Please create an account to participate in the Slashdot moderation system

 


Forgot your password?
Close
typodupeerror
×
NASA Space Science

NASA Picks Up Rainstorms On Titan 110

Posted by timothy from the you-can-still-grill-outdoors-though dept.
RedEaredSlider writes "Rainy seasons aren't just a regular occurrence on Earth — they also happen on Titan, the largest moon of Saturn. The rain isn't water, it's methane. And the seasons are years long, as Titan takes two weeks to go around Saturn and Saturn takes 29 years to complete one circuit of the Sun. Recent images from the Cassini probe, which is currently orbiting Saturn, show clouds forming in Titan's atmosphere and evidence that liquid methane is soaking the surface."
This discussion has been archived. No new comments can be posted.

NASA Picks Up Rainstorms On Titan More

NASA Picks Up Rainstorms On Titan

Comments Filter:

  • Years long... (Score:5, Interesting)

    by Kokuyo ( 549451 ) on Monday March 21, 2011 @01:52AM (#35556688) Journal

    Can someone explain to me how long these years are? I find the TFA confusing.

    Our years are calculated by the circuit of our own planet around the sun. So does this rainy weather last for literal earth years or are they talking about relative years? And then: Saturn yars or Titan years? And what would a Titan year be since it doesn't revolve around the sun directly.

    Yeah, I don't have a clue about astronomy ;).

    • Re:Years long... (Score:4, Insightful)

      by RoFLKOPTr ( 1294290 ) on Monday March 21, 2011 @01:55AM (#35556704)

      Can someone explain to me how long these years are? I find the TFA confusing.

      Our years are calculated by the circuit of our own planet around the sun. So does this rainy weather last for literal earth years or are they talking about relative years? And then: Saturn yars or Titan years? And what would a Titan year be since it doesn't revolve around the sun directly.

      Yeah, I don't have a clue about astronomy ;).

      And the seasons are years long, as Titan takes two weeks to go around Saturn and Saturn takes 29 years to complete one circuit of the Sun.

      Obviously we're talking about Earth years, because Saturn revolving once around the sun cannot possibly take 29 Saturn years as that would completely contradict the definition of the word "year".

      • Re:Years long... (Score:5, Informative)

        by The Great Pretender ( 975978 ) on Monday March 21, 2011 @02:05AM (#35556748)
        Caveat - I am not an astronomer. Actually, I agree with the original poster the article is confusing. I believe that they swap the point of reference without announcing they did. While the initial units are in Earth years: "as Titan takes two weeks to go around Saturn and Saturn takes 29 years to complete one circuit of the Sun." They then move to either the Saturn or Titan point of reference, as it would make no sense comparing Earths 'time of year' to a warming period for Titan "McEwan says the atmospheric models predicted that there would be clouds in the equatorial regions at this time of year, as the sun on Titan got warmer. "We saw these clouds suddenly, and then we saw the equatorial area darken," he said." As the warming period for Titan must be associated to Saturns position relative to the Sun I can only assume that this second seasonal reference is based on Staurns orbital year. Which would then also explain why the article claims the seasons are 'years long' as it is talking about Saturn seasons in Earth years.

        • from TFA:

          "In tropical regions moisture rises as the sun heats the surface, and it precipitates out as rain, which is why rain forests tend to occur in those latitudes."

          "Tend to occur" my ass. First, a rainforest is not always in the tropics. Second, a tropic rainforest, like the ones that 'tend to occur at those latitudes' occurs all around earth in the tropics where there is land because sunlight is maximum all year long- NOT because they get rain all year long. A high fraction of the water that is in the

    • Re: (Score:3, Interesting)

      by tsadi ( 576706 )

      Just a random thought; a day in Titan lasts almost 16 Earth days. If humans evolved in Titan instead, would that mean that we'd spend the equivalent of 16 Earth days awake also, and maybe almost the same amount sleeping?

      • Re: (Score:3)

        by euyis ( 1521257 )
        The latter part is quite fascinating...

      • Re:Years long... (Score:5, Informative)

        by pspahn ( 1175617 ) on Monday March 21, 2011 @02:33AM (#35556842)

        As far as I'm aware, the evolutionary effects on circadian rhythms on other planetary bodies is a study that has not yet been conducted.

        I guess that means the answer to your question is.... maybe.

        • Re:Years long... (Score:4, Interesting)

          by Progman3K ( 515744 ) on Monday March 21, 2011 @08:42AM (#35558398)

          There was a study where they put a subject in an underground mine (they built him and underground house in there, or lair if you prefer) and only let him have contact through a video link to an operator's booth above.
          The operators would be relieved and assigned shifts in a random way so that the subject could not infer how long each operator was present nor how long their shifts were.
          After a few weeks/months of this, the subject began having 33-hour days and 11-hour nights.
          So the sun really DOES influence human wake/sleep periods. What the 33/11 ratio means is anyone's guess though...

          • There was a study where they put a subject in an underground mine (they built him and underground house in there, or lair if you prefer)

            I know, personally, several participants in such experiments.

            and only let him have contact through a video link to an operator's booth above.

            They were carried out in the 1960s (when I was concentrating on potty training!) in various natural caverns in Northern England. Gaping Ghyll for one ; stump cross caverns for another. The "incarcerated person" was generally (alwa

            • Thanks for fascinating insight, RD.
              I know I saw a documentary about it some years ago, it might have been on The Nature of Things with David Suzuki, I'm not sure...
              Anyhow, interesting study. Thanks for the info!

      • Re: (Score:2)

        by jpapon ( 1877296 )
        One would think that would be the case. Another interesting thought is whether or not they would naturally process everything slower. Their "day" is 16 of our days, but would their consciousness experience it lasting about the same as we experience an earth day? So if we ever met such beings, would they seem to act abnormally slowly?

        • You mean Los verdes?

          (Reference to Pluton B.R.B Nero, a series you probably don't know, since AFAIK it never got English subs. It's Alex de la Iglesia's shot at space comedy. A sort of Spanish Red Dwarf, except Lorna is so much hotter than Kochanski ;) . It was absolutely brilliant, if you can find subs or understand some Spanish, you should definitely take a look at it. Specially if you enjoy Alex's movies, It's as clever as the Oxford Murders, as funny as El dia de la Bestia, and as bizarre as Mutant Actio

          • Well, forgot to explain the actual reference.

            In an Episode, they reach a planet that is 100 times the size of the earth, and it's inhabited by a humanoid species whose individuals seem to be motionless, but they are actually just incredibly slow.

      • I doubt it. People living in the Arctic circle don't sleep for 6 months.

        • Polar night varies from 20 hours at the Arctic Circle to 179 days at the pole, places like Barrow Alaska do polar night for 65 days, but that doesn't mean it's night outside every where, it gets a strange twilight for most of the area.

          Past 84 33' theres no twilight, but there are no permanent human settlements that far north/south, just science stations.

          • It was an offhand comment, I also missed the part about "if humans evolved on Tiatan", so my comparison was kinda irrelevant since humans did not evolve in the polar regions, rather they just moved there when technology allowed them to.
          • The Russian term is "white nights". Which raises a pun on "white knights" which at least one oil company has made use of before they got brought out.
      • Who really knows what we would be doing for sleep considering we'd bath in methane.

    • Years on Titan are the same as years on Saturn. A day on Titan is the same period as an orbit around Saturn. Years are important on Earth, Saturn and Titan because the axial tilt makes the sun move from North to South and back. Additionally the eccentricity in the orbit makes the planet move towards and away from the sun. The rainy season on Titan may actually last for Earth years. But particular period of rain may go for hours, days or weeks.

      • A day on Titan is the same period as an orbit around Saturn.

        Err, Titan and Saturn are in rotational/ orbital resonance?

        When Saturn-Titan-Sun are co-linear then Titan will get eclipses. Which are likely to be meteorologically important. For Titan. The corresponding solar eclipses on Saturn by Titan are unlikely to be significant to Saturn.

        Titan is essentially co-planar with Saturn's rings (gravity assures me of that). Saturn's rings are around 20 degrees inclined to the ecliptic.

        Without having (to hand)

        • A day on Titan is the same period as an orbit around Saturn.

          Err, Titan and Saturn are in rotational/ orbital resonance?

          I think its pretty clear. Ignoring issues of sidereal motion, the sun goes around the sky on Titan in the same time as Titan orbits Saturn.

          • You're right. I'm surprised that I'd never heard that before.

            It's a bit surprising too, because most of the cases of orbital synchronisation that I've heard of are when the orbit is very tight. Or, in the case of Earth-Moon, the synchronisation is thought to have developed very early in the evolution of the system when the Moon was very close to it's Roche limit.

            Interesting.

    • First to answer your question:
      The terms used ARE confusing because the terms "day", "month" and "year" are all relative to what planet you're talking about.

      Saturn's year (1 circuit around the sun) is 29 Earth-years, approximately.

      Saturn is, like earth, tilted about 26 degrees on its axis, so it would have 'seasons' approximately in the same way that earth does - as it goes around in its orbit, the sun would be shining directly on the northern hemisphere and southern hemispheres, alternately, with the solsti

  • All together now... (Score:1)

    by Anonymous Coward

    Raindrops keep falling on my head....AAAAAaaaaaarrrrrrrrrrggggggggghhhhhhhhhhhhhhhhh

    • Re: (Score:1)

      by Anonymous Coward

      A little methane never hurt anyone.

      • A little methane never hurt anyone.

        True... But we're talking a lot of methane, liquid methane at -180 degrees C; enough to carve channels in the landscape and form lakes. It's not just a little methane.

    • ....AAAAAaaaaaarrrrrrrrrrggggggggghhhhhhhhhhhhhhhhh

      I like your version better.

      • Methane on Titan would flash-freeze you, since Titan's temperature is around 93.7 K (179.5 C), so AAAAAaaaaaarrrrrrrrrrggggggggghhhhhhhhhhhhhhhhh is quite apt. Let's not forget that you'd have nothing to breathe, either.

        • Methane on Titan would flash-freeze you, since Titan's temperature is around 93.7 K (179.5 C).

          I think you mean -179.5 C but think of it this way. Titan is about twice as cold as the coldest place on Earth. I once had a job collecting data from remote weather stations in Antarctica. One day a station reported -75C.

          • Re: (Score:1)

            by Anonymous Coward

            It doesn't really make any sense to describe something as "twice as cold", especially when you're using a scale based on an arbitrary zero point.

            It does make sense to say that the coldest place on Earth is twice as warm as Titan, though.

            • Also accepting "half as warm."

              Although GP did not state it, the -75C temperature cited is 198K, which is a little more than twice as warm as Titan. Kelvin has a non-arbitrary zero point. (I am not insinuating that you dispute any of this, just making the GP's point perhaps a little more clear in light of the semantics lesson.)

              • Wikipedia gives 184 K (-89.2 C) as the coldest temperature on Earth and I suppose people would walk around with just very warm clothing on at that temperature. For a while, anyway. So my point (if I have one) is that while 93K sounds cold its actually not beyond possibility that a person could walk around on Titan with a bottle of oxygen and some well insulated clothing. Heated boots would be a good idea. Wear mittens, not gloves.

        • Let's not forget that you'd have nothing to breathe, either.

          Maybe he was dictating?

  • To some extent, i just wanna say that this post "NASA Picks Up Rainstorms On Titan" brings us much more pleasure for our daily life.
  • Unclaimed hydrocarbon rain on Titan?! Europa is a giant ball of water? Jupiter and Saturn have magnetospheric energy strong enough to power as many crafts as we would like (positioned accordingly of course) Not to mention the added bonus of a radiation shield from solar wind and CMEs. Somebody build a station in orbit for local planetary exploration already. Oh, and the ISS is being used as a lab for experimentation, another station is needed for this as the ISS is busy enough as it is. It's not like we ha

    • Re: (Score:1)

      by Anonymous Coward

      We haven't got the technology to do it. Nobody does.

      The gas giants are a long way away, and even with magical future-tech nuclear-electric engines several orders of magnitude more powerful than the ones we can build today, it'd still take over a year to get to them. If you're using something more realistic for a near future launch, like a combination of chemical rockets and solar-electric, you'd be talking about travel times close to a full decade.

      Long travel times like that are a death sentence for astrona

    • Re: (Score:2)

      by elrous0 ( 869638 ) *

      WAY too far away, my friend. Titan could be made of petroleum and gold and it still wouldn't be worth the effort.

    • Jupiter and Saturn have magnetospheric energy strong enough to power as many crafts as we would like (positioned accordingly of course)

      Nope, Saturn's magnetic field is actually less powerful than Earth's, although it is much larger. From Wiki:

      Saturn has an intrinsic magnetic field that has a simple, symmetric shape—a magnetic dipole. Its strength at the equator—0.2 gauss (20 T)—is approximately one twentieth than that of the field around Jupiter and slightly weaker than Earth's magnetic field. As a result Saturn's magnetosphere is much smaller than Jupiter's and extends slightly beyond the orbit of Titan. Most probably,

      • Well, I was certainly talking out my ass about Saturn's magnetic field being used as a source of power =D However, thermionic nuclear power sources have been used for decades. If you could prevent yourself from being buried in sulfur, Io would have tremendous geothermal energy. To be more accurate, the systems of Jupiter and Saturn do indeed have a fair amount of power in different forms that can be tapped into. For example, the gravitational forces induce a lot of heat, especially in the moons close to th
        • The gravitational forces create geothermal energy. Io has been said to be "turning itself inside out" every few hundred years, although I'm not sure how accurate a depiction this is of the activity observed on Io. There certainly have been large volcanic plumes observed by previous probes.

  • no practical reason? (Score:4, Insightful)

    by pablo_max ( 626328 ) on Monday March 21, 2011 @03:52AM (#35557092)

    Why do people always say that there is no practical reason for space exploration? I just don't get it.
    Titan is a wonderful example. A planet with literally 100's of times more hydrocarbons than Earth. That seems like a reasonable excuse to go there and develop mining and extraction techniques.
    You can get never get to the point where space exploitation makes sense unless you start.

    • Re: (Score:2)

      by j_sp_r ( 656354 )

      Shipping tons of hydrocarbons to earth doesn't sound like the best plan to me. It would decrease oxygen levels and increase CO2 if done in big enough numbers.

      • Re:no practical reason? (Score:4, Insightful)

        by MichaelSmith ( 789609 ) on Monday March 21, 2011 @04:06AM (#35557128) Homepage Journal

        GP didn't say they had to go to Earth. Those gasses would go a long way on Mars or Luna.

        (See Imperial Earth by Arthur C Clarke for a good book on the subject)

        • GP didn't say they had to go to Earth. Those gasses would go a long way on Mars or Luna.

          Where there's already no free oxygen to burn them with, so they'd be pretty much useless as fuel.

          • GP didn't say they had to go to Earth. Those gasses would go a long way on Mars or Luna.

            Where there's already no free oxygen to burn them with, so they'd be pretty much useless as fuel.

            Handy as an atmosphere though. Methane is a great greenhouse gas.

          • Re: (Score:2)

            by khallow ( 566160 )
            The Moon has a lot of oxygen. Any mining process which extracts metals from lunar crust will create oxygen as a byproduct.

        • Imperial Earth by Arthur C Clark

          Oh, I've read that book, but I didn't know it was written by him. Although this story did remind me of it immediately.

      • Shipping tons of hydrocarbons to earth would certainly be a waste of time, in the context of using it as a combustible fuel in our atmosphere. Look at it as a resource in other ways. How about a valuable local resource for generating new materials. This is just one compound of many, sitting there, with plenty of energy on hand to use.
        • For one thing, it would be useful as a source of propellant in moving materials in the first place. Locally and back to Earth.

    • Re: (Score:1)

      by Anonymous Coward

      Do you really want to pay fuel prices above 200 million USD per litre?

    • Why do people always say that there is no practical reason for space exploration? I just don't get it.

      Hard to say without finding someone who is actually saying that. Mostly I just hear people saying that there is no practical reason for sending humans to do a robots job.

      Titan is a wonderful example. A planet with literally 100's of times more hydrocarbons than Earth. That seems like a reasonable excuse to go there and develop mining and extraction techniques.

      Well, Titan isn't a planet. Also it isn't possible to carry enough methane (by mass) to make it worthwhile to transport from Titan. It would take more energy to transport to the inner planets then we could gain from the cargo, meaning it's cheaper to manufacture on-site.

    • 2 things:

      1. pure science for the sake of pure science always eventually winds up making incredible discoveries that alter history and result in trillions of dollars of economic activity. that's why worrying about "no practical reason" is silly: it just means the person raising the issue doesn't understand science or history

      2. mining hydrocarbons on titan, and taking them somewhere else: anywhere, even just another moon of saturn, is completely ridiculous. its like flying from LA to Hong Kong to get your lunch time sandwich. you need an oxidizer too

  • Weather (Score:3)

    by kellyb9 ( 954229 ) on Monday March 21, 2011 @11:06AM (#35560402)
    So what you're really telling me is - they can tell me its raining on Titan, but I can't seem to get reliable weather forcasts here.
    • We can't make reliable weather forecasts for Titan either... But at least we have an excuse, we've only observed Titan's weather patterns from the Titan equivalent of mid-December (when Earth-based observations of sufficient resolution began in 2002) to the equivalent of early- to mid-April (where we are now). And even then the data set (even from Cassini) is pretty sporadic. But I do have one reliable way of knowing when there won't be clouds on Titan. Acquire images of it with an observation with the wor
  • It won't be long before it might be worth it to go to Titan to fill up.

Slashdot Top Deals

"Being against torture ought to be sort of a multipartisan thing." -- Karl Lehenbauer, as amended by Jeff Daiell, a Libertarian

Close