Astronomy Picture Of the Day (APOD)Simulated Gamma ray Sky
Scheduled for launch in 2007, the Gamma-ray Large Area Space Telescope (GLAST) will explore the Universe in gamma-rays, the most energetic form of light. To get ready, consider this dynamic gamma-ray sky animation - constructed from simulating the first 55 days (seen above at one frame per day) of GLAST observations of cosmic gamma-ray sources.
Ancient Craters on Saturns Rhea
Saturn's ragged moon Rhea has one of the oldest surfaces known. Estimated as changing little in the past billion years, Rhea shows craters so old they no longer appear round their edges have become compromised by more recent cratering.
GRO J1655 40: Evidence for a Spinning Black Hole
In the center of a swirling whirlpool of hot gas is likely a beast that has never been seen directly: a black hole. Studies of the bright light emitted by the swirling gas frequently indicate not only that a black hole is present, but also likely attributes.
Gamma Ray Moon
If you could see gamma rays - photons with a million or more times the energy of visible light - the Moon would appear brighter than the Sun! The startling notion is demonstrated by this image...
Centaurus, the Centaur, is one of the most striking constellations in the southern sky. The Milky Way flows through this celestial expanse whose wonders also include the closest star to the sun, Alpha Centauri, and the largest globular star cluster in our galaxy, Omega Centauri.
NGC 1579: Trifid of the North
Colorful NGC 1579 resembles the better known Trifid Nebula, but lies much farther north in planet Earth's sky, in the heroic constellation Perseus. About 2,100 light-years away and 3 light-years across, NGC 1579 is a captivating study in color.
A Five Quasar Gravitational Lens
What's happening near the center of this cluster of galaxies? At first glance, it appears that several strangely elongated galaxies and fully five bright quasars exist there. In reality, an entire cluster of galaxies is acting as a gigantic gravitational lens that distorts and multiply-images bright objects that occur far in the distance.
Comet Schwassmann Wachmann 3 Passes the Earth
Rarely does a comet pass this close to Earth. Last week, dedicated astrofilmographers were able to take advantage of the close approach of crumbling 73P / Comet Schwassmann-Wachmann 3 to make time-lapse movies of the fast-moving comet. Large comet fragments passed about 25 times the Moon's distance from the Earth.
Maneuvering in Space
What arm is 17 meters long and sometimes uses humans for fingers? The Canadarm2 aboard the International Space Station (ISS). Canadarm2 has multiple joints and is capable of maneuvering payloads as massive as 116,000 kilograms, equivalent to a fully loaded bus. Canadarm2 is operated by remote control by a human inside the space station.
An Intermediate Polar Binary System
How can two stars create such a strange and intricate structure? Most stars are members of multiple-star systems. Some stars are members of close binary systems where material from one star swirls around the other in an accretion disk.