A team led by scientists from the University of Birmingham, UK, have discovered an ancient solar system dating back to the dawn of the Milky Way. What makes the system truly fascinating is the confirmed existence of five Earth-sized planets, which may have profound implications for the presence of ancient life existing from an early point in our galaxy's 13.8 billion year history.
The team discovered the system by analyzing data returned by NASA's Keplar space telescope. The five exoplanets were detected by observing the telltale dip in light emanating from the parent star that is indicative of a planetary body passing across its parent's stellar disk. From these light readings, the scientists were able to determine the planets' approximate sizes.
The age of Kepler-444 was determined via a technique known as asteroseismology, whereby astronomers detect oscillations taking place within the parent star, caused by sound trapped inside the stellar giant. These oscillations manifest themselves by shifts and sudden pulses of brightness that can be observed and used to characterize the fiery subject.
Using this method, the team approximates that Kepler-444 formed roughly 11.2 billion years ago, when the universe was only 20 percent its current age. Furthermore, astronomers believe that the five planets orbiting the distant star were already older than the Earth is now (4.54 billion years) by the time our planet began to form. This makes it the oldest solar system with terrestrial-sized bodies found to date.
The discovery has the potential to greatly impact current theories regarding ancient life in our galaxy. We now know that Earth-like planets were being created from very early on in our galaxy's lifespan, increasing the chances for the formation of ancient life. Further observation of the system will provide valuable insights into one of the earliest instances of planetary and moon formation in the galaxy.
A paper detailing the team's findings has been published in The Astrophysical Journal.
Source: University of Birmingham
