Astronomy Picture Of the Day (APOD)Circum axial Leaf Trails
Are photographs of star trails really evidence of the Earth's rotation about its axis? Yes they are, and science journalist Trudy E. Bell discovered that there is a simple way to demonstrate this, if you have the stomach for it.
M13: The Great Globular Cluster in Hercules
In 1714, Edmond Halley noted that M13 "shows itself to the naked eye when the sky is serene and the Moon absent." Of course, M13 is now modestly recognized as the Great Globular Cluster in Hercules, one of the brightest globular star clusters in the northern sky.
The Milky Way Near the Southern Cross
The glow of the southern Milky Way and the well-known Southern Cross are featured in this colorful skyscape recorded in April over La Frontera, Chile. The Southern Cross (Crux) itself is at the right of the 20 degree wide field of view, topped by bright, yellowish star Gamma Crucis.
Dark Matter Ring Modeled around Galaxy Cluster CL0024 17
How do we know that dark matter isn't just normal matter exhibiting strange gravity? A new observation of gravitationally magnified faint galaxies far in the distance behind a massive cluster of galaxies is shedding new dark on the subject.
Bright Spiral Galaxy M81 in Ultraviolet from Galex
Where are the hot stars in M81, one of the closest major spiral galaxies? To help find out, astronomers took a deep image in ultraviolet light of the sprawling spiral with the Earth-orbiting Galex telescope.
Rotating Earth from Galileo
When passing Earth on your way to Jupiter, what should you look for? That question arose for the robotic Galileo spacecraft that soundlessly coasted past the Solar System's most photographed orb almost two decades ago.
The Cats Eye Nebula from Hubble
Staring across interstellar space, the alluring Cat's Eye nebula lies three thousand light-years from Earth. A classic planetary nebula, the Cat's Eye (NGC 6543) represents a final, brief yet glorious phase in the life of a sun-like star.
HD 189733b: Hot Jupiter
HD 189733b is a Jupiter-sized planet known to orbit a star some 63 light-years away. But while the distant world is approximately the size of Jupiter, its close-in orbit makes it much hotter than our solar system's ruling gas giant.
LDN 1622: Dark Nebula in Orion
The silhouette of an intriguing dark nebula inhabits this cosmic scene, based on images from the Palomar Observatory Sky Survey. Lynds' Dark Nebula (LDN) 1622 appears against a faint background of glowing hydrogen gas only easily seen in long telescopic exposures of the region.
SN 2006GY: Brightest Supernova
The stellar explosion cataloged as supernova SN 2006gy shines in this wide-field image (left) of its host galaxy, NGC 1260, and expanded view (upper right panel) of the region surrounding the galaxy's core.