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A Moment Of Reckoning for Cassini

Posted by Hemos on 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."

36 comments

  1. Too Early!! by bhima · · Score: 2, Insightful
    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.

    --
    Nothing in the world is more dangerous than sincere ignorance and conscientious stupidity.
    1. Re:Too Early!! by meringuoid · · Score: 4, Informative
      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.

      --
      Real Daleks don't climb stairs - they level the building.
    2. Re:Too Early!! by Anonymous Coward · · Score: 3, Informative

      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.

  2. Nice image of saturn by Anonymous Coward · · Score: 0

    The true-color image of Saturn is incredible. Everything is so crisp and it is taken from the side (relative to the sun), so you get a god picture of Saturn's shadow playing across the rings. I hadn't realized how all of the regions on Saturn would look so perfectly parallel. Very nice.

  3. Oil? Oil! OIL! by rylin · · Score: 5, Funny

    ...which is believed to support oily lakes and seas...

    Americans! Invade!

    1. Re:Oil? Oil! OIL! by Anonymous Coward · · Score: 0

      Nah they don't have any money to do that anymore...

      BP however might see it as an investment oppertunity what's more they might even be able to exploit it.

  4. Too close to capture all of Saturn by Azahar · · Score: 4, Interesting

    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.

    --
    Cuiusvis hominis est errare; nullius nisi insipientis in errore perseverare.
    1. Re:Too close to capture all of Saturn by Profane+MuthaFucka · · Score: 2, Insightful

      It can take a photo of all of Saturn in super high resolution. One piece at a time, digitally stitched together. We'll get one of those, don't worry.

      --
      Fascism trolls keeping me up every night. When I starts a preachin', he HITS ME WITH HIS REICH!
  5. Suspense by smari · · Score: 5, Insightful

    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?

    1. Re:Suspense by AllUsernamesAreGone · · Score: 1

      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 now space exploration has to be done for the science and maybe, one day, for the profits. Science means nothing to the vast majority of people, they just aren't interested, aren't even curious about the universe. This annoys me more than you can believe, but it is true: the general population don't care about space, they don't care about a ball of rock millions of miles away, they don't see why we should be trying to get our backsides off this damp lump of rock.

      We can send probes up until we are blue in the face, we can probably send men up too, and people will be asking why we are spending money on it rather than throwing it at <insert some short-term and impossible to truely solve problem here>

      Bah.

    2. Re:Suspense by WormholeFiend · · Score: 1

      When was the last time you saw a teenager staring at the sky in awe?

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

      ^_^

    3. Re:Suspense by tzanger · · Score: 1

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

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

  6. The images are blurred by time exposure. by Anonymous Coward · · Score: 0

    They aren't parallel. The images are blurred by time exposure.

  7. Little Green Men in our neighborhood by Just+Some+Guy · · Score: 3, Interesting
    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?

    --
    Dewey, what part of this looks like authorities should be involved?
    1. Re:Little Green Men in our neighborhood by deglr6328 · · Score: 2, Informative

      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 than even this tiny amount. Life needs energy, lots of it, and there is precious little on Titan.

      --
      - "Hear that?! The percolations are imminent! Cease your ingress!"
    2. Re:Little Green Men in our neighborhood by frankie · · Score: 4, Informative
      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. 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.

    3. Re:Little Green Men in our neighborhood by tigersha · · Score: 4, Interesting

      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.

      --
      The dangers of excessive individualism are nothing compared to the oppressiveness of excessive collectivism
    4. Re:Little Green Men in our neighborhood by Just+Some+Guy · · Score: 1

      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?

      --
      Dewey, what part of this looks like authorities should be involved?
    5. Re:Little Green Men in our neighborhood by Just+Some+Guy · · Score: 1

      OK, that makes sense. In other words, we haven't found anything on Titan (or other bodies) that couldn't be explained by the natural local conditions, right?

      --
      Dewey, what part of this looks like authorities should be involved?
    6. Re:Little Green Men in our neighborhood by another_henry · · Score: 1

      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 a possibility. ET life may not be 'as we know it' but we should know it when we see it, and we aren't seeing it on Titan.

      --
      "Studies have shown that people who eat peanuts live longer than those who do not eat."
    7. Re:Little Green Men in our neighborhood by another_henry · · Score: 4, Informative
      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.

      --
      "Studies have shown that people who eat peanuts live longer than those who do not eat."
    8. Re:Little Green Men in our neighborhood by frankie · · Score: 1
      Exactly. To the best of our understanding, all we're seeing on Titan is rocks, ice, and some haze.

      Of course, that's just the rocky objects. It's hard to make an educated guess about life in a gas giant.

    9. Re:Little Green Men in our neighborhood by Anonymous Coward · · Score: 1, Interesting

      "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 intelligent, saurian life couldn't have evolved here 60 million years ago under better circumstances? But for that accident, perhaps the current masters of the planet might be wearing monkey skin shoes ;)

      I would criticize you on one small point, however: for the first few billion years of the universe's existence, life based on chemical reactions may not even have been possible because of high residual radiation (destroying complex, fragile molecules) and a lack of heavier elements. So, unless there's a hyper-intelligent form of hydrogen, the theoretical age of any life form is much shorter than the age of the universe; I'm not cosmologist enough to make a guess on the actual figure. But I still agree that another species being within 1 million years evolutionary time to us is fantastically improbable, as my dinosaur example illustrates. One little rock can make a big difference.

      That never stopped anyone inventing anal-probe stories under hypnosis, though.

    10. Re:Little Green Men in our neighborhood by dutky · · Score: 2, Insightful
      Just Some Guy 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 an atmosphere. If the ambient surface temperature is too high the average velocity of a molecule in the atmostphere exceeds the planet's escape velocity and all the atmostpheric gasses boil off into space.

      Titan is a very small planet (larger than Earth's moon but smaller than the planet Mars), so the gravitational pull of Titan is somewhere between 1/3 and 1/6 that of the earth. Similarly, the escape velocity from Titan is much lower than the escape velocity for Earth, somewhere between the escape velocities of the moon and mars.

      The only reason that Titan has any atmosphere at all is because it is so far from the sun that it is very cold. Primordial gasses that long since boiled off from the Earth's atmostphere (or Mars') are still trapped by Titan's weak gravity.

      The point the other posters were trying to make is that decades worth of spectrographic studies of Titan's atmosphere have shown the atmosphere to be chemically neutral. It is thought that the presence of life would result in a chemically active atmosphere (one that could support oxidation, which the life-forms would use as part of their metabolic processes, just as we extract oxygen from the air in order to metabolize sugars, producing carbon-dioxide). We are not saying that the atmosphere must contain oxygen, or that all life must be based on a carbon/oxygen metabolism, only that the atmosphere must present some way for life to extract energy, or the by-products of some kind of metabolism must be evident in the atmosphere.

      Since Titan's atmosphere is chemically neutral (mostly methane) there is no latent energy that could power living organisms, hence no organisms (at least, none that are still alive: they would have suffocated or frozen). If you say "But what if they are able to breath methane?" then you need to account for what they would do with the methane. Either you need to burn it (for which you need oxygen) or you need to get the energy from somewhere else (sunlight, for example). There isn't any oxygen in Titan's atmosphere, so burning isn't an option, and Titan is too far from the sun for sunlight to be of much use. That exhausts most of the possibilities.

      None of this should be taken as proof that there is no life on Titan, or that life on Titan is impossible: it's just not very likely, given what we expect life to be like. If there were life on Titan, it would have to be very different from what we generally expect: it would have to use very small amounts of energy, and it might have to extract that energy from some very novel sources. We are talking something that is, essentially, indistinguishable from pebbles, rocks and sand. Even then, this life-form would need to have little or no interaction with Titan's atmosphere, otherwise we would see some effect from it's respiration in the atmosphereic chemistry.

    11. Re:Little Green Men in our neighborhood by Just+Some+Guy · · Score: 1

      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.

      --
      Dewey, what part of this looks like authorities should be involved?
    12. Re:Little Green Men in our neighborhood by dutky · · Score: 1
      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 with a few volatiles thrown in for good measure. Most of the long-lived radioactive stuff is heavier than iron. I think it's not too likely that the minor satelites of the outer planets have a significant quantity of radioactive elements.

      Most of the talk of radiation on the jovian or saturnian moons comes from solar wind, cosmic rays and the Jupiter and Saturns equivalent of the Van-Allen belts, none of which is effectively blocked by the moons thin atmospheres and almost complete lack of magnetic fields. That kind of radiation doesn't create lots of heat but it sure clobbers biological chemistry. In any case, if there were enough radioactive elements on Titan to raise the temperature a significant amount, any possible life-forms would have bigger problems than suffocation.

      Again, I don't want to make it sound like life on Titan is impossible, only that it is unlikely given our understanding and definition of 'life'. When I said that any conceivable life-form that could arise on Titan might have to get energy from novel sources, I was thinking specifically of radioactive sources. It's not impossible, but I'm not aware of any similar mechanism that has actually been observed in nature. This is not an airtight argument: wheels work quite nicely, but we have no examples of organisms that evolved wheels instead of legs on Earth.

      There are stranger things in Heaven and Earth than are dreamt of in our philosopies.

  8. Crack smoking moderators: by Anonymous Coward · · Score: 0

    How exactly is a semi-obscure reference to Starblazers, the most badass show ever made, and their stop at Jupiter a troll?

    If you don't understand, just move along. Not everything you don't unknown to you is threatening.

  9. Thanks again! by Just+Some+Guy · · Score: 1

    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!

    --
    Dewey, what part of this looks like authorities should be involved?
  10. Off-topic: wheels in nature by Verteiron · · Score: 1

    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 these little guys would get more attention.

    --
    End of lesson. You may press the button.
    1. Re:Off-topic: wheels in nature by dutky · · Score: 1
      Verteiron 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 rotating shaft in nature, and it's about as ancient an example as you can find: the flagella of certain bacteria is actually a rotating screw, not a whip-like structure. I'm not aware of any other examples of rotating shafts in biological systems, however.

      Still, the point is that evolution is not perfect: not all parts of the solution space get well evaluated by the selection function. Just because we know that something is a workable solution to a problem (as wheels are to locomotion) doesn't mean that we will find an implementation in nature. We haven't, yet, found an example of organisms that extract energy from nuclear reactions, for instance.

  11. Cosmic reboot event? by Kap'n+Koflach · · Score: 2, Interesting

    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 the general point is valid, it is only really true if the conditions that allow intelligent life have remained the same for the entire history of the Universe. E.g. older stars were formed when there were fewer of the heavy elements (carbon, silicon, take your pick) required to support life, so they probably aren't harbouring ancient transcendant civilisations.

    To take another example from Science Fiction ('Space' by Stephen Baxter), what if something happens every few billion years that wipes out all life across an entire region of a galaxy - such as a very energetic Supernova or gamma ray burst. This might simultaneously destroy life in many nearby star-systems, starting them again from scratch. Although finding a local civ that is exactly the same age/level as your own would still be very unlikely, this sort of reboot would level the playing field a bit.