Questions for Chapter 6 *1. Discuss the statement, "A graviton is a quantum of gravity. But gravity is a result of the warping of spacetime. Therefore, the graviton should be a quantum of spacetime. But just as a quantum of the electromagnetic field, the photon, has energy, the graviton should also have energy. In fact, we can estimate the energy of a graviton. Therefore, is spacetime another aspect of energy? Is there only one fundamental quantity, energy?" 6-32 Chapter 6: Elementary Particle Physics and The Unification of The Forces *2. Does antimatter occur naturally in the universe? How could you detect it? Where might it be located? 3. When an electron and positron annihilate, why are there two photons formed instead of just one? 4. Murray Gell-Mann first introduced three quarks to simplify the number of truly elementary particles present in nature. Now there are six quarks and six antiquarks, and each can come in three colors and three anticolors. Are we losing some of the simplicity? Discuss. 5. Discuss the experimental evidence for the existence of structure within the proton and the neutron. 6. How did the Pauli exclusion principle necessitate the introduction of colors into the quark model? *7. If the universe is expanding from the Big Bang, will the gravitational force of attraction of all the masses in the universe eventually cause a slowing of the expansion, a complete stop to the expansion, and finally a contraction of the entire universe? *8. Just as there are electromagnetic waves associated with a disturbance in the electromagnetic field, should there be gravitational waves associated with a disturbance in a gravitational field? How might such gravitational waves be detected? *9. Einstein's picture of gravitational attraction is a warping of spacetime by matter. This has been pictured as the rubber sheet analogy. What might antimatter do to spacetime? Would it warp spacetime in the same way or might it warp spacetime to cause a gravitational repulsion? Would this be antigravity? Would the antiparticle of the graviton then be an antigraviton? Instead of a black hole, would there be a white hill? 10. Discuss the similarities and differences between the photon and the neutrino.