The discussion centers on the origins of matter in the universe, specifically addressing how particles were created following the Big Bang (BB) and the inflationary period. It is established that all visible matter originated from a high-energy state during the end of inflation, where energy density caused rapid expansion and subsequently led to particle formation through a process known as reheating. The conversation also touches on the role of high-energy photons in particle creation, particularly in generating electron-positron pairs when sufficient energy is present. Key concepts such as baryogenesis and nucleosynthesis are acknowledged as part of the broader complexity of the universe's matter composition.
PREREQUISITESCosmologists, physicists, and anyone interested in the fundamental processes that led to the formation of matter in the universe.
Well, basically all of the particles in the visible universe came from the end of inflation. During inflation, the universe was dominated by a form of matter that acted rather like a cosmological constant due to its properties. Everything that we see in our current universe started from a patch of this inflating stuff that was much, much smaller than the nucleus of an atom.cam875 said:I understand that it is said that the universe is expanding and all that but where did all the matter come from that exists, did it all come from a single point particle or is there another theory for this. It seems like one of those questions that it is still under investigation heavily by cosmologists.
Well, right. When you smack two photons together that have a center-of-momentum energy greater than twice the mass of the electron, they'll annihilate with one another to produce an electron-positron pair. If they have still more energy, they can produce heavier particle/anti-particle pairs.cam875 said:so basically extremely high energy photons will turn into fundamental particles?
Well, you certainly can't accelerate a photon in the same way you can accelerate charged particles. But you can add energy to an electromagnetic field, so much so that, on occasion, you get pair production. This will happen, for instance, if you charge up a capacitor to extreme levels so that the electric field between the plates is so large that some of the photons occasionally have energies high enough to produce electron/positron pairs.cam875 said:technically you can't accelerate a photon since its speed is constant.