A Saturnian storm larger than worlds

By Phil Plait | December 28, 2010 7:00 am

A couple of weeks ago, amateur astronomers discovered a new storm erupting on Saturn. The accomplished astrophotographer Anthony Wesley got pictures of it, and I wondered to myself when Cassini would snap some shots. Turns out, I didn’t have to wait long! The spacecraft took images of the planet on December 24th, returning — as usual — jaw-dropping pictures of Saturn showing the storm:

This image, taken with a blue filter, shows the storm clearly. The main spot is huge, about 6,000 km (3600 miles) across — half the size of Earth! Including the tail streaming off to the right, the whole system is over 60,000 km (36,000 miles) long.

Curious, I checked out the archive of raw Cassini images, and sure enough pictures were also taken in infrared filters which pick out the gas methane, abundant in Saturn’s atmosphere:

A lot more detail can be seen here! I’m not sure how to interpret this, but it’s interesting to me that in the main oval there’s a spot with less methane on the left, and a bright spot on the right with a faint ring of clouds circling it. The banding on the planet can be spotted more easily in this image as well.

There’s an added bonus in these images: the shadow of the rings on the planet’s clouds is obvious, but the rings are nearly invisible! You can just make out the rings as a thin line going horizontally across Saturn in the first image. These pictures were snapped when Cassini was almost directly above the rings, which are so thin they vanish when seen edge-on. Actually, that works out well as otherwise they might interfere with the view of the storm in these shots.

As I said above, the storm is so big it was actually discovered by amateurs here on Earth, so if you happen to have a good ‘scope you might be able to spot it yourself; Saturn is up in the middle of the night right now, so if you get up a couple of hours before dawn it’s well placed for viewing. Saturn’s about as far from Earth as it can be right now, unfortunately, at a distance of 1.4 billion kilometers, so its disk is pretty small, and the storm even smaller. So this is challenging, but possible.

Incidentally, I’ll add that with the raw images in different filters available in the archives, it’s possible to grab them and put them together to make pseudo-true-color images. Guillermo Abramson is an Argentinian physicist who contacted me and let me know about his efforts, one of which is displayed here. It’s not exactly true color because it’s difficult to compensate for the different filter properties, different exposure times, and so on, but his pictures are interesting. Playing with images in this way sometimes reveals details you might not see in grayscale versions… and with thousands of eyes able to look at the pictures things might be spotted which would otherwise be missed.

And I’ll just bet we’ll be seeing lots more images of this vast storm as time goes on. It’ll be very interesting to see how it evolves over time, and I’m sure there are lots of scientists across the planet (our planet, that is) who feel the same way.

Images credit: NASA/JPL/Space Science Institute

Related posts:

Follow-up: Jupiter impact video and a color picture
Putting the spin on Saturn’s hex
Saturn rages from a billion kilometers away
Epic lightning storm electrocuting Saturn for eight months

CATEGORIZED UNDER: Astronomy, Pretty pictures, Top Post
MORE ABOUT: Cassini, Saturn

Comments (42)

  1. Thanks, Phil! I want to mention also the shadow of Dione transiting the Southern Hemisphere! A distant eclipse seen from an unusual perspective…

  2. Cosmic spermatozoa reaches heavenly body! Film at…well, right now!

  3. BTW, any chance that bright spot could be the result of an impact, and the storm some sort of shock front?

  4. “It’ll be very interesting to see how it evolves over time” – this has been amply documented by amateur astronomers over the past weeks as e.g. this collection of images demonstrates. The best of them aren’t that much worse in resolution than Cassini’s …

  5. Chris

    I was wondering that too. It kind of looks like an impact with some shearing from the different winds. Probably not from the rings because it’s so far away from the equator.

  6. Sir Chaos

    “Spermatozoa”? You have a dirty mind. 😉 Let´s keep this safe for work and say “tadpole”.

  7. You always have amazing pictures. That storm is huge! :)

  8. Sam H

    Brief typo: Cassini is not almost directly ABOVE the rings, but WITHIN them. Amazing how thin they are :)!
    And the storm is wondrous too! kuhnigget: I don’t think it’s an impact front, must have been a pretty dang impactor and fireball for it to cause a disruption of that magnitude. As well, if it was an impact then these eagle-eyed amateurs should have picked it out too ;)!

  9. Pete Jackson

    The impact hypothesis is an interesting one; perhaps the hypothetical impact occurred on the side of Saturn not visible from Earth. Hopefully, more observations will trickle in.

  10. Keith Bowden

    I’d love to see some time-lapse video of this, it’s spectacular!

  11. Azam

    Does anyone know of either a good iphone app or a deskstop program that I can use to track the orbital location of planets in the solar system relative to earth? More or like a 2D top view that shows where the planets currently are on their orbits with respect to each other. Thanks!

  12. Robert

    I have to agree with others, this does not look like a storm, it has all the markings of an impact. The tail streaming off from the large impact zone, I think, is a most prominent suggestion of an event like this. But whatever it is, the photos are wonderful, thanks for posting!

  13. Anchor

    No impact involved. It’s a seasonal storm, an thermally-eruptive upwelling from deep in the atmosphere breaking the nominal cloud-deck, and the high-altitude plume (likely composed of ammonia ice crystals like those in cirrus clouds) is blown along the zone by jet-stream winds. Although it’s big it is fairly typical of the type. Professional and amateur astronomers have seen them erupt many times over the last century or more. It’s just the first big one Cassini (or any spacecraft on a flyby of Saturn) has been able to image.

  14. munky

    looks like an oil slick. BP been drilling on saturn?

  15. Anchor

    If it were due to an impact, one would need to explain:

    1. Why it’s white. Confirmed impacts on Jupiter are invariably DARK due to dust and soot imported by the disintegrated impactor.

    2. Why it coinicidentally struck in just the latitude zone within which other such storms have regularly appeared in the same season.

    3. Why Cassini hasn’t spotted nary a single other example of a substantially smaller impact since it arrived at Saturn. For every impactor of a given size, there are perhaps ten times that number of impactors half the size. If this feature was due to an impact, it would have had to be quite large. Statistically, Cassini should have seen smaller impacts, or this biggie was just a fluke. It’s seen no evidence of impacts in the atmosphere at all.

    4. Why Cassini has been detecting lots of strong radio bursts characteristic of lightning since this feature appeared.

    5. Why the morphology of the ‘head’ (clearly apparent in the infrared) shows a bright spot (upwelling) accompanied by a dark spot (downwelling). That’s characteristic of a storm with cyclonic and anticyclonic centers, not the signature of an impact site.

    6. Why it looks EXACTLY like a storm…Saturn-style. (Or Gas Giant-style: the feature looks as if it would be quite at home on Jupiter, for example)

    It’s an active and dynamic atmosphere and things can and do happen in it. No disturbance from the outside is necessary.

  16. MadScientist

    It’s Casper! Wouldn’t it be neat if Saturn developed an eye similar to Jupiter’s? Then they can take turns watching us – or in a few years when they’re closer together they can be a pair of eyes watching us.

  17. Monkey

    Of course its an impact, and anybody telling you otherwise is simply lying to you. Obviously The NASA is using Cassini as a transportation device to launch preserved alien bodies into a safe hiding place. THis is a basic recon photo to record the big cover-up that was leaked to public sources.

    Cassini didnt even go to the moon.

    THe world will end on SATURday, because…

    *Random spittle enducing ranting motions continue*

    You JUST DONT GET IT!!!!


    Ok, ok…enough. Awe inspiring photo. IT does look like an impact, but whadda I know. I just know what I learn as I go.

  18. Jamie

    @12 Azam: have you looked at Star Walk or Solar Walk (both iPhone/iPad apps)?

  19. Joseph G

    It’s probably not that surprising that it looks kinda like an impact, because it’s a huge vertically developed disturbance in Saturn’s atmosphere, not unlike, well, an impact. It’s more of a (relatively) slow upwelling then a violent collision, but something did “push aside” the cloud-tops.
    A thunderhead on earth is tall and wide at the top for the same reason that a nuclear mushroom cloud is, after all. The heat source is all that’s different.

  20. Okay, so I’ll go back to my spermatozoa theory… 😛

  21. Messier Tidy Upper

    Spectacular image. Thankyou Cassini (& BA as always) – surely the most reliable source of solar system wonders around. :-)

    The main spot is huge, about 6,000 km (3600 miles) across — half the size of Earth!

    That’s size in terms of diameter / area / volume counting only Earth’s surface I presume?

    Earth’s measures for comparison :

    Mean radius 6,371.0 km
    Equatorial radius 6,378.1 km
    Polar radius 6,356.8 km
    Circumference 40,075.16 km (equatorial)
    40,008.00 km (meridional)
    Surface area 510,072,000 km2
    148,940,000 km2 land (29.2 %)
    361,132,000 km2 water (70.8 %)

    Source : Wikipedia – Earth page.

    How much mass is contained in this swirling storm and how deep will it extend I wonder?

    18. MadScientist Says:

    It’s Casper! Wouldn’t it be neat if Saturn developed an eye similar to Jupiter’s? Then they can take turns watching us – or in a few years when they’re closer together they can be a pair of eyes watching us.

    Aren’t there already enough paranoid peopel inthe world without needing to have giant eyes on alien planets staring on us too like a gargantuan solar system Big Bother? 😉

    @16. munky Says:

    looks like an oil slick. BP been drilling on saturn?

    If only..? 😉

    No solid surface & no oil on Saturn – Titan, OTOH, might be a better bet for oil mines with lots of complex hydrocarbon tholins. There was once a theory that Venus was a planet full of oil too but alas, that turned out not to be so.

    @11. Keith Bowden :

    I’d love to see some time-lapse video of this, it’s spectacular!

    Seconded by me. :-)

  22. Messier Tidy Upper

    D’oh! Sorry folks. Forgot to close the underline tag. I just meant to underline the word source which is :


    EDIT to add – & now all the underlining has vanished? Huh? Oh well, thanks, I guess?

  23. Douglas Troy

    I’ve seen this exact same thing happen in my coffee when I pour creamer into it … Saturn must be made of *gasp* COFFEE!


    Great story and photos Phil, I look forward, in the coming weeks, to updates from you on this subject.

  24. Saul Trabal

    If this storm is putting out lightning (and I strongly suspect it is), some of the bolts must be powerful enough to incinerate a city the size of New York City or London! The rounded end might be the leading edge of the thunderclouds(s). I hope Cassini does a search for radio signals, indicating lightning flashes and their strength. And also-a scan of this storm system when it’s on Saturn’s night side should be done to check for lightning flashes. I’d suspect they’d rival anything we’ve ever seen, even on Jupiter.

  25. Gary Ansorge

    Almost looks like a Yin/Yang symbol,,,oh well, back to the coffee pot.

    Great pics.

    Gary 7

  26. Phoenix59

    That’s an incredible photo. Hard to imagine a storm so huge that it could swallow our planet and not even… *BURRRRRRRRRRRP!*

    ‘Scuse me.

  27. Azam

    @20 Jamie. Yeah. I have star Walk but it only shows locations. I am looking for more of a 2D simulation where you can figure out when a certain planet will be closest to earth for optimal viewing.
    I haven’t checked out Solar Walk but I’ll give that a shot next. Thanks!

  28. Azam

    @20 Jamie. solar walk did the trick! thanks!

  29. Could it be that Saturn is experiencing global warming also? That could prove Earth’s global warming is non-anthropogenic…

  30. Tea

    Looks like someone poured more milk into the tea.

  31. Necronn9

    This is not fooling anyone.

    We shot a rocket with all our toxic waste and trash and now its doing evolution.

    So now we know what our trash looks like on a different planet.

  32. Jesus did come back! he just got the wrong planet :O


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