7 rocky Earth-size planets discovered orbiting nearby star

LOS ANGELES - Seven planets similar to our inner solar system have been discovered revolving around a star about 40 light years away, the US space agency NASA announced on Wednesday.

"The discovery gives us a hint that finding a second Earth is not just a matter of if, but when," said Thomas Zurbuchen, associate administrator of NASA's Science Mission Directorate.

By using powerful space telescopes and ground-based observatories, an international team of astronomers discovered the first known system of seven Earth-size planets orbiting the nearby ultra-cool dwarf star TRAPPIST-1 in the constellation Aquarius, he said.