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> Scientists suspect that Titan might even have water—real, actual H2O—lurking beneath its surface. Not just a little, but a lot of water: > The density of T

by apo 7y ago

> Scientists suspect that Titan might even have water—real, actual H2O—lurking beneath its surface. Not just a little, but a lot of water: > The density of Titan is consistent with a body that is about 60% rock and 40% water. > ... > Pre-Cassini models of impact trajectories and angles suggest that where the impactor strikes the water ice crust, a small amount of ejecta remains as liquid water within the crater. It may persist as liquid for centuries or longer, sufficient for "the synthesis of simple precursor molecules to the origin of life".[107] https://en.wikipedia.org/wiki/Titan_(moon) https://en.wikipedia.org/wiki/Titan_(moon)

4ntonius8lock 7y ago
Thanks, I seemed to remember reading about H2O on Titan. When the article didn't mention it, I thought I was confused. Didn't bother to look it up. Your comment furthered my understanding. I think this type of projects would be a great bipartisan way to unite the country, as happened during the space race in the middle of the 20th century. It might also revive some interest in STEM.
dmurray 7y ago
> The density of Titan is consistent with a body that is about 60% rock and 40% water. That's extremely misleading. First, rocks have different densities. Sandstone weighs 2g/cc, basalt weighs 3g/cc, so a density "consistent with" 50% basalt, 50% water would be equally consistent with 100% sandstone, not to mention the possibilities of rocks with drastically different densities such as pumice or iron. Secondly, we are pretty certain Titan has large quantities of liquid methane and/or ethane (check the same Wikipedia link) which certainly account for some of the difference in density between Titan and other rocky bodies. So yes, there is water on Titan, but it's about as likely to be 40% water as it is to be 40% cheese or 40% iPhones, even if its density suggests a makeup consistent with that.
- apo 7y ago
  > That's extremely misleading. You're right - I should have said: "potentially a lot of water." Sandstone (silicon oxides) seems unlikely given the reducing nature of the atmosphere. I'm no expert, but when liquid hydrocarbons rain down, there's not a lot of free oxygen on the surface at least. Ditto for basalt, which is about 40-50% silicon oxide. Still there could have been some process by which the interior sequestered most of the planet's oxygen, leaving what remained on the surface as water. In contrast, liquid hydrocarbons seem plausible given the stuff rains down from the atmosphere and its density (methane ~0.5 g/mL, -162 C). Titan's orbit provides some evidence consistent with a body that's more dense at the surface than at the core. One explanation is large amounts of subsurface liquid, but there are others: https://www.popsci.com/science/article/2011-04/titan-could-harbor-massive-ocean-beneath-its-methane-lakes-study-says/ https://www.popsci.com/science/article/2011-04/titan-could-h... There's been some discussion about the apparent massive block of ice in Titan's surface, so the idea that Titan's putative subsurface ocean could contain water isn't too wild a speculation: https://www.space.com/titan-saturn-moon-weird-ice-formation.html https://www.space.com/titan-saturn-moon-weird-ice-formation.... A subsurface ocean composed of water and liquid hydrocarbons would be consistent with everything I've been able to find so far.

by apo 7y ago

4ntonius8lock 7y ago

Thanks, I seemed to remember reading about H2O on Titan. When the article didn't mention it, I thought I was confused. Didn't bother to look it up. Your comment furthered my understanding. I think this type of projects would be a great bipartisan way to unite the country, as happened during the space race in the middle of the 20th century. It might also revive some interest in STEM.

dmurray 7y ago

> The density of Titan is consistent with a body that is about 60% rock and 40% water. That's extremely misleading. First, rocks have different densities. Sandstone weighs 2g/cc, basalt weighs 3g/cc, so a density "consistent with" 50% basalt, 50% water would be equally consistent with 100% sandstone, not to mention the possibilities of rocks with drastically different densities such as pumice or iron. Secondly, we are pretty certain Titan has large quantities of liquid methane and/or ethane (check the same Wikipedia link) which certainly account for some of the difference in density between Titan and other rocky bodies. So yes, there is water on Titan, but it's about as likely to be 40% water as it is to be 40% cheese or 40% iPhones, even if its density suggests a makeup consistent with that.

apo 7y ago
> That's extremely misleading. You're right - I should have said: "potentially a lot of water." Sandstone (silicon oxides) seems unlikely given the reducing nature of the atmosphere. I'm no expert, but when liquid hydrocarbons rain down, there's not a lot of free oxygen on the surface at least. Ditto for basalt, which is about 40-50% silicon oxide. Still there could have been some process by which the interior sequestered most of the planet's oxygen, leaving what remained on the surface as water. In contrast, liquid hydrocarbons seem plausible given the stuff rains down from the atmosphere and its density (methane ~0.5 g/mL, -162 C). Titan's orbit provides some evidence consistent with a body that's more dense at the surface than at the core. One explanation is large amounts of subsurface liquid, but there are others: https://www.popsci.com/science/article/2011-04/titan-could-harbor-massive-ocean-beneath-its-methane-lakes-study-says/ https://www.popsci.com/science/article/2011-04/titan-could-h... There's been some discussion about the apparent massive block of ice in Titan's surface, so the idea that Titan's putative subsurface ocean could contain water isn't too wild a speculation: https://www.space.com/titan-saturn-moon-weird-ice-formation.html https://www.space.com/titan-saturn-moon-weird-ice-formation.... A subsurface ocean composed of water and liquid hydrocarbons would be consistent with everything I've been able to find so far.