Study helps unlock secrets of star formation 12 January 2021 A new study by an international team of researchers has used computer power to map the so-called "sonic scale", showing the key role turbulence plays in star formation. The sonic scale marks the transition from supersonic turbulence, which is faster than the speed of sound, to subsonic turbulence, which is slower than the speed of sound. Gas below the sonic scale may collapse to form stars. Their simulation is the biggest ever of its kind and could help answer a major question in astrophysics - when and how do stars form in interstellar gas clouds.