dipper@utastro.UUCP (Debbie Byrd) (08/05/85)
The planet Jupiter today falls behind Earth in the race around the sun. More -- after this. August 4 Jupiter at Opposition Sunday the giant world Jupiter falls behind our Earth in the race of planets around the sun. If you'd looked down from far above the solar system early this morning, you'd have seen Earth coming up fast -- toward an imaginary line in space between Jupiter and the sun. Then Earth rushed between the giant planet and the sun -- moving at more than 18 miles per second, as compared to Jupiter's 8 miles per second. Now our faster Earth is moving ahead of Jupiter. In our sky, the planet Jupiter currently appears opposite the sun -- since from our point of view at this time it really is opposite the sun in space. That's why astronomers say that Jupiter is now at opposition. Like any object at opposition, Jupiter rises when the sun sets and wheels across the sky until dawn. But by the end of the month, Earth will be so far ahead in orbit that Jupiter will already have risen in the southeast when evening begins -- and it'll set before dawn. You can probably spot Jupiter now, and for the next few months, as the very bright object in the east each evening. Jupiter shines brilliantly by virtue of its large size, its bright cloud cover which reflects sunlight so well, and its relative nearness to Earth right now. As for the Earth, with no more outer planets ahead in orbit, our world has now successfully lapped them all until next year -- when we come up on the outer planets from behind again -- and the series of oppositions starts over once more. Script by Deborah Byrd. (c) Copyright 1984, 1985 McDonald Observatory, University of Texas at Austin