"WEINBERG'S FRAMES TO FOLLOW THE STATE OF VERY EARLY UNIVERSE"

Honorable Professor late Weinberg did not say anything about the state of the universe at the cosmic time, t=ZERO,because in standard big bang theory,all cosmic parameters blow up to infinities and Einstein's Field Equations Gij =-kTij break down.

Weinnberg's frames

(1) First frame: This is t=0.01 s,just after the big bang.The temperature is about TEN TO THE POWER OF ELEVEN KELWIN ,which is well above the threshold for electron-positron pair production.The main constituents of the universe are photons,neutrinos and antineutrinos,and electron-positron pairs.There is also a small"Contamination" of neutrons,protons and electrons.The energy density of electron-positron pairs is roughly equal to that of neutrinos and antineutrinos,both being7/4 times the energy density of photons.The total energy density is about 3.8×TEN TO THE POWER ELEVEN gm per cm cubed.The characteristic expansion time of the universe(that is the reciprocal of Hubble's "constant" at that instant,which is the age of the universe if the rate of expansion had been the same from the beginning as at that instant) is 0.02s.The neutrons and the protons cannot form into nuclei,as the latter is unstable.The spatial volume of the universe would be either infinite or,if it is one of the finite models,say with density twice the critical density,it's circumference would be about FOUR light years.

(2) Second frame.This is at cosmic time t=0.12s,when the temperature has dropped to about 3×TEN TO THE POWER OF TEN KELVIN.NO qualitative changes have occurred since the first frame.As in the first frame,the temperature is above electron-positron pair threshold,so that these particles are relativistic, and the whole mixture behaves more like radiation than matter,with the equation of state given by pressure =(1/3)density×.velocity of light×velocity of light.The total density about 3×TEN TO THE POWER OF SEVEN gm per cm cubed.The characteristic expansion time is about0.2 s.No nuclei can be formed yet,but the previous balance between numbers of neutrons and protons,which are being transformed into each other through the reaction (neutron+ nutrino.------->proton+electron)AND(proton+electron------->neutron+nutrino),is the beginning to be disturbed as neutrons now turn more easily into the lighter protons than vice versa.Thus the neutron-proton ratio becomes approximately 38 percent neutrons and 62 percent protons.The thermal contact between neutrinos and other forms of matter is beginning to cease.

(3) Third Frame. This is at cosmic time t=1.1 s,when the temperature has fallen to about TEN TO THE POWER OF TEN KELVIN.The thermal contact between neutrinos and other particles of matter and radiation ceases.Thermal contact is here taken to mean the conversion of electron-positron pairs into neutrino-antineutrino pairs and vice versa,the conversion of neutrino-antineutrino pairs into photons and vice versa,etc.Henceforth neutrinos and antineutrinos will not play an active role,but only provide a contribution to the overall mass-energy density.The density is of the order of TEN TO THE POWER OF FIVE gm per cm cubed. and the characteristic expansion time is a few seconds.The temperature is near the threshold temperature for electron-positron pair production,so that these pairs are beginning to annihilate more often to produce photons than their creation from photons.It is still too hot for nuclei to be formed and neutron-proton ratio has changed to approximately 24 percent neutrons and 76 percent protons.

(4)Fourth Frame. This is approximately at cosmic time t=13s,when the temperature has fallen to about3×TenToThePower of Nine Kelvin.(to be continued)