The solar system does not end abruptly past the planets. Beyond the orbit of Neptune, the outermost planet (it orbits the sun at a distance of 30 AU, where one AU is the average distance...

(Written by Christine Pulliam, Smithsonian Astrophysical Observatory, for Science at the Smithsonian, a website featuring highlights of scientific research at the Smithsonian Institution....

The Triangulum Galaxy, at a distance of only 2.6 million light-years, is one of the closest spiral galaxies to earth. It is also the third largest member of our galactic neighborhood (af...

Become an astronomer for a day! Enjoy telescope tours, interactive multimedia exhibits, hands-on activities, live demonstrations, and our ever-popular Scientist Cafe, where visitors can c...

Since the first planet around another star (an "extrasolar planet") was discovered by SAO astronomers and others in 1989, over 450 extrasolar planets have been found. Their study now comp...

Cambridge, MA NASA's recently launched Solar Dynamics Observatory, or SDO, is returning early images that confirm an unprecedented new capability for scientists to better understand our ...

Although many of the details about star formation are vigorously debated, the general principles are reasonably well understood. Stars form as the gas and dust in a molecular cloud coal...

In 2010, what great mysteries now confront astronomy? What do the next generation of observatories look like? Dr. Charles Alcock, Director of the Harvard-Smithsonian Center for Astrophysi...

Almost 400,000 years after the universe was created in the big bang, matter cooled sufficiently for neutral atoms to form, thereby allowing the pervasive light to propagate almost complet...

Distant galaxies are not only far away in space. Because it takes time for their light to reach us, they are also very far away in time -- snapshots from the distant past. The most dista...