1 1 1 Introduction Cosmology is the study of the universe as a whole, its structure, its origin, and its evolution. Cosmology is soundly based on observations, mostly astronomical, and laws of physics. These lead naturally to the standard framework of modern cosmology, the Hot Big Bang theory. As a science, cosmology has a severe restriction: there is only one universe. 1 We cannot make experiments in cosmology, and observations are restricted to a single object: the Universe. Thus we can make no comparative or statistical studies among many universes. Due to this special nature of cosmology, it is quite possible, that there will be some important questions, which can never be answered. Nevertheless, the last few decades have seen a remarkable progress in cosmology, as a significant body of relevant observational data has become available with modern astronomical instruments. We now have a good understanding of the overall history 2 and structure of the universe, but important open questions remain, e.g., the nature of dark matter and dark energy. Hopefully observations with more advanced instruments will resolve many of these questions in the coming decades. The fundamental observation behind the big bang theory is the redshift of distant galaxies. Their spectra are shifted towards longer wavelengths. The further out they are, the larger is the shift. This implies that they are receding away from us; the distance between them and us is increasing. According to general relativity, we understand this as the expansion of the intergalactic space itself, 3 not as actual motion of the galaxies. As the space expands, the wavelength of the light traveling through space expands also. This expansion appears to be uniform over large scales: the whole universe expands at the same rate. 4 We describe this expansion by a time-dependent scale factor, a(t). Starting from the observed present expansion rate, H ȧ/a, we can use general relativity to calculate a(t) as a function of time. The result is, that a(t) 0 about billion years ago (billion 10 9 ). At this singularity, the beginning of the big bang, which we choose as the origin of our time coordinate, t = 0, the density of the universe ρ. In reality, we do not expect general relativity to be applicable at extremely high energy densities. At the so called Planck density, ρ Pl kg/m 3, quantum gravitational effects should be large. To describe the earliest times, the Planck era, we would need a theory of quantum gravity, which we do not have. 5 Thus these earliest times, including t = 0, have to be excluded from the scientific big bang theory. Questions like, what was before the big bang, or what caused the big bang, remain unanswered or in the realm of speculations. Thus the proper way to understand the term big bang, is not as some event 1 There may, of course, in principle, exist other universes, but they are not accessible to our observation. 2 Except for the very beginning. 3 More properly, curvature of spacetime. 4 This applies only at distance scales larger than the scale of galaxy clusters, about 10 Mpc. Bound systems, e.g., atoms, chairs, you and me, the earth, the solar system, galaxies, or clusters of galaxies, do not expand. The expansion is related to the overall averaged gravitational effect of all matter in the universe. Within bound systems local gravitational effects are much stronger, so this overall effect is not relevant. 5 String theory is a candidate for the theory of quantum gravity. It is, however, very difficult to calculate definite predictions for the very early universe from string theory. This is a very active research area at present, but remains quite speculative.
2 1 INTRODUCTION 2 by which the universe started or came into existence, but as a period in the early universe, when the universe was very hot, 6 very dense, and expanding rapidly. Moreover, the universe was then filled with an almost homogeneous soup of particles, which was in thermal equilibrium for a long time. Therefore we can describe the state of the early universe with a small number of thermodynamic variables, which makes the time evolution of the universe calculable. There are some popular misconceptions about the big bang. The universe did not really start from a point. The part of the universe which we can observe today was indeed very small at very early times, possibly smaller than 1 mm in diameter at the earliest times that can be sensibly discussed within the big bang framework. And if the inflation scenario is correct, even very much smaller than that before inflation, so in that sense the word point is maybe appropriate. But the universe extends beyond what can be observed today (beyond our horizon ), and if the universe is infinite (we do not know whether the universe is finite or infinite), it has always been infinite, from the very beginning. As the universe expands it is not expanding into some space around the universe. The universe contains all space, and this space itself is growing larger. Because of the high temperature, the particles had large energies in the early universe. To describe matter in that era, we need particle physics. The standard model of particle physics is called SU(3) c SU(2) w U(1) y, which describes the symmetries of the theory. From the viewpoint of the standard model, we live today in a low-energy universe, where the symmetries of the theory are broken. The natural energy scale of the theory is reached when the temperature of the universe exceeds 100 GeV (about K), which was the case when the universe was younger than s. Then the primordial soup of particles consisted of free massless fermions (quarks and leptons) and massless gauge bosons mediating the interactions (color and electroweak) between these fermions. The standard model also includes a particle called the Higgs boson. Since the Higgs boson has not yet been observed experimentally, this part of the standard model is not well known. Higgs boson is responsible for the breaking of the electroweak symmetry. This is one of the phase transitions in the early universe. In the electroweak (EW) phase transition the electroweak interaction becomes two separate interactions: 1) the weak interaction mediated by the massive gauge bosons W ± and Z 0, and 2) the electromagnetic interaction mediated by the massless gauge boson γ, the photon. Fermions acquire their masses in the EW phase transition. The mass is due to the interaction of the particle with the Higgs field. The EW phase transition took place when the universe cooled below the critical temperature T c 100 GeV of the phase transition at t s. Another phase transition, the QCD phase transition, or the quark hadron transition, took place at t 10 5 s. The critical temperature of the QCD phase transition is T c 150 MeV. Quarks, which had been free until this time, formed hadrons: baryons, e.g., the nucleons n and p, and mesons, e.g., π, K. The matter filling the universe was converted from a quark gluon plasma to a hadron gas. The order of these transitions is not yet known, but if they are first-order phase transitions (the two phases have different energy densities at the critical temper- 6 The realization that the early universe must have had a high temperature did not come immediately after the discovery of the expansion. The results of big bang nucleosynthesis and the discovery of the cosmic microwave background are convincing evidence that the Big Bang was Hot.
3 1 INTRODUCTION 3 ature), they proceed through the formation of bubbles of the new phase, and the transition takes up a significant time and may have interesting consequences. To every type of particle there is a corresponding antiparticle, which has the same properties (e.g., mass and spin) as the particle, but its quantum numbers, like charge, have opposite sign. At high temperatures, T m, where m is the mass of the particle, particles and antiparticles are constantly created and annihilated in various reactions, and there is roughly the same number of particles and antiparticles. But when T m, particles and antiparticles may still annihilate each other (or decay, if they are unstable), put there is no more thermal production of particle-antiparticle pairs. As the universe cools, heavy particles and antiparticles therefore annihilate each other. These annihilation reactions produce additional lighter particles and antiparticles. If the universe had had an equal number of particles and antiparticles, only photons and neutrinos (of the known particles) would be left over today. The presence of matter today indicates that in the early universe there must have been slightly more nucleons and electrons than antinucleons and positrons, so this excess was left over. The lightest known massive particle is the electron, 7 so the last annihilation event was the electron-positron annihilation which took place when T m e 0.5 MeV and t 1 s. After this the only remaining antiparticles were the antineutrinos, and the primordial soup consisted of a large number of photons (who are their own antiparticles) and neutrinos (and antineutrinos) and a smaller number of left-over protons, neutrons, and electrons. When the universe was a few minutes old, T 100 kev, protons and neutrons formed nuclei of light elements. This event is known as Big Bang Nucleosynthesis (BBN), and it produced about 75% (of the total mass in ordinary matter) 1 H, 25% 4 He, H, He, and Li. (Other elements were formed much later, mainly in stars). At this time matter was completely ionized, all electrons were free. In this plasma the mean free path of a photon was short, the universe was opaque. The universe became transparent when it was a few hundred thousand years old. At a temperature T 3000 K ( 0.25 ev), the electrons and nuclei formed neutral atoms, and the photon mean free path became longer than the radius of the observable universe. This event is called recombination (although it actually was the first combination of electrons with nuclei, not a recombination). Since recombination the primordial photons have been traveling through space without scattering. We can observe them today as the Cosmic Microwave Background (CMB). It is light from the early universe. We can thus see the big bang. CMB tells us that the early universe was very homogeneous, unlike the present universe, where matter has accumulated into stars and galaxies. The early universe had, however, very small density variations, at the 10 4 or 10 5 level, which we see as small intensity variations of the CMB (the CMB anisotropy). Due to gravity, these slight overdensities have grown in time, and eventually became galaxies. This is called structure formation in the universe. The galaxies are not evenly distributed in space but form various structures, galaxy groups, clusters (large gravitationally bound groups), superclusters, filaments, and walls, separated by large, relatively empty voids. This present large scale structure of the universe forms a significant body of observational data in cosmology, which we should explain by cosmological 7 According to recent observational evidence from neutrino oscillations, neutrinos also have (very) small masses. However, at temperatures less than the neutrino mass, the neutrino interactions are so weak, that the neutrinos and antineutrinos cannot annihilate each other.
4 1 INTRODUCTION 4 theory. There are two parts to structure formation: 1. The origin of the primordial density fluctuations, the seeds of galaxies. These are believed to be due to some particle physics phenomenon in the very early universe, probably well before the EW phase transition. The particle physics theories applicable to this period are rather speculative. The two main competing theories for the origin of primordial fluctuations have been inflation and topological defects. Such defects (e.g., cosmic strings) may form in some phase transitions. The accumulation of more observational data in recent years has supported inflation and practically ruled out topological defects as a theory of structure formation. 2. The growth of these fluctuations as we approach the present time. The growth is due to gravity, but depends on the composition and total amount (average density) of matter. One of the main problems in cosmology today is that most of the matter and energy content of the universe appears to be in some unknown forms, called dark matter and dark energy. The dark matter problem dates back to 1930 s, whereas the dark energy problem arose in late 1990 s. From the motions of galaxies we can deduce that the matter we can directly observe as stars, luminous matter, is just a small fraction of the total mass which affects the galaxy motions through gravity. The rest is dark matter, something which we observe only due to its gravitational effect. We do not know what most of this dark matter is. A smaller part of it is just ordinary, baryonic, matter, which consists of atoms just like stars, but does not shine enough for us to notice it. Possibilities include planet-like bodies in interstellar space, failed stars (too small, m < 0.07m, to ignite thermonuclear fusion) called brown dwarfs, old white dwarf stars, and tenuous intergalactic gas. In fact, in large clusters of galaxies the intergalactic gas 8 is so hot that we can observe its radiation. Thus its mass can be estimated and it turns out to be several times larger than the total mass of the stars in the galaxies. We can infer that in other parts of the universe, where this gas would be too cold to be observable from here, also contain significant amounts of thin gas; which thus is apparently the main component of baryonic dark matter (BDM). However, there appears not be nearly enough of it to explain the whole dark matter problem. Beyond these mass estimates, there are more fundamental reasons (BBN, structure formation) why baryonic dark matter cannot be the main component of dark matter. Most of the dark matter must be non-baryonic, meaning that it is not made out of protons and neutrons 9. The only non-baryonic particles in the standard model of particle physics that could act as dark matter, are neutrinos. If neutrinos had a suitable mass, 1 ev, the neutrinos left from the early universe would have a sufficient total mass to be a significant dark matter component. However, structure formation in the universe requires most of the dark matter to have different properties than neutrinos have. Technically, most of the dark matter must be cold, instead of hot. These are terms that just refer to the dynamics of the particles 8 This gas is ionized, so it should more properly be called plasma. Astronomers, however, often use the word gas also when it is ionized. 9 And electrons. Although technically electrons are not baryons (they are leptons), cosmologists refer to matter made out of protons, electrons, and neutrons as baryonic. The electrons are anyway so light, that most of the mass comes from the true baryons, protons and neutrons.
5 1 INTRODUCTION 5 making up the matter, and do not further specify the nature of these particles. The difference between hot dark matter (HDM) and cold dark matter (CDM) is that HDM is made of particles whose velocities were large when structure formation began, but CDM particles had small velocities. Neutrinos with m 1 ev, would be HDM. The standard model contains no suitable particles to be CDM. Thus it appears that most of the matter in the universe is made out of some unknown particles. Fortunately, particle physicists have independently come to the conclusion that the standard model is not the final word in particle physics, but needs to be extended. The proposed extensions to the standard model contain many suitable CDM particle candidates (e.g., neutralinos, axions). Their interactions would have to be rather weak to explain why they have not been detected so far. Since these extensions were not invented to explain dark matter, but were strongly motivated by particle physics reasons, the cosmological evidence for dark matter is good, rather than bad, news from a particle physics viewpoint. Since all the cosmological evidence for CDM comes from its gravitational effects, it has been suggested by some that it does not exist, and that these gravitational effects might instead be explained by suitably modifying the law of gravity at large distances. However, the suggested modifications do not appear very convincing, and the evidence is heavily in favor of the CDM hypothesis. Most cosmologists consider the existence of CDM as an established fact, and are just waiting for the eventual discovery of the CDM particle in the laboratory (perhaps with the Large Hadronic Collider (LHC) at CERN). The situation with the so-called dark energy is different. While cosmologists are comfortable with dark matter, they are uncomfortable with dark energy. The accumulation of astronomical data relevant to cosmology has made it possible to determine the geometry and expansion history of the universe more accurately. It looks like yet another component to the energy density of the universe is required to make everything fit. This component is called dark energy or quintessence. Unlike dark matter, which is clustered, the dark energy should be relatively uniform in the observable universe. And while dark matter has negligible pressure, dark energy should have large, but negative pressure. The simplest possibility for dark energy is a cosmological constant or vacuum energy. Unlike dark matter, dark energy was not anticipated by high-energy-physics theory, and it appears difficult to incorporate it in a natural way. Again, another possible explanation is a modification of the law of gravity at large distances. In the dark energy case, this possibility is still being seriously considered; perhaps mainly because the various proposed models for dark energy do not appear very natural. Units and terminology We shall use natural units where c = = k B = 1. c = 1 Relativity theory unifies space and time into a single concept, the 4-dimensional spacetime. It is thus natural to use the same units for measuring distance and time. Since the (vacuum) speed of light is c = m/s, we set 1 s m, so that 1 second = 1 light second, 1 year = 1 light year, and c = 1. Velocity is
6 1 INTRODUCTION 6 thus a dimensionless quantity, and smaller than one 10 for massive objects. Energy and mass have now the same dimension, and Einstein s famous equivalence relation between mass and energy, E = mc 2, becomes E = m. This justifies a change in terminology; since mass and energy are the same thing, we do not waste two words on it. As is customary in particle physics we shall use the word energy, E, for the above quantity. By the word mass, m, we mean the rest mass. Thus we do not write E = m, but E = mγ, where γ = 1/ 1 v 2. The difference between energy and mass, E m, is the kinetic energy of the object. 11 k B = 1 Temperature, T, is a parameter describing a thermal equilibrium distribution. The formula for the occupation number of energy level E includes the exponential form e βe, where the parameter β = 1/k B T. The only function of the Boltzmann constant, k B = J/K, is to convert temperature into energy units. Since we now decide to give temperatures directly in energy units, k B becomes unnecessary. We define 1 K = J, or 1eV = 11600K = kg = J. (1) Thus k B = 1, and the exponential form is just e E/T. = 1 The third simplification in the natural system of units is to set the Planck constant = h/2π = 1. This makes the dimension of mass and energy 1/time or 1/distance. This time and distance give the typical time and distance scales quantum mechanics associates with the particle energy. For example, the energy of a photon E = ω = ω is equal to its angular frequency. We have A useful relation to remember is 1 ev = m 1 = s 1. (2) = 197 MeV fm = 1, (3) where we have the energy scale 200 MeV and length scale 1 fm of strong interactions. Equations become now simpler and the physical relations more transparent, since we do not have to include the above fundamental constants. This is not a completely free lunch however; we often have to do conversions among the different units to give our answers in reasonable units. Astronomical units A common unit of mass and energy is the solar mass, m = kg, and a common unit of length is one parsec, 1 pc = 3.26 light years = m. One 10 In the case of real (as opposed to coordinate ) velocities. 11 The talk about converting mass to energy or vice versa can be understood to refer to conversion of rest mass into kinetic energy.
7 1 INTRODUCTION 7 parsec is defined as the distance from which 1 astronomical unit (AU, the distance between the earth and the sun) forms an angle of one arcsecond, 1. (Astronomers and cosmologists only use light years when they talk to simple people). More common in cosmology is 1 Mpc = 10 6 pc, which is a typical distance between galaxies.
Chapter 23 The Beginning of Time 23.1 The Big Bang Our goals for learning What were conditions like in the early universe? What is the history of the universe according to the Big Bang theory? What were
23. The Beginning of Time Somewhere, something incredible is waiting to be known. Agenda Announce: Solar Altitude Lab (#2) due today Read Ch. 24 for Thursday Observation make-up next week Project Presentations
Topic 3 Primordial nucleosynthesis Evidence for the Big Bang! Back in the 1920s it was generally thought that the Universe was infinite! However a number of experimental observations started to question
The Birth of the Universe Newcomer Academy High School Visualization One Chapter Topic Key Points of Discussion Notes & Vocabulary 1 Birth of The Big Bang Theory Activity 4A the How and when did the universe
Evolution of the Universe from 13 to 4 Billion Years Ago Prof. Dr. Harold Geller email@example.com http://physics.gmu.edu/~hgeller/ Department of Physics and Astronomy George Mason University Unity in the
Big Bang (model) What can be seen / measured? basically only light (and a few particles: e ±, p, p, ν x ) in different wave lengths: microwave to γ-rays in different intensities (measured in magnitudes)
Your years of toil Said Ryle to Hoyle Are wasted years, believe me. The Steady State Is out of date Unless my eyes deceive me. My telescope Has dashed your hope; Your tenets are refuted. Let me be terse:
Transcript 22 - Universe A few introductory words of explanation about this transcript: This transcript includes the words sent to the narrator for inclusion in the latest version of the associated video.
REALIZING EINSTEIN S DREAM Exploring Our Mysterious Universe The End of Physics Albert A. Michelson, at the dedication of Ryerson Physics Lab, U. of Chicago, 1894 The Miracle Year - 1905 Relativity Quantum
The Universe The Universe is everything. All us, the room, the U.S. the earth, the solar system, all the other stars in the Milky way galaxy, all the other galaxies... everything. How big and how old is
Origins of the Cosmos Summer 2016 Pre-course assessment In order to grant two graduate credits for the workshop, we do require you to spend some hours before arriving at Penn State. We encourage all of
STRING THEORY: Past, Present, and Future John H. Schwarz Simons Center March 25, 2014 1 OUTLINE I) Early History and Basic Concepts II) String Theory for Unification III) Superstring Revolutions IV) Remaining
Nuclear Composition - the forces binding protons and neutrons in the nucleus are much stronger (binding energy of MeV) than the forces binding electrons to the atom (binding energy of ev) - the constituents
Chapter 20 The Big Bang The Universe began life in a very hot, very dense state that we call the big bang. In this chapter we apply the Friedmann equations to the early Universe in an attempt to understand
Where is Fundamental Physics Heading? Nathan Seiberg IAS Apr. 30, 2014 Disclaimer We do not know what will be discovered. This is the reason we perform experiments. This is the reason scientific research
Big Bang Nucleosynthesis The emergence of elements in the universe Benjamin Topper Abstract. In this paper, I will first give a brief overview of what general relativity has to say about cosmology, getting
Neutrinos & Cosmology 1 Cosmology: WHY??? From laboratory experiment limits can be set ONLY in neutrino mass difference No information if neutrino masses are degenerated From kinematic experiment limits
Data Provided: A formula sheet and table of physical constants is attached to this paper. DEPARTMENT OF PHYSICS AND ASTRONOMY Autumn Semester (2014-2015) DARK MATTER AND THE UNIVERSE 2 HOURS Answer question
Name: _Answer key Pretest: _2_/ 58 Posttest: _58_/ 58 Pretest Ch 20: Origins of the Universe Vocab/Matching: Match the definition on the left with the term on the right by placing the letter of the term
Build Your Own Universe You will need: At least 10,000,000,000,000,00 0,000,000,000,000,000,000,00 0,000,000,000,000,000,000,00 0,000,000,000,000,000,000,00 0,000 x Down quarks At least 10,000,000,000,000,000,
Nuclear Physics Nuclear Physics comprises the study of: The general properties of nuclei The particles contained in the nucleus The interaction between these particles Radioactivity and nuclear reactions
Concepts in Theoretical Physics Lecture 6: Particle Physics David Tong e 2 The Structure of Things 4πc 1 137 e d ν u Four fundamental particles Repeated twice! va, 9608085, 9902033 Four fundamental forces
Astro 102 Test 5 Review Spring 2016 See Old Test 4 #16-23, Test 5 #1-3, Old Final #1-14 Sec 14.5 Expanding Universe Know: Doppler shift, redshift, Hubble s Law, cosmic distance ladder, standard candles,
A Universe of Galaxies Today s Lecture: Other Galaxies (Chapter 16, pages 366-397) Types of Galaxies Habitats of Galaxies Dark Matter Other Galaxies Originally called spiral nebulae because of their shape.
Curriculum for Excellence Higher Physics Success Guide Electricity Our Dynamic Universe Particles and Waves Electricity Key Area Monitoring and Measuring A.C. Monitoring alternating current signals with
Rate Equations and Detailed Balance Initial question: Last time we mentioned astrophysical masers. Why can they exist spontaneously? Could there be astrophysical lasers, i.e., ones that emit in the optical?
95% Session 42 Review The Universe, and its Dark Side Dec 9, 2011 Email: firstname.lastname@example.org Announcements Final exam: Monday 12/12, 2:30-4:20 pm Same length/format as previous exams (but you can have
WHERE DID ALL THE ELEMENTS COME FROM?? In the very beginning, both space and time were created in the Big Bang. It happened 13.7 billion years ago. Afterwards, the universe was a very hot, expanding soup
I N F O R M A T I O N F O R T H E P U B L I C The Royal Swedish Academy of Sciences has decided to award the Crafoord Prize in Astronomy 2005 to James Gunn, Princeton University, USA, James Peebles, Princeton
Astronomy & Physics Resources for Middle & High School Teachers Gillian Wilson http://www.faculty.ucr.edu/~gillianw/k12 A cosmologist is.... an astronomer who studies the formation and evolution of the
P AUL A. M. DIRAC Theory of electrons and positrons Nobel Lecture, December 12, 1933 Matter has been found by experimental physicists to be made up of small particles of various kinds, the particles of
Malcolm S. Longair Galaxy Formation With 141 Figures and 12 Tables Springer Contents Part I Preliminaries 1. Introduction, History and Outline 3 1.1 Prehistory 3 1.2 The Theory of the Expanding Universe
Pearson Physics Level 30 Unit VIII Atomic Physics: Chapter 17 Solutions Student Book page 831 Concept Check Since neutrons have no charge, they do not create ions when passing through the liquid in a bubble
Chapter 16 Constituent Quark Model Quarks are fundamental spin- 1 particles from which all hadrons are made up. Baryons consist of three quarks, whereas mesons consist of a quark and an anti-quark. There
Cosmology: Will the universe end? 1. Who first showed that the Milky Way is not the only galaxy in the universe? a. Kepler b. Copernicus c. Newton d. Hubble e. Galileo Ans: d 2. The big bang theory and
Basics of Nuclear Physics and Fission A basic background in nuclear physics for those who want to start at the beginning. Some of the terms used in this factsheet can be found in IEER s on-line glossary.
Section 7: In this section, we present a basic description of atomic nuclei, the stored energy contained within them, their occurrence and stability Basic Nuclear Concepts EARLY DISCOVERIES [see also Section
Exploring the Universe Through the Hubble Space Telescope WEEK FIVE: THE HUBBLE DEEP FIELD + LIMITATIONS OF HUBBLE, COLLABORATIONS, AND THE FUTURE OF ASTRONOMY Date: October 14, 2013 Instructor: Robert
Enter your answers on the form provided. Be sure to write your name and student ID number on the first blank at the bottom of the form. Please mark the version (B) in the Key ID space at the top of the
1 Candidates should be able to : CONTENTS OF THE UNIVERSE Describe the principal contents of the universe, including stars, galaxies and radiation. Describe the solar system in terms of the Sun, planets,
CANADA S NATIONAL LABORATORY FOR PARTICLE AND NUCLEAR PHYSICS Owned and operated as a joint venture by a consortium of Canadian universities via a contribution through the National Research Council Canada
Nuclear Physics and Radioactivity 1. The number of electrons in an atom of atomic number Z and mass number A is 1) A 2) Z 3) A+Z 4) A-Z 2. The repulsive force between the positively charged protons does
Physics 114 Midterm 2 Review: Solutions These review sheets cover only selected topics from the chemical and nuclear energy chapters and are not meant to be a comprehensive review. Topics covered in these
Inflationary Big Bang Cosmology and the New Cosmic Background Radiation Findings By Richard M. Todaro American Physical Society June 2001 With special thanks to Dr. Paul L. Richards, Professor of Physics
5 Particle Physics This lecture is about particle physics, the study of the fundamental building blocks of Nature and the forces between them. We call our best theory of particle physics the Standard Model
I The Sun and Solar Energy One of the most important forces behind global change on Earth is over 90 million miles distant from the planet. The Sun is the ultimate, original source of the energy that drives
Lesson 6: Earth and the Moon Reading Assignment Chapter 7.1: Overall Structure of Planet Earth Chapter 7.3: Earth s Interior More Precisely 7-2: Radioactive Dating Chapter 7.5: Earth s Magnetosphere Chapter
Main properties of atoms and nucleus. Atom Structure.... Structure of Nuclei... 3. Definition of Isotopes... 4. Energy Characteristics of Nuclei... 5. Laws of Radioactive Nuclei Transformation... 3. Atom
A Unified Physics by by Steven Weinberg 2050? Experiments at CERN and elsewhere should let us complete the Standard Model of particle physics, but a unified theory of all forces will probably require radically
Week 1-2: Overview of the Universe & the View from the Earth Hassen M. Yesuf (email@example.com) September 29, 2011 1 Lecture summary Protein molecules, the building blocks of a living organism, are made
Stars, Galaxies, Guided Reading and Study This section explains how astronomers think the universe and the solar system formed. Use Target Reading Skills As you read about the evidence that supports the
What is the Sloan Digital Sky Survey? Simply put, the Sloan Digital Sky Survey is the most ambitious astronomical survey ever undertaken. The survey will map one-quarter of the entire sky in detail, determining
2. The Three Pillars of the Big Bang Theory The evolution of the Universe can be compared to a display of fireworks that has just ended: some few wisps, ashes and smoke. Standing on a cooled cinder, we
2 ATOMIC SYSTEMATICS AND NUCLEAR STRUCTURE In this chapter the principles and systematics of atomic and nuclear physics are summarised briefly, in order to introduce the existence and characteristics of
. Degenerate Pressure We next consider a Fermion gas in quite a different context: the interior of a white dwarf star. Like other stars, white dwarfs have fully ionized plasma interiors. The positively
Remodelling the Big Bang Dewey B. Larson Unquestionably, the most significant development that has taken place in cosmology in recent years is the replacement of the original Big Bang theory by a totally
School of Mathematical and Computing Sciences Te Kura Pangarau, Rorohiko Einstein s cosmological legacy: From the big bang to black holes Matt Visser Overview: 2005 marks 100 years since Einstein discovered
3 Thermal History In this chapter, we will describe the first three minutes 1 in the history of the universe, starting from the hot and dense state following inflation. At early times, the thermodynamical
Axion/Saxion Cosmology Revisited Masahiro Yamaguchi (Tohoku University) Based on Nakamura, Okumura, MY, PRD77 ( 08) and Work in Progress 1. Introduction Fine Tuning Problems of Particle Physics Smallness
Low- and high-energy neutrinos from gamma-ray bursts Hylke B.J. Koers Low- and high-energy neutrinos from gamma-ray bursts Hylke B.J. Koers HK and Ralph Wijers, MNRAS 364 (2005), 934 (astro-ph/0505533)
Cambridge International Examinations Cambridge International Advanced Subsidiary and Advanced Level *0123456789* PHYSICS 9702/02 Paper 2 AS Level Structured Questions For Examination from 2016 SPECIMEN
Imperial College London BSc/MSci EXAMINATION June 2008 This paper is also taken for the relevant Examination for the Associateship SUN, STARS, PLANETS For Second Year Physics Students Wednesday, 4th June
GCE Physics A Unit G485: Fields, Particles and Frontiers of Physics Advanced GCE Mark Scheme for June 014 Oxford Cambridge and RSA Examinations OCR (Oxford Cambridge and RSA) is a leading UK awarding body,
Atomic Structure: Chapter Problems Bohr Model Class Work 1. Describe the nuclear model of the atom. 2. Explain the problems with the nuclear model of the atom. 3. According to Niels Bohr, what does n stand
The Dawn of PHYSICS BEYOND THE By Gordon Kane 68 SCIENTIFIC AMERICAN STANDARD MODEL The Standard Model of particle physics is at a pivotal moment in its history: it is both at the height of its success
Basic Concepts in Nuclear Physics Paolo Finelli Corso di Teoria delle Forze Nucleari 2011 Literature/Bibliography Some useful texts are available at the Library: Wong, Nuclear Physics Krane, Introductory
MASS DEFECT AND BINDING ENERGY The separate laws of Conservation of Mass and Conservation of Energy are not applied strictly on the nuclear level. It is possible to convert between mass and energy. Instead
WIMPs and MACHOs WIMP is an acronym for weakly interacting massive particle and MACHO is an acronym for massive (astrophysical) compact halo object. WIMPs and MACHOs are two of the most popular DARK MATTER
First Discoveries The Sloan Digital Sky Survey began operating on June 8, 1998. Since that time, SDSS scientists have been hard at work analyzing data and drawing conclusions. This page describes seven
Name Date Period 30 GALAXIES AND THE UNIVERSE SECTION 30.1 The Milky Way Galaxy In your textbook, read about discovering the Milky Way. (20 points) For each item in Column A, write the letter of the matching
1 Strontium-90 decays with the emission of a β-particle to form Yttrium-90. The reaction is represented by the equation 90 38 The decay constant is 0.025 year 1. 90 39 0 1 Sr Y + e + 0.55 MeV. (a) Suggest,
Chapter 15.3 Galaxy Evolution Elliptical Galaxies Spiral Galaxies Irregular Galaxies Are there any connections between the three types of galaxies? How do galaxies form? How do galaxies evolve? P.S. You
Part 1 Composition of Earth Composition of solar system Origin of the elements Part 2 Geochronometry: Age of Earth Formation of Earth and Moon. Differentiation of core and mantle. Isotope tracing: sequence
Introduction to Elementary Particle Physics. Note 01 Page 1 of 8 Natural Units There are 4 primary SI units: three kinematical (meter, second, kilogram) and one electrical (Ampere 1 ) It is common in the
TEACHER BACKGROUND INFORMATION THERMAL ENERGY In general, when an object performs work on another object, it does not transfer all of its energy to that object. Some of the energy is lost as heat due to
JOURNAL OF MATHEMATICAL PHYSICS VOLUME 42, NUMBER 7 JULY 2001 The future of string theory John H. Schwarz a) California Institute of Technology, Pasadena, California 91125 Received 2 January 2001; accepted
111 111 Chapter 6. Dimensions 111 Now return to the original problem: determining the Bohr radius. The approximate minimization predicts the correct value. Even if the method were not so charmed, there
1. Most interstellar matter is too cold to be observed optically. Its radiation can be detected in which part of the electromagnetic spectrum? A. gamma ray B. ultraviolet C. infrared D. X ray 2. The space
Sputtering Vacuum Evaporation Recap Use high temperatures at high vacuum to evaporate (eject) atoms or molecules off a material surface. Use ballistic flow to transport them to a substrate and deposit.
Galaxy Evolution is the study of how galaxies form and how they change over time. As was the case with we can not observe an individual galaxy evolve but we can observe different galaxies at various stages
Submitted to the Gravity Research Foundation s 2006 Essay Contest How Fundamental is the Curvature of Spacetime? A Solar System Test Robert J. Nemiroff Abstract Are some paths and interactions immune to
H9 Modeling the Expanding Universe Activity H9 Grade Level: 8 12 Source: This activity is produced by the Universe Forum at NASA s Office of Space Science, along with their Structure and Evolution of the
The Search for Dark Matter, Einstein s Cosmology and MOND David B. Cline Astrophysics Division, Department of Physics & Astronomy University of California, Los Angeles, CA 90095 USA firstname.lastname@example.org
SPECIMEN MATERIAL v1.1 AS PHYSICS (7407/1) Paper 1 Specimen 2014 Morning Time allowed: 1 hour 30 minutes Materials For this paper you must have: a pencil a ruler a calculator a data and formulae booklet.