Just how ancient is a newly discovered solar system? "By the time the Earth formed, the planets in this system were already older than our planet is today," University of Birmingham researcher Tiago Campante tells the BBC. The solar system—a star named Kepler-444 that's orbited by five planets—was uncovered via an analysis of data gathered by the Kepler telescope over a four-year period. The work was published yesterday in the Astrophysical Journal. Why the find is attracting so much attention: It's being described as a "replica" or "twin" solar system of our own. In terms of size, the planets fall between Mercury and Venus, making it the "oldest known system of terrestrial-sized planets," per the study.
But likely not a life-sustaining one: The planets are too close to the star to permit life, with orbits about 10% of the distance Earth is from the sun. As far as age goes, the solar system came into being 11.2 billion years ago, a determination researchers made using asteroseismology (sound waves trapped within the star cause natural resonances that spur tiny changes in the star’s brightness; age is measured from these variations, reports YaleNews). And as far as distance goes, it's 117 light-years away. How the researchers frame the significance of the discovery: "We thus show that Earth-size planets have formed throughout most of the universe's 13.8 billion year history, leaving open the possibility for the existence of ancient life in the Galaxy." That leads Discovery News to ask, "Could alien life have already come and gone in our galaxy’s history?" (Another noteworthy find: the coldest spot in the universe.)