There are millions of planets orbiting stars around which astronomers have not attempted to detect planets.

The best current astronomical theories predict that almost all planets around other stars are probably hundreds of times larger than the earth.

A planet orbiting a star similar to the sun would be more likely to be earthlike in size than would a planet orbiting a much smaller star.

The smaller a planet is relative to the star it orbits, the more difficult it is for astronomers to detect.

The observations would have detected any small, earthlike worlds orbiting the stars around which larger planets have been detected.