<p>As one might expect,  <a href="https://en.wikipedia.org/wiki/Supernova_remnant" rel="nofollow noreferrer">wikipedia</a> is our friend:</p>
<blockquote>
<p>the resulting supernova explosion expels much or all of the stellar
material with velocities as much as 10% the speed of light (or
approximately 30,000 km/s). These speeds are highly supersonic, so a
strong shock wave forms ahead of the ejecta.</p>
</blockquote>

CC BY-SA 4.0
2020-10-09T15:20:17.087Z
Thanks. To be "highly supersonic", the matter needs to move through a medium with a set speed of "sound" i.e. shockwave propagation. Is interstellar gas ever dense enough to give meaning to such a concept?
Zsolt Szilagyi
CC BY-SA 4.0
2020-10-12T09:03:41.393Z
@ZsoltSzilagyi Yes; see the various answers to this Physics Stack Exchange question: https://physics.stackexchange.com/questions/162184/what-is-the-speed-of-sound-in-space
Peter Erwin
CC BY-SA 4.0
2020-10-09T13:14:40.677Z
2020-10-09T13:14:40.677Z
Carl Witthoft
<p>A common notion is that supernovae create shock waves in interstellar gas, and can compress them to star forming densities.</p>
<p>How is that shockwave transmitted? Is it by ejected (sublight) particles, or is the radiation strong enough to move several solar masses of gas?</p>

<supernova>
What is the "shockwave" of a supernova?
Zsolt Szilagyi
# What is the "shockwave" of a supernova?

(Asked by: username_0 on 2020-10-09)

A common notion is that supernovae create shock waves in interstellar gas, and can compress them to star forming densities.

How is that shockwave transmitted? Is it by ejected (sublight) particles, or is the radiation strong enough to move several solar masses of gas?

**Tags:** supernova

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## 1 answers

### Answer by username_1 on 2020-10-09. Score: 1 | Accepted answer

As one might expect, [wikipedia](https://en.wikipedia.org/wiki/Supernova_remnant) is our friend:

> the resulting supernova explosion expels much or all of the stellar
> material with velocities as much as 10% the speed of light (or
> approximately 30,000 km/s). These speeds are highly supersonic, so a
> strong shock wave forms ahead of the ejecta.

> **Comments:**
> **username_0**: Thanks. To be "highly supersonic", the matter needs to move through a medium with a set speed of "sound" i.e. shockwave propagation. Is interstellar gas ever dense enough to give meaning to such a concept?  
> **username_2**: @ZsoltSzilagyi Yes; see the various answers to this Physics Stack Exchange question: https://physics.stackexchange.com/questions/162184/what-is-the-speed-of-sound-in-space  

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