SUNSET: 
Mercury's Polar Ice Defies the Odds
Today scientists confirmed a suspicion raised some 20 years ago: despite all logic to the contrary, the hellish planet Mercury is hiding substantial deposits of water ice in its polar regions.
Making the Moon Anew
One of the solar system's most nagging problems literally stares into the collective faces of planetary scientists on many nights every month. It's the Moon — or, specifically, how it came to exist.
Tour November's Sky! | November 1st, 2012
Mars is very low in the west after sunset, and Jupiter rises a couple hours later. But most of the planetary action is in the eastern sky before dawn.
S&T's Audio Sky Tour for December 2012
Mars lurks low in the west after sunset, just as Jupiter rises dramatically in the east. Meanwhile, a mythic tale unfolds among the stars and constellations overhead.
News From Across the Solar System
From new models of the Moon's formation to planets forming around distant stars, nearly 800 planetary scientists had plenty of new results to present this week when they met in Reno, Nevada.
A Problem with Pluto's Moons
The discovery of two tiny moons circling the most famous "dwarf planet" has raised concerns that the New Horizons spacecraft might be endangered when it flies by in July 2015.
Meteor Storm Brewing for 2014?
Dynamicists know for certain that on May 24, 2014, Earth will plow through a dense stream of dust particles shed by the periodic comet 209P/LINEAR. The only question is: how intense will the assault be?
Comet Hergenrother Puts on a Show
Astronomers predicted that Comet 168P/Hergenrother wouldn't get any brighter than 15th magnitude this month. But the comet had other ideas: an ongoing outburst has brightened it to within reach of medium-size backyard telescopes.
Big Meteoroid Boomerangs Around Earth
Late on September 21st, a bright fireball broke apart as it skimmed the atmosphere over northwestern Europe — then it became a temporary satellite, looping completely around the planet before its searing finale over eastern North America.
Curiosity Finds Ancient Streambed
NASA's newest rover has found strong evidence near its landing site inside Gale crater that vigorous steams of liquid water once flowed across the Martian surface.
Much Ado at Mars
It's a great time to be a Red Planet researcher. Right now three orbiters and two rovers — including the increasingly mobile Curiosity — are checking out Earth's planetary neighbor from very close range.
S&T's Audio Sky Tour for November 2012
Mars is very low in the west after sunset, and Jupiter rises a couple hours later. But most of the planetary action is in the eastern sky before dawn.
Bright Fireball Spotted Near Jupiter
Amateur astronomers have spotted a brief flare of light on Jupiter, the third such explosion in as many years. The impactor was too small to penetrate deeply enough into the Jovian upper atmosphere, and no impact "scar" has been seen.
Charting a Course for Heliophysics
A new report by the U.S. National Academy of Sciences examines how studies of the Sun and its influence on Earth have advanced in the past decade and makes recommendations for what should be tackled next.
Dawn Bids Vesta Adieu
With a gentle, constant nudge from its ion-propulsion system, NASA's asteroid explorer has departed its first target and begins a 2½-year cruise to the second one.
Americans Will See Total Solar Eclipse in 2017
Mark your calendars for August 21, 2017 — when the Moon's umbral shadow will race coast to coast across the United States for the first time in nearly a century.
S&T's Audio Sky Tour for October 2012
Mars is managing to hang on low in the west after sunset, while in the east you'll see the Square of Pegasus and, later on, the giant planet Jupiter.
Curiosity Zaps Its First Martian Rock
A rapid-fire burst of 30 laser pulses from the rover's ChemCam instrument created an incandescent hotspot on a fist-sized rock about 10 feet away.
Mount Sharp or Aeolis Mons?
Scientists associated with the Curiosity mission have two names for the towering peak inside Gale crater. SkyandTelescope.com readers told us which one they liked best.
August 13th's Occultation of Venus
If you're up for a bit of a challenge, drag out your telescope to watch a thin crescent Moon glide over brilliant Venus. This cover-up is a daylight event in the U.S., but it occurs in dark skies before dawn on the 14th for lucky observers in Japan.
