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Concluding Comments For the Course. Cosmology Fascinating Past Highly accomplished present (for example, the material covered in this course). Really exciting future. Time. The History of the Universe. Today. Anti-Gravity?*!. Galaxy Formation . Last Scattering.
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Concluding Comments For the Course • Cosmology • Fascinating Past • Highly accomplished present (for example, the material covered in this course). • Really exciting future
Time The History of the Universe Today Anti-Gravity?*! Galaxy Formation Last Scattering Nuclear & High Energy Physics Inflation? Extra Dimensions? High Energy & Temp
Concluding Comments For the Course • Cosmology • Fascinating Past • Highly accomplished present (for example, the material covered in this course). • Really exciting future
Past: Cosmology provided a great source of inspiration and new ideas:
Concluding Comments For the Course • Cosmology • Fascinating Past • Highly accomplished present (for example, the material covered in this course). • Really exciting future
Present: Deep understanding of our universe comes from 1) Application of known laws of physics Atomic energy levels Emission Absorption
Present: Deep understanding of our universe comes from 1) Application of known laws of physics
Present: Deep understanding of our universe comes from 2) Collecting amazing data sets
Present: Deep understanding of our universe comes from 3) Putting Data and physics together to get the big picture Big Bang Theory
What we know about the big picture 1) On large scales the matter in the Universe is spread out very smoothly (“Homogeneous”) Mean density: 2) The Universe is expanding Hubble law:
The homogeneity of the Universe Galaxy Isotropy of the microwave background (from the “edge of the observable universe”) to one part in 100,000
The homogeneity of the universe We are here Radial Direction Galaxy surveys
The homogeneity of the universe We are here Radial Direction From 1986 Galaxy surveys
Time The History of the Universe Today Anti-Gravity?*! Galaxy Formation Last Scattering Nuclear & HEP Inflation? Extra Dimensions? High Energy & Temp
Present: Deep understanding of our universe comes from 4) Exploring and observing consequences of the Big Bang such as CMB: The edge of the observable universe
The Edge of the Observable Universe: As we look back in space we look back in time. We see: Light traveling from far away =from distant past Here & Now Long ago (about 14 Billion years) the Universe was so hot and dense it was opaque: The edge of the observable universe
Properties of the Edge of the Observable Universe: Similar to surface of Sun at time of emission • Today: • Only 2.726K above absolute Zero • “Microwave Radiation” (The “Cosmic Microwave Background”: CMB) • 1,000,000 times weaker than ambient radiation in a pitch dark room. Here & Now
Properties of the Edge of the Observable Universe: Similar to surface of Sun at time of emission Cools off due to cosmic expansion Same thing happens with stars “Oblers’ paradox” (see section 23.4) • Today: • Only 2.726K above absolute Zero • “Microwave Radiation” (The “Cosmic Microwave Background”: CMB) • 1,000,000 times weaker than ambient radiation in a pitch dark room. Here & Now
Observing the Microwave Background, Past, present and future:
Time The History of the Universe New Image of the “Last Scattering Surface” from NASA’s WMAP satellite released Feb 11 2003 High Energy & Temp
Maps of the microwave sky (the “edge of the observable universe” 1993 Real data Updated after WMAP announcement, Feb 2003 Real data ! 2009 Simulated data
WMAP map of the “edge of the observable universe” plotted as a sphere
Note: we are really on the inside looking out WMAP map of the “edge of the observable universe” plotted as a sphere
Present: Deep understanding of our universe comes from 4) Exploring and observing consequences of the Big Bang such as Formation of Nuclei
Time The History of the Universe Today Anti-Gravity?*! Galaxy Formation Last Scattering Nuclear & High Energy Physics Inflation? Extra Dimensions? High Energy & Temp
Present: Deep understanding of our universe comes from 5) New ideas such as cosmic inflation that seem to explain the start of the Big Bang and fit the data nicely
WMAP • Characteristic oscillations in the CMB power Inflation Temperature Power “Active” models Adapted from Bennett et al Feb 11 ‘03 Angular scale I.1 Successes
The future is exciting because of • Deep Mysteries • Dark Matter • Dark Energy
Cosmic acceleration (newest data) Using supernovae (exploding stars) as cosmic “mileposts”, acceleration of the Universe has been detected. Here for inflation Preferred by modern data Amount of “antigravity” matter “Gravitating” non accelerating matter Supernova Amount of gravitating matter
Here for inflation Preferred by modern data Amount of “antigravity” matter “Gravitating” non accelerating matter Supernova Amount of gravitating matter • Accelerating “Dark Energy” is what makes U=1 (required to give consistency with inflation) • Acceleration or (required for inflation) is possible (+) • Dark Energy *very* poorly understood (-/+)
95% of the cosmic matter/energy is a mystery. It has never been observed even in our best laboratories Ordinary Matter (observed in labs) 5% Dark Matter 25% Dark Energy (accelerating) 70%
The future is exciting because 2) Fantastic new data sets will enable us to explore these mysteries (and hopefully resolve some of them)
The future of cosmological data • The James Webb (Next Generation) Space Telescope
The SNAP Satellite Here for inflation Preferred by modern data Amount of “antigravity” matter Proposed new experiment “Ordinary” non accelerating matter Supernova Amount of ordinary matter
The future of cosmological data • The LSST (Large-aperture Synoptic Survey Telescope) NB: the director of LSST is Prof Tony Tyson of UCD
The future of cosmological theory • The new data will allow us to resolve hotly contested issues • Expect progress on: • Can we explain/understand the beginning of the universe? • What is accelerating the universe? • What caused the galaxies to form? • What is the fundamental nature of matter and gravity?
For the future: • -I hope this course has made you better able to understand new results as they are reported in the press. • Feel free to come around to my office hours at any time in the future with questions. • Perhaps some of you would like to make a career in cosmology research (feel free to see me & discuss that)