Ultrasounds can be used to "listen" to the age of stars.

A new study published in the journal Science demonstrated infant stars can be distinguished from adolescents by listening to the acoustic waves they emit, KU Leuven reported.

Stars tend to be born in clusters; as they grow their gravitational pull causes them to contract. As the stars age they get smaller and hotter until their core begins the nuclear burning of hydrogen. The star then stabilizes and is considered to be an adult. Determining the age of a star can be tricky, but researchers have come up with a new way to determine the age of stars by measuring the acoustic vibrations they give off using ultrasound technology similar to what is used in the medical field. Acoustic vibrations are produced by radiation pressure within the star.

To make their findings the researchers looked at the vibrations of 34 stars; these stars were all under 10 million years old and between one and four times the mass of our Sun.

"Our data shows that the youngest stars vibrate slower while the stars nearer to adulthood vibrate faster. A star's mass has a major impact on its development: stars with a smaller mass evolve slower. Heavy stars grow faster and age more quickly," first author Konstanze Zwintz, a postdoctoral researcher at KU Leuven's Institute for Astronomy, said.

Theoretical physicists have suggested in the past that young stars have different vibrations that older stars, but this study is the first to confirm this idea through concrete data straight from outer space.

"We now have a model that more precisely measures the age of young stars," Zwintz said. "And we are now also able to subdivide young stars according to their various life phases."

The data was obtained by the Their data was obtained from the Canadian MOST satellite and the European CoRoT satellite as well as from ground-based facilities such as the European Southern Observatory (ESO) in Chile.