This may be my favorite picture of Saturn’s moon Enceladus yet:
Quick! It’s trying to get away!
My first thought (well, my real first thought was that this is Enceladus on full afterburners) was that this was a composite: two images combined. The moon is icy and very bright, while the plumes of water shooting away from cracks in its surface are faint. But actually, there are two separate light sources here! The face of the Moon we see here is being lit by a full Saturn (think of Saturn as being behind you as you look at the picture). But the Sun is behind Enceladus (not directly behind, but mostly behind and off to the side of the picture), and is illuminating the geysers. That’s why the fainter plumes are visible; we’re looking at the dark side of the moon! If Saturn weren’t lighting it up, the moon would look much darker, and the plumes would be even more visible.
I love how the plumes look like a rocket exhaust. With the moon itself just a little offset in the picture, a little above the center, our brains make it look like it’s jetting up, up, and away!
But don’t worry about it actually rocketing into the wild black yonder. I’ve seen various estimates for the amount of water erupting away in the plumes, but a reasonable amount is about 250 kg/sec, or a ton of water every 4 seconds. That may sound like a lot, but a ton of water is only a cubic meter*!
Enceladus has a mass of about 1020 kg, or 400 quadrillion times the mass it loses from the geysers per second! So even though this picture looks dramatic, the amount of mass Enceladus is losing is actually, and almost literally, a drop in the bucket… but still, enough to resupply the ice particles in Saturn’s diffuse E-ring. Amazing.
* And while some of the material does escape into space, acting like an extremely weak rocket, a lot of it falls back onto the surface of Enceladus. Those particles can’t move the moon, any more than pulling up on your shoes can make you fly.
Credit: NASA/JPL/Space Science Institute. Tip o’ the cosmic umbrella to Carolyn Porco.
Related posts:
- Enceladus is erupting!
- Cassini dances with Enceladus once again
- Enceladus!
- Midnight on a ringed world
October 1st, 2010 at 10:05 am
Hey, this is like that cheesy Japanese sci-fi movie from the late 70s, where the bad guys propel their enslaved planet towards Earth. What was that movie called?
October 1st, 2010 at 10:07 am
Reminds me of the big spherical lunar landing ship in “2001″
Any idea of why these geysers are concentrated at the south pole?
October 1st, 2010 at 10:11 am
THAT’S NO MOON! IT’S A SPACE STATION!
October 1st, 2010 at 10:16 am
Brian Schlosser:
Because the ones on the north pole don’t have enough strength to push so far up. The ones near the south pole are all pointed down, making it easier to escape.
BA:
Of course they can! The “thrust” of pushing them away moves the moon, and then the force of the particles smashing back down pushes the moon even farther!
“Conservation of momentum”? “Center of mass”? Never heard of them. Why do you ask?
October 1st, 2010 at 10:19 am
Ian Muir:
You’re thinking of Mimas, not Enceladus.
October 1st, 2010 at 10:20 am
I see an egg being fertilized. Whatever that says about me.
October 1st, 2010 at 10:32 am
Are you certain that ejecta that falls back does 0 thrust? Its been ages since my mechanics lectures to I can’t visualize entire system accurately.
Anyway. The particles that are going above Enceldaus escape speed will certainly exert thrust, and also the change of mass of the moon should be shifting its orbit?
October 1st, 2010 at 11:06 am
Death Star? Aries 1b from 2001? Cheesy planet of enslaved kaiju? Naah…
Larry Niven fans all recognize the Long Shot.
October 1st, 2010 at 11:09 am
@9 Jeff Fite: Of COURSE! Its a General Products Type IV hull! And, given its opaque nature, the statis shield must be on!
October 1st, 2010 at 11:14 am
Or, worse yet :
Great picture.
Enceladus isn’t the twelfth satellite of Saturn is it? It sure looks alive though – where’s Cirocco “Rocky” Jones & Gaby when you need them?
–
* Ref. to John Varley’s ‘Titan” novel case anyone’s wondering.
October 1st, 2010 at 11:14 am
Is it possible for these exhaust plums to have a small effect on the moons orbit?
October 1st, 2010 at 11:15 am
Enceladus:1999
I think I see Martin Landau and Barbara Bain!
October 1st, 2010 at 11:16 am
[...] Highlighting Plumes (NASA Cassini Saturn Mission Images) Enceladus on full afterburner [...]
October 1st, 2010 at 11:18 am
@ Aleksandar
Enceldaus’ orbit is affected, however it will take about 1000 millenia for the change to be actually noticable (assuming the gysers push at a constant rate for all that time).
October 1st, 2010 at 11:45 am
It looks fake, almost like someone hung an ice ball from a string then photo-shopped in the “tail.”
~Rhaco
October 1st, 2010 at 12:03 pm
that is definitely the most “real time active” phenomenon I’ve seen imaged on a planet other than earth. Maybe only the old Voyager pics of IO come close.
This solar system really is big and unexplored. I taught earth science 20 years and even today still keep learning things about our home planet, imagine how much is still hidden and may remain hidden from mankind about other worlds. I even read that certain areas of earth such as parts of Alaska are still unexplored. Theme to me is, mankind, all your arrogance stand aside, the solar system will show you your true place in the scheme of things.
October 1st, 2010 at 3:29 pm
Its sprung a leak! Now it’s gonna go flat.
October 1st, 2010 at 4:07 pm
I second the question from post #1; what was the name of that Japanese movie where they put rockets on the Earth to evade a runaway star?
(geez, can’t believe I remember that after so many years!)
Anyway, pretty cool! It does look like it’s escaping.
And here’s an idea; since we had “Space:1999″, this can be “Space:2099″!
October 1st, 2010 at 4:08 pm
[...] A moon of Saturn is trying to escape! (OK, not really. Here’s the real scoop) [...]
October 1st, 2010 at 5:51 pm
What was that movie called?
Gorath.
That was off the top of my head, BTW. I saw it on TV as a kid, and there’s a night scene of the ocean and high winds and the moon drifting across the sky as it gets pulled toward Gorath that still sticks with me.
Wikipedia fills in the details:
http://en.wikipedia.org/wiki/Gorath
Hey, this is like that cheesy Japanese sci-fi movie from the late 70s, where the bad guys propel their enslaved planet towards Earth.
Gorath was a rogue star. Humanity builds giant rocket engines in Antarctica to move the Earth out of the way. Complete awesomeness to me. Well, be fair, I was seven when I saw it. It’s kind of like When Worlds Collide, but with bigger goals.
October 1st, 2010 at 6:20 pm
Low thrust over a long period of time…. uh, kinda like an ION ENGINE???
Wonder if this will affect the orbit of the moon over very long periods of time?
October 1st, 2010 at 6:26 pm
[...] jetstrålar från sydpolen. Avståndet var 617000 km när bilden togs. Skeptikern och astronomen Phil Plait blev misstänksam när han såg bilden och trodde den var ett montage. Anledningen var att [...]
October 1st, 2010 at 7:00 pm
Vader to Commander: Make way to reposition the Death St-, er, hello children! Enceladus! I meant Enceladus.
October 1st, 2010 at 7:10 pm
That’s got to be my favorite now too. Wish it had been higher res…but Casini still has plenty of sand in the upper chamber of its hourglass…
Phil says, “I love how the plumes look like a rocket exhaust.”
Yes indeed. Gases dispersing into a vacuum. Just like that.
Generally, however, Hollywood visual effects meisters don’t pay attention to such physics, so they habitually show rocket plumes and explosions as ludicrous BILLOWING phenomenon, with an expulsion of (hot) gases into an air-filled medium, since those are the kinds of effects they think audiences will read as ‘authentic’ exhausts or explosions.
It is the counterpart phenomenon to the ‘self-fullfilling prophecy”: give the audience what they think they’ll accept as an ‘explosion’ or ‘exhaust’, and the audience will continue to expect the bull.
October 1st, 2010 at 7:24 pm
“Quick! It’s trying to get away!”
Ah – excellent. I was in a funk writing up some stuff for uni, and then I saw this. For some reason, it just cracked me up and made my day.
Cheers Phil!
October 1st, 2010 at 9:36 pm
Get away?
More like…
http://en.wikipedia.org/wiki/Operation_Tumbler-Snapper
October 1st, 2010 at 10:41 pm
Mind-blower. Seriously.
And, hey…this one’s in my neighborhood!
October 2nd, 2010 at 12:04 am
Saturn, the space ship parking garage of the solar system.
October 2nd, 2010 at 12:34 am
But Enceladus has been there for thousands of millennia. If this phenomenon lasts that long, it must have has a measurable impact. Perhaps the effect is swamped by other uncertainties and random variables. Has anyone done the maths?
October 2nd, 2010 at 4:40 am
Jeff said…”Theme to me is, mankind, all your arrogance stand aside, the solar system will show you your true place in the scheme of things”.
….Well said Jeff, What else is out there we haven’t even discovered yet, even just in our own solar system.
What an incredible image, and what a place! Enceladus is very very special, at just the size of England you could drive across the thing in a day…and all this activity in such a small body! Those jets are coming from a nice “warm” place in the Tiger Stripes travelling at 2,100 km per hour. There’s liquid salty water slopping about at, and under the surface with possibly an entire ocean below the ice. No wonder Enceladus is a member of that exclusive club of moons with possible extratterestrial life.
Long gone are the days when we thought sunlight was the only energy source for life, tidal heating vastly increases the places for possible organisms to exist.
Was Earth right at the back of the queue when moons were being handed out?
Of course we love Luna to death, but just think…!
October 2nd, 2010 at 6:52 am
Enceladus reminds me of the old tv show Shadow Raiders.
October 2nd, 2010 at 10:04 am
“Message from Space”! That’s the name of that Japanese “Star Wars” movie from the late 70′s. Thank you Google!
October 2nd, 2010 at 10:13 am
Wouldn’t that be full afterfreezer? Anyway lovely moon that Enceladus. Beautiful plumage.
October 2nd, 2010 at 10:39 am
Shades of Stanley Schmidt’s novel Lifeboat Earth.
October 2nd, 2010 at 2:00 pm
daleks. DALEKS I Tell YOU!
October 2nd, 2010 at 3:25 pm
Shades of “Pushing Ice” by Alastair Reynolds . . . the moon that got away.
October 2nd, 2010 at 7:20 pm
Going cruisin’ in a spaceship, we’re so good at being bad
We’ll destroy your little planet if you ever get us mad …
October 2nd, 2010 at 11:18 pm
@Anchor #24 – or how whenever an aircraft in a movie is in a power dive or death spiral, the accompanying sound effect is always that of the wind-driven siren of a Junkers Ju-87 Stuka dive bomber.
October 3rd, 2010 at 7:02 am
[...] Enceladus on full afterburner | Bad Astronomy | Discover Magazine [...]
October 3rd, 2010 at 7:37 am
[...] this is a totally cool image, so [...]
October 4th, 2010 at 6:07 am
Hi Phil, I had some fun with my blog posting…
http://nzscience.blogspot.com/2010/10/ufo-alert-alien-spaceship-seen-as.html
October 4th, 2010 at 8:11 am
Is anyone else reminded of the Invader Zim episode Battle of the Planets or is that just me?
October 4th, 2010 at 9:27 pm
my husband showed this picture to my 8 year old tonight. not only did he correctly name the moon and its planet, but he also told me that the “volcanos” were really water and the source of the E ring. science channel ftw.
October 7th, 2010 at 1:57 pm
[...] Science publications are going nuts over Enceladus, one of Saturn’s moons, which has—get this—a fizzy ocean that sends plumes of water vapor, gas, and ice erupting out of its south pole. This photo, captured by the Cassini spacecraft on the dark side of the moon, has confirmed researchers’ hypothesis of an underground sea bubbling (literally) miles beneath the surface. [...]