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Matter vs. Mass[edit]

Would matter be defined as anything that has mass? Could you call a neutrino matter? It has no mass and does not interact (albeit very weakly). Se7enEight 23:10, 9 September 2010 (UTC)

A very belated answer, but there have been discussion about whether neutrinos might have a small but non-zero mass, and they do have momentum. Since Newton's 2. law is best framed in terms of momentum, it is pretty much the same. If there's a physicist out there, a more precise answer would be welcome. Sorte Slyngel (talk) 18:09, 18 December 2015 (UTC)
I made a mistake there. Neutrinos have mass. The original poster was probably thinking about photons. They carry momentum but have zero rest-mass. Sorte Slyngel (talk) 19:40, 27 December 2015 (UTC)