neutrinos carry away momentum, is it lost forever

[bobsmith76]

This is from my text:

The existence of the neutrino was first predicted in 1931 by Wolfgang Pauli, when certain nuclear reactions appeared to be violating the laws of conservation of energy and momentum. Rather than modify or discard the law, Pauli suggested that an unseen, chargeless and probably massless particle was carrying away some of the energy and momentum

My question is will this energy and momentum ever affect "normal" matter again? (normal matter being the stuff you and I are made of. It looks like neutrinos rarely interact with matter, so is this energy forever trapped in the neutrinos, never to effect matter again?

[alexg]

They certainly effected the matter of the Opera detector at Gran Sasso laboratory.

[bobsmith76]

Yea, but that observatory seems to be set up to observe very rare and extraneous situations. It doesn't seem to relate to the "real" world.

[alexg]

If by 'real' world you mean the universe, I'd say that it's a part of it.

[Chronos]

Neutrino momentum is a conserved quantity, according to QED. They rarely interact, but, that merely delays the inevitable.

[kurros]

From a practical perspective I think it is fair to say it is mostly gone forever, yes. I would expect most neutrinos will escape the visible universe before they interact with anything again, seeing as how it takes a few light years of lead to have a high chance of stopping one. I haven't checked any calculations though.

There could also be some gravitational effects which might affect things on the large scale, but I think even those are understood to be very small these days.