Astronomy Picture Of the Day (APOD)GLAST Gamma Ray Sky Simulation
What shines in the gamma-ray sky? This simulated image models the intensities of gamma rays with over 40 million times the energy of visible light, and represents how the sky might appear to the Gamma-ray Large Area Space Telescope (GLAST) after its first year in orbit.
Eros Craters And Boulders
From a delicate orbit around asteroid 433 Eros, the NEAR Shoemaker spacecraft's camera has now imaged the entire surface of the small oddly-shaped world at least once. Recorded on July 7th from a distance of 50 kilometers, this dramatic view is about 1.8 kilometers across.
AR9077: Solar Magnetic Arcade
On July 14th, solar active region 9077 (AR9077) produced a massive flare. The event also blasted an enormous cloud of energetic charged particles toward planet Earth, triggering magnetic storms and dramatic auroral displays. This striking close-up of AR9077 was made by the orbiting TRACE satellite shortly after the flare erupted.
Globular Cluster M19
M19 appears to be a typical globular cluster of stars - except for its shape. If one looks closely at the cluster, pictured above, it appears to be longer (top to bottom) than it is wide.
A Russian Proton Rocket Launches Zvezda
The Russian Proton rocket is the tallest rocket in routine use. First deployed in 1965, the rocket stands typically 40 meters tall, can carry unusually heavy payloads into space, and maintains a high record of reliability.
Lightning on Earth
Nobody knows what causes lightning. It is known that charges slowly separate in some clouds causing rapid electrical discharges (lightning), but how electrical charges get separated in clouds remains a topic of much research.
M57: The Ring Nebula
Except for the rings of Saturn, The Ring Nebula (M57) is probably the most famous celestial band. This planetary nebula's simple, graceful appearance is thought to be due to perspective -- our view from planet Earth looking straight into what is actually a barrel-shaped cloud of gas shrugged off by a dying central star.
Star Trails in Southern Skies
As the Earth spins on its axis, the stars seem to rotate around us. This motion produces the beautiful concentric arcs traced out by the stars in this time exposure of the southern hemisphere night sky. In the foreground is the dome of the Anglo-Australian Telescope in central New South Wales, Australia.
Crater On Ice
Impact craters are common on Earth's moon but on Jupiter's large ice moon Europa, they are very rare. Over time, both bodies have been subjected to an intense pounding by the solar system's formative debris, but geological activity on Europa's surface seems to have erased most of these impact scars.
LP 944-20: A Failed Star Flares
The tiny spot circled on the right actually represents a big astronomical discovery -- the first detected flare from a failed star. Failed stars, termed brown dwarfs in astronomers' parlance, are too low in mass to ignite nuclear hydrogen burning in their cores, yet