Western Slope Skies
9:40 am
Tue December 4, 2012

Jupiter

This month marks an anniversary for Western Slope Skies. Our first broadcast was in November of 2011 and Jupiter was the topic. Once again this year, Jupiter will be the brightest object in the night sky. It rises in the east during evening twilight in late November.


Jupiter is the largest planet in our solar system. More than 1,300 Earths could fit inside Jupiter. While it orbits the Sun once every 12 years, Jupiter spins on its axis in just 10 hours. So, a Jupiter-day is only 10 hours long!

Similar to the other three planets outside of the asteroid belt, Jupiter is a gas giant. While Jupiter’s upper atmosphere is almost entirely hydrogen and helium, the colors that we see are caused by small amounts of other compounds, including ammonia, phosphorus, sulfur, and hydrocarbons.

Visible in the constellation of Taurus for the remainder of the year, Jupiter will stay in the evening sky in the west until May.

The star cluster called The Pleiades, is also close to Jupiter during the late fall and winter. The Pleiades is visible to the naked eye from moderately dark sites and easily visible with binoculars. Look for a tight grouping of stars, just west of Jupiter.

If you have access to a telescope, Io, one of Jupiter’s moons, will cross the face of Jupiter beginning at 8:26 PM on November 30th. This crossing or transit will take slightly longer than 2 hours. It is easier to see the shadow of a moon than the moon itself.

Western Slope Skies is produced by members of the Black Canyon Astronomical Society.

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