From the January 2009 issue

I’ve read about stellar explosions propagating at “supersonic speed.” On Earth, supersonic means faster than the speed of sound. How does this idea apply to stars?

Paul Marsh, Weare, New Hampshire
By | Published: January 26, 2009 | Last updated on May 18, 2023
Stellar blasts are supersonic because they move faster than the ISM’s sound speed.