ASTR 1120 ASTR 1120 General Astronomy: General Astronomy: Stars & Galaxies Stars & Galaxies • FINAL: FINAL: Saturday, Saturday, Dec 12th, 7:30pm, HERE Dec 12th, 7:30pm, HERE • • ALTERNATE FINAL ALTERNATE FINAL : Monday, : Monday, Dec 7th, 5:30pm Dec 7th, 5:30pm • in Muenzinger Muenzinger E131 E131 in • Last OBSERVING session, Tue, Dec.8th, 7pm Last OBSERVING session, Tue, Dec.8th, 7pm • • Please check your grade on clickers, midterms, Please check your grade on clickers, midterms, • HWs on CU learn - e-mail Thomas if you see on CU learn - e-mail Thomas if you see HWs discrepancies/missing grades discrepancies/missing grades • Homework #9 due TODAY, by 5pm Homework #9 due TODAY, by 5pm •
OUR Universe: : OUR Universe REVIEW Accelerating Universe REVIEW Accelerating Universe • Dark Energy Dark Energy is is • causing the causing the expansion of expansion of the universe to the universe to speed up over over speed up time! time! • Scientists don Scientists don’ ’t t • know what this know what this dark energy dark energy might be. might be.
Chapter 23: In the VERY VERY Beginning Beginning Chapter 23: In the
BIG BANG: beginning of Time BIG BANG: beginning of Time Early times in the Universe were really Early times in the Universe were really Hot Stuff!! Hot Stuff!! • If the universe is cooling • If the universe is cooling and expanding now… … and expanding now – The Universe was The Universe was hotter hotter at at – earlier times earlier times • The temperature at the • The temperature at the earliest times was more earliest times was more than the energy we create than the energy we create in even our largest particle in even our largest particle accelerators accelerators • Cosmology at the earliest • Cosmology at the earliest times is explored via times is explored via particle physics particle physics
Matter, Antimatter, and Energy Matter, Antimatter, and Energy Photons converted into Photons converted into particle-antiparticle particle-antiparticle pairs and vice-versa pairs and vice-versa (Matter and Energy are (Matter and Energy are the same!!) the same!!) 2 E = mc E = mc 2 Early universe was full Early universe was full of particles and of particles and radiation because of its radiation because of its high temperature high temperature
Planck Era Planck Era 0 - 10 -43 -43 sec sec 0 - 10 Before Before Planck time Planck time =??? =??? •Things were Things were • so small and so small and so dense… … so dense modern modern physics fails physics fails –No theory No theory – of quantum of quantum gravity gravity
The Four Known Known The Four Forces in the Universe Forces in the Universe • Gravity Gravity • • Electromagnetism Electromagnetism • • Strong Force Strong Force • • Weak Force Weak Force •
Do forces unify at Do forces unify at high temperatures? high temperatures? Four known forces Four known forces in the universe: in the universe: • Gravity Gravity • • Electromagnetism Electromagnetism • • Strong Force Strong Force • • Weak Force Weak Force •
Do forces unify at Do forces unify at high temperatures? high temperatures? Four known forces Four known forces in the universe: in the universe: • Gravity Gravity • • Electromagnetism Electromagnetism • • Strong Force Strong Force • • Weak Force Weak Force • Yes! Yes! (Electroweak) (Electroweak)
Do forces unify at Do forces unify at high temperatures? high temperatures? Four known forces Four known forces in the universe: in the universe: • Gravity Gravity • • Electromagnetism Electromagnetism • • Strong Force Strong Force • • Weak Force Weak Force • Yes! Yes! Maybe Maybe (Electroweak) (Electroweak) (Grand Unified Theories) (Grand Unified Theories)
Do forces unify at Do forces unify at high temperatures? high temperatures? Four known forces Four known forces in the universe: in the universe: • Gravity Gravity • • Electromagnetism Electromagnetism • • Strong Force Strong Force • • Weak Force Weak Force • Yes! Yes! Maybe Maybe Who knows? Who knows? (Electroweak) (Electroweak) (GUT) (GUT) (String Theory) (String Theory)
GUT Era GUT Era ~10 -43 -43 -10 -10 -38 -38 sec sec ~10 Lasts from Lasts from Planck time to Planck time to end of GUT end of GUT force force
Inflation of the Universe Inflation of the Universe • As strong force As strong force • becomes distinct (end becomes distinct (end of GUT era), a huge a huge of GUT era), amount of energy is is amount of energy released released • Universe Universe INFLATES: INFLATES: • – Universe of atomic Universe of atomic – nucleus size becomes nucleus size becomes solar system size in solar system size in 10 -36 -36 sec sec 10
Electroweak Electroweak Era Era ~10 -38 -10 -10 sec ~10 -38 -10 -10 sec Lasts from end of Lasts from end of GUT force to end GUT force to end of electroweak of electroweak force force •Universe still Universe still • made up of made up of elementary elementary particles (quarks) (quarks) particles
Particle Era Particle Era (10 -10 -10 -.001 sec) -.001 sec) (10 Finally Finally temperatures low temperatures low enough that enough that quarks can quarks can combine to form combine to form subatomic subatomic particles (protons, (protons, particles antiprotons, antiprotons, neutrons, neutrons, antineutrons, antineutrons, etc… …) ) etc
The Particle The Particle Era Era • Universe still hot: 10 Universe still hot: 10 15 to • 15 to 10 12 12 K K 10 • Particles now exist: Particles now exist: • electrons, protons, anti- electrons, protons, anti- protons, anti-electrons, protons, anti-electrons, neutrinos etc. neutrinos etc. • Particle soup! Particle soup! Particles Particles • and photons/energy and photons/energy created and annihilated created and annihilated
Clicker Question Clicker Question At the end of the particle era, temperatures are low At the end of the particle era, temperatures are low enough that photons cannot collide to create enough that photons cannot collide to create matter/anti-matter anymore. Nearly all the matter and Nearly all the matter and matter/anti-matter anymore. antimatter that is in the universe at that time collides antimatter that is in the universe at that time collides and forms photons. But a little bit of bit of some some type of type of and forms photons. But a little matter remains remains… … which type is it? which type is it? matter A. Regular matter Regular matter A. B. Anti-matter B. Anti-matter C. There There’ ’s no way we s no way we C. can tell! can tell!
Clicker Question Clicker Question At the end of the particle era, temperatures are low At the end of the particle era, temperatures are low enough that photons cannot collide to create enough that photons cannot collide to create matter/anti-matter anymore. Nearly all the matter and Nearly all the matter and matter/anti-matter anymore. antimatter that is in the universe at that time collides antimatter that is in the universe at that time collides and forms photons. But a little bit of bit of some some type of type of and forms photons. But a little matter remains remains… … which type is it? which type is it? matter A. Regular matter Regular matter A. B. Anti-matter B. Anti-matter C. There There’ ’s no way we s no way we C. can tell! can tell!
Matter and Anti-matter Matter and Anti-matter • At end of particle era, • At end of particle era, universe contains matter! universe contains matter! • Protons must have • Protons must have slightly outnumbered anti- slightly outnumbered anti- protons protons • Universe ratio today today: : • Universe ratio – 1 billion photons (light) for 1 billion photons (light) for – every 1 proton (matter) every 1 proton (matter) • Universe ratio then then: : • Universe ratio – 1 billion and 1 protons for 1 billion and 1 protons for – every 1 billion anti-protons every 1 billion anti-protons
Era of Nucleo- Nucleo- Era of synthesis synthesis 0.001 sec-3 min 0.001 sec-3 min Begins when Begins when matter annihilates matter annihilates remaining remaining antimatter antimatter
Era of Nucleosynthesis Era of Nucleosynthesis (Fusion) (Fusion) • Matter particles are • Matter particles are “frozen out frozen out” ” “ – no longer no longer – spontaneously spontaneously generated to/from generated to/from photons photons • Temperatures hot • Temperatures hot enough to fuse fuse enough to protons (hydrogen (hydrogen protons nuclei) into helium nuclei) into helium nuclei nuclei
Recommend
More recommend
