[meteorite-list] Neutron and Proton production in hyper-velocityimpacts

From: Chris Peterson <clp_at_meteoritecentral.com>
Date: Fri, 28 Dec 2007 11:38:31 -0700
Message-ID: <038901c84980$df044660$0a01a8c0_at_bellatrix>

All it takes to knock neutrons out of a nucleus is energy, so of course
photons can do this. But in general (for the sort of common elements we
find in meteoroids) it takes a _lot_ of energy. You need photons with
gamma ray energies (which is also what the reference you list says).
Gamma ray photons are far more energetic than the visible light photons
you see (literally) in meteors. Gamma rays have not been associated with
meteors, nor with impacts.

Meteors heat up the air, which causes it to ionize. That is, electrons
get stripped from atoms. That takes a lot less energy than breaking up
atomic nuclei. Some atoms simply get electrons kicked into higher energy
states, and visible light photons are released when the electrons relax
back to lower energy states. Nobody has much idea about what causes
electrophonic noise, but one theory suggests it might be turbulence of
ionized gas in the meteor wake. In any case, however, all of these
phenomena involve energies that are five or six orders of magnitude
lower than what's required to produce neutrons.

Chris

*****************************************
Chris L Peterson
Cloudbait Observatory
http://www.cloudbait.com


----- Original Message -----
From: "E.P. Grondine" <epgrondine at yahoo.com>
To: <meteorite-list at meteoritecentral.com>
Sent: Friday, December 28, 2007 11:08 AM
Subject: [meteorite-list] Neutron and Proton production in
hyper-velocityimpacts


> Hi all -
>
> Over the last several days, I've cited several C14
> spikes associated with hyper-velocity impacts.
>
> It turns out that photons can release neutrons and
> protons from a nucleus:
>
> http://galileo.phys.virginia.edu/classes/252/Nuclear_Notes/nuclear_notes.html
>
> To give you idea of the energies involved, we've all
> watched the photons given off by meteors traveling at
> cosmic speeds. If I remember right, those photons come
> from excited electrons - as does the electrophorenic
> sound discussed so many times here on the list over
> the years.
Received on Fri 28 Dec 2007 01:38:31 PM PST