Looking up to Saturn

By Phil Plait | October 30, 2012 7:00 am

Just in case you’ve forgotten how brain-destroyingly big Saturn is:

[Click to encronosenate.]

This shot of the ringed wonder was taken by the Cassini spacecraft when it was well over 2 million kilometers from the planet. The spacecraft was south of the rings, looking "up" toward the north. The Sun is shining down on the rings from this perspective, so they look darker than you might expect, and the use of a near-infrared filter accentuates storms in the southern hemisphere cloudtops.

So why does this picture grind my mind to dust? Look at the the very top, near the center. Can you see that dot of light? You might need to click the picture to get the hi-res version to see it better; that’s how small it is.

Except it isn’t. That dot of light is Mimas, a moon of Saturn, and it’s 400 km – 250 miles – across! That’s roughly the size of the state of Missouri, and compared to Saturn it’s reduced to a mere pixel of light. And even then, Saturn’s rings are still too big to fit in this picture!

The scale of the solar system crushes me. And yet there we are, poking around and sticking our noses into it. We humans are pretty awesome.

Image credit: NASA/JPL-Caltech/Space Science Institute

Related Posts:

The moon that almost wasn’t
OMG! They killed Mimas!
A trillion and five moons
An unusual view of the Death Star moon

CATEGORIZED UNDER: Astronomy, Pretty pictures
MORE ABOUT: Cassini, Mimas, Saturn

Comments (16)

  1. Chris

    I really need to clean my monitor. Most of my dust specks are bigger than Mimas!

  2. Superluminous photo there. I love it. Cheers. :-)

    Mimas looks minute indeed – a tiny moon indeed looking there paradoxically like a star.

    Size is, of course, very much relative. Saturn is huge compared with Earth – far huger still compared with Mimas – but not so much compared to Jupiter at least mass ~wise and in all senses compared to our Daytime Star! ūüėČ

    Even Mimas itself would loom large compared to some moons like Pluto’s Nyx and Hydra, Phobos or even some of the much smaller Saturnean (natural) satellites.

    To see how our butterscotch planet compares with a whole range of other heavenly bodies I suggest folks check out the youtube clip linked to my name (Planets, Stars, Nebulae, Galaxies – Universe Size Comparison 2009 by nixxxon18 on youtube) which has Saturn and much, much more. :-)

  3. Plus when it comes to cosmic size comparisons this clip :


    too is another huge favourite of mine.

    Putting “Death Star” Mimas in perspective as one of our solar systems smallest worlds is this pi-chart :


    from here :


    via the usual fount of all knowledge.

    Hope these are interesting / enjoyable / helpful here. :-)

  4. How do we know Cassini is looking “up”? Since there’s no up or down in space, it could just as well be looking down, and the picture is upside-down. (I know I’m stating the obvious, but I couldn’t resist it!)

  5. Jeffrey

    Is it correct to assume that at that distance the Earth would only be 32 pixels across?

  6. Nigel Depledge

    Sorry, can’t resist . . .

    The BA said:

    That dot of light is Mimas, a moon of Saturn, . . .

    That’s no moon!

    Oh, wait. Yes it is.

  7. lepton

    Since Mimas is above the ring in the picture, it is actually a little bit closer to Cassini than Saturn is. Indeed the size comparison is amazing.

    This makes me appreciate our Moon even more, our earth has the proportionally biggest natural satellite of all planets.

  8. sevenof9fl

    Proportionally, my understanding of the field Astronomy is about the size of Mimas as compared to Saturn. But that doesn’t mean reading about it doesn’t knock my socks off and I strive to understand the enormity of it all, from our small, hum-drum solar system to the most far-flung galaxies we can detect. As a species, we must always strive to learn more; but I am astonished and delighted with each new piece of information.

  9. @Jeffrey
    If you’re asking how big Earth would be in this camera at the same distance as Mimas is here, I believe that the answer is “about 96 pixels.” I’m just scribbling out an answer, though, so don’t take that as writ. It tracks, though: Saturn’s diameter here is about 1000 pixels and it’s about 10 times larger in linear scale than Earth is.

  10. Mark P

    Well, there is a definition of “up” relative to rotating objects. It’s a convention, but it’s there.

  11. Grand Lunar

    First saw this via a link from Carolyn Porco’s Twitter page.

    VERY awesome to see.

  12. Chet Twarog

    Agreed it is a fantastic view from Cassini but I would just gladly eliminate all the extraneous “ups and downs” anywhere: “The spacecraft was south of the rings looking north. The Sun is shining on the rings from this perspective.”
    We don’t live on a flat wall map…it’s worth it, for me, to keep trying to point out poor semantics. Think spherically!

  13. Phil raises an interesting quandary: Is it possible to be both awed and awesome? Simultaneously the “awe-er” and “awe-ee”? :)

  14. Il Dio piccin’ della piccina terra
    Ognor traligna ed erra,
    E, a par di grillo
    Saltellante, a caso
    Spinge fra gli astri il naso,
    Poi con tenace fatuità superba
    Fa il suo trillo nell’erba.

  15. Matt B.

    @4 Elwood Herring said – ‘How do we know Cassini is looking ‚Äúup‚ÄĚ? Since there‚Äôs no up or down in space, it could just as well be looking down, and the picture is upside-down.’

    Well, since up and down are really defined in terms of gravity, Cassini was looking down, i.e. toward an object at lower gravitational potential.

  16. @Chet Twarog
    Speaking as someone who was partially responsible for the wording of that: Sure, the wording could be cold and precise, but that’s boring and it fails to convey the majesty and the joy of space exploration. So I stand by “up”.


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