Jimmy Westlake: Saturn closest to Earth
February 18, 2008
Steamboat Springs — Reminder: Don’t forget to watch the total eclipse of the Snow Moon between 6:43 p.m. and 10:09 p.m. on Wednesday.
On Feb. 24, the ringed planet Saturn will be at its closest point to the Earth for the year, a point called opposition. At the moment of opposition, the Earth is positioned directly between Saturn and the sun, placing the two planets as close together as they can be. Oppositions of Saturn happen about every 12 1/2 months as the faster moving Earth gains a lap on Saturn and catches up to it from behind. This year, on Feb. 24, Saturn will be 775 million miles from Earth.
Saturn is surrounded by a set of magnificent rings that completely encircles the planet’s equator. The rings are composed of millions of tiny ice particles, probably particles blasted off of one or more of Saturn’s small, icy moons by the impact of a comet.
And, speaking of moons, Saturn has quite a large family of worlds and mini-worlds orbiting around it. To date, astronomers know of 60 moons orbiting Saturn. The largest is Titan, a planet-sized moon with a thick, cloudy atmosphere. Saturn, Titan and many other moons are being studied right now by NASA’s Cassini spacecraft, which was placed into orbit around Saturn in July 2004. Spectacular photographs of the Saturn system are beamed back to Earth daily, helping us to understand the mysteries of this distant world.
You can spot Saturn, without any optical aid, rising in the eastern sky just after sunset. It appears as a bright, yellowish star that doesn’t twinkle like a regular star, but gleams with a steady light. This year, Saturn is positioned near the head of the constellation Leo, the Lion, and Leo’s brightest star, Regulus. Icy-blue Regulus rises just minutes before Saturn.
If you own a telescope – even a small one – try aiming it at Saturn. Saturn offers the biggest “wow” factor of any other object visible through a small telescope. You can easily see Saturn’s magnificent icy rings and its largest moons. Try looking around Tuesday, Feb. 27, and March 6 when the giant moon Titan appears farthest from the rings and is easiest to spot. Titan will look like a little orange star just beyond the edge of the rings.
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Check out the latest amazing Cassini images of Saturn at the Web site Saturn.jpl.NASA.gov.
Professor Jimmy Westlake teaches astronomy and physics at Colorado Mountain College’s Alpine Campus. He is an avid astronomer whose photographs and articles have been published on the Web sites of CNN.com, NASA’s “Astronomy Picture of the Day” Web site, Spaceweather.com, Space.com, Discover.com, MSNBC.com, NationalGeographic.com and in Sky & Telescope, Astronomy, Night Sky, Discover, and WeatherWise magazines. His “Celestial News” article appears weekly in the Steamboat Pilot & Today.. His “Cosmic Moment” radio spots can be heard on local radio station KFMU. Also, check out his Web site at http://www.jwestlake.com.