There is now overwhelming evidence that the center of our Milky Way galaxy contains a giant black hole with a mass of about four million suns. The most convincing data come from the motio...

As modern telescopes peer more and more deeply into the universe, they are seeing older and older galaxies. The current record is a galaxy whose light has been traveling towards us for w...

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Solar flares, prominences, and so-called coronal mass ejections are three different manifestations of stored magnetic energy near the sun's surface being released in sudden eruptions. Th...

Radio galaxies are cosmic beacons, with the brightest ones beaming nearly a trillion solar-luminosities of radiation into space at radio wavelengths. The origin of this intense emission ...

Mars, Jupiter, and all the other planets and asteroids in the night sky that are visible to us can be seen because they reflect sunlight. The "albedo" is the quantity that quantifies a b...

Near Earth Objects (NEOs) are small solar system bodies that are infamous because their orbits take them near earth's orbit; sometimes they pass dangerously close to the earth or even col...

Polaris, the North Star, is not only renowned as a reliable beacon for early navigators. It is a Cepheid variable star, that is, a star whose mass and age are just right to prompt periodi...

The sun's photosphere is hot, about 6000 kelvin, and so the sun emits about 70% of its light in the visible portion of the electromagnetic spectrum, and about one-quarter in the infrared....

The Smithsonian Astrophysical Observatory is pleased to announce that Dr. Giovanni Fazio will receive the 2008 Royal Society of London/COSPAR Massey award for outstanding contributions to...