Artistic concept of the Kepler 444 system (Image Tiago Campante/Peter Devine)

Using data collected by the Kepler space telescope, a group of researchers led by asteroseismologists from the University of Birmingham discovered five planets orbiting the star Kepler-444. They’re small rocky planets: the smallest has a size similar to Mercury, the largest has a diameter about three-quarters of the Earth. Another special feature is that the star Kepler-444 is very ancient, with an age estimated to around 11.2 billion years.