Jupiter, Moon and Venus are just a bit closer now

Seattle - On Monday evening, weather permitting, stargazers in North America will be treated to a rare phenomenon that won’t happen again for another 44 years.

At approximately 6 pm on December 1, Jupiter, Venus, and a fingernail-thin crescent moon–the three brightest objects in the night sky–will appear in close proximity to each other, forming a bright, celestial triangle low in the southwest sky. They’ll be so close together that all three bodies can be covered by your thumb, held at arm’s length in front of your eyes. Within ninety minutes, the bright planets will disappear beyond the horizon, so be sure to get out to look early.

The conjunction is, of course, an optical illusion caused by the angle of the viewer from the Earth’s surface. In reality, Venus, Jupiter and the moon are nowhere near each other, and the phenomenon even looks different from different parts of the globe. The triangular conjunction will be clearly visible from North America, but in several European locations, stargazers will instead be treated to an eclipse of Venus, as the moon passes between the Earth and our planet’s brightest neighbor. This phenomenon, called an occultation, is also fairly rare, and prized by experienced stargazers.

The orbits of Jupiter and Venus have been bringing them into position gradually over the last few days, and after Monday night, they’ll appear to be moving away from each other again. While a similar triangular formation will be visible again as early as March of 2012, the planets and our moon won’t appear this close together, or as bright, until 2052.

If you’re fortunate enough to own a telescope, turn it toward the bright lights of Venus and Jupiter and you’ll be able to see them even more up-close and personal. Venus will be in a gibbous phase (past the half phase but not quite full), but will show as little more than a bright light even under magnification. Jupiter, on the other hand, shows its colorful bands, and, depending on the power of your telescope, you might even catch a glimpse of a handful of its many moons. Likely candidates for viewing are Callisto, Io, Ganymede and Europa.

Historically, such conjunctions of celestial objects have been interpreted as portents–usually unpleasant ones. Whether Monday’s display of Jupiter, the Moon and Venus in a triangle predicts great things–or catastrophes–to come is anybody’s guess. One thing’s certain, though–it will be a beautiful spectacle you won’t want to miss.