Stargazing Upcoming Supernova? | Nature News

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Neutrinos from a supernova arrive before the light due to their ability to escape the star's dense outer layers almost immediately, while light takes longer due to interactions with ions and electrons. The process begins with the neutronization phase, where neutrinos are released right away, whereas photons are delayed as they travel through the star. This phenomenon highlights that over 99% of a core-collapse supernova's energy is emitted as neutrinos rather than light. The shock wave from the supernova can take hours to become visible, further contributing to this timing difference. Understanding this sequence is crucial for astrophysical studies of supernovae.
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Sorry for the question, but why will the Neutrinos arrive slightly before the light from the supernova?
 
berkeman said:
Sorry for the question, but why will the Neutrinos arrive slightly before the light from the supernova?
Does seem backwards, doesn't it. Perhaps the mechanism of the supernova releases neutrinos before the visible explosion (implosion?) occurs?
 
berkeman said:
Sorry for the question, but why will the Neutrinos arrive slightly before the light from the supernova?
The answer is in the text of the linked article.

Although the shock wave can take many hours to make it through the outer layers of the star and to become visible, neutrinos come out right away, practically at the speed of light. More than 99% of the energy from a core-collapse supernova escapes not as light, but as neutrinos.
Photons interact strongly with the ions and free electrons in the outer layers of the star, but neutrinos don't.

I recall reading previously that it can take years for em energy generated in our Sun's core to reach the surface.
 
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berkeman said:
why will the Neutrinos arrive slightly before the light from the supernova?
Neutrinos come at the start - the neutronization phase. Light, and for that matter, antineutrinos, come over a longer period as short-lived nuclei decay.
 
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