Astronomy Picture Of the Day (APOD)Elements of the Swan Nebula
In the depths of the dark clouds of dust and molecular gas known as M17, stars continue to form. Also known as the Omega Nebula and Horseshoe Nebula, the darkness of M17's molecular clouds results from background starlight being absorbed by thick filaments of carbon-based smoke-sized dust.
Our Moon's appearance changes nightly. This time-lapse sequence shows what our Moon looks like during a lunation, a complete lunar cycle. As the Moon orbits the Earth, the half illuminated by the Sun first becomes increasingly visible, then decreasingly visible. The Moon always keeps the same face toward the Earth.
A Perseid Aurora
Just after the Moon set but before the Sun rose in the early morning hours of 2000 August 12, meteors pelted the Earth from the direction of the constellation Perseus, while ions pelted the Earth from the Sun.
Blue Stragglers in NGC 6397
In our neck of the Galaxy stars are too far apart to be in danger of colliding, but in the dense cores of globular star clusters star collisions may be relatively common. In fact...
Palomar at Night
What's wrong with this picture? The summer night sky is clear, and moonlight illuminates the dome of the Hale 200-inch Telescope at Palomar Observatory, northeast of San Diego, California, USA. The familiar stars of the Teapot asterism in the constellation Sagittarius shine above the dome and to the right.
Dusty Galaxy Centaurus A
Why is peculiar galaxy Centaurus A so dusty? Dramatic dust lanes that run across the galaxy's center mark Cen A. These dust lanes are so thick they almost completely obscure the galaxy's center in visible light.
How does a space shuttle that landed in California get back to Florida for its next launch? The answer is by ferry. NASA operates two commercial Boeing 747 airplanes modified to carry a space shuttle on their backs.
In the Center of the Virgo Cluster
The Virgo Cluster of Galaxies is the closest cluster of galaxies to our Milky Way Galaxy. The Virgo Cluster is so close that it spans more than 5 degrees on the sky - about 10 times the angle made by a full Moon.
Ice Fishing for Cosmic Neutrinos
Scientists are melting holes in the bottom of the world. In fact, several holes have been melted near the South Pole, and they are now being used as astronomical observatories. Astronomers with the Antarctic Muon and Neutrino Detector Array (AMANDA) lower into each vertical lake a string knotted with basketball-sized light detectors.
Island Universe, Cosmic Sand
On August 13, 2002, while counting Perseid meteors under dark, early morning Arizona skies, Rick Scott set out to photograph their fleeting but fiery trails. The equipment he used included a telephoto lens and fast color film. After 21 pictures he'd caught only two meteors, but luckily this was one of them.