[ExI] Neutrino interaction web

[Richard Loosemore]

Adrian Tymes wrote:
> 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.

Oh, just light-heartedly joshing you, is all :-).

Full marks for lateral thinking, I gotta say.




Richard Loosemore