Side view of the Death Star moon

By Phil Plait | April 13, 2011 9:36 am

Saturn’s icy satellite Mimas is the Rick Astley of moons. It got one huge hit* and that’s all it’s been known for ever since.

But the Cassini Saturn probe sometimes sees things a little differently, and recently provided us with a sideways view of Mimas. Literally.

[Click to rickrollenate.]

On January 31, 2011, Cassini snapped this picture of the moon with the planet’s rings in the background. I really like this shot, since we see Mimas’s giant impact crater from the side. I don’t think I’ve ever seen it quite this way before.

A long time ago, Mimas got hit pretty hard with something pretty big. The apocalyptic impact carved a crater 130 km (80 miles) across in the moon, which we now call Herschel. In most pictures we see it from an angle and Mimas winds up looking an awful lot like the Death Star.

But in the big picture above the crater was almost edge-on, and you can see how seriously it messed up the moon: a pretty hefty portion of the edge of Mimas looks flat where the rim of the crater distorts the horizon. An impact this size anywhere on Earth would be, well, bad. Very very very bad. And it’s not like Mimas hasn’t suffered enough, as you can see it’s been hit thousands of times; the surface is saturated with craters.

But that’s the way it is in the solar system. A lot of debris is floating out there, and over billions of years physics cannot be denied. After all… you know the rules and so do I. If you’re a moon, those small objects are gonna run around and hurt you.


* That link is safe. Seriously. I promise. Go ahead, click it. I dare you.


Related posts:

- Wocka wocka wocka Mimas wocka wocka
- The moon that almost wasn’t
- The raw face of the Death Star moon
- Saturn’s million moons cast shadows

CATEGORIZED UNDER: Astronomy, Pretty pictures

Comments (43)

  1. Adam

    What blows my mind is that there doesn’t seem to be much deformation opposite the crater site. Often times you get mountain ranges opposite large impact sites. Did the surface heat enough that it smoothed out?

  2. AliCali

    How many comments before someone writes, “That’s no moon…”?

  3. sjgadsby

    Thank you for another interesting and educational blog post and for bringing more stunning cosmic imagery to the world’s attention. I appreciate it.

    I’m amused by the following though:

    “The apocalyptic impact carved a crater 130 km (80 miles) across in the moon, which we now call Herschel.”

    That sentence states that we’ve renamed the moon itself “Herschel”.

    Not that there’s anything wrong with that, mind you. Herschel is a fine name for a moon.

  4. David

    You should have had the [Click to rickrollenate.] actually Rick-Roll people.

  5. Charles

    @alicali Just two.

  6. Wayne on the Plains

    Two, apparently.

    And yes, that’s what I always think when I see Mimas. That, and about the fish I once had named Mimas. :-) (If you must know, I got the fish the same month as the Cassini Orbit Insertion. Seemed fitting at the time.)

  7. AliCali, you just did. :D 2 it seems.

  8. Messier Tidy Upper

    @ 2. AliCali : Er .. two – or five if you’re just counting this one and not your ref. ;-)

    That’s no moon .. oh wait it is a moon – of Saturn’s no less! ;-)

    Great image from a different memorably Mimetic angle.
    Thankyou BA and Cassini team. :-)

  9. Messier Tidy Upper

    @3. Wayne on the Plains : I have a cat – or rather she has me – named Zosma after the proper name of the star Delta Leonis.

    http://stars.astro.illinois.edu/sow/zosma.html

    So I’m not saying anything. ;-)

  10. flash

    That’s no moon…

    (@AliCali: I win :p)

  11. rick astley

    ‘never gonna give you up’ and ‘together forever’ both number one in the us. That’s two songs.

  12. Kinda has the same profile as South Park’s ill-fated Kenny…

  13. bigjohn756

    It’s amazing to me that there’s anything left after getting hit like that. Seems like an impact of that magnitude would reduce the thing to ring dust.

  14. bigjohn756

    I have golf balls that look like that after I hit them a few times.

  15. Jeff

    Very very very bad.

    Matter of opinion, I myself think if humans continue at this rate, they’ll wreck the environment all by themselves.

    referring Rick Astley, watch it , you are chronologically dating yourself!

  16. It kind of loooks like an eyeball from that angle.

  17. HvP

    A long time ago, in a galaxy far, far away, Mimas got hit pretty hard with something pretty big.

    ^ This is what went through my head reading this ^

  18. @ 17. Jeff Says:
    “referring Rick Astley, watch it , you are chronologically dating yourself!”

    If you really *have* to refer to Rick Astley without dating yourself, click my name.

    Btw, Mimas’ scar is bad ass! I’m sure it would agree that the impact was worth it.

  19. mike burkhart

    “Since you are relucted to give us the location of the rebel base we will test this station destructive power on your home planet of Alderan” By the way George Lucas had denied that he got the look of the Death Star from Mimas (In fact I think when Star Wars came out there where no photos of Mimas yet Star Wars was released in 1977, the photos where takeing in 1980 or am I mistaken ?) Off Topic: If you looking for a good guide to Extraterrestrials the find a copy of : Barlowe’s Guide to Extraterrestrials. you will get all the info on the great sci-fi Aliens found in books including `info on there : physical characteristics, habitat,culture and reproduction and full color illstrations plus a size comparsion . A must read for all sci-fi lovers.

  20. Magrathea

    Always amazes Me how the people manning those missions can squeeze out the most of every possible orbit, that angle shot required some really funky timing, I don’t know how many hours or countless reiterations of simulations they’ve done, but they really do a wonderful job.

  21. amphiox

    That’s no moon…

    OK, this is what we absolutely must, MUST, do now.

    We have to, one day (hopefully not too long from now), go there, and turn it into a space station.

    And install a big research laser installed at the center of the crater.

  22. Pulsar

    The Rick Astley of moons? More like the Vanilla Ice of moons… it’s made of ice ice baby!

  23. Egad

    I agree with Adam @1. It’s hard to see any effect of the giant impact at the antipodes or anywhere else on the moon. No chaotic terrain, no crater chains, no rays, no nuthin’. Presumably the giant crater was created early in Mimas’ history and subsequent cratering and other resurfacing processes have wiped out such secondary signs.

  24. Other Paul

    J Major – Kenny. Decapitated from behind. No question. First thing I thought. http://twitpic.com/4khybw

  25. Keith Bowden

    That’s no space station…
    (Someone had to say it.)

    Phil, for referencing Rick Astley I take back every nice thing I said about you on Goodreads.

  26. Egad

    > No chaotic terrain, no crater chains, no rays, no nuthin’.

    Well, looking at the side view again and engaging my pareidolia and really-want-to-see-it engines, I guess I could imagine a couple of groves and a crater chain leading from the big crater antipodesward. Hopefully the planetologists will be on the case and figure it out.

  27. Scott

    That’s no moon….Oh wait, it is. Carry on.

  28. Nigel Depledge

    Amphiox (24) said:

    We have to, one day (hopefully not too long from now), go there, and turn it into a space station.

    And install a big research laser installed at the center of the crater.

    Yes!

    And use the laser to ignite nuclear fusion in Saturn . . . or was that in a film I saw once?

  29. i should read the titles before commenting

  30. Messier Tidy Upper

    @3. sjgadsby Says:

    Thank you for another interesting and educational blog post and for bringing more stunning cosmic imagery to the world’s attention. I appreciate it.

    Well said & seconded by me. :-)

    “The apocalyptic impact carved a crater 130 km (80 miles) across in the moon, which we now call Herschel.”That sentence states that we’ve renamed the moon itself “Herschel”. Not that there’s anything wrong with that, mind you. Herschel is a fine name for a moon.

    It as an alternative to – & would have been better than – Uranus for that planet which Wilhelm Herschel discovered 13th March 1781 – 230 years ago this year. :-)

    @ 11. flash: That’s no moon… (@AliCali: I win :p)

    No, you don’t – *I* beat you to it! See comment # 8. :P

    Ps. : + P without the plus sign = the :P emoticon here if that helps. :-)

  31. Messier Tidy Upper

    @22. mike burkhart :

    “…In fact I think when Star Wars came out there where no photos of Mimas yet Star Wars was released in 1977, the photos were taken in 1980 or am I mistaken ?”

    Saturn was first visited by Pioneer 11 in September 1979.” [Emphasis added - it didn't view Mimas well.]

    Source : http://en.wikipedia.org/wiki/Exploration_of_Saturn

    Voyager 1′s Saturnian flyby occurred in November 1980,

    Pretty sure that was the first spacecraft to image Mimas closely and in good detail.

    See : http://en.wikipedia.org/wiki/Voyager_1#Encounter_with_Saturn

    Then it was Voyager 2′s turn :

    The closest approach to Saturn [by Voyager II] occurred on August 26, 1981. [Brackets added.]

    Guess what my source for that is? Yes its :

    http://en.wikipedia.org/wiki/Voyager_2#Encounter_with_Saturn

    The fount of all knowledge again! ;-)

    Same online source notes that the first StarWars movie was “released on May 25, 1977,” – so, yeah the Lucas Death Star preceded our knowing of the Mimas one – & you are quite correct! :-)

  32. HSolo

    That’s no moon!

  33. Kevin Kirby

    I remember being 10 years old and seeing that Mimas-Death Star image come back from Voyager 1. Pretty much everyone had the same “OH S-” reaction I had.

NEW ON DISCOVER
OPEN
CITIZEN SCIENCE
ADVERTISEMENT

Discover's Newsletter

Sign up to get the latest science news delivered weekly right to your inbox!

ADVERTISEMENT

See More

ADVERTISEMENT
Collapse bottom bar
+

Login to your Account

X
E-mail address:
Password:
Remember me
Forgot your password?
No problem. Click here to have it e-mailed to you.

Not Registered Yet?

Register now for FREE. Registration only takes a few minutes to complete. Register now »