[denphone]

http://www.bbc.co.uk/news/science-environment-16515944

Every star twinkling in the night sky plays host to at least one planet, a new study suggests.

That implies there are some 10 billion Earth-sized planets in our galaxy.

Using a technique called gravitational microlensing, an international team found a handful of exoplanets that imply the existence of billions more.

The findings were released at the 219th American Astronomical Society (AAS) meeting, alongside reports of the smallest "exoplanets" ever discovered.

Most news of exoplanets in recent years has come from the Kepler telescope, which spots planets by looking for the slight dimming of their host stars' light as planets pass in front of them.

That method is better at finding large planets close to their host stars.

While a more difficult effect to catch, gravitational microlensing is better at finding planets of all sizes and distances.

It can currently spot a planet as small as Mercury, orbiting at a similar distance to its host star, or as far away as Saturn.

In December, the Kepler team announced the first Earth-sized planet, the smallest yet detected.

At the AAS meeting on Wednesday, the Kepler team announced even smaller planets, all three orbiting a tiny red dwarf star called KOI-961.

The planets are just 0.78, 0.73 and 0.57 times the radius of Earth.