Will a supernova explode this year, or will a fresh comet streak past? We can only wait and see. But the dance of the planets runs like clockwork, and the schedule of new space missions is at least broadly predictable. The forecast: an oddly front-loaded year. If you want to enjoy a good look at our neighboring worlds, put on your coat and get out now.
The year begins with a brief, brilliant last hurrah for Venus, which blazes like a diamond low in the evening twilight. This is a one-week special; Earth's sister planet vanishes into the sun's glare by midmonth and then shifts into the early-morning sky for most of the year. Likewise, Mars shines brightly in January but then steadily fades and disappears from view by August.
On January 4, Earth reaches perihelion, the point in its orbit where it comes closest to the sun. As a result, the sun now looks 7 percent brighter than it will in July, but its low winter elevation keeps things chilly in the Northern Hemisphere during the run-up to the premier space event of 2006: the return of the Stardust spacecraft after a six-year mission. Stardust collected samples from comet Wild 2 a year ago and is scheduled to parachute onto the Utah desert on January 15, carrying its precious cargo. The same day, the Cassini spacecraft makes the first of 13 extremely close 2006 swings past Saturn's enigmatic moon Titan, a world of methane rain and ice volcanoes.
Saturn is at its year's best on January 27, when it is directly opposite the sun. Perched in front of the constellation Cancer, Saturn remains bright and high overhead for the rest of the winter and will still be nicely visible into the spring.
The Sky This Month
Mercury makes decent but quick forays into the evening sky in late February and mid-June and into the morning sky in early August and late November.
Venus sinks into the sun's glare by mid-January and spends most of the rest of the year shining brilliantly but relatively low in the east before dawn.
Mars starts the year high and bright, then steadily dims as it slides toward the sun and vanishes from the evening sky by August.
Jupiter is reliable as always, reaching peak brilliance in early May and remaining prominent after sunset until September.
Saturn peaks in late January and spends the next two weeks near the Beehive star cluster, a pretty sight through binoculars. By mid-July, it is lost in the twilight.
Uranus is at its brightest in early September. Although it is easily visible under dark skies, it looks just like a star until seen through a telescope.
Elusive Mercury makes a fleeting evening appearance. The solar system's innermost planet never strays far from the sun. It is best seen during the last half of the month, when it stands out as the only notable point of brightness in western twilight, 40 minutes after sunset.
The Mars Reconnaissance Orbiter reaches its destination on March 10. Over the next few years, the spacecraft will map the
Martian surface in unprecedented detail, with an emphasis on finding evidence of water.On March 29, a total solar eclipse sweeps across Africa through the Mediterranean and into Asia. Cruise lines, local expeditions, and scientific teams will be stationed along the track to catch four minutes of daytime darkness.
On April 11, NASA launches the Stereo mission, sending a pair of matching observatories into space, one orbiting the sun ahead of the Earth, the other trailing behind. The twin satellites will create stunning 3-D pictures of the sun, focusing on the huge magnetic eruptions that spew billions of tons of energetic particles in our direction.
Jupiter makes its closest approach to Earth during 2006 on May 5. The solar system's largest planet will dominate the spring and summer sky with the dim constellation Libra as a backdrop.
June 17 brings the launch of the Dawn spacecraft, which will provide the first close look at the two biggest asteroids, Vesta and Ceres. Recent studies show that the latter may be like a miniplanet, with polar caps and a thin atmosphere.
Astronomy's summer doldrums. Even the reliable Perseid meteor shower in August is spoiled by a nearly full moon.
Now's the time to spot the faintest planet visible to the unaided eye. Uranus is directly opposite the sun on September 5 and can be located in the constellation Aquarius, shining just at the edge of human vision.
On November 8, Mercury transits the sun. The last time sky watchers in North America had a good opportunity to witness this event, during which the planet showed up as a moving dot on a projected image of the sun, was in 1960.
Mercury, Jupiter, and Mars form a pretty triangle, visible to early risers ready to survey the predawn sky, on December 9. Meanwhile, the Geminid meteors will put on a splendid display before midnight on December 13.