Comments on: Do oceans turn under the face of Titan? http://blogs.discovermagazine.com/badastronomy/2008/03/20/do-oceans-turn-under-the-face-of-titan/ I am an astronomer, writer, and skeptic. I likes reality the way it is, and I aims to keep it that way. My real name is Phil Plait, and I run the Bad Astronomy blog. Sun, 05 Jul 2009 08:19:24 +0000 http://wordpress.org/?v=2.3.1 By: SomethingEvil.com » Blog Archive » Oceans Under Titan? http://blogs.discovermagazine.com/badastronomy/2008/03/20/do-oceans-turn-under-the-face-of-titan/#comment-77846 SomethingEvil.com » Blog Archive » Oceans Under Titan? Tue, 29 Apr 2008 03:19:47 +0000 http://blogs.discovermagazine.com/badastronomy/2008/03/20/do-oceans-turn-under-the-face-of-titan/#comment-77846 [...] I knew it all along. I saw it with my scrying glass. [...] […] I knew it all along. I saw it with my scrying glass. […]

]]> By: Naomi http://blogs.discovermagazine.com/badastronomy/2008/03/20/do-oceans-turn-under-the-face-of-titan/#comment-77845 Naomi Sat, 22 Mar 2008 10:15:10 +0000 http://blogs.discovermagazine.com/badastronomy/2008/03/20/do-oceans-turn-under-the-face-of-titan/#comment-77845 Correct me if I'm wrong (wouldn't surprise me), but the organic compounds on the upper layers of Titan's atmosphere are tholins, right? And when tholins are mixed with liquid water or ammonia, they produce amino acids? With that in mind, is there any way that tholins could be mixed in with subsurface oceans of water or ammonia? Because if there is, and they're producing amino acids, that'd be the coolest thing EVER. Get a dedicated lander to Titan, stat! Correct me if I’m wrong (wouldn’t surprise me), but the organic compounds on the upper layers of Titan’s atmosphere are tholins, right? And when tholins are mixed with liquid water or ammonia, they produce amino acids? With that in mind, is there any way that tholins could be mixed in with subsurface oceans of water or ammonia?

Because if there is, and they’re producing amino acids, that’d be the coolest thing EVER. Get a dedicated lander to Titan, stat!

]]> By: Davol http://blogs.discovermagazine.com/badastronomy/2008/03/20/do-oceans-turn-under-the-face-of-titan/#comment-77844 Davol Fri, 21 Mar 2008 22:28:54 +0000 http://blogs.discovermagazine.com/badastronomy/2008/03/20/do-oceans-turn-under-the-face-of-titan/#comment-77844 I think if there is water under the surface of Titan it is frozen water. That doesn't mean there isn't a liquid ocean under the surface. It just means it isn't water. That's where the ammonia comes in since at normal tempatures ammonia is a gas, however it is one of thoes gasses that becomes a liquid at lower tempatures. That's why we are talking about windex instead of water here. I don't know what windex does to make the ammonia a liquid. I think if there is water under the surface of Titan it is frozen water. That doesn’t mean there isn’t a liquid ocean under the surface. It just means it isn’t water. That’s where the ammonia comes in since at normal tempatures ammonia is a gas, however it is one of thoes gasses that becomes a liquid at lower tempatures. That’s why we are talking about windex instead of water here. I don’t know what windex does to make the ammonia a liquid.

]]> By: Adam Crowl http://blogs.discovermagazine.com/badastronomy/2008/03/20/do-oceans-turn-under-the-face-of-titan/#comment-77843 Adam Crowl Fri, 21 Mar 2008 21:56:56 +0000 http://blogs.discovermagazine.com/badastronomy/2008/03/20/do-oceans-turn-under-the-face-of-titan/#comment-77843 Titan's oceans shouldn't be too surprising. Back in the early 1970s John Lewis worked out that the radioactives in the silicate component of the moons would be enough to melt much of the icy mantles - ever since people have been arguing over whether solid state convection would chill the mantles out or not. Convection is a much more efficient heat transport process than conduction, but the rheological properties (i.e. ability to flow under pressure) of large amounts of ice are hard to model and study experimentally, so lots of guesswork was needed to work out whether the ice mantles of the moons would be frozen or still liquid. Looks like experiment has come down on the side of liquid under all that ice. Above the ocean will be a layer of convecting ice - imagine great balloons of "warm" ice floating up through the crust, just like granite batholiths in Earth's crust. Below the ocean will be a layer of high-pressure ice phases (ammonia freezes solid at 300 K when under 10,000 bars of pressure), and below that will be the muddy core. When we have more seismological data from Titan we might learn if its silicate core has differentiated into rock and metal. Titan’s oceans shouldn’t be too surprising. Back in the early 1970s John Lewis worked out that the radioactives in the silicate component of the moons would be enough to melt much of the icy mantles - ever since people have been arguing over whether solid state convection would chill the mantles out or not. Convection is a much more efficient heat transport process than conduction, but the rheological properties (i.e. ability to flow under pressure) of large amounts of ice are hard to model and study experimentally, so lots of guesswork was needed to work out whether the ice mantles of the moons would be frozen or still liquid.

Looks like experiment has come down on the side of liquid under all that ice. Above the ocean will be a layer of convecting ice - imagine great balloons of “warm” ice floating up through the crust, just like granite batholiths in Earth’s crust. Below the ocean will be a layer of high-pressure ice phases (ammonia freezes solid at 300 K when under 10,000 bars of pressure), and below that will be the muddy core. When we have more seismological data from Titan we might learn if its silicate core has differentiated into rock and metal.

]]> By: Barton Paul Levenson http://blogs.discovermagazine.com/badastronomy/2008/03/20/do-oceans-turn-under-the-face-of-titan/#comment-77842 Barton Paul Levenson Fri, 21 Mar 2008 15:50:24 +0000 http://blogs.discovermagazine.com/badastronomy/2008/03/20/do-oceans-turn-under-the-face-of-titan/#comment-77842 Titan is a very cool world. In the physical sense, too, of course -- its albedo of 0.3 gives it an equilbrium temperature of 82 K, and the surface temperature is 94 K. It has a greenhouse effect due to methane, brief nitrogen-methane pairs, and, weirdest of all nitrogen-nitrogen pairs. Nitrogen isn't a greenhouse gas at the temperatures we're used to, but it is on Titan. Plus the haze high in its atmosphere gives it an <i>anti</i>greenhouse effect -- the haze absorbs sunlight but allows infrared to pass through it, thus lowering the temperature of the ground. The Titan greenhouse effect of 21 K should bring the temperature up to 103 K at the surface, but the antigreenhouse effect takes 9 K off that, leaving us with 94 K. Then you have the 1.467 bar surface pressure -- the closest atmospheric pressure to Earth of any known world in the solar system. You'd need serious heating systems to move around there in a space suit, but air pressure would not be a problem. I don't know how fierce the wind would be, but I suspect not very -- Titan rotates only once in 15 days, since it's tidally locked to Saturn. There's a high atmosphere level that "superrotates," as there also is on Venus, but that doesn't much affect ground conditions. I'm sorry they didn't get a good atmosphere breakdown from Huygens. I was waiting for percentage figures to come through like we got when Viking landed on Mars in 1976. Everyone had expected Martian air to be high in argon, as much as 25-28%; it was a surprise when argon turned out to be only 1.6% of Martian air. We know Titan has mostly nitrogen, argon of less than 12%, and methane somewhere in the 3-6% range, but I want better figures than that. I hope they send more landers with better instruments in the future. And the landforms are awesome. I wonder what color it all is in human vision? Makes me think of the landscapes that flashed by during Dave Bowman's FTL trip in 2001, where Kubrick took Earth landscapes and gave them bizarre colors just to make them look alien. Titan is a very cool world. In the physical sense, too, of course — its albedo of 0.3 gives it an equilbrium temperature of 82 K, and the surface temperature is 94 K. It has a greenhouse effect due to methane, brief nitrogen-methane pairs, and, weirdest of all nitrogen-nitrogen pairs. Nitrogen isn’t a greenhouse gas at the temperatures we’re used to, but it is on Titan.

Plus the haze high in its atmosphere gives it an antigreenhouse effect — the haze absorbs sunlight but allows infrared to pass through it, thus lowering the temperature of the ground. The Titan greenhouse effect of 21 K should bring the temperature up to 103 K at the surface, but the antigreenhouse effect takes 9 K off that, leaving us with 94 K.

Then you have the 1.467 bar surface pressure — the closest atmospheric pressure to Earth of any known world in the solar system. You’d need serious heating systems to move around there in a space suit, but air pressure would not be a problem. I don’t know how fierce the wind would be, but I suspect not very — Titan rotates only once in 15 days, since it’s tidally locked to Saturn. There’s a high atmosphere level that “superrotates,” as there also is on Venus, but that doesn’t much affect ground conditions.

I’m sorry they didn’t get a good atmosphere breakdown from Huygens. I was waiting for percentage figures to come through like we got when Viking landed on Mars in 1976. Everyone had expected Martian air to be high in argon, as much as 25-28%; it was a surprise when argon turned out to be only 1.6% of Martian air. We know Titan has mostly nitrogen, argon of less than 12%, and methane somewhere in the 3-6% range, but I want better figures than that. I hope they send more landers with better instruments in the future.

And the landforms are awesome. I wonder what color it all is in human vision? Makes me think of the landscapes that flashed by during Dave Bowman’s FTL trip in 2001, where Kubrick took Earth landscapes and gave them bizarre colors just to make them look alien.

]]> By: Rapture, is not an exit strategy… « Homeless on the High Desert http://blogs.discovermagazine.com/badastronomy/2008/03/20/do-oceans-turn-under-the-face-of-titan/#comment-77841 Rapture, is not an exit strategy… « Homeless on the High Desert Fri, 21 Mar 2008 12:52:19 +0000 http://blogs.discovermagazine.com/badastronomy/2008/03/20/do-oceans-turn-under-the-face-of-titan/#comment-77841 [...] 21, 2008 in Physics But Titan, Saturn’s giant moon, may be. [...] […] 21, 2008 in Physics But Titan, Saturn’s giant moon, may be. […]

]]> By: Chuck Anziulewicz http://blogs.discovermagazine.com/badastronomy/2008/03/20/do-oceans-turn-under-the-face-of-titan/#comment-77840 Chuck Anziulewicz Fri, 21 Mar 2008 12:31:17 +0000 http://blogs.discovermagazine.com/badastronomy/2008/03/20/do-oceans-turn-under-the-face-of-titan/#comment-77840 Titan always struck me as kind of ... mushy. How I envy the explorers of this bizarre world in the distant future. Titan always struck me as kind of … mushy. How I envy the explorers of this bizarre world in the distant future.

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