A "twin" of our solar system has been discovered by an international team of scientists that includes astronomers from Tel Aviv University. Its report on the revelation appeared in Thursday's issue of the prestigious Science journal. The newly discovered planets and the sun around which they revolve are very different from the 10 other solar systems discovered during the past decade. However, the new solar system is significantly similar to our solar system, especially in regard to the planetsâ€š relative weights and distances between them. Most of the 10 other systems were discovered by measuring the "wobbly paths" of their suns, said Dr. Shai Caspi of TAU. These variations are caused by the the gravitational pull of the planets. This is the technique used especially for discovering heavy planets like Jupiter, but in pathways close to their sun. But the new planets were discovered a different way - by the ability of mass to serve as a type of "lens" that magnifies far-off light sources, which is a phenomenon predicted by Albert Einstein's General Theory of Relativity. This technique makes it possible to discover small planets, if they exist, that are located at large distances from the mother star. By following the light from the solar system around the clock over a period of two weeks using a network of powerful telescopes, researchers can reach their conclusions about the existence of a star orbited by a Jupiter or Saturn-like planet. While the newly discovered solar system resembles ours, it is much smaller. The mother star has half the mass of ours, and the Jupiter and Saturn-like planets have half the masses of ours, while the planets' distance from their sun is half that of our planets' from our sun. The Israeli data, provided by TAU's Wise Observatory at Mitzpe Ramon, were vital to the discovery. "Without our observations, which were carried out when it was daylight where the other observatories are located, it would have been impossible to conclude that the Saturn-like planet existed," said Prof. Dan Maoz, another member of the Israeli team. "Only five planets have been discovered so far by the 'lens' technique. What we have found hints to the existence of similar solar systems, and there may be some planets similar to Earth. If there are other Earths, they could be discovered soon."