|
diac.
• Look for this brilliant beauty of a planet high in southern sky as soon as darkness falls. (As seen from the Southern Hemisphere, Jupiter appears in the northern sky.) Far brighter than any star, this blazing world is even visible from a light-polluted city. In a dark sky you may see Jupiter shining in between two beautiful stellar signposts: the star Aldebaran and the glorious Pleiades star cluster.
• Jupiter, the fifth planet outward from the sun, always goes eastward in its orbit all year long. However, as seen from Earth, all superior planets - solar system planets residing outside of Earth's orbit - go westward in front of backdrop stars for a portion of the year. In their outward order from the sun, the superior (exterior) planets are Mars, Jupiter, Saturn, Uranus and Neptune.
• When the Earth in its smaller and swifter orbit swings by any superior planet, that planet appears to be going backward in its orbit for a few to several months. It's comparable to passing a car on the highway, with that car appearing to be going backward relative to distant background. But you know that car isn't really going in reverse at all. It's the same idea when Earth goes by Jupiter or any superior planet.
• The farther the planet is from the Earth and sun, the longer the westward retrograde motion as seen from Earth. Jupiter's recent retrograde lasted about 118 days. Saturn, the sixth planet outward, will be in retrograde this year from February 19, 2013, to July 9, 2013, for a total of nearly 139 days.
• Starting today, Jupiter will be moving eastward in front of the stars along the ecliptic - away from the Pleiades cluster but toward the star Aldebaran.
•
|
|
