Hubble Gives Us Saturn

The Hubble took this amazing photo of Saturn on June 6 when the planet was about 870 million miles (1.4 billion km)  from Earth. From the outside in we can see the A ring split by a narrow, dark rift called the Encke Gap. Cassini’s Division, the much wider gap, separates the A from the brighter B ring. The inner rings comprise the fainter C ring. Data from NASA’s Cassini mission suggest that the rings formed about 200 million years ago, about the time of the dinosaurs during the Jurassic period. The origin of the rings is still something of a mystery, but they likely originate from a moon that was either disrupted as it spiraled into toward the planet or was struck and blasted to pieces by an asteroid. The icy debris spread out to form the rings. The planet’s banded structure, clearly visible in the new image, is caused by the winds and the clouds at different altitudes. NASA, ESA, A. Simon (GSFC) and the OPAL Team, and J. DePasquale (STScI)

Enjoy this photo of Saturn from one of the finest instruments on the planet. Or off the planet. The Hubble Space Telescope orbits 335 miles (540 km) above the Earth’s surface and completes one revolution in about 97 minutes. The color and detail in the photo are stunning. Be sure to click on the image for a large, monitor-filling version.

On June 6, a month before Saturn reached opposition — its closest to Earth this year — Hubble was used to observe and photograph the planet, which presents its rings at near maximum tilt this year. Jupiter, Uranus and Neptune all have rings but they’re no match for Saturn’s, the largest, brightest and most spectacular in the solar system. The north face of the rings and north polar region are tipped into view. The white spot and wisps at the edge of the polar region comprise a storm, now slowly disintegrating, that’s been active the past couple months. While it shows up well in the Hubble photo and in images taken by amateur astronomers, it’s too small to eyeball in a typical telescope.

In 2013 (left), the entire interior of the hexagon appeared blue. By 2017, most of the hexagon’s interior was covered in yellowish haze, and only the center of the vortex remained blue. The seasonal arrival of the sun’s ultraviolet light triggers the formation of air-borne chemicals, creating the haze. The yellowing of the polar region is believed to be caused by smog particles produced by increasing solar radiation shining on the polar region as Saturn approached the northern summer solstice back in 2017. NASA/JPL-Caltech/Space Science Institute/Hampton University

Also visible is the hexagonal pattern to the dark clouds around the north pole. The “polar hexagon” is a stable and persistent wind feature that was discovered by the Voyager 1 space probe in 1981. The sides of the hexagon each measure about 8,600 miles (13,800 km) long or about 700 miles wider than the diameter of the Earth. Scientists were able to re-create the hexagon by spinning a liquid in a tank at one speed in its center and another speed around its circumference. It’s thought that strong changes in wind speed with changing latitude at Saturn may give rise to the pattern.

This composite image, taken by Hubble shows the ringed planet Saturn with six of its 62 known moons. The image is a composite because the moons move during the Saturn exposures, and individual frames must be realigned to make a color portrait. Click for a larger version. NASA, ESA, A. Simon (GSFC) and the OPAL Team, and J. DePasquale (STScI)

Hubble also managed to capture images of six of Saturn’s 62 currently known moons: DioneEnceladusTethysJanusEpimetheus, and Mimas. The first three are visible in 6-inch and larger telescopes right from your backyard.

Saturn is currently due south in the lower third of the sky at twilight gives way to night. It shines from Sagittarius the Archer right in the middle of the Milky Way. We’re currently in a perfect stretch of time to bring out a telescope for a look. No scope? Check online to see if there’s an astronomy club in your area. Contact them and ask when their next public observing session will be held.

4 Responses

  1. Edward M. Boll

    Well Bob, S3 is still out there. It has been seen in the last day or 2 at magnitude 7.9. Faint but a nice surprise for me.

    1. astrobob

      Yes, I saw this morning that J.J. Gonzalez reported it brighter than most of us had imagined it would be. Very difficult object for me because of the northerly latitude. Just coming up in twilight very low in the east. It looks like I won’t have another opportunity to see it. I did catch it last month when it was around mag. 7 and a very nice blue-green ball in the scope.

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