The day Earth came to life
At some point in the dim past, non-living matter started to replicate itself. Scientists are still trying to figure out how.
Ammonia, silicon, and hydrocarbons can theoretically support life.
What revved up the galaxy’s hyperfast stars?
Since 2003 astronomers have found 16 stars escaping the Milky Way’s gravity. The slingshot could be our galaxy’s central black hole.
A simulation shows how merging galaxies can fling stars to hypervelocities.
A new day dawns for Hubble
Shuttle astronauts installed two new instruments, fixed two older ones, and upgraded the space telescope’s gyroscopes and batteries.
The stars that revealed the vastness of the universe
Cepheids are pulsating variable stars that astronomers use to measure cosmic distances. They remain at the heart of solving key cosmic riddles.
The first known Cepheid variable star lies in the southeastern corner of Cepheus the King. Here’s how to find it.
Astronomy’s 2009 Astroimaging Contest
Amateurs accepted the challenge and sent us these dazzling images.
See all the entries of the 2009 Astroimaging Contest.
10 tips for beginning astroimagers
Use these techniques to produce celestial images you’ll be proud to share with friends and relatives.
This month in Astronomy
Bob Berman’s Strange Universe
David H. Levy’s Evening Stars
The Sky this Month
Stephen James O’Meara’s Secret Sky
Glenn Chaple’s Observing Basics
The Cosmic Grid