Saturn’s moons

October 27, 2011 • 12:53 pm

Alert reader Diane G. sent me this amazing photo (from Astronomy picture of the day) of four of Saturn’s moons and part of its rings (be sure to click to enlarge):

Image Credit:Cassini Imaging Team, ISS, JPL, ESA, NASA

The explanation:

A fourth moon is visible on the above image if you look hard enough. First — and farthest in the background — is Titan, the largest moon of Saturn and one of the larger moons in the Solar System. The dark feature across the top of this perpetually cloudy world is the north polar hood. The next most obvious moon is bright Dione, visible in the foreground, complete with craters and long ice cliffs. Jutting in from the left are several of Saturn’s expansive rings, including Saturn’s A ring featuring the dark Encke Gap. On the far right, just outside the rings, is Pandora, a moon only 80-kilometers across that helps shepherd Saturn’s F ring. The fourth moon? If you look closely in the Encke Gap you’ll find a speck that is actually Pan. Although one of Saturn’s smallest moons at 35-kilometers across, Pan is massive enough to help keep the Encke gap relatively free of ring particles.

More information on this photo is here.

And, as Diane wrote, “Pandora does look like a potato”.  Pandora is the bright speck just to the right of the ring, and its mean radius is only about 41 km:

30 thoughts on “Saturn’s moons

      1. Does that support or refute “lucky to be alive” … ? I have/am neither of those, and now I feel luckier. doctors save lives with amputations, and I have met amputees who feel lucky to be alive …

      2. Is the fact that the dead child is an orphan supposed to make the image more poignant or potent? The universe does not care about us Bobo. I take it that either you care so much that the pain of existence eclipses what others see as wonderful or beautiful or amazing, or you are angry at the world, which in a godless universe is bizarre to me -?

        1. Arguably, the uncaring universe is more depressing than the god-works-in-mysterious-ways one, in which at least one assumes (so I hear) that there will be some resolution in the hereafter.

      1. According to 16th-17th century Catholic scholar Leo Allatius’s De Praeputio Domini Nostri Jesu Christi Diatriba, the Holy Prepuce ascended into Heaven at the same time as Jesus himself to become the rings of Saturn (which had been recently observed).

  1. Beats the hell out of a burning bush or the zombie son of an invisible sky daddy any day.

    We are living in a privileged time, just sitting at my computer as a non-scientist I can experience the universe like no human has ever been able to, real time video from the surface of Mars, the moons of Jupiter, the ring system of Saturn all the way to the birth of the universe and in the other direction down to the sub-atomic particle.

    1. I couldn’t agree more. It’s so ironic that these days, despite the fantastic web presence of the space program, I’d say a far smaller percentage of the population is aware of what’s going on with it than were back in the days of only newspapers and 3 TV networks. Or care.

      1. So were the newspapers and 3 networks covering science because the public was interested, or were people reading about and watching science coverage because that’s what was available? Did the media only recently discover the lucrative rewards of appealing to the LCD?

        1. Those are excellent questions, probably each worthy of some sort of Liberal Arts dissertation. Thus way out of my league.

          I’d postulate that the Cold War played a large part. The Soviets launched Sputnik, sending the US into a tizzy. Human spaceflight was brand new, and each launch fraught with unknowns; now it seems ho-hum to most. The “moral” constraints on broadcasting, for all their idiocy, did tend to encourage the coverage of such national-interest items (since no time could be spent on whomever’s mistresses). (Bear in mind that at the same time the free press brought unspun footage of the Viet Nam quagmire to our dinner hours nightly. The Pentagon exerts far more control, now.)

          Broadcast news was not quite at the “if it bleeds, it leads” stage, and the networks (and newspapers) seemed to take their responsibility as the only organs of information dissemination seriously. (Except, of course, for info relative to personal peccadillos and the like.)

          As late as the 60’s there was still a sense of national unity related to coming through the Great Depression and then ‘triumphing’ (according to American legend, anyway) in WWII, and a sense of optimism related to the resurgent economy and middle-class comfort that allowed people to think beyond their own struggles for existence.

          Gawd, that sounds like so much fogey bullshit. Suffice it to say, it was a different point in American cultural evolution. Yet still so very recent, historically speaking.

          I could not live without the Internet, but do worry about us spending too much time at self-affirming sites and becoming thus more and more Balkanized. Social life, for better or for worse, is about compromise.

          (…says an unabashed recluse…)

  2. That’s amazing, nebulous, numinous, trancedence inducing, meditative, oneness-with-the-cosmos !

    We will see no Thor passing by, some will still see angel’s wings or mother-mary …

    Truly, this is a special times to live, in the next decades, pictures like this will have less awe (if our robots already trotting on their surfaces).

  3. I wish NASA had put more money into Cassini / Hubble type robot missions and less money into manned missions.

    1. Oh, I think a lot of NASA wishes so as well! Unfortunately their funding depends as much on what the public desires as on what the science sees as most effective, cost- or otherwise.

  4. QUESTION: What distinguishes “Pan” from all of the other rocks in Saturn’s ring? Is it just a certain size threshold? If so, what is the threshold? Or is it just a case similar to Pluto: opinions differ as to what is a moon/planet?

    1. I suspect opinions differ. Pluto’s “demotion” riled some, but OTOH it elevated Ceres (the largest asteroid between Mars & Jupiter) to dwarf planet status.

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