Saturn’s Violent Storm Rages On

If you're an early riser like some runners I know, see how many of the planets you can spot before sunrise. Jupiter is easiest, followed by Venus, Mercury and faint Mars. Binoculars help! Map: Stellarium

It’s still a traffic jam of planets in the morning sky, the longest I can recall in years. Depending on your latitude, it’s more or less easy to see up to four planets gathered in the eastern sky about 1/2 hour before sunrise. The map at left shows the scene tomorrow morning.

For folks living in the northern U.S., Europe and Canada, they’re all quite low, requiring haze-free skies and a clear horizon view to see. In Duluth in particular, I can happily recommend Lake Superior as the place for a.m. planet watching. The farther south you live, the better placed Mars, Mercury, Venus and Jupiter become. Best is the southern hemisphere, where the four planets line up almost straight up in the east before sunrise.

The 'Spring Triangle' is high in the south at nightfall in late May. One fist held at arm's length separates Spica and Saturn. The other two sides of the triangle are about '3 fists' long. Photo: Bob King

Saturn is still the only evening planet. Along with its bright neighbors Spica and even brighter Arcturus, it’s part of a ‘spring triangle’ that dominates the southern sky at nightfall. Without interference from moonlight, I was pleasantly surprised last night to see how bright this trio appeared.

We’ve followed the progress of Saturn’s monster northern hemisphere thunderstorm on several blogs since it exploded on the scene in December 2010. Super storms like these are rather rare with only six recorded since 1876. But what they lack in frequency they make up in intensity.

The current storm now reaches completely around the planet, measuring some 223,000 miles long. To put that in perspective, imagine a line of swirling clouds, blizzards of ammonia ice crystals and torrential winds stretching from Earth almost to the moon!

“Our new observations show that the storm had a major effect on the atmosphere, transporting energy and material over great distances – creating meandering jet streams and forming giant vortices – and disrupting Saturn’s seasonal [weather patterns],” according to Glenn Orton, based at NASA’s Jet Propulsion Laboratory and co-author of a recent paper about the upheaval.

This colorized picture of Saturn taken in three wavelengths of infrared light by the orbiting Cassini probe shows large amounts of ammonia ice particles dredged up by the storm, shown in yellow. Credit: NASA/JPL/Univ. of Arizona

Yeah, this is a biggie. Powerful updrafts from the storm pulled ammonia gas from 30 miles beneath the visible cloud deck into the bitter cold upper atmosphere, where it condensed into large ice crystals. Winds and associated storm clouds punched through the cloud tops with such force they penetrated Saturn’s normally serene stratosphere.

“On Earth, the lower stratosphere is where commercial airplanes generally fly to avoid storms which can cause turbulence,” says Brigette Hesman, a scientist at the University of Maryland in College Park and second author on the paper. “If you were flying in an airplane on Saturn, this storm would reach so high up, it would probably be impossible to avoid it.”

In this May 18 photo, the storm is the white band near the top split in two by a thin darker cloud belt. The warmer-toned belt below the storm is Saturn's North Eq. Belt. Credit: Efrain Morales

According to NASA, it’s the most violent event ever observed at Saturn by an orbiting spacecraft. Seeing this violence in amateur telescopes takes persistence because its appearance is subtle and requires high magnification (200x and up) and a night of very calm, steady air to see. Look for a pale white zone bordering the length of Saturn’s grey-toned North Equatorial Belt.

To help you find it, use this much smaller version of Efrain’s photo at right. I’ve taken and flipped it, so south is up the way you’d see it in most telescopes. The view simulates about how the planet appears on a steady night when magnified around 250x. Good luck telescopic observers!

2 Responses

  1. Jim Schaff

    Hi Bob,

    How are you doing? Been busy here.

    I was looking at Saturn tonight. I think I saw a bit of the storm. Anyway, there was a bright spot around the latitude you show in your picture. The air was pretty stable and I was able to view 300 to 400x. Saturn’s other features were awesome too: the Cassini Division, the Crepe ring, the shadow of the ring on the planet and the planet on the ring. Sure got to like these Florida skies. The transparency wasn’t the greatest but I could still the two of the trio in Leo, and M51. M3, M13, and M92 looked good but were diminished some by the light pollution here at my driveway.

    Thanks for writing your blog. I read it daily.

    take care,

    1. astrobob

      Really good to hear from you Jim. Sounds like just the right conditions to see the storm. We’re cloudy tonight but the air’s almost like summer and smells good. Lots of frogs still out, too. I’ve got a few days off now and look forward to a clear night or three.

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