PANEL 0: AND COSMOS, on a logarithmic time scale ~10 1 sec 3 min 10

10 O Starry (Stelliferous)Starry Epoch

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 age Dark related particles 20 Strong and gravity are separate. formed 10 weak nuclear forces and the L M electromagnet- Lepton epoch ic force are uni- Photon ed; gravitional Cosmic expansion force is sepa- epoch emits light Nothing in rate. Universe (m) of the observed Radius 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 “Re”-combination:r elect galaxies form and evolve Stars continually forming, Photon epoch of the Big Bang and during the (continuing to present):

Dark Age, but this is an artifact produced by formed particles r Elect the log scale of time. After ination, expansion

F Backg (Cosmicr Mic Emission of CMB -20 ons and r

decelerated, due to the pull of gravity, until ac- Nucleosynthesis (Helium nuclei formed) 10 celeration due to began to take

G r

eect much later, as shown in the Cosmic-his- ound -43 sec: tory panel (B-1). 10 elated

Planck time radiation) owave owave (beginning of the smooth ons a r time we are 10-40 familiar with) In ation e captu r E 240,000 yr 380,000 yr

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