Astronomy Picture Of the Day (APOD)A Year of Assessing Astronomical Hazards
Could an asteroid destroy civilization on Earth? Mountain-sized space rocks could potentially impact the Earth causing global effects, and perhaps even be mistaken for a nuclear blast of terrestrial origin. Such large impacts are rare but have happened before. Modern telescopes have therefore begun to scan the skies for signs of approaching celestial hazards.
A Sun Pillar
Have you ever seen a sun pillar? When the air is cold and the Sun is rising or setting, falling ice crystals can reflect sunlight and create an unusual column of light. Ice sometimes forms flat, stop-sign shaped crystals as it falls from high-level clouds.
NGC 1818: A Young Globular Cluster
Globular clusters once ruled the Milky Way. Back in the old days, back when our Galaxy first formed, perhaps thousands of globular clusters roamed our Galaxy. Today, there are perhaps 200 left. Many globular clusters were destroyed over the eons by repeated fateful encounters with each other or the Galactic center.
This dream-like image of Mir was recorded by astronauts as the Space Shuttle Atlantis approached the Russian space station prior to docking during the STS-76 mission. Sporting spindly appendages and solar panels...
X Ray Mystery in RCW 38
A mere 6,000 light-years distant and sailing through the constellation Vela, star cluster RCW 38 is full of powerful stars. It's no surprise that these stars, only a million years young with hot outer atmospheres, appear as point-like x-ray sources dotting this x-ray image from the orbiting Chandra Observatory.
Searching for Meteorites in Antarctica
Where is the best place on Earth to find meteorites? Although meteors fall all over the world, they usually just sink to the bottom of an ocean, are buried by shifting terrain, or are easily confused with terrestrial rocks.
Orion always comes up sideways ... and was caught in the act earlier this month by astronomer Jimmy Westlake, stargazing eastward over the Rocky Mountains north of Leadville, Colorado, USA. To make this gorgeous image, Westlake placed his camera on a tripod for two exposures.
Spring Dust Storms at the North Pole of Mars
Spring reached the north pole of Mars in May, and brought with it the usual dust storms. As the north polar cap begins to thaw, a temperature difference occurs between the cold frost region and recently thawed surface, resulting in swirling winds between the adjacent regions.
Stars and Dust Through Baades Window
Billions of stars light up the direction toward the center of our Galaxy. The vast majority of these stars are themselves billions of years old, rivaling their home Milky Way Galaxy in raw age. These stars are much more faint and red than the occasional young blue stars that light up most galaxies.
Summer at the South Pole
The December solstice brings the beginning of Winter to Earth's Northern Hemisphere and Summer time to the South! This view of Earth's Southern Hemisphere near the beginning of Summer was created using images from the Galileo spacecraft taken during its December 1990 flyby of our fair planet.