In the spring of the year 1006, one thousand and seven years ago this April, observers in China, Egypt, Iraq, Japan, Switzerland (and perhaps North America) reported seeing what might be ...

Cambridge, MA In our solar system, only one planet is blessed with an ocean: Earth. Our home world is a rare, blue jewel compared to the deserts of Mercury, Venus and Mars. But what if o...

The universe was created about fourteen billion years ago in a blaze of light known as the big bang. After about 380,000 years or so, once matter had cooled enough for neutral atoms (mos...

Collisions between galaxies are common. Indeed, most galaxies have probably been involved in one or more encounters during their lifetimes. One example is our own Milky Way, which is bou...

Cambridge, MA Spiral galaxies are some of the most beautiful and photogenic residents of the universe. Our own Milky Way is a spiral. Our solar system and Earth reside somewhere near one...

At some stage after its birth in the big bang, the universe began to make galaxies. No one knows exactly when, or how, this occurred. For that matter, astronomers do not know how the lin...

Cambridge, MA Until now, supernovas came in two main "flavors." A core-collapse supernova is the explosion of a star about 10 to 100 times as massive as our sun, while a Type Ia supernov...

Sometimes, science fiction is also science fact. Katherine Wyman of the Harvard-Smithsonian Center for Astrophysics (CfA), began her Thursday night discussion, "Dark Cloud Encounters," by...

Galaxies today come very roughly in two types: reddish, elliptically shaped collections of older stars, and bluer, spiral shaped objects dominated by young stars. The conventional wisdom ...

The Sun glows with a surface temperature of about 5500 degrees Celsius. Meanwhile its hot outer layer (the corona) has a temperature of over a million degrees, and ejects a wind of charge...