4 ms·

with volcano: https://www.youtube.com/watch?v=BUREX8aFbMs https://www.youtube.com/watch?v=BUREX8aFbMs and meteor: https://youtu.be/VPFSyokDrec?t=251 https://yo

with volcano: https://www.youtube.com/watch?v=BUREX8aFbMs https://www.youtube.com/watch?v=BUREX8aFbMs and meteor: https://youtu.be/VPFSyokDrec?t=251 https://youtu.be/VPFSyokDrec?t=251

nemo44x 11y ago
Amazing how you can actually see the volcano explosion's blast radius push the clouds away.
- Jyaif 11y ago
  FYI, the clouds aren't pushed away, they are created by the difference in pressure the shockwave (temporarily) creates. Waves in general do not move matter (except for the temporary oscillation).
  - mannykannot 11y ago
    I am sure you are right about the apparent cloud movement in this case, but shockwaves can result from sudden displacement. I read somewhere that Fermi made a good estimate of the Trinity bomb yield by dribbling a stream of shredded paper from his hand. After the shockwave passed him, he paced out the displacement of those that were in the air at the time. http://www.dannen.com/decision/fermi.html http://www.dannen.com/decision/fermi.html
  - NamTaf 11y ago
    Just to expand on this (pun intended), a sound wave is just a change in the local pressure of the fluid it's going through. The rapid and sudden pressure drop across the leading edge of the shock wave causes vapour in the air to condense and form clouds. This happens because lower pressure air has a lower temperature (in this case, because it cannot reach equilibrium fast enough) and lower temperature air holds less humidity. That humidity is the vapour that condenses. You'll see this same effect on some jet fighters going transonic, contrails from wingtip vorticies on aircraft and other various natural phenomina.
    - BrandonMarc 11y ago
      Indeed. This occurs with rockets, too. One of my favorite pictures is one of a Saturn V going supersonic. See here: https://en.wikipedia.org/wiki/Vapor_cone#Gallery https://en.wikipedia.org/wiki/Vapor_cone#Gallery As that gallery shows, the same effect is in play with nuclear explosions (and any significantly large explosion, really)
- bmir-alum-007 11y ago
  It's a longitudinal "wave" impulse, so matter is not moved much, but energy is transferred outward by compression and decompression. https://wikipedia.org/wiki/Longitudinal_wave https://wikipedia.org/wiki/Longitudinal_wave

with volcano: https://www.youtube.com/watch?v=BUREX8aFbMs https://www.youtube.com/watch?v=BUREX8aFbMs and meteor: https://youtu.be/VPFSyokDrec?t=251 https://youtu.be/VPFSyokDrec?t=251

nemo44x 11y ago

Amazing how you can actually see the volcano explosion's blast radius push the clouds away.

Jyaif 11y ago
FYI, the clouds aren't pushed away, they are created by the difference in pressure the shockwave (temporarily) creates. Waves in general do not move matter (except for the temporary oscillation).
- mannykannot 11y ago
  I am sure you are right about the apparent cloud movement in this case, but shockwaves can result from sudden displacement. I read somewhere that Fermi made a good estimate of the Trinity bomb yield by dribbling a stream of shredded paper from his hand. After the shockwave passed him, he paced out the displacement of those that were in the air at the time. http://www.dannen.com/decision/fermi.html http://www.dannen.com/decision/fermi.html
- NamTaf 11y ago
  Just to expand on this (pun intended), a sound wave is just a change in the local pressure of the fluid it's going through. The rapid and sudden pressure drop across the leading edge of the shock wave causes vapour in the air to condense and form clouds. This happens because lower pressure air has a lower temperature (in this case, because it cannot reach equilibrium fast enough) and lower temperature air holds less humidity. That humidity is the vapour that condenses. You'll see this same effect on some jet fighters going transonic, contrails from wingtip vorticies on aircraft and other various natural phenomina.
  - BrandonMarc 11y ago
    Indeed. This occurs with rockets, too. One of my favorite pictures is one of a Saturn V going supersonic. See here: https://en.wikipedia.org/wiki/Vapor_cone#Gallery https://en.wikipedia.org/wiki/Vapor_cone#Gallery As that gallery shows, the same effect is in play with nuclear explosions (and any significantly large explosion, really)
bmir-alum-007 11y ago
It's a longitudinal "wave" impulse, so matter is not moved much, but energy is transferred outward by compression and decompression. https://wikipedia.org/wiki/Longitudinal_wave https://wikipedia.org/wiki/Longitudinal_wave