antiparticle• Because the particle and antiparticle in effectcancel each other out, their appearancetogetherdoes not violate the laws of physics.• The laws of physics seem to be the same for particles and antiparticles.• The reason is that the laws of physics are not quite the same for particles and antiparticles.• In the same way that matter is constituted of fundamental particles, antiparticles are the building blocks of antimatter.• From the observedabsence of such annihilation radiation we can conclude that our galaxy is made entirely of particles rather than antiparticles.• Two antiparticles could therefore be drawn together by antigravity, but a particle of matter would be repelled by an antiparticle.