Venus oceans?

[JonClarke]

That would be nice. But my understanding is the highlands are no noticably older than the lowlands. But as I said, you would look in the tectonically active areas for former sediments.<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>

 

[alokmohan]

But we rule out the oceans and venusians.

 

[3488]

Hi Jon,<br /><br />That too is my understanding.<br /><br />H20universe did raise a valid point though. Look at the Columbia Hills in Gusev Crater on Mars.<br /><br />In less than one meter, the MER A Spirit detected totally different geology where the Columbia<br />Hill rose from the lava lake that once flooded that part of Gusev Crater.<br /><br />In short, the Columbia Hills were an island in the lake of lava in Gusev Crater, during that<br />time since, very long gone.<br /><br />The highlands of Venus would logically follow a similar pattern, islands in an ocean of lava.<br /><br />Unfortunately on Venus, this does not appear to be the case, the highlands are not<br />appreciably older than the lava plains that surround them. There<br />appear to have been no islands in Venus's global lava ocean during the last resurfacing<br />event.<br /><br />This Magellan radar image of Maxwell Mons, the tallest mountain on Venusm whose <br />summit rises 11,000 metres / 36,100 feet (which <br />appears compressional, <br />rather than volcanic), does look like a fairly 'young' feature.<br /><br />Maxwell Mons here rises from eastern Lakshmi Planum, which is a young region with volcanic<br />features.<br /><br />For scale, the width of the image is 300 kilometres.<br /><br />Maxwell Mons. This is a large image 3.8 MB.<br /><br />Thabk you Jon for your answer about the possible state of preservation of a potential primordial<br />marine environment. <br /><br />I doubt myself that life would have had enough time to start in said primordial ocean<br />(if it even existed), before the atmosphere thickened up, the Sun brightened & <br />the runaway greenhouse effect kicked in.<br /><br />The posiible ways of knowing may be to either drop seismometers & listen out for <br />Venusquakes & see if any evidence of density changes close to the surface, point to <br />the likelihood of a possible ancient ocean floor under all of that <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>

 

[mithridates]

Yes, that's the reason why I don't think Venus will ever be terraformed - not because we won't ever have the ability to but because by the time we get around to having the ability I suspect we'll already have quite a large civilization in the clouds that wouldn't like to see things changed, given how much easier it is. <div class="Discussion_UserSignature"> <p>----- </p><p>http://mithridates.blogspot.com</p> </div>

 

[mithridates]

I'm betting that we'll have people on the surface of Ceres before both Mars and Titan.<br /><br />Oh, and also: I read before somewhere that the atmosphere of Titan is actually toxic, not just unbreathable, and that even the smallest leak would cause a person to die. I have no idea where I read that though. Is that true? <div class="Discussion_UserSignature"> <p>----- </p><p>http://mithridates.blogspot.com</p> </div>

 

[MeteorWayne]

Regarding your con #1.<br /><br />Shade or not, the thick atmosphere makes the temperature relatively constant. The high temperature are more due to the greenhouse effect than insolation. <div class="Discussion_UserSignature"> <p><font color="#000080"><em><font color="#000000">But the Krell forgot one thing John. Monsters. Monsters from the Id.</font></em> </font></p><p><font color="#000080">I really, really, really, really miss the "first unread post" function</font><font color="#000080"> </font></p> </div>

 

[3488]

Apparently at the Median Level, as Venus has no sea level, there is only a 4 Celsius<br />difference between day & night.<br /><br />If a shade was used, true it would cool down, but it would take a very long time.<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>

 

[h2ouniverse]

Alokmohan,<br /><br />Here we are speaking of potential ancient oceans several billions of years ago. There is no reason for now to think that Venus should have received significantly less water than Earth (both planets formed within frost limit, but have been bombarded as any other inner system object). And solar flux should have been much lower at the beginning of the Solar System history. <br /><br />Our ancestors imagining oceans and farmers were in fact just lacking imagination, as they were simply projecting what they knew on what they did not.<br />By seeing Venus as it is today, a hellish hot dry acidic place, it is tempting to imagine that it has always been like that. Another way of being trapped by the illusion of constancy (this time in time rather than in space).<br />But things change much faster than we tend to imagine. <br /><br />Best regards.

 

[3488]

Hi mithridates,<br /><br />I have posted an answer on the Titan Thread, as I thought that would be better there,<br />rather than on a Venus thread.<br /><br />Hi Joel, <br /><br />I suspect that any ocean Venus may have had, was very, very short lived.<br /><br />The Sun was approx 70% as powerful then as it is now, so even with that, the solar energy at early<br />Venus was still 40% greater than what we get ourselves even now. <br /><br />Then the Sun started to brighten up.<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>

 

[h2ouniverse]

Hi Andrew,<br /><br />I have no personal shares in the 2-billion year theory, but apparently some believe in it:<br />from a 2003 article http://space.newscientist.com/article/dn4136<br /><br />"Until now, the best estimate, calculated 15 years ago by James Kasting, of the Pennsylvania State University, was four billion years ago - just 600 million years after the Solar System's birth.<br />But new work by David Grinspoon, at the Southwest Research Institute in Boulder, Colorado, suggests the momentous transition may have occurred much later. He points out the Kasting's estimate was just a lower limit on when the change happened, because it did not include the effect of clouds in the Venusian atmosphere. <br />Reflected sunlightClouds reflect sunlight back to space and therefore cool a planet's surface, and Grinspoon's preliminary calculations indicate that the effect can be dramatic - keeping the atmosphere 100 Kelvin cooler than without them.<br />Although more detailed modeling remains to be done, Grinspoon says the difference could mean that oceans and pleasant temperatures may have persisted on Venus for at least two billion yearsThis also suggests that another global transformation on Venus about 700 million years ago, in which the whole planet's surface appears to have melted and reformed, may actually have been a continuation of the same greenhouse warming that dried out the planet.<br />Once the water was lost, Grinspoon says, plate tectonics would have stopped completely, and with it the most efficient way for the planet to shed its internal heat. This could have led to a buildup that eventually caused the whole crust to melt and then reform.<br />More generally, if this analysis is right, it means that the "habitable zone" for planets around other stars may be much wider than has been assumed, since Venus had been thought to be far outside it.<br />Grinspoon presented his work at the American A

 

[MeteorWayne]

Nice link, thanx! <div class="Discussion_UserSignature"> <p><font color="#000080"><em><font color="#000000">But the Krell forgot one thing John. Monsters. Monsters from the Id.</font></em> </font></p><p><font color="#000080">I really, really, really, really miss the "first unread post" function</font><font color="#000080"> </font></p> </div>

 

[h2ouniverse]

I've fixed it. A parenthesis was glued to the link. Works now.

 

[MeteorWayne]

Worked fine for me. which I actually tried after you fixed it I guess <img src="/images/icons/smile.gif" /><br /><br />I wasn't complaining, it was a great excerpt.<br />Very educational, though from NewScientist, my philosophy is "find the original research" <img src="/images/icons/smile.gif" /> <div class="Discussion_UserSignature"> <p><font color="#000080"><em><font color="#000000">But the Krell forgot one thing John. Monsters. Monsters from the Id.</font></em> </font></p><p><font color="#000080">I really, really, really, really miss the "first unread post" function</font><font color="#000080"> </font></p> </div>

 

[3488]

It is a very nice link, I agree with MeteorWayne 100%.<br /><br />Very interesting reading.<br /><br />Thank you very much for posting it.<br /><br />If you find more stuff like that, please link it always.<br /><br />Yes Venus is a single plated planet, hence no spreading rifting (like the East Africa Rift Valley)<br />& no subduction zones either. The volcanism, does appear to be more in the nature of<br />hot spot volcanism, like Hawaii, Yellowstone & the Galapagos Islands,<br />where a plume of magma rises through the mantle & burns through the crust.<br /><br />If in the case of Venus, that crust is too thick over most of the planet, then lava resurfacing<br />does appear to be the only effective way, to rid excessive internal heat, as the regular<br />hot spot volcanoes, are not sufficient on their own.<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>

 

[h2ouniverse]

What I find astonishing is the virtuous circle that the presence of water is able to create on phenomena as powerful as plate tectonics:<br /><br />1) apparently this contributes to lubricate the plates and to generate plate tectonics, helping to evacuate the core heat in a smooth way<br /><br />2) by hydrating mantle rocks, granite and other lighter rocks are formed, enabling continents to rise (otherwise density would be 3.3 not 2.7) with two different types of crust (continental and ocean floor).<br /><br />Best regards.

 

[3488]

This would explain why Earth alone appears to have active plate tectonics @ the <br />present time. Yes water does lubricate plate tectonics particularly in the Subduction Zones<br />& also makes the rock more 'pliable' less rigid also.<br /><br />I had heard about your second point before. If there were no oceans on Earth, the planet may well<br />be single plated like Mercury, Venus, Moon & Mars with one type of crust.<br /><br />To humans, the oceans seem immense, but compared to the mass of the Earth, the amount of mass they contain, is negligible, yet<br />as you say, they play an important role with how out planet rids excessive internal heat.<br /><br />Strange stuff indeed.<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>

 

[vandivx]

water lubricates the Earth so its crust moves, money lubricates people so that they move, they both make the world go around<br /><br />vanDivX <div class="Discussion_UserSignature"> </div>

 

[alokmohan]

I had a idea that venus has tectonics.Can you confirm if I am wrong?

 

[3488]

Hi Alokmohan,<br /><br />You may be interested in the following.<br /><br />The top link is a highly detailed topographical map of Venus, clearly showing <br />the distribution of mountainous terrain & the lower lava plains.<br /><br />Venus topographical Map.<br /><br />The bottom link is a description of Venus resurfacing events & how lack of Cytherean plate <br />tectonics, causes periodic mass hot spot volcanism, resurfacing the planet.<br /><br />Article on Venus resurfacing.<br /><br />BTW, I do not understand you last sentence <font color="yellow"><br /><br />Andrew Brown.</font> <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>

 

[robnissen]

<font color="yellow">BTW, I do not understand you last sentence.</font><br /><br /><br />My guess: I wish to die gallantly???<br /><br />How about it Alokmohan, am I right?<br />

 

[MeteorWayne]

No, I'll bet he means with the magenta label, as in the SDC rank. <div class="Discussion_UserSignature"> <p><font color="#000080"><em><font color="#000000">But the Krell forgot one thing John. Monsters. Monsters from the Id.</font></em> </font></p><p><font color="#000080">I really, really, really, really miss the "first unread post" function</font><font color="#000080"> </font></p> </div>

 

[h2ouniverse]

Also these recent considerations about tetonics on super-Earths:<br />http://space.newscientist.com/article/mg19626255.500-superearths-will-have-plate-tectonics.html