Cassini Discovers First River On Another World 230
AbsoluteXyro writes "NASA's Cassini orbiter, which has been dutifully exploring the Saturn system since 2004, has captured images of the first river ever observed on another world — and it's a biggun. 200 miles of flowing hydrocarbons meandering down a valley in the north polar region of Saturn's moon Titan, emptying into the awesomely named Kraken Mare — itself a body of liquid roughly the size of the Mediterranean Sea back on Earth. But don't think of going for an extraterrestrial skinny dip quite yet, temperatures on Titan average a brutally cold 290 degrees below zero (Fahrenheit)."
Re:How could water be flowing (Score:5, Informative)
I get that no one on Slashdot RTFA, but this time even the description says "200 miles of flowing hydrocarbons."
Re:How could water be flowing (Score:5, Informative)
It's hydrocarbons, not water.
Titan's surface pressure is 1.5 bars, 50% higher than Earth.
Rivers & methane seas already known (Score:5, Informative)
I don't get how this is new. Cassini has been detecting branching river systems and large lakes (Great Lakes size) filled with liquid methane since early in the mission. This latest release is adding to the mapped area, but isn't particularly new in that regard. However, if you read the original NASA press release on the Cassini web site [nasa.gov], it makes more sense. This is not the first, but the longest river system that has been observed so far on Titan, at about 400km long.
It's not so cold. (Score:5, Informative)
It's only -179 C. Not exactly shorts weather, mind you.
Re:I'm lost (Score:5, Informative)
I'm quite ignorant of organic chemistry, but I thought hydrocarbons were fossils. How can there be hydrocarbons without life?
Or am I WAY off in my ASSumptions?
There are plenty of organic molecules out in space. All organic means is "contains carbon".
Organic compounds form anywhere there is carbon, which is made in stars and spread around by supernovae. Given that hydrogen makes up 99.8% of the stuff out there most of the carbon compounds you find in space are simple hydrocarbons, either aliphatic stuff like methane and ethane or aromatics like naphthalene and other poly-aromatic systems.
Re:Oil may not be a fossil fuel then? (Score:5, Informative)
Where to begin....
"Fossil fuels' are mostly compressed algae and diatoms although the carbon sources doesn't really make any difference - it's just hydrogenated carbon chains squished under a lot of pressure, heat and time that flow into relatively impermeable areas and collect. It is NOT mostly bits of T. rex and friends. Coal is an early form of this process - less time and heat and pressure - so you can occasionally see the original (mostly plant) source material.
Natural gas refers to the various blends of short chain hydrocarbons that are created in the process and that tend to migrate to different places (but not always). "Oil" tends to be longer chains. Oil sands (oil rock) has long chains imbedded in an annoying matrix of one composition or another. Natural gas is a 'fossil fuel' although the term is not a very apt description of how the stuff was produced. All of those descriptions are arbitrary and the material is produced along a spectrum.
Hopefully, you are not trying to be an abiotic oil nutcase.
Re:I'm lost (Score:5, Informative)
I'm quite ignorant of organic chemistry, but I thought hydrocarbons were fossils. How can there be hydrocarbons without life?
Or am I WAY off in my ASSumptions?
Organic chemistry is a misnomer. Most of the hydrocarbon molecules formed in the universe have been created without life. Just a byproduct of carbon, oxygen (mostly as Carbon Monoxide), hydrogen and a few other random chemicals along with a bit of fusion and a lot of time.
It would still burn OK (if there was any oxygen around). You could still make hydrogen and power fusion reactions (if we knew how). Lots of potential energy in the universe, more than we could ever use. Just hard to get to.
If you think drilling on the northern end of Siberia is hard, try a Jovian moon. Makes for nice science fiction reading, but as far as it being an instructional video, we have a ways to go.
Re:Metric system, please (Score:5, Informative)
0C is the freezing temperature of fresh water, which is far more relevant a point than anything to do with seawater (and Fahrenheit didn't use real seawater anyway, it was ammonium chloride). 0C is the point your drinking water freezes, which is a lot more relevant to most humans. If immersed in freezing seawater or freezing freshwater you'll be dead before you have much time to think about the difference in human perception between 0F and 0C. They're both deadly without special protection. 10C is cool but easy to handle with a light coat, 20C is comfortable room temperature. Anything over 30C is freaking hot. Divide between those points accordingly. 100C is the temperature of boiling water (at STP) that you shouldn't be sticking your hands into.
I don't buy the "human experience" aspect at all for the silliness that is Fahrenheit. The freezing point of fresh water is THE most important point on a temperature scale relating to human effects, and Celsius puts that at a logical 0 rather than weird 32. I always thought it was dumb that you had to do a bit of albeit simple math to figure out how many degrees you were above or below the freezing point using the Fahrenheit scale. With Celsius, it's the + or -. Much simpler.
It's just what you're used to, and I see no downside to Celsius at all. Furthermore, Celsius degrees are a little bigger than Fahrenheit degrees. Less precise, you say? Human perception can't reliably tell the difference between 1 degree F anyway, and struggles to consistently perceive Celsius degrees (I can usually estimate +-2 or 3 Celsius at best).
At -179C, it doesn't really matter if it is in F or C. It's far outside normal human experience unless you have a habit of dipping body parts in liquified gases.
Re:Metric system, please (Score:2, Informative)
10C is cool but easy to handle with a light coat, 20C is comfortable room temperature. Anything over 30C is freaking hot.
This is a good example of why we like Fahrenheit. We can easily talk about more than three temperature ranges. In the 30s you need a warm but not superwarm coat. In the 40s you need similar coat but you'll feel more comfortable wearing it. In the 50s you have light jacket weather. In the 60s the light jacket is optional. The 70s are perfect. The 80s are hot enough for swimming but not uncomfortably hot. The 90s are uncomfortably hot. Over 100 and you pretty much stay indoors.
If you want to be more precise you can say the "low 90s" (still good swimming weather) or "high 90s" (good swimming weather for youngster, indoor weather for older people)
And in the winter w can talk about the weather being in the 20s or teens, or perhaps near 0. It has to get pretty cold before we need to go negative (although there are plenty of places up north that need to do that regularly).