Inflationary Universe and Quick survey about iClickers Review of Big Bang model of universe Review of Evidence for Big Bang Examining Inflation Survey Questions 2 The iClickers used in class were beneficial for learning A Strongly agree B Agree C Neutral D Disagree E Strong disagree Survey questions 1 The iClickers used in class encouraged me to attend class A B C D E Strongly agree Agree Neutral Disagree Strong disagree Survey questions 3 The online resources and tutorials helped me understand the material in class A B C D E Strongly agree Agree Neutral Disagree Strong disagree Survey questions 4 I used the online Powerpoint lectures to review and study for exams A B C D E Strongly agree Agree Neutral Disagree Strong disagree Review of the Standard Model of the Big Bang Theory of the Origin of the Universe 1 43 Planck Era t 10 sec This era the first instant lasted for 10 43 sec Because we are as yet unable to link quantum mechanics our successful theory of the very small general relativity our successful theory of the very large We are powerless to describe what happened in this era 43 sec after the Big Bang is as far back as our 10 current science will allow us to go We suppose that all four natural forces were unified during this era GUT Grand Unified Theory Era 43 38 10 t 10 sec 38 Electroweak Era 10 t 10 10 sec The Universe contained three natural forces The Universe contained two natural forces gravity Grand Unified Theory GUT force electromagnetic strong nuclear weak forces unified This lasted until the Universe was 10 38 sec old gravity strong electroweak This lasted until the Universe was 10 10 sec old at this time the Universe had cooled to 1015 K the electromagnetic weak forces separated This was experimentally verified in 1983 at this time the Universe had cooled to 1029 K the strong force froze out of the GUT force the energy released by this caused a sudden and dramatic inflation of the size of the Universe discovery of W Z bosons electroweak particles predicted to exist above 1015 K Particle Era 10 10 t 10 3 sec The four natural forces were now distinct Particles were as numerous as photons 4 When the Universe was 10 sec old quarks combined to form protons neutrons their antiparticles At 10 3 sec old the Universe cooled to 1012 K protons antiprotons neutrons antineutrons could no longer be created from two photons radiation the remaining particles antiparticles annihilated each other into radiation slight imbalance in number of protons neutrons allowed matter to remain Q Which statement is incorrect A B C D E The electroweak force consists of electromagnetism and the weak force The first of the four elementary forces to freeze out in the Big Bang was the strong force The 4 elementary forces in nature consist of gravity electromagnetism strong force weak force By 10 3 sec all four forces were distinct In the GUT Era only gravity was a distinct force Electrons positrons are still being created from photons 2 Era of Nucleosynthesis 10 3 sec t 3 min During this era protons neutrons started fusing but new nuclei were also torn apart by the high temperatures When the Universe was 3 min old it had cooled to 109 K at this point the fusion stopped Afterwards the baryonic matter leftover in the Universe was 75 Hydrogen nuclei i e individual protons 25 Helium nuclei trace amounts of Deuterium H isotope Lithium nuclei Era of Atoms 3 8 x 105 t 109 yr The Universe was filled with atomic gas sometimes referred to as the Cosmic Dark Ages Density enhancements in the gas and gravitational attraction by dark matter Era of Nuclei 3 min t 3 8 x 105 yr The Universe was a hot plasma of H He nuclei and electrons photons bounced from electron to electron not traveling very far the Universe was opaque When the Universe was 380 000 yrs old it had cooled to a temperature of 3 000 K electrons combined with nuclei to form stable atoms of H He the photons were free to stream across the Universe the Universe became transparent Era of Galaxies t 109 yr The first galaxies came into existence about 1 billion years after the Big Bang This is the current era of the Universe eventually form protogalactic clouds the first star formation lights up the Universe which provokes the formation of galaxies Summary of Big Bang stages Era Time Comment Planck 10 43 s All 4 forces united GUT 10 43 s 10 38 s Gravity splits ends with inflation Electroweak 10 38 s 10 10 s 3 forces gravity strong electroweak quark sea Particle 10 10 First particles protons neutrons Nucleosynthesis 10 3 s 3 min Fusion stops light elements H He Li form Nuclei 3min 380 000y Ionized elements decoupling redshift z 1 000 Atoms 380 000y 109 y Neutral atoms no stars cosmic dark ages redshift 1000 z 10 Galaxies 109 yr present Stars galaxies form redshifts z 10 to 0 s 10 3 s Evidence for the Big Bang 1 Cosmic Background radiation 2 Cosmic helium abundance 3 Heavy element abundance 4 Expansion of the universe galactic redshifts 3 Cosmic Microwave Background Evidence for the Big Bang Theory A good scientific model should make predictions which can be verified The Big Bang model makes two predictions which have been verified since the 1960s the existence and characteristics of the cosmic microwave background the expected Helium abundance in the Universe The model predictions agree with current observations The Universe is immersed in a sea of radiation This is the same radiation which was unleashed at the end of the Era of Nuclei 380 000 years after the Big Bang the Universe had cooled enough for free electrons to become bound into atoms of H He without electrons to scatter them photons were able to travel unhindered throughout the Universe the Universe became transparent Cosmic Microwave Background The spectral distribution of this radiation was the same as radiation from a 3 000 K object Since then the Universe s size has expanded 1 000 times like the surface of a red giant cosmological redshift has turned this radiation into microwaves This Cosmic Microwave Background predicted by theory In the Era of Nucleosynthesis i e the first three minutes number of protons neutrons roughly equal as long as T 1011 K below 1011 K proton to neutron reactions no longer occur neutrons still decay into protons protons begin to outnumber neutrons At T 1010 K the products of fusion reactions no longer break up was mapped by the COsmic Background Explorer COBE in 1990s While very smooth and uniform across the sky COBE did find slight temperature variations from