Quote (RaXaR)
I don't know how much of a crackpot either of those guys are but I did read somewhere that when particles are collided in a particle accelerator, the mass of the sum of the all the parts after the collision is greater than the mass of the particles that collided. The implication being that kinetic energy was converted to matter. If that is true then it's not too far fetched to think that neutrinos could convert to matter upon collision and therefore increase the mass of the object it collided with... I have no idea/guess of how much matter that would be though
Neutrinos have an extremly low interaction probablity with matter. To absorb one neutrino, you should build a plumbum wall of thickness of... several light years. Neutrinos easily fly through Earth and even the Sun. This is why they are so difficult to detect. A huge tank of water with sensitive photometers can detect a few neutrinos during a year! (It detects Cherenkov light from electrons, that are generated by nuclear reaction with neutrino and atomic nuclei). The density of neutrinos is relatively high (1010 per cm2 per second), but only a few of them can be absorbed by Earth and increase its mass. I can't calculate it precisely now, but I think this increase will be very low. You can calculate it yourself if you want 
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