I’m an astronomer, not a geomorphologist.
No, I didn’t make that word up (though I thought I did before checking Wikipedia). A geomorphologist studies the structures of landforms and tries to figure out how they got that way. I guess I do that professionally for some objects (planetary nebula, supernova remnants, and esoteric stuff like that), but not for planets and moons. That’s a confusing job, so I leave it to the other professionals. When I do it, it’s speculation for my own amusement (or in this case, I hope, for yours too).
And it’s places like Hyperion, a moon of Saturn, where I know I’ve made the right choice. The Cassini probe took some close-up snapshots of the weirdo little iceball recently, and look what it saw:
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| Click image for a bigger version, or here for a huge one, from The Planetary Society blog page. All images are courtesy of NASA/JPL/Space Science Institute, and CICLOPS. |
What a mess! I have no desire to try to figure this one out.
OK, that’s a lie. I’d love to know what makes this look like a big old loofah sponge. There are two things that strike me about the image. Well, three, if you count the fact that Hyperion is completely freaking weird.
The first is the enormous crater. It’s really big, but is it shallow? It’s hard to say what the depth is from just one picture, but it sure looks shallow. From the appearance of all the other craters, Hyperion looks very fragile to me, crumbly even (what material scientists call friable). An asteroid smacks into it, and the crater collapses back on itself. You get rims, and steep walls, but the crater fills in. If the impact that created that crater had been any bigger, I bet it would have shattered the moon, much like Saturn’s moon Mimas and its scary big crater Herschel. *
The second thing are all the little craters. It’s covered with them! In some icy moons, the craters get covered over when the ice melts under a new impact, or some other event washes over the surface. Not Hyperion. Those craters look pretty fresh.
Weirder even, when you look at closeups, the craters all have black stuff at the bottom. What’s that? They aren’t shadows; the angles are all wrong. It’s actual black stuff.
In that image, you can see it, and you can also see how the walls of the craters have slumped. I would expect the junk at the bottom to be made of the same material as the stuff in the walls, but I’m not so sure. Why is it black? I think (that is, I’m speculating), that the material turned black after the walls slumped. See the crater in the upper right of the closeup? The landslide from the slump appears to partially cover up the black stuff on the bottom, implying the black stuff turns black in a separate event. Maybe this crater had a second landslide, covering up the stuff that had turned black from the first landslide.
Weird, weird, weird. Even for a moon of Saturn.
I’ll remind you again, I am not a geomorphologist. Anything I say here is speculation on my part. But I’ll be keeping an eye out for word form the real scientists working on this. Hey! Come to think of it, I’ll be meeting Cassini Imaging Team Leader Carolyn Porco at James Randi’s The Amaz!ng Meeting 4 in January (in fact, I’m introducing her, gloat gloat). I’ll ask her then.
Until then, I’ll have to settle for more speculation, while I peruse the raw Cassini images of Hyperion. You should too. Take a look at how odd, how mysterious, and how wonderful our solar system is, and think about how much more there is to see.
* Now, after writing this, I wonder… that crater is nearly the size of the moon. That strikes me as not possible. Some scientists are wondering how solid comets are; maybe they are more like rock piles held together by ice. It’s not beyond my imagination that Hyperion (which is icy like a comet) could have had hollow pockets in it, maybe where there was frozen gas. I’m wondering now if it was a smaller event, and the impact heated the volatile gas, which escaped, causing a much larger slump than the impact itself could have caused. Think of driving a nail into a shaken soda can and you’ll get the idea. Hmmm… speculation is fun, and it’s free.
October 18th, 2005 at 10:49 pm
Maybe Hyperion itself is a fragment of a shattered moon (though where the other fragments are, I have no idea). Or maybe it was shattered then put back together via gravity.
October 18th, 2005 at 11:30 pm
I’m no geomorphologist either, but I kinda wish I was so I could have that title on my business cards.
What kind of forces or reactions could make icy/light stuff go black? Could it be more like something from the inside of the moon that wells up through the bottom of the crater — a bit like the maria on our moon? Maybe it’s stuff that was melted when the big impact occurred and now seeps into the bottom of more recent craters?
October 18th, 2005 at 11:48 pm
In some of the images on the Cassini site, there are small craters in the black stuff in the bottom of larger craters: these have light rims but black interiors. But if the small impacts happened after the stuff in the bottom of the crater turned black, where do the light rims come from?
Weird.
October 19th, 2005 at 2:46 am
“Mind you, I am not a geomorphologist (I want credit if that words starts getting used)”
You should also get credit if the grammar error in this sentence ever becomes a part of standard English (you’ll be just like Thomas ‘unalienable’ Jefferson)
*hides from the BA*
October 19th, 2005 at 2:50 am
” Now, after writing this, I wonder… that crater is nearly the size of the moon. That strikes me as not possible. Some scientists are wondering how solid comets are; maybe they are more like rock piles held together by ice. It’s not beyond my imagination that Hyperion (which is icy like a comet) could have had hollow pockets in it, maybe where there was frozen gas. I’m wondering now if it was a smaller event, and the impact heated the volatile gas, which escaped, causing a much larger slump than the impact itself could have caused. Think of driving a nail into a shaken soda can and you’ll get the idea. Hmmm… speculation is fun, and it’s free.”
Well maybe the little craters are from material was spit out and then fell back?
October 19th, 2005 at 3:10 am
The only thing better that a geomorphologist is a fluvial geomorphologist. Studier of the landforms greated by rivers.
October 19th, 2005 at 5:15 am
It is really weird. That image literally strikes me. When it was released, it quickly became one of my wallpapers.
(I have a program that changes wallpapers every boot! So I have a good variety…)
It does look like a sponge. In fact, I have a sea sponge my mom bought in Florida that looks like this!
Now that you say that the black shadows are not shadows… I’m a bit less concerned. I knew the shadowing was off. Weird weird weird. I can’t wait to see what they find out about it! Hyperion may be small but it’s a really interesting object.
October 19th, 2005 at 8:46 am
Captured comet. That thing has been close to the Sun. OK, it’s a wild guess, but you heard it here first.
October 19th, 2005 at 9:12 am
I’d love to see what the side opposite looks like. It reminds me of what a watermelon looks like when you shoot it. I’m thinking that if Hyperion were a slush of rocks and hydrocarbons, and it took a heavy impact on the far side, instead of expending it’s energy on the far side creating a crater there, it might expand out to create a much larger crater on this side.
Like that famous photo of a bullet piercing an apple, only on a grand scale.
October 19th, 2005 at 10:19 am
Bradley, I like that analogy of the bullet-and-apple photo. I’ve seen other pics of Hyperion on the CICLOPS site (including a way cool stereogram–get your 3D glasses), but I don’t know if those views were directly opposite of the view BA posted here.
October 19th, 2005 at 10:57 am
I don’t know if it is feasible, but one thing that occured to me is that people seem to be assuming it was a direct hit by another body. What if a body about the same size or even larger than hyperion simply grazed huperion’s side? If hyperion is as fragile as BA says, it is at least possible (based on my absolutely zero knowledge of astrophysics) that the other body might have shaved off part of hyperion, leaving an extremely shallow crater-like region where parts of hyperion where simply ground right off. That would explain how hyperion survived without shattering, there was no major impact that could shatter it. It might also explain the asymmetrical shape of the crater and the fact that the crater is only on one fact of the body (where you think the crater would be on the lower face of hyperion in the picture there is nothing out of the ordinary).
October 19th, 2005 at 11:36 am
Could Hyperion aid in a manned Titan mission?
I believe a manned mission to Titan may be achievable with a VASIMR-type propulsion system and a pitstop on Hyperion. The small moon orbits near Titan with a 3:2 resonance.
I ran a crude simulation some time ago of such a hypothetical mission. I imagined a small “mother ship� with a VASIMR rocket and a couple of landers with chemical rockets. I used power, mass and specific impulse levels from published specifications of what a future VASIMR rocket could have. Upon arrival in the Saturn system, the large scale-height and low molecular weight of the planet’s atmosphere would allow significant aerobraking for later insertion into Titan orbit.
After exploration of the Titan surface is complete, the mother ship and near-empty landers would move into Hyperion orbit. The landers are reused to mine and store ice from Hyperion’s surface. The nuclear reactor that is used to power the VASIMR rocket is then used to break down the ice into hydrogen and oxygen, which would then refuel the landers. Pure hydrogen would also be used to refuel the VASIMR rocket. The craft would then put itself on a trajectory toward Saturn. Very near the planet, and traveling very near escape velocity, the engines from the Titan landers burn to produce a delta V for a gravity assist. Saturn’s escape velocity is about 80,000 M.P.H., therefore a craft would leave the Saturn system at 41,000 M.P.H. after a 10,000 M.P.H. delta V near the planet.
The whole mission could last a few years.
October 19th, 2005 at 12:13 pm
I wonder how Cassini measures the surface density of Saturn’s moons. Has the density been measured for Hyperion? Perhaps the association of the moon is a lot looser then most suspect. It’s possibly that Hyperion could have only recently been shattered apart, and reformed.
On an incidental note, It’s frontiers of science like the Cassini mission that makes the universe a more wonderous place. Those creationsts, and anti-scientists alike are missing out on the beauty and spectacle of the universe; denying their innate sense of wonder and appreciation. Having to create an illogical explanation for all that surrounds us, must take a lot of the most amazing aspects to existence out of life.
In their minds, they may think they’re saving themselves, but it’s us, who must save them. We must save them from stupidity, and irrational thought. It’s our duty as scientists to show as many people as possible the true path to rational thought, logic, and the aesthetic beaty of the universe.
October 19th, 2005 at 2:25 pm
To Tim G
I’ll go, where do I sign up?
October 19th, 2005 at 5:42 pm
I think the crater looks too much like a traditional crater to be the result of a grazing impact, but I like the bullet-through-the-apple proposal. Let’s ask a geomorphogenist — someone who studies the origins of land formations.
(I learned that word from http://phrontistery.info/)
October 20th, 2005 at 10:24 am
I’m jealous. You’re meeting Carolyn Porco! That’s awesome. She’s so cool, she’s even answered my dumb questions via email.
October 20th, 2005 at 11:06 am
I met her once before, actually. I was visiting some astronomy friends at SWRI in Boulder, and she swung by the restaurant for like ten seconds. That was pretty funny! I doubt she remembers it.
October 20th, 2005 at 11:36 am
I think it’s just as cool that you are going to meet the mythbusters.
Has anybody told you that you look a bit like Adam?
October 20th, 2005 at 7:36 pm
The black stuff is very intersting…PAHs? Didn’t Spitzer see these from Temple1?
I suppose the physcological impact of the crater is as big as the moon, right?
Very cool curiosity, BA. Thanks.
October 22nd, 2005 at 8:16 am
Every asteroid or moonlet like this I see looks just like a baked potato. It must be intelligent design!
October 23rd, 2005 at 3:01 am
You’re meeting Porco and the Mythbusters?!?! I should become an astronomer too!! If Phil shaved his head, wore and earring, and 1960’s geek glasses he would look even more like Adam, i agree.
October 25th, 2005 at 7:35 am
I wonder… that crater is nearly the size of the moon. That strikes me as not possible.
Unless the “snowball” analogy is more than just an anology, no? It sure looks like an old, icy & dirty snowball.
My first thought was that it looks remarkably similar to the fist-sized chunk of coral I have on desk.
Either way, I find it wonderful that apparently very different processes can result in such similar looking attributes.
The big pic is GREAT desktop wallpaper. Thanks Phil.
November 1st, 2005 at 7:41 am
I don’t believe the large crater that you refer to is an impact crater as it looks more like a huge subsidence as you can see the craters that were on the edge of the subsidence have been elongated when the surface dropped.
As for the black stuff on the bottom of the craters after fooling around with the image in photoshop it appears to be more like some sort of stain rather than extra material covering the bottom of the crater.
Whatever it is it’s a facinating place.
January 4th, 2008 at 6:23 am
This satellite has to be a leftover from cosmic collision. To me, I would think something BIG hit a even bigger “former” satellite of Saturn and this is a blob of matter from that collision.
The HUGE, almost moon sized crater, could be a leftover from that same collision. It is almost too obvious that the white and grayish areas can be traced into a circle. Something had to force this circle to appear to be blown outwards. The impact is so gigantic and deep that the crater fills in with magma, much like a mare on our own moon.
Another crazy thing about Hyperion which supports this theory, is that it flips and spins wildly. If something huge did hit it in it’s younger stage, it would have to be something so strong that it makes the satellite flip and rotate at the same time.
As for the black bottoms: It only seems to be black on the deeper impacts. There is something, rock or otherwise, darker beneath the thin gray surface???
However, I also like the theory ACW had above of a comet that just had to stop and rest at at Saturn for a few million years.