"In fourteen hundred and ninety-two," the familiar poem says, "Columbus sailed the ocean blue."

Columbus was often credited with discovering the New World, though other, lesser known travelers had come earlier.

While there is no prospect that man will find new continents on Earth, it is intriguing that astronomers have spotted in a distant solar system two planets roughly the size of Earth circling a star that isn't too much different from our sun.

That is a first, according to scientists.

One of the planets is named Kepler-20f. It's slightly larger than Earth, and its atmosphere may have a great deal of water vapor.

The other, Kepler-20e, is a tad smaller than Earth.

The discovery of Earth-size planets has spurred talk of life "out there." But life seems improbable on these particular planets. Scientists say both are likely far too hot to sustain life. Kepler-20f and Kepler-20e fully orbit their star in a "year" that equals less than one month for us earthlings.

Still, as the popularity of space-related movies and TV shows has demonstrated, there's an endless and understandable fascination with the prospect of one day greeting what we hope will be friendly aliens.