Titan's missing craters

[JonClarke]

http://space.com/scienceastronomy/070326_titan_craters.html<br /><br />What this means is that Titan has roughly the same number of craters as Earth and thus a geology of roughly similar degrees of activity. Most exciting!<br /><br />Jon <div class="Discussion_UserSignature"> <p><em>Whether we become a multi-planet species with unlimited horizons, or are forever confined to Earth will be decided in the twenty-first century amid the vast plains, rugged canyons and lofty mountains of Mars</em>  Arthur Clarke</p> </div>

 

[JonClarke]

To quantify it a bit, Earth has six times the surface area of Titan and ~40 craters of 20 km or larger, Titan perhaps 30. Only Europa, Io, Earth and venus have a higher crater obliteration rate.<br /><br />Jon <div class="Discussion_UserSignature"> <p><em>Whether we become a multi-planet species with unlimited horizons, or are forever confined to Earth will be decided in the twenty-first century amid the vast plains, rugged canyons and lofty mountains of Mars</em>  Arthur Clarke</p> </div>

 

[saurc]

Hmm as far as I know, there are fewer craters observable on Earth because they get worn down by erosion ( wind, water, plant life etc) over millions of years. Are you suggesting something similar might be happening on Titan ?<br /><br />Or perhaps due to a thicker atmosphere most of the meteorites burn up therefore fewer craters? I mean Titan has a thicker atmosphere than Earth.<br /><br />Whatever, it is an interesting topic.

 

[JonClarke]

If you read the artice it says that craters less than 20 km across are unlikely on titan because of the thick atmosphere. So I used the stats on craters of 20 km and above for earth.<br /><br />The implication is obvious, on Titan wind action (there are extensive dune seas), cryovolcanism ice lavas) and liquid action (methane rain, runoff, coast erosion and sedimentation beneath lakes and seas) all obliterate the craters in a way analogous to wind, water and silicate volcanism do on earth.<br /><br />Jon <div class="Discussion_UserSignature"> <p><em>Whether we become a multi-planet species with unlimited horizons, or are forever confined to Earth will be decided in the twenty-first century amid the vast plains, rugged canyons and lofty mountains of Mars</em>  Arthur Clarke</p> </div>

 

[3488]

Hi Jon.<br /><br />Firstly thank you for starting this fascinating thread.<br /><br />The same is true on Venus. There appears to be a minimum size of impact craters because of the dense atmosphere burns up the smaller impactors!!<br /><br />Titan's craters are being erased, no doubt. If the ratio quoted turns out to be correct globally, than the craters are being wiped out in a relatively short time (compare the density of similarly sized craters on Rhea, Tethys, Dione, Iapetus, etc).<br /><br />I am convinced that cryovolcanism is alive & well on Titan, with Ganesa Macula being a possible large cryovolcano. We are just awaiting absolute proof of it. Also erosion will happen due to methane rain, snow, winds, hydrocarbon ice crystals being blown about. Titan may even have Titanquakes, as I suspect Titan may well be seismically active.<br /><br />Andrew Brown. <div class="Discussion_UserSignature"> <p><font color="#000080">"I suddenly noticed an anomaly to the left of Io, just off the rim of that world. It was extremely large with respect to the overall size of Io and crescent shaped. It seemed unbelievable that something that big had not been visible before".</font> <em><strong><font color="#000000">Linda Morabito </font></strong><font color="#800000">on discovering that the Jupiter moon Io was volcanically active. Friday 9th March 1979.</font></em></p><p><font size="1" color="#000080">http://www.launchphotography.com/</font><br /><br /><font size="1" color="#000080">http://anthmartian.googlepages.com/thisislandearth</font></p><p><font size="1" color="#000080">http://web.me.com/meridianijournal</font></p> </div>

 

[centsworth_II]

<font color="yellow">"...on Titan wind action... cryovolcanism.. and liquid action... all obliterate <br />the craters in a way analogous to wind, water and silicate volcanism do on Earth."</font><br /><br />I think the Big Question is... <b>plate tectonics?</b>. <div class="Discussion_UserSignature"> </div>

 

[3488]

Hi centsworth_II.<br /><br />I would not rule it out. <br /><br />Titan is or at least in the very recent geological past has been active. Something to definately look for in further raday images, to see evidence of rifting.<br /><br />I think that evidence has already been seen for lateral faulting in Cassini Radar images of Xanadu.<br /><br />Andrew Brown. <div class="Discussion_UserSignature"> <p><font color="#000080">"I suddenly noticed an anomaly to the left of Io, just off the rim of that world. It was extremely large with respect to the overall size of Io and crescent shaped. It seemed unbelievable that something that big had not been visible before".</font> <em><strong><font color="#000000">Linda Morabito </font></strong><font color="#800000">on discovering that the Jupiter moon Io was volcanically active. Friday 9th March 1979.</font></em></p><p><font size="1" color="#000080">http://www.launchphotography.com/</font><br /><br /><font size="1" color="#000080">http://anthmartian.googlepages.com/thisislandearth</font></p><p><font size="1" color="#000080">http://web.me.com/meridianijournal</font></p> </div>

 

[JonClarke]

Hi Andrew<br /><br />A water ice crust can't subduct into a water-ammonia-rich athenosphere. So unless the composition is very different from a water ice crust and mantle, plate tectonics as envisaged for earth can't happen.<br /><br />Cheers<br /><br />Jon <div class="Discussion_UserSignature"> <p><em>Whether we become a multi-planet species with unlimited horizons, or are forever confined to Earth will be decided in the twenty-first century amid the vast plains, rugged canyons and lofty mountains of Mars</em>  Arthur Clarke</p> </div>

 

[3488]

Thanks Jon,<br /><br />I understand that lateral faulting has been seen on Titan. Good point there about the water - ammonia rich asthenosphere. I was not too sure of the chemistry involved, so thanks for clearing that up.<br /><br />centsworth_II raises a good point though. The surface is far too young to just account for precipitation runoff & slow hydrocarbon infilling IMO, etc. I still think Titanquakes are a real possibilty.<br /><br />What we really need is a proper network of fully equipped landers (Pancams, multispectral imagers, meteorological equipment & seismometers). The seismometers networked can measure how shock waves travel through the globe of Titan, thus helping to determine internal makeup, levels of diffrentiation, etc, just as on Earth (I propose something similar for Mars, Venus, Europa & Io).<br /><br />MeteorWayne on another thread is also correct. It is time that those in power really took exploration of our solar system more seriously. See what has been achieved IMO with really what are small sums, two MERs that refuse to quit & continue to send amazing images & other results, Cassini orbiter & New Horizons, performing better than expected, amongst others, etc.<br /><br />Once again, thanks Jon.<br /><br />Andrew Brown. <div class="Discussion_UserSignature"> <p><font color="#000080">"I suddenly noticed an anomaly to the left of Io, just off the rim of that world. It was extremely large with respect to the overall size of Io and crescent shaped. It seemed unbelievable that something that big had not been visible before".</font> <em><strong><font color="#000000">Linda Morabito </font></strong><font color="#800000">on discovering that the Jupiter moon Io was volcanically active. Friday 9th March 1979.</font></em></p><p><font size="1" color="#000080">http://www.launchphotography.com/</font><br /><br /><font size="1" color="#000080">http://anthmartian.googlepages.com/thisislandearth</font></p><p><font size="1" color="#000080">http://web.me.com/meridianijournal</font></p> </div>

 

[JonClarke]

Ten percent of global defence spending being diverted into solar system exploration would be good! <div class="Discussion_UserSignature"> <p><em>Whether we become a multi-planet species with unlimited horizons, or are forever confined to Earth will be decided in the twenty-first century amid the vast plains, rugged canyons and lofty mountains of Mars</em>  Arthur Clarke</p> </div>

 

[ajna]

Hi Jon,<br /><br />With cryovolcanism likely on Titan, do you think there could be the equivalent of Earth's deep-sea vents? It seems from what everyone has said above the moon is somewhat active geologically. Is it active enought to produce even moderate heat and kickstart life around a vent in the ocean floor?

 

[JonClarke]

Well, "Titan's hydrosphere" would be of methane, so maybe there are liquid methane vents surrounding water volcanoes, depositing chimneys of waxes and other complex hydrocarbons.<br /><br />There may also be a deep zone of liquid water beneath the crust, On the interface between this and the silicate core you might get Earth-like vents.<br /><br />Jon <div class="Discussion_UserSignature"> <p><em>Whether we become a multi-planet species with unlimited horizons, or are forever confined to Earth will be decided in the twenty-first century amid the vast plains, rugged canyons and lofty mountains of Mars</em>  Arthur Clarke</p> </div>

 

[3488]

Hi Jon,<br /><br />If in your opinion Plate tectonics cannot happen on Titan, than any 'hydrothermal vents' under hydrocarbon lakes would be the cryovolcanic equivalent of hot spot volcanism, if I am correct???<br /><br />Andrew Brown. <div class="Discussion_UserSignature"> <p><font color="#000080">"I suddenly noticed an anomaly to the left of Io, just off the rim of that world. It was extremely large with respect to the overall size of Io and crescent shaped. It seemed unbelievable that something that big had not been visible before".</font> <em><strong><font color="#000000">Linda Morabito </font></strong><font color="#800000">on discovering that the Jupiter moon Io was volcanically active. Friday 9th March 1979.</font></em></p><p><font size="1" color="#000080">http://www.launchphotography.com/</font><br /><br /><font size="1" color="#000080">http://anthmartian.googlepages.com/thisislandearth</font></p><p><font size="1" color="#000080">http://web.me.com/meridianijournal</font></p> </div>