While Orion’s stepping into the evening sky followed by Jupiter in Leo, the lord of the rings has returned to punctuate the dawn. It’s great to see Saturn back in view. Along with Venus, which we’ll take a look at later this week, there are now three evening planets (Mars, Jupiter, Venus) and one in the morning.
While still low in the southeast, the delicate crescent moon has a happy meeting with Saturn this Friday the 19th two nights after a conjunction with Virgo’s brightest star Spica. The rings are tilted a hair more than 24° or near the maximum of 27°. Any telescope will show the rings at 30x or higher magnification. You can even see the planet’s oval shape due to the extra girth provided by the rings in a pair of 10x binoculars.
In honor of the rings, we present a recent photo of Saturn taken by the Cassini spacecraft on August 14 this year. Although Saturn’s rings look solid when viewed from Earth, they’re really translucent, composed of floating chunks of water ice in size from about 1/2-inch (1 cm) to 33 feet (10 meters). I wouldn’t put it past some future entrepreneur to gather up these smaller chunks and market them to those wishing to sip their hard liquor “on the rocks” as it were.
It wasn’t until 1859 that physicist James Clerk Maxwell demonstrated the rings must be made of many individual particles; if they were solid they’d be unstable and break into pieces. Spectroscopic studies in the 1970s, where astronomers determine the composition of an object by examining the light it reflects and absorbs with a spectroscope, proved beyond a shadow that the rings were made of mostly water ice.
One of my favorite astronomical daydreams is to imagine myself in the ring plane gently hopping from one low-gravity ice chunk to the next. Once I arrived at a piece large enough to make for a comfortable seat, I’d tether myself to it so as not to float off and then ponder the millions of small, icy world-lets tumbling across my field of view.
A lovely vision on a wintery afternoon.