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Announcements:

Announcements:.

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Announcements:

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  1. Announcements:  On Monday, November 24 at 11:30am there will be an hour long workshop on Preparing for Multiple Choice Exams in the Sciences and Technology Library's Computer Lab.  The workshop is being done by Jim Honeyford from the Academic Learning Centre.  There are no sign ups and all are welcome to attend!  Need a volunteer for the SEEQ. Did this week’s star fleet academy people get my email?

  2. Fill in forms now! ABORIGINAL UNDERGRADUATE STUDENT RESEARCH AWARD Interested in gaining valuable experience in research over the summer months? Come learn about a great opportunity for Indigenous students through the NSERC USRA Program! Information Session: Tues, Nov 25, 201 Armes (4:30-5:30) Presentations by guest speakers and program participants Questions? Contact Amanda: fontesa@myumanitoba.ca

  3. Lecture 32: Cosmology 2MASS Observations – colour code on radial velocity • Upcoming: • Various models of the Universe • Life on other worlds • e.g. Drake Equation Learn the material in the lectures. Much of it is NOT in the textbook. Use the textbook for reference. • Homogeneous: the same everywhere • Isotropic: the same in all directions

  4. How galaxies trace the universe: z == Redshift • Hubble’s Law v = Ho * distance • Galaxies in general are are receding from us!  The universe is expanding.

  5. Past & Future: Past Credit: Nature Journal

  6. Past & Future: Future - The Expansion of the Universe: Observations • At large distances we are looking at past. • x-axis can be translated to time.

  7. Hubble plot:

  8. Hubble plot:

  9. Hubble plot:

  10. Hubble plot:

  11. Past & Future: Future - The Expansion of the Universe: Observations The expansion is accelerating! • At large distances we are looking at past. • For same unit of distance, change in velocity was smaller in past than currently.  The speed of expansion has increased with time.

  12. The Accelerating Universe • In 1998, SNe Ia showed universe accelerating! • Huge shock for cosmology. • Some “force” seems to be counter-acting gravity to cause the galaxies to fly apart faster than expected. • This energy == Dark Energy (DE). 2012 Nobel Prize ! Saul Perlmutter Brian Schmidt Adam Reiss

  13. Overview of experiments  DE

  14. The Accelerating Universe • Matter ~ 27 - 32% (mainly DM) • Energy ~ 68 - 73% • Values for Planck Mission: • 4.9% regular matter • 26.8% DM • 68.3% Dark Energy

  15. The Accelerating Universe • Possibilities for DE: • Cosmological Constant (Einstein) • DE constant with time •  Vacuum Energy Density • (Casimir Effect – virtual particle pairs.) • Quintessence •  DE varies with time

  16. Λ Cold Dark Matter Model • Λ == lambda (capital) • DE constant with time • comes from GR equations • constant included to make models of the universe static • Einstein wasn’t aware of expansion • this constant is now used to represent the acceleration

  17. λ Cold Dark Matter Model • “cold”: means that matter moved slowly • allows matter to clump early in universe’s history • matches observations that galaxies exist at high z

  18. λ Cold Dark Matter Model: Evidence Artist Concept BOSS experiment using Sloan Digitized Sky Survey, > 10**6 galaxies positions & z. • Baryonic Acoustic Oscillations == tendency of galaxies to align (cluster) on spheres • spheres originated as density waves traveling through the plasma of the early universe

  19. λ Cold Dark Matter Model: Evidence • Combining measurements from CMB, accelerating expansion via SN, & Baryon Acoustic Oscillations  suggest that dark energy is a cosmological constant whose strength does not vary in space or time.

  20. Acceleration : The Fate of the Universe: Observations The expansion is accelerating! • expand forever • cool • photons become redshifted • gas  stars  black dwarfs • black holes evaporate • protons and neutrons decay

  21. The Fate of the Universe: Expands Forever!

  22. The Origin of Spacetime: QUANTUM GRAVITY THEORIES • Difficulty reconciling gravity & QM  what if space & t are not fundamental? What if they are “emergent”? • like colour – which is not fundamental but “emerges” from more fundamental items: wavelength & eye-brain system

  23. Complementary Colours o

  24. The origin of spt • Thermodynamic characteristic of Hawking radiation  fundamental particles. • What could be the fundamental “atoms” or “pixels” that spt emerges from?

  25. The origin of spt

  26. The origin of spt • Doesn’t include other forces • how does spt emerge?

  27. The origin of spt • Links go from past to present • “tree” structure forms spt fabric • predicted accelerating expansion

  28. The origin of spt • chunks of spt in sea of QM flucuations • need to include causality for models similar to observed universe

  29. The origin of spt • Holograms are 2D objects that contain apparently 3D information. • Interior has gravity; surface elements (pixels) only experience QM • Spt emerges from QM

  30. Is time an illusion? • t may also be emergent • Scientific American article by Craig Callender

  31. Again: Discuss cosmology with your neighbour. What do you find the most intriguing thing about it? Which is the most challenging concept for you?

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