Astronomy Picture Of the Day (APOD)Islands of Four Mountains from Above
Our Earth is covered by volcanoes. Volcanoes are breaks in the Earth's cool surface where hot liquid rock from the interior comes out -- sometimes suddenly. In the above image from the ASTER camera...
Sunrise Solstice at Stonehenge
Today the Sun reaches its northernmost point in planet Earth's sky. Called a solstice, the date traditionally marks a change of seasons -- from spring to summer in Earth's Northern Hemisphere and from fall to winter in Earth's Southern Hemisphere.
Abell 2218: A Galaxy Cluster Lens
What are those strange filaments? Background galaxies. Gravity can bend light, allowing huge clusters of galaxies to act as telescopes, and distorting images of background galaxies into elongated strands. Almost all of the bright objects in this Hubble Space Telescope image are galaxies in the cluster known as Abell 2218.
Get out your red/blue glasses and float next to asteroid Itokawa, a diminutive world of the solar system only half a kilometer across. Boulders strewn across its rough surface and the lack of craters indicate that this asteroid is a rubble pile, formed as smaller pieces collected and were kept together by gravity.
Star Trails and Tajinastes
What bizarre planet do these alien creatures inhabit? It's only planet Earth, of course. In this well-composed scene, the sky is filled with star trails around the north celestial pole. A reflection...
Comet McNaught Passes NGC 1245
Of the many comets named for discoverer Robert McNaught, the one cataloged as C/2009 R1 is gracing dawn skies for northern hemisphere observers this month. Seen here on June 13th from southern New Mexico, this Comet McNaught's long ion tail sweeps across the telescopic field of view (a negative image is inset).
APOD is 15 Years Old Today
Welcome to the quindecennial year of the Astronomy Picture of the Day! Perhaps a source of web consistency for some, APOD is still here. As during each of the 15 years of selecting images...
Starry Night Scavenger Hunt
Did you know that Van Gogh's painting Starry Night includes Comet Hale-Bopp? Hopefully not, because it doesn't. But the above image does. Although today's featured picture may appear at first glance...
The Red Rectangle Nebula from Hubble
How was the unusual Red Rectangle nebula created? At the nebula's center is a young binary star system that surely powers the nebula but does not, as yet, explain its colors. The unusual...
Why would Mars appear to move backwards? Most of the time, the apparent motion of Mars in Earth's sky is in one direction, slow but steady in front of the far distant stars. About every two years, however, the Earth passes Mars as they orbit around the Sun.