Venus, and Jupiter, and the moon, oh my!

With only slight apologies to Dorothy, Toto, and their three amigos, people in North and South America have an opportunity to enjoy a visual feast over the next two evenings.

For people in the US, look west around sunset, clouds willing. Jupiter, Venus, and a sliver of a crescent moon will form a spectacular, tight triangle in the early evening sky, near the horizon. On Dec. 1 they will be so tightly packed that you'll be able to cover them with your thumb at arms length.

Our solar system is nothing if not thoughtful. It put on a similar show for "morning people" around dawn last February. Now, it's giving folks who aren't morning people a chance to catch the view. And if you're in right spot in Western Europe, you'll get more than this function at the conjunction. The moon will actually cover Venus for a while -- an occultation.

Of the three participants, Venus is the most impressive. Although it's 93 million miles from Earth about now, it shines with a brilliance people have mistaken for UFOs or landing lights from a incoming airliner. But the moon is no slouch, either.

View the moon with a slightly averted glance and you're likely to pick up the dull but noticeable glow of Earth light reflecting off the darkened lunar surface. As for Jupiter's brightness? Cut it some slack. Despite its enormous size, it's currently about 472 million miles away.

If you're looking for something musical to accompany the view, we suggest a bit of Gustav Holz's "The Planets." And as you watch, consider that humans are virtual visitors to two of the objects. And a new mission is planned to the third.

Currently, Japan, China, and India have robotic spacecraft orbiting the moon. The US will join them next year with its Lunar Reconnaissance Orbiter. The European Space Agency's Venus Express is orbiting the second rock from the sun, yielding new insights into a cloud-shrouded world with surface temperatures so high they can melt lead.

And on Nov. 24, the National Aeronautics and Space Administration announced it was taking a significant step toward a new mission to Jupiter. Mission designers say they expect to launch the orbiter, dubbed Juno (Jupiter's wife), in 2011. The craft should reach the planet by 2016 and orbit the giant gas ball for a year.

If all goes well, it will be the first such craft to operate at such a long distance from the sun on solar power alone. If you're into barnstorming, Juno will dip to within 3,000 miles of the giant's cloud-tops as it gathers data. What a view of the Great Red Spot that would yield!