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Space Science

A Moment Of Reckoning for Cassini 36

Posted by Hemos from the give-it-one-moment-in-time dept.
No_Weak_Heart writes "The NASA/ESA Cassini-Huygens probe has caught sight of Titan and is now returning images that 'rival anything scientists have seen before - and that includes images from the Hubble telescope.' See more detailed images at the mission homepage."
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A Moment Of Reckoning for Cassini More

A Moment Of Reckoning for Cassini

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  • Too Early!! (Score:3, Insightful)

    by bhima ( 46039 ) <Bhima,Pandava&gmail,com> on Monday May 10, 2004 @06:30AM (#9105173) Journal
    OK, I admit that I too am excited by the prospects of Cassini (OK! I mean the pretty pictures that Cassini will send us).

    But this is a fuzzy dot!Can't we just wait a few months untill it's there.

    • Re:Too Early!! (Score:5, Informative)

      by meringuoid ( 568297 ) on Monday May 10, 2004 @06:53AM (#9105282)
      But this is a fuzzy dot!Can't we just wait a few months untill it's there.

      Then it'll be a fuzzy disc. It's Titan, proud possessor of the solar system's second smoggiest shroud. You're not going to see any detail through that lot.

      • Re:Too Early!! (Score:3, Informative)

        by Anonymous Coward
        In the visible spectrum, probably not, but there may be something to see in the near IR or near UV range. Also, the Huygens probe has a camera on it, so we may get images during the decent. Plus Cassini has the capability to radar map the surface.

  • Oil? Oil! OIL! (Score:5, Funny)

    by rylin ( 688457 ) on Monday May 10, 2004 @07:57AM (#9105705)
    ...which is believed to support oily lakes and seas...

    Americans! Invade!

  • Too close to capture all of Saturn (Score:4, Interesting)

    by Azahar ( 113797 ) on Monday May 10, 2004 @08:05AM (#9105756)
    Now that Cassini is so close that it can't take a photo that includes all of Saturn I think it is a good time to start paying more attention to the photos coming back.

    This is one probe that promises so much that I have decided to enjoy the anticipation and appreciate the photos as they return, slowly and beautifully.

    Saturn is the dream planet after all, all those rings, all that mystery. I can't say that I would like to live in orbit around it though.

  • Suspense (Score:5, Insightful)

    by smari ( 257143 ) <`si.rajye.gulv' `ta' `mps'> on Monday May 10, 2004 @08:06AM (#9105776) Homepage
    I remember when Cassini was launched - I considered it my birthday present from NASA at the time. Now, it's not long to go... suspense is rising.

    Let's hope they find something that gives the general public a run for their money; We need another space race or something to get people out of bed in the mornings.

    When was the last time you saw a teenager staring at the sky in awe?
    • I'd agree, except that people just don't care about space. Back in the cold war the space race captivated people's minds because it was "us against them" - America showing it was better than the USSR (or vice versa, depending on which side you were on). It was something people could take pride in.

      Now?

      The only Big Enemy is "terrorism", and there's no single country you can hold up for that, no place likely to take part in dick-measuring games. Yeah, there's China, and that might help a bit, but essentially
    • When was the last time you saw a teenager staring at the sky in awe?

      At a UFO-watching party, people staring at Venus...

      ^_^

      • At a UFO-watching party, people staring at Venus...

        I dunno, sounds like a better time than everyone sitting around staring at Uranus.

  • I know this is pretty off-topic, but given that we've never had a good look at the surface of some of these moons, is there any reason that they couldn't be inhabited be sentient creatures at the social equivalent of medieval Europe? Put another way, if there were a somewhat advanced society on Titan 1000 years ago, but one that hadn't ventured into space yet, how would they have been able to know that there was life on Earth at that time? We weren't broadcasting radio signals at that time, and hadn't made any large-scale modifications to the planet that would be visible from space (ie giant agricultural regions, cities at night).

    I'm not a LGM kook - I have no expectation at all that we'd find any sort of life there. Still, is there any particular reason why we seem to be so sure of that?

    • Well, its surface temperature is 95 Kelvins for starters(almost 300F bleow zero or ~20C above the boiling point of liquid nitrogen) there can be no liquid water on the surface. Also I don't think it is believed to have the great geothermal energy like the moons of Jupiter do because of tidal effects, so no energy there either. Finally, the sunlight it recieves is ~100 times weaker than what we get here on earth, with the amount that can actually get through the atmosphere and down to the surface much less
      • But it does have a thick atmosphere, which would seem to mean that it has at least enough energy to keep a large amount of matter in a gaseous state. Also, that hypothesized hydrocarbon sea should hold quite a bit of chemical energy, shouldn't it?
        • Actually the opposite is true - the colder a planet is, the more atmosphere it can hold on to. This is because the thermal velocity, that is the average speed of the gas molecules, depends on the temperature and increases on hotter planets or moons. If it's above the escape velocity, bye-bye atmosphere. Incidentally this is why the Earth has no hydrogen or helium in its atmosphere, because those lighter gases need less heat to reach high thermal velocities, and they just go zipping off into space.

          Some chemist correct me here, but I don't think there's any potential energy in just the hydrocarbons. You need oxygen to burn them in as well, which Titan doesn't have. I can't think of a way to extract energy from them alone.

        • Just Some Guy [slashdot.org] wrote:


          But it does have a thick atmosphere, which would seem to mean that it has at least enough energy to keep a large amount of matter in a gaseous state. Also, that hypothesized hydrocarbon sea should hold quite a bit of chemical energy, shouldn't it?

          No, just the oposite. If you want to have a thick atmosphere on a planet, you want to have very little energy at the surface. The smaller the planet, the lower ambient surface temperature (hence energy at the surface) required to sustain

          • Thanks for the explanation; that's definitely why I asked here. One final question: is there any non-remote possibility that Titan could have enough radioactive material to generate significant quantities of heat? If so, would we be able to detect that from here? BTW, can y'all tell that I majored in Comp. Sci. and not Astronomy? :) I don't know nearly as much about these things as I'd like.
            • We probably could detect an abnormal surface temperature on Titan. Remote sensing in the infrared and microwave bands is a pretty mature technology (such techniques have been used for decades on weather satalites), which are just the methods you would want to use to determine the surface temperature on a celestial body.

              I'm no planetary geologist, just an interested amature, but my understanding is that most of the minor satelites of the outer planets are predominantly made of light elements: ice and rock w

              • On the subject of biological wheels, I was going point out the Golden Wheel spider of the Mojave desert. Its legs are pretty much all the same length, and I saw a documentary once that showed the thing cartwheeling right down a dune to the bottom.

                Oddly, though, I did a quick search for it which turned up only a few informational tidbits, and no pictures of the spider in motion. Makes me wonder if this thing really exists. I'm certainly not aware of any other examples of wheels in nature, so you'd think the
                • Verteiron [slashdot.org] wrote:


                  On the subject of biological wheels, I was going point out the Golden Wheel spider of the Mojave desert. Its legs are pretty much all the same length, and I saw a documentary once that showed the thing cartwheeling right down a dune to the bottom.

                  A wheel is not a wheel without an axel. If you just count things that tumble head or heels (or do cartwheels, backflips, etc.) then I can think of any number of examples: pillbugs and tumbleweeds spring to mind.

                  There is one example of a rotat

    • Re:Little Green Men in our neighborhood (Score:5, Informative)

      by frankie ( 91710 ) on Monday May 10, 2004 @12:17PM (#9108246) Journal
      any particular reason why we seem to be so sure of that?

      Spectrometry. We've looked at all of the local objects fairly carefully and haven't seen signs of chemicals related to organic life as we know it [astrobio.net]. For example, Earth's atmosphere is full of highly reactive oxygen (aka fire, rust, krebs cycle, etc) and should not be abundant unless something is constantly producing it.

      If memory serves, the atmosphere of Titan is not so different from that of the Earth a few billion years ago, before life began. So if there's life there, either it's inconceivably unlike us or it hasn't gone much up the ladder.

    • Re:Little Green Men in our neighborhood (Score:5, Interesting)

      by tigersha ( 151319 ) on Monday May 10, 2004 @12:20PM (#9108274) Homepage
      Arthur C Clarke once wrote a nice little piece called "Apes or Angels" (Ok, the title may be wrong). Basically his point is that the universe is 10 billion years old, we have been here for 5 million years. That is a tiny drop in the lifetime of the universe. So if we hit alien species the chances that life on the planet would be exactly in the same range as our evolutionary scale is pretty remote because 1 million years back or forth yould not be much in the tiemscale that the universe operates in.

      There is a much better chance that they would be either millions of years behind us (bacterial or so) or millions of years ahead. They would more probably or not be either Apes or Angels.

      Btw, this is one argument to use to say why we have not found any aliens yet: No ways to find bacteria on a long range and perhaps if they are millions of years ahead they would be so strange to us that we would not now what to look for. All advanced technology looks like magic.

      So the chances of finding a civilization close to here which is about 1000 year ahead or behind us is pretty much zilch purely from a statistical point of view.

      Of course, the argument does not quite hold in the Solar System since all the bodies in it are about the same age per definition (they were formed at the same time). But then you could still be talking a million years give or take. No human-like organisms then.

      • Re:Little Green Men in our neighborhood (Score:1, Interesting)

        by Anonymous Coward
        "Of course, the argument does not quite hold in the Solar System since all the bodies in it are about the same age"

        Since the conditions for humanoid life (just the right gravity, surface temperature that allows liquid water) exist nowhere else in the solar system, any intelligence we find would most likely be radically different from ours, even if life did arise on another body at roughly the same time as earth. But then, the dinosaurs were a widely varied species, wiped out suddenly; who's to say intellig
      • Arthur C Clarke once wrote a nice little piece called "Apes or Angels" (Ok, the title may be wrong). Basically his point is that the universe is 10 billion years old, we have been here for 5 million years. That is a tiny drop in the lifetime of the universe. So if we hit alien species the chances that life on the planet would be exactly in the same range as our evolutionary scale is pretty remote because 1 million years back or forth yould not be much in the tiemscale that the universe operates in.
        Although
    • Basically, the radiation and lack of sunlight (Titan is very cold) pretty much rule out the possibility of life. Spectra from Earth-based telescopes show no signs of oxygen in the atmosphere - this isn't required for basic life but I think the consensus is that anything advanced enough to have developed intelligence needs a lot of energy and that has to come from respiration with oxygen. People talk about other forms of life based on silicon etc, but I'm pretty sure that no serious scientists think that's
    • Once again, thanks to everyone who responded. Everything I'd previously learned about xenobiology came from sci-fi novels, so it's nice to hear a few scientific thoughts on the subject. I appreciate explanations, and am especially grateful for the complete lack of flaming. Nice job, everyone!

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