As I understand, photons have mass (even though they're not Catholic, sorry), so what is the weight of photons hitting the earth? If a photon behaves like a wave does it still have mass? Photons may be timeless but they must have age. I assume that photons hitting the earth now originated in the sun's core, but how long ago has it taken for them to tunnel out?
Where is the source of neutrinos? I think I read that they originate in neutron stars but is there another source? Like photons, can they be both particles and waves?