Washington, Feb 23 The seven newly discovered Earth-sized planets in the ultra cool dwarf star system may only face one way towards their sun, similar to the Earth’s moon, and orbit very close to it, scientists have found. Astronomers, using NASA’s Spitzer Space Telescope, announced the discovery of the first known system of seven Earth-sized planets around a single star – located a mere 40 light years away – that could have liquid water, and possibly host alien life.