Tag Archives: gravitation/circular motion

The dark side of the universe

By Stephen Ornes / April 26, 2011
The ghostly blue clouds in the center of the Abell 1689 galaxy cluster show where Dan Coe and his team think dark matter is hiding. Abell 1689 is home to about 1,000 galaxies and trillions of stars. Credit: NASA, ESA, and Dan Coe (NASA JPL/Caltech and STScI)

Most of the cosmos is invisible, but that doesn’t stop scientists from searching for it

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Planetary paparazzo

By Stephen Ornes / April 20, 2011
Flying circles around Mercury MESSENGER, shown in an artist’s drawing, will spend 12 months in orbit around Mercury. . Credit: NASA

NASA satellite snaps historic photographs of Mercury

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Wrong-way planets do gymnastics

By Stephen Ornes / April 28, 2010

A group of planets that orbit the wrong way may have flipped over their stars.

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The solar system’s biggest junkyard

By Stephen Ornes / September 23, 2008

The science of tracking millions of pieces of garbage that orbit Earth is tricky and essential.

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Strange Universe: The Stuff of Darkness

By Emily Sohn / February 9, 2004

Figuring out what’s hidden in outer space between the visible stars and galaxies isn’t easy.

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