Hydrocarbon Rain Swells Titan's Lakes 110
Rob Carr writes "According to the Cassini team, 'Recent images of Titan from NASA's Cassini spacecraft affirm the presence of lakes of liquid hydrocarbons by capturing changes in the lakes brought on by rainfall.' The northern lakes are now larger following a period in which hydrocarbon clouds covered their skies. (The research was published in the journal Geophysical Research Letters.) This change adds to the evidence these areas are indeed hydrocarbon lakes. But this discovery raises several more questions: where is the methane in the atmosphere coming from, and how long can this complex hydrocarbon cycle on Titan go on? The new evidence emphasizes the need for another mission to Titan."
Re:Another "planet" with resources... (Score:5, Insightful)
You must be a nut to think that "Dubya" will be a single, isolated incident in the history of mankind.
Re:Another "planet" with resources... (Score:2, Insightful)
...to wage war over. It'll happen.
It is kinda disappointing to read about interesting places in the solar system and realize that war or no, our race will only be interested enough to get there when the profit motive is clear.
Re:bad modding (Score:3, Insightful)
You 99%correct. Wars are normally fought over resources. It was land as farms weren't that good. Near Future wars will be over oil. Howver far into the future the mainstay resources will shift. Currently oil literally drives us. It used to be food(people, horses ,etc). It will probably be the element that enables FTL.
Re:bad modding (Score:3, Insightful)
FTL may not even be possible. I think our likely "far future" will be shaped by the development of strong artificial intelligence and the realization of a technological singularity. It's hard to predict what will follow that, almost by definition ... but it's hard for me to imagine that it will involve humans fighting wars over material resources. Which is not to say such conflict won't be replaced by something even more appalling.
Re:Space Oil Tanker... (Score:4, Insightful)
So not only do we fill our atmosphere with the CO2 produced from burning our own hydrocarbons, but then we fill our atmosphere with the CO2 produced by burning an entire other planet's worth of hydrocarbons. Brilliant!
I suppose we could build sequestration plants on Titan and pump all the exhaust back up there though.
Re:source http://www.esa.int (Score:4, Insightful)
If all the observed liquid on Titan is methane, it would only last a few million years, because as methane escapes into Titan's atmosphere, it breaks down and escapes into space.
Doesn't sound right. At a glance, from Wikipedia [wikipedia.org], if I assume methane is an ideal gas, the average velocity of methane gas is roughly:
v = sqrt(3kT/M).
Here, T = 94K, k =1.38*10^-23 m^2 kg/ (s^2 K), and M = 2.32*10^-26 kg (mass of a molecule of methane). Crunching the numbers I get that the average velocity of methane is roughly 400 m/s. In comparison, escape velocity from Titan's surface is 2.65 km/s. Titan's radius is more than 2,500 km. As I understand it, escape velocity scales as the square root of radius. So you'd have to be above 6,000 km radius in order to get escape velocities down to 400 m/s. But the atmosphere is nowhere near 3500 km thick. I just don't think this is a credible option for methane loss.
The second possibility is decomposition of methane due to UV light. Using the above formula, H2, which has a seventh the mass of methane has an average velocity of under 1100 m/s. That's not escape velocity until you're at a radius of 4,000 km. Plus, being on average 9.5 AU from the Sun, means that solar influx is far lower than on Earth. So you get something like 15 W/m^2 compared to 1300 W/m^2 at Earth. Hydrogen loss on Earth is pretty minuscule too. Plus, we're probably well below methane's freezing point by the time we get to the upper atmosphere (which I'd guess is probably mostly nitrogen with traces of other molecules). So just like water vapor freezes at high altitudes, I imagine that little methane reaches the upper atmosphere.
Solar wind doesn't play a role since apparently Titan is just inside [ucla.edu] Saturn's magnetosphere. The linked paper indicates that the dominate mass wasting process is the atmosphere's interaction with Saturn's magnetosphere.
To summarize, I just don't see the process that's going to eliminate most methane from Titan's atmosphere on the order of millions of years.
Re:source http://www.esa.int (Score:2, Insightful)
The critical thing you have there is that you are calculating the average velocity, not the fraction that is trotting along at > 2.65km/s. That will be e^(- (2.65km/s / 400m/s)^2), or about 1 in 1e19 methane molecules will have escape velocity. In the case of H2 that'd be a full 0.3% of molecules having escape velocity.
The actual loss rate will depend on a few other things, such as the mean free path of the molecules (i.e. how likely are they to bump into another before escaping, and how frequently they get their energies reset to a function of the average).
Look up Boltzmann distributions for more.
American Rebellion (Score:3, Insightful)
American revolution - not resources (at least not entirely, Britain probably did want access to North American resources)
It was totally about resources - the American colonies taking control of the sugar/rum/slave trade triangle from Britain.
And don't forget Bush's little oil war.