keywords: exoplanets planets smallest astronomers planet
text: Astronomers Spot Smallest Planets Yet American astronomers say they have discovered the two smallest planets yet orbiting nearby stars, trumping a small planet discovery by European scientists five days ago and capping the latest round in a frenzied hunt for other worlds like Earth.    All three of these smaller planets belong to a new class of "exoplanets" - those that orbit stars other than our sun, the scientists said in a briefing Tuesday...