PLANETSSTARSGALXES AST 1002
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This 33 page Class Notes was uploaded by Stephan Gorczany on Thursday September 17, 2015. The Class Notes belongs to AST 1002 at Florida State University taught by Staff in Fall. Since its upload, it has received 69 views. For similar materials see /class/205665/ast-1002-florida-state-university in Astronomy at Florida State University.
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Date Created: 09/17/15
osmology E e v n H w 39 quot125 quot39 g 39 3 9amp7 Hydrogen Vatum Fmtngalaxy x 39 Q Hellumakom e quot gen l n 39 Tune 1053 Sec 3OOKDDO yrs 1 bluiun yrsV 15 billmn yrs rempurnluve 100DDquotC 200quotC 7 The casmus quot 39 v v m 31 g 5Eledmlls Gravity makes 7 As rums I39o combine wilh hydrugen and clublcr protons and helium as Ingehm mlch neurons In arm coalesce to harm xlxlv v lllf ins the giant clouds xlms le md upL39W that wlll becum hum ILmums galaxlus smaller inu kde U Hum clumps at gas will uwnluauy caliapse to form Imm mln new the rst stars mamnmnnmnmnwydmmmmmmmm nanmmmnupmnmnmwmummwlzcmmwmmmuuum 39 mmmumimmjsmz u huwknangnnmlswl Outline 0 An Expansion of the Universe The Geometry of the Universe Deceleration o Universe infancy inflation and forces The Universe s fate 0 Concluding remarks J Estimate5 distance iur H3 F1 kl r h39 m Mpf 139 l39n lpr mine It w Galaxy Galaxy 1 a nearby duster l U I39LI39MIL 330 ITuIiiDn n 4 Galafo in a FIG396 dimm cluster ACID ME Ilium Ir w Galaxy in a very distant cluster nanimmea The Universe is expanding according to Hubble s law quot 39 H 39 Hubble s law 7 T Hubble s time s Hubble s time gives an estimation for University age I l There is no center of eXpansion of the Universe Expanding Universe represented as 2d surface of the expanding sphere Notice that the center of expansion is not a part of this 2d Universe ully Fisher quot 39 39 l galaxy dispersrons Velocity kmsec C o oo 6 n a E gt 395 2 0 gt Ha kmsecMpc 4633 000 Distance M 0 Distance Mpc P to 2004 musmIElmoks Cole The value of Hubble s constant was determined using Cepheid variables A and Supernova Type la at larger distances At small distances uniformity of expansion is disturbed by gravitational interaction of Galaxies in groups and clusters It all depends on the average density of the Universe QM pavepcrit pcrit 3H2875G r lllli39nlr Ill L39l Medium SIM 1 Separation between galaxies Dense film llI tn linowl39 Age QM lt 1 J i The Universe expands forever QM gt 1 The Universe will eventually contract QM 1 i 39 fr The Universe expands forever butjust barely the speed of expansion becomes zero after infinite time I l Discovery of SN 1997cj 28 April 1997 7 April 1997 sift v 39 h LY A L 039 i i Recession speed gt Distance gt Supernovae Type Ia were used to find distances to the most distant galaxies i t k Mm a ama amw It turned out that the Universe expanding with and not with deceleration rn Il39mnl Composition of the Universe o 30 is matter QM 025 5 is in a form of common matter hydrogen hemnnemQB00 25 is in a form of cold dark matter the origin of which is unknown QD 025 o 70 is dark energy the origin of which is unknown at present GA 070 QBQDQA1 o J Forces o Gravity The weakest long range force Electromagnetism Long range force which is 1039 times stronger than gravity Strong nuclear force Short range force 103915 m which is 1OO times stronger than electromagnetic force Weak nuclear force Short range force 103917 m which is 106 times weaker than electromagnetic force J The evolution of the Universe Planck time 103943 sec T 1032 K We think that all forces at Tgt1O32 K are acting as one they are unified 0 Theory of Everything TOE is needed to describe the properties of the Universe before Planck time Possible candidate is Mbrain theory At Planck time 103943 sec gravity is predicted to separate from other forces this is the first phase transition or spontaneous symmetry breaking Grand Unified Theory GUT which unifies strong weak and electromagnetic forces is governing the Universe between 103943 sec and 103936 sec T1O27 K 0 At 103936 sec strong force separates from electromagnetic and weak force This is the Era of the second phase transition 0 103936 sec to 103932 sec extraordinary inflation Era The Universe expands by a factor of 1020 1030 in this incredibly brief time It is more than in entire Universe s life 3914 billion years 1032 sec 10396 sec QuarkAntiquark Era Particle antiparticle and photon equilibrium phase During QuarkAntiquark Era at time 103912 sec the third and final phase transition appears Weak force separates from electromagnetic force 0 At 10396 sec the Universe cooled down to 1013 K so that protons and neutrons could form from quarks and antiquarks Most protons and neutrons annihilated with their anticounterparts but due to tiny imbalance between matter and antimatter caused by GP symmetry violation few protons and neutrons survived There was one protonneutron per 109 photons yI 39 l l l 1 7 Hammi m 7 39 c mm a 1 Charge unil 10396 sec 10392 sec Protons and neutrons get converted one into another rapidly and their number is about equal The Universe is mostly light 109 photons per one proton or neutron Electronpositron pairs produced and destroyed at about the same rate 10391 sec neutron is heavier than proton and is harder to produce at lower energies hence the number of neutrons settled to only A of that of protons by 1 sec This decouples neutrinos from matter 0 At 1 sec the temperature dropped to 1010 K and the typical photon energy becomes too low to produce electronpositron pair Annihilation of electrons with positrons leads to their depletion Only one in every billion electron survives due to tiny imbalance between electrons and positrons o Neutrons begin to decay to protons increasing imbalance between protons and neutrons By the time of 3 m there are 86 of protons and 14 of neutrons Energy wise the Universe consists of photons and neutrinos at this time J At 3 m of age the Universe becomes cool enough for Deuteriumto form T 39 begins and last until 10 minutes m I photon Deuterium quot7 7 quot n e 39 w p a we Deuterium Deuterium Helium3 n aquot 9 Tritium 07 n 1 lasha3 e Deuterium Halium Heliumd m n J 7 g nquot way 39v Deuterium TriLiUm Helium4 o The ratio of protons to neutrons at the start of primordial nucleosynthesis is 71 gt for each 2 neutrons there are 14 protons o 2 protons and 2 neutrons are converted to helium 0 After nucleosynthesis is over there should be one helium nucleus per 12 protons so there should be 25 of helium and 75 of hydrogen in the Universe by mass The latter prediction of Big Bang Theory is confirmed experimentally 4 o At an age of about 10 m the Universe is a fireball of protons helium deuterium electrons photons and neutrinos The Universe is transparent for neutrinos at this age but opaque for photons From 10 m to 400000 years the Universe cools down At t400000 years the temperature becomes about 3000 K cool enough for hydrogen and helium atoms to form So protons and helium capture electrons Neutral atoms form and light becomes decoupled with matter 4 Cosmic Microwave Background V o In 1965 the microwave radiation coming from all directions in the sky was discovered lt lookes like black body radiation of an object at 3 K Penzias and Robert W Wilson CMB comes from the era when light was decoupled from matter at the age of the Universe of 400000 years It has redshift of 1000 3000 K 3 K 1 Ripples in CMB o CMB is very uniform However small deviations in temperature of about 30 microkelvins were found 0 These deviations represent seeds for superclusters clusters and galaxies formation Ball Observation of Millimetric Extragalactic Radiation and Geophysics J x BOOMERANG image of OMB From Studying various features of OMB can H Measure the age of the Universe 137o2 billion yr Measure Hubble s constant 714 kmsecMpc Find the Geometry of the Universe Angular scale in degrees 9 1o02 90 2 02 Measure the denSIty of may Data i normal type of matter and 1 cm i ACBAR dark matter The relative number and amplitude of variations in the i sky versus their angular size Data are from WMAP Wilkinson Microwave Anisotropy Probe Inflation 0 Foundations of the Big Bang theory CMB Relative proportion of various light isotopes Expansion of the Universe Evolution of the Universe over finite amount of time Problems Horizon problem Flatness problem Inflation process proposed by Alan Guth in 1979 resolves the problems of the Big Bang theory E to M G g Q U F E 2 C 2 39D l gt L Q5 Q1 5 I u C I I r 2 quotU N I 1039 ICI 1U Tame seconds The fate of the Universe We now live in the stelliferous era plenty of stars o The Sun will become a white dwarf in about 6 billion yr Mtype stars will die as white dwarfs by the age of the Universe 1013 years 0 Ltype stars will certainly be gone by t1015 years 0 After that the Universe will enter degenerate era It will be filled with cold brown dwarfs white dwarfs very cold neutron stars black holes and planets o By t1020 years most stars and planets will be ejected from galaxies o By t1030 years black holes will swallow most of the remaining objects in galaxies o All remaining objects except black holes will disintegrate by t1038 years due to proton decay o The Universe will enter the blackhole era There will be only black holes Stellarmass blackholes will evaporate by t1065 years due to Hawking quantum process Giant Black Holes million solar masses will evaporate by t1083 years Galaxy mass black holes will evaporate by t10100 googol years 4 Dark Era The Universe will enter the dark era Only low energy photons neutrinos and some other elementary particles will fill the Universe X J Multiverse and anthropic principle o It is possible that our Universe is just one of many other Universes Multiverse Parameters of other Universes and laws of physics as well could be very different 0 Why then the parameters of our Universe is so fine tuned that life can emerge Well if it wouldn t be the case there would be no one to ask this question anthropic principle o J The Drake equation What are our chances to find intelligent life beyond the Earth Number of Rate Of Star Fraction Average number Fraction technological formation of Stars of habitabie of those intelligent averaged X having X planets within X habitable X civilizations over the planetary those planetary planets now present Lifetime of Systems Systems 9n Wmch in the Galaxy the Galaxy life arises Fraction Fraction Average of those of those lifetime of a X habitable X intelligent X technologically planets life planets competent on which that develop Civilization intelligence technological evolves society Summary o The Universe is expanding at increasing rate o It consist of 75 of dark energy 20 of dark matter and 5 of common baryon matter 0 There was a Big Bang 137 billion years ago 0 Spacetime itself forces elementary particles and light elements were created in first 10 minutes after The Big Bang Neutral atoms were formed 400000 years after the Big Bang and left CMB behind o The Universe will expand forever toward full J disintegration
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