"The Moon Pays a Visit to the Two Inner Planets, and How To Watch It"

Scheduled air date: 2001 Jan 15-21


Click on the above image to see an animated QuickTime® presentation! (695 KB)
The planets Mercury and Venus orbit closer to the Sun and in less time than our own planet, Earth.  As illustrated above, in the time it takes Mercury to make a complete revolution around the Sun (one orbit), Venus makes less than one-half revolution, and Earth slightly less than one- quarter.
(Planets shown at 11 Earth-day intervals from above the Sun's North Pole.)


Because Mercury and Venus are closer to the Sun, they are usually seen only a short time before sunrise, or after sunset.  Being the farther of the two from the Sun, Venus can, at times, be seen up to a few hours before sunrise or after sunset.  Mercury's appearances, however, are much briefer and rarer.  Next week is a particularly good time to view both of these planets, with the bonus of a Waxing Crescent Moon appearing near each.
(Shown half an hour after sunset for mid-Northern latitudes on the evenings of January 25th through 28th.)

If you wish to view illustrations for other episodes, please see our Star Gazer Illustrated directory.


Illustrations on this page were created using TheSky Astronomy Software, an advanced desktop planetarium program designed for Windows.

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