U.S. astronomers say the finding of an alien solar system with planets arranged as in our own system suggests most planetary systems start out looking the same. The researchers have been looking at a star system 10,000 light years from earth that has three known planets all orbiting in the same plane and lined up with the rotation of the star, mirroring the arrangement of our own solar system. Such an arrangement is in line with the commonly held theory of planet formation which assumes planets are born in a disk of dust and gas that spins around newborn stars. "In agreement with the theory, we have found the star's spin to be aligned with the planets," study co-author Dan Fabrycky, of the University of California, Santa Cruz, told SPACE.com. "So this result is profound because it is basic data testing the standard planet formation theory." The system, detected in January by NASA's Kepler space telescope and dubbed Kepler-30, is made up of three known extrasolar planets, Kepler-30b, Kepler-30c and Kepler-30d, all much larger than Earth, with two being even more massive than Jupiter. Though possessing only three known planets, the Kepler-30 system is similar to our own solar system with its eight planets all lined up neatly along the sun's rotational equator. Both systems probably formed from a spinning disk of dust and gas, strengthening the common formation theory, researchers said.