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Is a supernova explosion really fast or is it just fast, metaphorically speaking? Can you cite the fastest known phenomenon in astronomy (neutron stars, pulsars) besides supernovae in terms of explosions?

EDIT: yes, i mean the shockwave from supernova

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  • $\begingroup$ Would light fit into what you are asking? Or are you asking specifically for explosions. $\endgroup$ – CipherBot Aug 24 '15 at 2:17
  • $\begingroup$ @CipherBot Specifically for explosions. Edited question. $\endgroup$ – interstellar773382 Aug 24 '15 at 6:28
  • $\begingroup$ Most of the energy in a supernova explosion is actually neither in the shock wave, nor in the light, but in the massive amount of neutrinos emitted. Neutrinos travel almost at the speed of light. Does that count? $\endgroup$ – pela Aug 28 '15 at 9:46
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If you count unique events as well, the fastest known event would be the exponential expansion of the Universe during inflation which lasts from about $10^{-36}\,\rm s$ to $10^{-32}\,\rm s$ right after the Big Bang. In this time, the Universe grew by a factor of about $10^{26}$.

You have to note, however, that space itself expands, so you are not limited to the speed of light which would be the case for phenomena such as stellar explosions or pulsars.

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  • $\begingroup$ I don't think this is what the OP means. The shockwave from a supernova is incredibly fast, and I think that was his implication. $\endgroup$ – HDE 226868 Aug 27 '15 at 23:11
  • $\begingroup$ @HDE226868 yes you are correct $\endgroup$ – interstellar773382 Aug 28 '15 at 8:32
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I am assuming you are talking about how long the event lasts. See question on this site "How long does a supernova explosion last?". The answer is that if you are talking about how long it brightens then dims (its light curve), then it typically takes a couple of days to get to full brightness then weeks to months to fade. Core collapse can be a fraction of a second (keep in mind there are different kinds of supernovae).

The "fastest" pulsar found so far spins 716 times a second. If you really want fast, how about the standard for atomic clocks? The used transition is between two ground states of the element caesium that are very close together and lasts about $1\times 10^{-10}$ seconds. There are even better atomic clocks now.

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    $\begingroup$ I don't think this is what the OP means. The shockwave from a supernova is incredibly fast, and I think that was his implication. $\endgroup$ – HDE 226868 Aug 27 '15 at 23:11

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