The oldest known clusters of stars buried within our galaxy have just been caught “singing” their galactic songs. The tunes come from our very own Milky Way.
Astrophysicists from the University of Birmingham have reported the detection of resonant acoustic oscillations of stars in ‘M4’ some 13 billion years old. By using data from the NASA Kepler/K2 mission, the team was able to study the resonant oscillations using a technique called asteroseismology.
These oscillations lead to very tiny changes or pulses in brightness, and are caused by the sound trapped within the stars. By measuring the tones, the team was able to determine the mass and age of individual stars.
So what do they sound like? Listen to these recordings from each of the stars (keep listening, there are four in total):
Stars are able to make sound naturally; this happens in the outermost layers of the stars by turbulence, which then gets trapped like the sounds in a musical instrument. As the star resonates, it “breathes” in and out, making it appear to be brighter as it heats up, and then gets dimmer as it cools down.
Dr. Andrea Miglio, from the University of Birmingham’s School of Physics and Astronomy, who led the study, said in a statement:
“We were thrilled to be able to listen to some of the stellar relics of the early universe. 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.”
Dr. Guy Davies, from the University of Birmingham’s School of Physics and Astronomy, and co-author on the study, said:
“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. In this research we have been able to prove that asteroseismology can give precise and accurate ages for the oldest stars in the Galaxy.”
Professor Bill Chaplin, from the University of Birmingham’s School of Physics and Astronomy, and leader of the international collaboration on asteroseismology, said:
“Just as archaeologists can reveal the past by excavating the earth, so we can use sound inside the stars to perform Galactic archaeology.”