Astronomy Picture of the Day 9-06-03

Explanation: Slice Jupiter from pole to pole, peel back its outer layers of clouds, stretch them onto a flat surface ... and for all your trouble you'd end up with something that looks a lot like this. Scrolling right will reveal the full picture, a color mosaic of Jupiter from the Cassini spacecraft. The mosaic is actually a single frame from a fourteen frame movie constructed from image data recorded by Cassini during its leisurely flyby of the solar system's largest planet in late 2000. The engaging movie approximates Jupiter's cloud motions over 24 jovian rotations. To make it, a series of observations covering Jupiter's complete circumference 60 degrees north and south of the equator were combined in an animated cylindrical projection map of the planet. As in the familiar rectangular-shaped wall maps of the Earth's surface, the relative sizes and shapes of features are correct near the equator but become progressively more distorted approaching the polar regions. In the Cassini movie, which also features guest appearances by moons Io and Europa, the smallest cloud structures visible at the equator are about 600 kilometers across.

Jupiter was at conjunction on August 22nd, so it won't be visible in night skies for a while yet. It should start rising out of morning twilight around the beginning of fall.

The following stats are for 45 degrees north latitude, Daylight Savings Time. On 9-21 it will be about 6 degrees above the horizon, just north of east, at 5:20 AM. 2 weeks later it will be 14 degrees above the eastern horizon at the same time.

Jupiter will reach opposition (and midnight culmination) around March 5, 2004.

Jupiter is the fifth planet from the Sun and by far the largest. It is more than twice as massive as all the other planets combined (318 times Earth).

orbit: 778,330,000 km (5.20 AU) from Sun
diameter: 142,984 km (equatorial)
mass: 1.900e27 kg

Jupiter has 61 known satellites (as of May 2003): the four large Galilean moons, 34 smaller named ones, plus many more small ones discovered recently but not yet named.

Cassini saw Jupiter from outside its orbit: something Earthbound observers will never see.

Jupiter in crescent phase:

Disclaimer: Opinions posted on Free Republic are those of the individual posters and do not necessarily represent the opinion of Free Republic or its management. All materials posted herein are protected by copyright law and the exemption for fair use of copyrighted works.