Naked Science Forum

Non Life Sciences => Physics, Astronomy & Cosmology => Topic started by: dentstudent on 25/05/2009 14:36:56

Title: Is it true that a neutrino could pass unimpeded through a light-year of lead?
Post by: dentstudent on 25/05/2009 14:36:56

I heard this on another podcast. Is it really true, and if so, what would be the likelihood of this happening?  [???]

Title: Is it true that a neutrino could pass unimpeded through a light-year of lead?
Post by: Soul Surfer on 25/05/2009 23:36:02

I am not sure of the actual interaction probability but my impression was that it was nothing like as far as this.  neutrinos come straight out of the centre of the sun with a very low likelihood of interaction.  I understood that if there was solid lead between the earth and the sun a neutrino would have about four interactions on the way to the earth.  This is quite a low interaction probability but it is interesting to know that the flux of neutrinos coming out of a supernova core collapse has a significant effect on the disruption of the outer layers of the star.

The interaction probability is many orders of magnitude more likely than the gravity only interactions of dark matter.  They could well make their way through more than a light year of lead!