Methane Rain on Titan

[paulanderson]

First the discovery of the hydrocarbon (methane / ethane) lakes, and now further confirmation that it also rains liquid methane on Titan, ranging from ongoing drizzles to larger storms:<br /><br />http://www.nasa.gov/centers/ames/news/releases/2006/06_57AR.html<br />http://www.nature.com/nature/journal/v442/n7101/edsumm/e060727-06.html<br />http://www.planetary.org/blog/article/00000658<br />http://www.newscientistspace.com/article/mg19125623.600-titan-weather-methane-downpours-and-drizzle.html

 

[3488]

Exometeorology is not a new subject. The Viking 1 & Viking 2 landers on Mars carried out extensive Exometeorology, Pioneer Venus at Venus, as did the atmospheric entry probe of the Galileo Jupiter spacecraft in December 1995, not to mention the Voyagers, Galileo & Cassini since.<br /><br />Seeing it happen on Titan though is very interesting.<br /><br />The below article about the 'constant drizzle' on Titan is interesting. <br /><br />Liquid methane drizzles on the surface of Titan, a moon of Saturn, according to a paper by NASA and university scientists that appears in today's issue of the journal, Nature. <br /><br />Data from the European Space Agency's Huygens probe indicates there is a lower, barely visible, liquid methane-nitrogen cloud that drops rain to the surface of Titan, reported a team of scientists from universities, an observatory and NASA. The probe collected the data on January 14, 2005, when it approached and landed on Titan. <br /><br />"The rain on Titan is just a slight drizzle, but it rains all the time, day in, day out. It makes the ground wet and muddy with liquid methane. This is why the Huygens probe landed with a splat. It landed in methane mud," said Christopher McKay, a scientist at NASA Ames Research Center in California's Silicon Valley and second author of the study. The principal author is Tetsuya Tokano from the University of Cologne, Germany. <br /><br />On Titan, the clouds and rain are formed of liquid methane. On Earth, methane is a flammable gas, but Titan has no oxygen in its atmosphere that could support combustion. Also, the temperatures on Titan are so cold -- minus 300 degrees Fahrenheit (minus 149 degrees Celsius) -- that the methane can form liquid. Titan's landscape includes fluvial, river-like features that may well be formed by methane rain, scientists noted. <br /><br />A gap separates the liquid methane cloud -- the source of the rain -- from a higher, upper methane ice cloud, according to the scientific study. Scientist <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>

 

[tom_hobbes]

Very interesting articles, thanks. Guess I won't be going to Titan for my holidays, apart from being a little nippy, it's always raining... <div class="Discussion_UserSignature"> <p><font size="2" color="#339966"> I wish I could remember<br /> But my selective memory<br /> Won't let me</font><font size="2" color="#99cc00"> </font><font size="3" color="#339966"><font size="2">- </font></font><font size="1" color="#339966">Mark Oliver Everett</font></p><p> </p> </div>

 

[alokmohan]

Science fiction?Give web reference.Any way I like to know if umbrella is required and made of what material?

 

[JonClarke]

Thew first direct measurements of the atmosphere of another planet was by Venera 4 in 1967. Exometerology probably began with the discovery of transitory clouds on Mars, supposedly by Herscehl in 1784. There were not completely inaccurate models of Martian atmsopheric circulation before the first probes.<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>

 

[paulanderson]

<i>Science fiction?Give web reference.</i><br /><br />His text is from the same NASA link I had posted already at the beginning of this thread (the first link listed). Plus see the other links for more information, as well as the other thread regarding the methane lakes just found on Titan. No, this is not science fiction...

 

[3488]

I agree. This is as real & as strange as it gets. Titan is becoming a real world in its own right. Impact craters, cryovolcanoes, hills, mountains, ridges, canyons, valleys, dunes, hydrocarbon lakes, winds, hazes, clouds, seasons & now methane rain.<br /><br />A few years ago, this would have been in the realms of quality Science Fiction, but is now very much a part of science fact.<br /><br />I hope that these Titan threads will continue as we learn more about this planet sized fascinating object orbiting Saturn. <br /><br />Titan, Enceladus & Iapetus in my own opinion are the three 'interesting' moons of Saturn & are the only ones worthy of serious further study. Phoebe also because of its peculiar origins in the Kuiper Belt. <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>

 

[4saken]

The links are all interesting. I'm doing a project work, sort of intense research and the links you posted really helped me a lot.. I have to read them in a more subtle way now..

 

[alokmohan]

Its all presumtion.I fail to understand how one concludes from photographs.New scientist has commercial aspect also in making far fetched conclusions.

 

[mikeemmert]

Hi, Andrew, check out the August 2006 issue of Scientific American, page 40, <i>The Strangest Satellites in the Solar System</i>. Very interesting data there about captured bodies and how their orbits evolve with time. <br /><br />I am of the opinion that Titan is a captured body that formed in the Sun/Saturn Lagrange points L4 and L5.<br /><br />From the Scientific American article (transposed by hand, typos are mine):<br /><br />"<font color="yellow">...for a body to be permantently captured from heliocentic orbit into a bound, stable orbit around a planet, it must lose some of it's initial energy. Essentially the body has to be slowed down to prevent it from escaping again...In the 1970, theorists proposed three possible mechanisms, all functioning during or soon after the epoch of planet formation...<br /><br />The first, advanced by James B Pollack and Joseph A. Burns, then at the NASA Ames Research Center, and Michael E. Tauber of Cornell University, argues that the moons lost energy to friction generated as they passed through the vastly extended atmospheres of the embryonic gas giant planets...Before settling into their modern, relatively compact forms, the planets may have passed through a transient, distended phase, during wihich their atmospheres extended hundreds of times farther than they do now".<br /><br /><font color="white">This is the scenario that I propose for Titan.<br /><br />"<font color="yellow">The second method also places capture during the planetary growth phase. The accretion of gas onto the cores of the gas giants would have caused their mass to shoot upward in a self reinforcing process, leading to sudden growth in the size of the Hill sphere around each planet. Asteroids and other objects that were unlucky enough to be nearby at the moment of this runaway growth would have found themselves trapped by the abruptly extended reach of the planets' gravity. This mechanism of captur</font></font></font>

 

[JonClarke]

Post deleted by JonClarke <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>

 

[vonster]

<blockquote><font class="small">In reply to:</font><hr /><p><br />Its all presumtion.<p><hr /></p></p></blockquote><br /><br />do you read?<br /><br />.

 

[alokmohan]

Concluding drizzle may be too much.It may raise false expectations of going to titan.After all we vagueely know.Public may take it to realm of fantasy.Example:having alien life is scientifically possible.But see the perversion to UFO.

 

[CalliArcale]

Your analogy is very poor. Alien life is possible, but there is absolutely no evidence for it. Nothing at all has ever been observed to support a specific observation of alien life. All we have is an absence of information refuting it.<br /><br />Liquid methane on Titan is an entirely different matter. There is observational evidence from both Huygens and Cassini.<br /><br />Skepticism is good, but denial is not. There is far more evidence than you seem willing to admit. <div class="Discussion_UserSignature"> <p> </p><p><font color="#666699"><em>"People assume that time is a strict progression of cause to effect, but actually from a non-linear, non-subjective viewpoint it's more like a big ball of wibbly wobbly . . . timey wimey . . . stuff."</em>  -- The Tenth Doctor, "Blink"</font></p> </div>

 

[mikeemmert]

Dear Calli;<br /><br />I think we have a bit of confusion here about the post by our foreign guest from India.<br /><br />First, let's try to clear this up. From alokmohan:<blockquote><font class="small">In reply to:</font><hr /><p>Public may take it to realm of fantasy.Example:having alien life is scientifically possible.But see the perversion to UFO.<p><hr /></p></p></blockquote>And you said:<blockquote><font class="small">In reply to:</font><hr /><p>Alien life is possible, but there is absolutely no evidence for it. Nothing at all has ever been observed to support a specific observation of alien life. All we have is an absence of information refuting it.<p><hr /></p></p></blockquote>Which are the same statements. Cut the guy some slack, he's apparently not a native English speaker.<br /><br />I was mystified at the tone here, but then I found what the difference seems to be. alokmohan said:<blockquote><font class="small">In reply to:</font><hr /><p> Concluding drizzle may be too much.It may raise false expectations of going to titan.After all we vagueely know.Public may take it to realm of fantasy<p><hr /></p></p></blockquote>And you replied:<blockquote><font class="small">In reply to:</font><hr /><p> Liquid methane on Titan is an entirely different matter. There is observational evidence from both Huygens and Cassini. <br /><br />Skepticism is good, but denial is not. There is far more evidence than you seem willing to admit.<p><hr /></p></p></blockquote>I think, at this time, and my mind is open on this, that alokmohan was refering to <i>direct</i> evidence of "drizzle". I don't see any direct evidence either. But there is direct evidece of "dew", since it condensed on the camera lens. Descent photos show clear skies below the permanent cloud deck. Perhaps the photo from the surface may reveal drizzle but I'm not good a processing photos, and we have experts who post here who may be able to answer that question.<br /><br />Liquid methane, for which there is evidence, does not directly infer specific meteorologi

 

[paulanderson]

For something that is only "science fiction" there is a lot of data available, collected by Huygens and Cassini, as also just announced here by ESA:<br /><br /><b>Huygens Scientific Archive Data Set Released</b><br />http://www.esa.int/SPECIALS/Cassini-Huygens/SEM8TYIZBQE_0.html<br /><br />As stated, it can all be downloaded by the public as well as scientists (links are on the same page). See also all the other links already provided. The Cassini team itself is saying they have the evidence for methane rain and lakes, not just other publications, etc. One of the articles I linked to (forget which one offhand) also mentions that the Cassini imaging team has <i>possible</i> evidence as well for waves on some of the lakes (not as certain yet, but they mention it). The lakes seem to be in various stages of evaporation, but the Cassini imaging team is almost certain that at least some of them are still at least partially filled with liquid.

 

[alokmohan]

But the rain?

 

[3488]

Thinking about it, Alokmohan is correct. I assumed that methane drizzle on Titan was a proven fact. However, currently it had not been seen directly.<br /><br />IMO Methane Rain on Titan is a reality, but Alokmohan correctly states that it has NOT BEEN ACTUALLY OBSERVED. Two very different things. <br /><br />Cryovolcanoes, impact craters, mountains, hydrocarbon lakes, channels, dunes, ice pebbles, etc HAVE BEEN OBSERVED & we can say hand on heart that these features are real & do physically exist on Titan. <br /><br />Perhaps the PROOF of the existence of Methane Rain on Titan is still lurking in the Huygens data, not yet analyzed. <br /><br />The EVIDENCE is mounting for the existence of Methane Rainl, but as Alokmohan says, IT HAS NOT ACTUALLY BEEN OBSERVED, hence his perfectly justified scepticism.<br /><br />His English is extremely good. I have no problem with understanding with anything that he is saying. <br /><br />Alokmohan raises a good point here. The line between fact & theory is becoming increasingly blurred, even if compelling evidence for the latter is there (the case of Methane Rain on Titan). I think it exists & it is real. Just because I think it is real, does not make it so. <br /><br />I found it interesting that when Huygens descended through the Tropopause of Titan (some 40 kilometres / 25 miles above the surface), the temperature dropped to a horrendous Minus 212 Celsius / 61 Kelvin for a brief period. I understand the the ESA engineers did not expect this & were mortified that Huygens could have been killed off. <br /><br />A cold trap when ever there was one. Makes the Minus 180 Celsius / 93 Kelvin on the surface look tropical!! <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>

 

[alokmohan]

Thank you for your compliments.We should be dispassionate and not be guided by likes and dislikes.It would be nice t have man on mars,but sorry there is none.We should not go beyond what has been detected.