5 more astronomy questions

Find answers to questions about the number of planets in the solar system, the search for extraterrestrial life, and more.

By David J. Eicher

Published: January 25, 2010

Astronomers have found more than 400 planets beyond our solar system. The nearest one known lies 10.5 light-years away and orbits the star Epsilon Eridani. In this illustration, a hypothetical family of moons orbits the planet.

Photo by NASA/ESA/G. Bacon (STScI)

In Astronomy's March 2010 issue, I shared insight into five of the biggest questions facing astronomy today. But that was just an arbitrary list, and there are plenty more cosmic conundrums scientists face every day. So below I address five more questions that have crossed many minds over the years.

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