cause 'tides' in the lake/sea?

Re: APOD: Mystery Feature Now Disappears in... (2016 Mar 07)

by Boomer12k » Mon Mar 07, 2016 5:01 pm

I am wondering how much is Camera Related....2007 is very clear, the others not so...with maybe static...then in 2015 is clear again. It also, appears to be "lower", then "more full"... but is "full" in 2007.

I would like to see the "full size" lake images of the times mentioned...to see any other changes around the lake.

:---[===] *

Re: APOD: Mystery Feature Now Disappears in... (2016 Mar 07)

by Fred the Cat » Mon Mar 07, 2016 4:07 pm

The fractal appearance of the tributaries leading into the lake is surprisingly like that of Earth's water networks. Fractals must have more in common with geometry than chemistry.

But is "fractisity" a universal feature that is related to gravity or scale?

Re: APOD: Mystery Feature Now Disappears in... (2016 Mar 07)

by iblevine » Mon Mar 07, 2016 3:09 pm

I notice there is a straight line in the upper left-hand corner of the photo. Is it an artifact in the photo? I think it's quite unusual to see a straight line, which seems to go on for miles, in nature. Any ideas as to what it might be?

Re: APOD: Mystery Feature Now Disappears in... (2016 Mar 07)

by LouisDyer » Mon Mar 07, 2016 3:07 pm

Looks exactly like the Sometimes Islands in Lake Travis outside Austin, TX. When the lake level drops enough, the islands join to become a peninsula connected to the shore. When lake levels rise enough, they disappear altogether. The rest of the shoreline doesn't change as much with varying lake levels because they are made up of close to vertical cliffs. Does the radar data provide absolute altitude measurements of the lake level?

Re: APOD: Mystery Feature Now Disappears in... (2016 Mar 07)

by neufer » Mon Mar 07, 2016 2:07 pm

Coil_Smoke wrote:
The island melted back into the liquid it solidified from.
This seems pretty likely, I am a bit surprised it is not already on the list.
https://en.wikipedia.org/wiki/Ligeia_Mare wrote:
<<Ligeia Mare is a lake in the north polar region of Titan, the planet Saturn's largest moon. It is the second largest known body of liquid on Titan, after Kraken Mare. Larger than Lake Superior on Earth, it is composed of nearly pure liquid methane. The shorelines of Ligeia Mare and other north polar lakes and maria have been stable over the period of observation by Cassini, in contrast to south polar Ontario Lacus, where there has been significant shoreline recession. However, transient phenomena have been observed including a 260 square kilometre feature dubbed "Magic Island" by Cassini scientists. The "Magic Island" area only appeared in 2014 and may be waves, bubbles or subsurface ice rising to the surface as the lake warms up during spring, or possibly silt like material suspended in the liquid hydrocarbon sea.>>
http://sen.com/news/winter-ice-will-float-in-titan-s-methane-and-ethane-rich-lakes wrote:
Ice may float on the lakes of Saturn's moon Titan
Charles Black, Founder of Sen, Jan 15, 2013, 0:00 UTC

<<Scientists previously assumed that, because of its density, solid methane would sink on liquid methane. However, they have constructed a new model that takes into account the atmosphere and which adds pockets of nitrogen gas in the ice blocks, and which also takes into account changes in temperature. The results found that winter ice will float in Titan's methane and ethane rich lakes and seas if the temperature is below the freezing point of methane (90.4 K). Provided the ice had 5% or more "[nitrogen] air"... then it would float. If the temperature falls by a few degrees the ice will sink because of the relative proportions of nitrogen gas in the liquid versus the solid. The paper suggests that where the temperature is close to the freezing point of methane there could be both floating and sinking ice – a hydrocarbon ice crust above the liquid and blocks of the ice on the bottom of the lake or sea.

"We now know it's possible to get methane-and-ethane-rich ice freezing over on Titan in thin blocks that congeal together as it gets colder - similar to what we see with Arctic sea ice at the onset of winter," said Jason Hofgartner, lead author of the research and a Natural Sciences and Engineering Research Council of Canada scholar at Cornell University. "We'll want to take these conditions into consideration if we ever decide to explore the Titan surface some day.">>

- See more at: http://sen.com/news/winter-ice-will-flo ... iPjpr.dpuf

Re: APOD: Mystery Feature Now Disappears in... (2016 Mar 07)

by Coil_Smoke » Mon Mar 07, 2016 1:10 pm

It's not 'Dirt' we are looking at. The island melted back into the liquid it solidified from. This seems pretty likely, I am a bit surprised it is not already on the list. Methane, Ethane ... Frozen or Liquid ? The real mystery is the origin of these so called "Fossil Fuels" ?

Re: APOD: Mystery Feature Now Disappears in... (2016 Mar 07)

by Buddy » Mon Mar 07, 2016 11:41 am

I like the small circular shape top center. It looks like a crater remnant with a small peak.

Top