[ExI] Neutrino interaction web

Adrian Tymes atymes at gmail.com
Fri Mar 4 20:34:40 UTC 2011

On Fri, Mar 4, 2011 at 10:25 AM, Richard Loosemore <rpwl at lightlink.com> wrote:
> Adrian Tymes wrote:
>> On Fri, Mar 4, 2011 at 5:54 AM, Richard Loosemore <rpwl at lightlink.com>
>> wrote:
>>> I wouldn't go that far :-), but the collision cross section for neutrinos
>>> is
>>> estimated to be such that if you want to catch a significant fraction of
>>> them you need *roughly* a 1 light-year thick sheet of lead.
>> Ah, but that's with atoms.  All that empty space.
> Gee, Adrian:  you got a one-light-year-thick wall of lead there, which has
> been compressed into a nice convenient-sized sheet! 8-)  I reckon each
> neutrino will hit, what? 10^^17 nuclei on its way through???  I don't think
> the empty space is your problem.  :-)

We're violently agreeing.  I said that the reason you needed 1 light year
thickness with lead was because normal lead has all that empty space.
Compressing does indeed solve that.

> So, next step.  You've got your neutron star, and it is definitely
> collecting a lot of the neutrinos from the sun:  now what do you do with it?
>  :-)

Eh.  It was a thought experiment to see if neutrinos could be interacted with
at all.  Some possible applications are analogues to sails: tack against the
neutrino wind for propulsion or power.  But mostly, I was just seeing if the
interaction could be done in the first place.

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