The orbiting Kepler telescope has spotted a Jupiter-sized planet around another star -- a sighting that demonstrates it can see Earth-like planets if they are out there, scientists reported on Thursday.

The planet, called HAT-P-7b, was already among the 300 or so known so-called extrasolar planets, the team led by the U.S. space agency NASA reported. But measurements of its orbit by Kepler show the telescope will be able to see smaller planets, they reported in the journal Science.

We think it is likely that Kepler is going to find oodles and oodles of Earths, astrobiologist Alan Boss of the Carnegie Institution of Washington told a news conference.

Boss said one day we'll be able to stand outside ... and say 'Hey kids, look out there see that star? That one has an Earth.

The team, led by William Borucki of the NASA Ames Research Center in Moffett Field, California, said the telescope not only detected the hot Jupiter, which orbits very close to its sun, but was able to get readings that could give information about its atmosphere.

This ability will help scientists tell whether Earth-like planets have water or oxygen on their surfaces.

Kepler was launched in March with the specific goal of finding Earth-sized planets that might support life outside our solar system. It orbits the sun behind the Earth and in theory should be able to spot things that Earthbound telescopes and even the orbiting Hubble telescope cannot.

It uses a standard planet-hunting method -- watching for the slight dimming of a star's light as a planet passes in front of it.

Borucki's team is looking at data from Kepler's observations of more than 50,000 stars. The question remains how many Earths are there out there for Kepler to find, Boss said.

(Editing by Cynthia Osterman)