In space, no one can hear you scream, but that doesn’t mean that it's devoid of sound. Waves propagate through gas clouds, the solar wind, and even inside stars.
Researchers from the University of Birmingham have now been able to detect the acoustic oscillations of stars in "M4" – one of the oldest clusters of stars in the Milky Way, which formed around 13 billion years ago. A paper describing their findings is published in the Monthly Notices Of The Royal Astronomical Society.
Sound waves in stars can be measured by looking at their light. Resonant oscillations produce small but significant changes in the star's brightness, and our telescopes are sensitive enough to measure them using a technique called asteroseismology. By measuring the star's oscillations, or pulses, with this technique, it is possible to measure the mass and age of each individual star.
“The age scale of stars has so far been restricted to relatively young stars, limiting our ability to probe the early history of our Galaxy,” said Dr. Guy Davies, co-author of the study, in a statement. “In this research, we have been able to prove that asteroseismology can give precise and accurate ages for the oldest stars in the Galaxy.”
The stars, eight in total, were observed by the NASA Kepler space observatory and they are part of the targets in the K2 mission. The eight objects are very old and either red giants or helium burning stars, and the data gathered from them lends confidence to using astroseismology to study the beginning of the Milky Way.
“We were thrilled to be able to listen to some of the stellar relics of the early universe," said Dr. Andrea Miglio, who led the study. "The stars we have studied really are living fossils from the time of the formation of our Galaxy, and we now hope to be able to unlock the secrets of how spiral galaxies, like our own, formed and evolved."
The team have prepared an interactive infographic where you can hear the sound of these stars. Check it out below.