Earth-sized planets may be much more common than previously thought, as a new estimate published in Science claims that nearly one in four stars like the Sun could have small, rocky planets like Earth.
A US team has found that on average small, so-called rocky planets are much more common in orbit close to their star than giant planets planets similar in size to Jupiter.
This estimate is based on observations from nearby stars taken by the the twin 10-metre Keck telescopes in Hawaii. These show that 22 of the stars had detectable planets.
The researchers estimated that about 1.6% of the Sun-like stars in their sample had Jupiter-size planets and 12% had so-called "super-Earths", which are between three and 10 times the mass of the Earth.