SATURNS RING Saturn, the sixth planet from the sun, is one of the most easily identified targets for astronomers, largely due to its large and distinct ring system. The rings of Saturn have fascinated stargazers for centuries, ever since telescopes were first pointed toward the sky. When Galileo Galilei first observed Saturn in 1610, he thought that the rings were enormous moons, one positioned on each side of the planet. Over several years of observations, he noted that the rings changed shape and even disappeared, as they changed their inclination with respect to Earth. We now know that Galileo was observing a ring plane crossing. Saturns equator is tilted relative to its orbit around the sun by 27 degrees – similar to Earths 23-degree tilt. As Saturn circles the sun, first one hemisphere and then the other is tilted sunward. The tilt causes seasons, just as it does on Earth, and when Saturn reaches equinox, its equator and ring plane are directly in line with the sun. Sunlight hits the rings edge-on, and the fine line of the rings is difficult to detect. The rings are wide — 170,000 miles across (273,600 km) — but only about 30 feet (10 meters) thick.
Posted on: Sun, 10 Aug 2014 06:34:09 +0000