What is this? PH1600: Introductory Astronomy Lecture 23: Early Forces and Inflation

PH1600: Introductory Astronomy Lecture 21: Early Forces and Inflation Study: Chapter 19 in The Cosmos book Next Lecture: Chapter 20: Life in the Universe School: Michigan Technological University Professor: Robert Nemiroff Book: The Cosmos by Pasachoff & Filippenko Online Course WebCT pages: This class can be taken online ONLY, class attendance is not required!

You are responsible for…  Reading the book One chapter per “quiz period” Anything from that chapter can appear on quizzes or tests, even if I never mention them during my lecture(s) This quiz period covers Chapters 18  APODs posted during the semester APOD review every week during lecture  Completing the Quizzes Chapter 1, 2, 4, 6, 7, 8, 10, 11, 13, 14, 15 & 18 quizzes already due Chapter 19 quiz due next See WebCT at for detailshttp://courses.mtu.edu/

Inflating the Universe Credit: WMAP Science Team, NASA APOD: 2006 March 23

Forces in the Universe  Gravity  Electromagnetism  Strong Nuclear Force  Weak Nuclear Force  Electroweak force  Grand unified theories  Superstring theories

Different types of energy Dark Energies (gravitationally repulsive)  Phantom energy (hypothesized)  Cosmological constant  Domain Walls  Cosmic Strings

Different Types of Energy  Matter Dark matter, atoms,  Radiation Light, neutrinos, axions, etc.  Ultralight (?) Only hypothesized  Scalar fields

Problems with Original Big Bang  Horizon problem Why is the universe so uniform? How does the left part of the universe know to have the same temperature as the right part?  Flatness problem Why is the geometry of the universe so close to flat?  Magnetic monopole problem

Inflation to the Rescue  Universe suddenly begins to expand exponentially  Caused by phase transition as strong nuclear force freezes out  A repulsive “cosmological constant” temporarily dominates the energy density of the universe  As inflation ends, matter and radiation are (again?) created

Timeline for the Early Universe  t= sec, T=10 33 K Planck scale: theory of everything  t= sec, T=10 29 K Grand unified theory phase transition Strong nuclear force freezes out Inflation  T= sec, T=10 28 K Inflation ends Particles created

Timeline for the Early Universe  t= sec, T=10 16 K Weak nuclear force freezes out Particles acquire masses  t=10 -6 sec, T=10 13 K Quarks combine to form protons  t=10 -2 sec, T=10 10 K Neutrinos decouple from protons

Higher Dimensional Universes  Could our universe have more than three spatial dimensions?  Large far away dimensions Tension force holds us to 3D  Small rolled up dimensions? Small scales hide higher dimensions  be.html

Multiverse Hypotheses  Many other universes might exist  In space: causally disconnected  In space: occupying other dimensions  In time: Oscillatory universes Example: Bang, crunch, bang, crunch. Etc.

Multiverse Hypotheses  Many Worlds Interpretation Every possible outcome of every random event actually exists We occupy only one realization Zillions of “you” exist in other “parallel universes” Only conjecture  Might not even be testable

Multiverses: Do Other Universes Exist? Illustration Credit & Copyright: Clifford Pickover APOD: 2006 March 1

The Anthropic Principle  Only universes where we exist are allowed  Example: A quick Big Crunch universe that never developed life could not be our universe  Controversial when used Statistical occurrences hard to quantify

A Force from Empty Space: The Casimir Effect Credit & Copyright: Umar Mohideen (U. California at Riverside) APOD: 2002 September 17