Astronomy Picture Of the Day (APOD)Expansive Comet Holmes
The spherical coma of Comet Holmes has swollen to a diameter of over 1.4 million kilometers, making the tenuous, dusty cloud even bigger than the Sun. Scattering sunlight, all that dust and gas came...
Earthrise from Moon Orbiting Kaguya
What does the Earth look like from the Moon? A new version of this space age perspective was captured by the robotic Kaguya spacecraft currently in orbit around Earth's Moon. Launched two months...
Aurora in the Distance
Some auroras can only be seen with a camera. They are called sub-visual and are too faint to be seen with the unaided eye. The reason is that the human eye only accumulates light for a fraction of a second at a time, while a camera shutter can be left open indefinitely.
M45: The Pleiades Star Cluster
Perhaps the most famous star cluster on the sky, the Pleiades can be seen without binoculars from even the depths of a light-polluted city. Also known as the Seven Sisters and M45, the Pleiades is one of the brightest and closest open clusters.
Forest and Sky
With pine trees in dim silhouette, this skyscape from Breil-sur-Roya in southern France was captured on November 11. In the early evening scene, a satellite seems to streak through the branches, while bright, round, fuzzy Comet Holmes appears to lie just beyond them, near the stars of the constellation Perseus.
This gorgeous image of Orion shows off the constellation's young stars and cosmic clouds of hydrogen gas and dust. Made with a film camera tracking the stars on November 11, the exposure lasted some 40 minutes.
M13: The Great Globular Cluster in Hercules
M13 is modestly recognized as the Great Globular Cluster in Hercules. A system of stars numbering in the hundreds of thousands, it is one of the brightest globular star clusters in the northern sky.
Tunguska: The Largest Recent Impact Event
Yes, but can your meteor do this? The most powerful natural explosion in recent Earth history occurred on 1908 June 30 when a meteor exploded above the Tunguska River in Siberia, Russia. Detonating with...
The Inner Coma of Comet Holmes
What's happening to Comet Holmes? The rare comet remains visible to the unaided eyes of northern observers as an unusual small puff ball in the constellation of Perseus. A high resolution set of images of the comet's inner coma, taken last week and shown above, reveals significant detail.
Cosmic Rays from Galactic Centers
Where do cosmic rays come from? A major step toward answering this century old question may have just come in from the Auger Observatory project, the world's premier cosmic ray observatory. That high energy fundamental particles are barreling through the universe has been known for about a century.