PANEL 0: BIG BANG AND COSMOS, on a logarithmic time scale ~10 1 sec 3 min 10 10 O Starry (Stelliferous) Epoch Starry (Stelliferous) J -6 -12 AK -36 I sec sec H sec Electroweak epoch Quark Hadron Grand epoch The weak nuclear force epoch B N unication and the electro- magnetic First matter Protons, D epoch force are unied; the formed neutrons, and strong nuclear force and Dark age related particles 20 Strong and gravity are separate. formed 10 weak nuclear forces and the L M electromagnet- epoch Lepton ic force are uni- Photon ed; gravitional Cosmic expansion force is sepa- epoch emits light Nothing in Universe rate. Radius of the observed (m) Universe Plasma: H and He 0 nuclei in a sea of 10 The convex-upward curvature at the right end unattached electrons of this plot of Cosmic expansion at rst sug- gests that expansion accelerated during the by H and He nuclei to form neutral atoms neutral form H and He nuclei to by “Re”-combination: elect “Re”-combination: galaxies form and evolve and evolve galaxies form Stars continually forming, forming, continually Stars Photon epoch of the Big Bang and during the present): to (continuing Dark Age, but this is an artifact produced by particles formed Elect the log scale of time. After ination, expansion r F Backg Mic (Cosmic Emission of CMB -20 ons and decelerated, due to the pull of gravity, until ac- (Helium nuclei formed) Nucleosynthesis 10 celeration due to dark energy began to take G r eect much later, as shown in the Cosmic-his- ound -43 sec: tory panel (B-1). r 10 elated r Planck time radiation) owave (beginning of r the smooth ons a time we are 10-40 r familiar with) Ination e captu E 240,000 yr 380,000 yr r ed C ~100 Myr 20 min Today 10-60 4.36 x 10 -40 -35 -30 -25 -20 -15 -10 -5 5 10 15 A 10 10 10 10 10 10 10 10 1 10 10 10 Seconds after “the Beginning” 17 sec = 13.8 Gyr 3 kyr = thousand (10 ) years 1 yr 1 kyr 1 Myr 1 Gyr Years after “the Beginning” Myr = million (106) years Gyr = billion (109) years A fundamental • On a linear time scale, the Big Bang, to the end of the Lepton epoch (3 minutes), is a trivial fraction of Cosmic history. paradox: • On a log time scale like this, the Big Bang, with 45 orders of magnitude, is most of Cosmic history! © Walter Álvarez, 2019.