SUNSET: 
A Close Visitor Tumbles By
The little asteroid 1998 WT24, about 1 kilometer wide, was radar-imaged by NASA's Goldstone antenna last week when it flew within five Moon-distances of Earth. Click on image for animated movie of the asteroid's rotation.Courtesy Steve Ostro, Lance Benner, Jon Giorgini (JPL), Jean-Luc Margot (Caltech), and Mike Nolan (Arecibo Observatory).…
First Planet of a Giant Star
An artist's concept of a Jupiter-like planet eclipsing the giant star Iota Draconis, which is 13 times larger than the Sun.Courtesy JPL/NASA. About 80 planets are known to orbit main-sequence stars that are more or less like the Sun — ranging from spectral type F (a little hotter and larger…
Mars's Active Snow and Ice
These eroded pits in Mars's south polar cap widened noticeably from October 1999 (left) to August 2001 (right). Their walls, several meters high, retreated by about 3 meters during one Martian year. Such rapid change indicates that the material here is frozen carbon dioxide — dry ice — rather than…
September 11th Asteroid Memorials
Astronomy and all of science, at their best, embody the finest aspects of the human race — and its grandest hopes for an enlightened future. Guided by such thoughts, a committee of the International Astronomical Union has announced its memorial of the events of September 11th. Sky & Telescope senior…
Mars in a Dust Cocoon
The Hubble Space Telescope captured a dramatic change in Mars's weather.Courtesy NASA, James Bell (Cornell University), Michael Wolff (STScI), and the Hubble Heritage Team (STScI/AURA). The dust storm that wiped out Martian surface features in amateur telescopes last July could hardly be more dramatic than in the pair of natural-color…
The Heart of Omega Centauri
Left: Some 50,000 stars are individually resolved in a Hubble Space Telescope view through the center of the globular cluster Omega Centauri. Click on the image for a low-resolution view, or here for a full-resolution view. Right: The Hubble frame is only 13 light-years wide, but the entire cluster sprawls…
Smoking Gun for Milky Way's Black Hole
Astronomers find conclusive evidence for a black hole in the center of the Milky Way
SuperWASP Scrutinizes Swarms of Stars
In a hunt for extrasolar planets, hundreds of thousands of the brightest stars are getting measured precisely many times per night.
First Planet Found by Microlensing
Astronomers have detected a Jupiter-mass planet by its gravity's effect on the light from a background star.
Astro Image in the News:
No Moon for Sedna
Images from the Hubble Space Telescope reveal that Sedna is solitary and smaller than initially indicated.
Redshift Record Smashed Again
Astronomers have used a gravitational lens to view a baby galaxy 96.5 percent of the way back to the Big Bang.
New Light on Dark Energy
By measuring distances to the farthest Type Ia supernovae yet, astronomers and getting a sense of how dark energy works.
Black Hole Rips Star Apart
A supermassive black hole in a distant galaxy has shredded a star that ventured too close.
Opportunity Lands, Spirit Revives
This 360° panorama was assembled from some of the first images beamed to Earth from NASA's Opportunity rover after it landed at Meridiani Planum on Mars.Courtesy NASA/JPL. NASA got a double dose of good news from Mars last night. The Opportunity rover landed successfully on Meridiani Planum and began sending…
The Most Massive Star
A luminous blue variable star located some 45,000 light-years away could be the most massive and perhaps the most luminous star ever discovered.
More Galaxies that Jump the Gun
Astronomers have found a distant string of galaxies that took shape earlier than current cosmology can explain.
The Sun's Closest Twins
Astronomers hope to learn much from our Sun's doppelgangers.
Explaining Supernova Explosions
Astronomers are one step closer to understanding how white dwarfs blow themselves up.
Old Galaxies in the Young Universe
A survey of galaxies has found that not all star systems in the early universe were small.
Auroras Light Up the Sky
Many skywatchers who kept an aurora vigil during the morning hours of October 29, 2003, were richly rewarded by a spectacular display.
