The Kepler space telescope measures the sizes and ages of stars five times better than any other means – when it “listens” to the sounds they make. Bill Chaplin, speaking at the AAAS conference in Washington, said that Kepler was an exquisite tool for what is called “astroseismology”. The technique measures minuscule variations in a star’s brightness that occur as soundwaves bounce within it. The Kepler team has now measured some 500 far-flung stars using the method. Bill Chaplin of the University of Birmingham told the annual meeting of the American Association for the Advancement of Science that astroseismology was, in essence, listening to the “music of the stars”. But it is not sound that Kepler measures. Its primary job is spotting exoplanets, by measuring the tiny dip in the amount of light that it sees when a planet passes in front of a distant star. Such precision light-level measurements also work for astroseismology, because as sound waves resonate within a star, they slightly change both the brightness and the colour of light that is emitted. I could literally spend the rest of my research career working on these dataBill Chaplin, University of Birmingham Researchers can deduce the acoustic oscillations that gave rise to the ripples on the light that Kepler sees. Like a musical instrument, the lower the pitch, the bigger the star. That means that the sounds are thousands of times lower than we can hear. But there are also overtones – multiples of those low frequencies -…more detail
