Flashbacks

1. Flashbacks • In your own words, describe the Big Bang Theory.

2. Flashback Mondy • 1. The force that keeps everyone on the planet and keeps the planets in orbit. a. weight • b. mass • c. gravity • 2. Which of the following lists (below) is in order from smallest to largest? • a. Universe, solar system, galaxy, earth • b. earth, galaxy, solar system, Universe • c. solar system, earth, galaxy, Universe • d. earth, solar system, galaxy, Universe

3. Flashback Friday 1. As a galaxy moves away from another galaxy, we say that it is: a.)red shifted b.) blue shifted • 2. Which color has the longest wavelength? • a. red • b. green • c. indigo

4. How the Universe got its Spots The Big Bang

5. Goals • Where did the Universe come from? • Where is it going? • What evidence supports the Big Bang Theory?

6. Time line: Cosmic Soup, Radiation Era, Matter Dominated Era

7. The Big Bang • Big Bang: the event from which the Universe began expanding. • Into what did the Universe expand? • Where was the Big Bang? • Where is the center of the Universe?

8. The Big Bang theory states that approximately 14 billion years ago the universe burst into being from an unknown cosmic trigger. The early universe, contained within just a few millimeters, was very hot and densely packed with matter called a SINGULARITY. Ever since that initial explosion, the universe has continued to expand and cool.

9. Singularity • A ball of infinite density and energy smaller than an atom that exploded into the universe that we know.

10. Expanding Universe • Space itself is expanding, not matter flying apart within space. • Examples: • dots • rubber band • raisin bread • It does not mean we are at the center of the Universe • every part of the Universe sees everything moving away from it

11. Looking Back in Time • Remember it takes time for light to reach us • travels at 300,000 km/s • So we see things “as they were” some time ago • The farther away, the further back in time we are looking • 1 billion LY means looking 1 billion yearsback in time • So the greater the redshift, the further back in time • redshift of 0.1 is 1.4 billion lightyears which means we are looking 1.4 billion years into the past

12. Big evidence for Big Bang George Lemaitre proposed the idea that the universe was expanding in 1927 He named it the “Hypothesis of the primeval atom”. there was a definite beginning to the universe. universe

13. Flipbook Directions • Fold 2 pieces of paper into 4 sections and cut out your pages (1st page will be a Title Page). • I will come around to staple your book as you work. • Create a flipbook using at least 7 pages showing the Big Bang. • Start with a “Singularity” and finish the Universe as we know it today. • Use color, creativity, and your imagination to illustrate the book.

15. l - l observed rest = l rest 1. Galactic Redshifts • Edwin Hubble (1889-1953) and colleagues • measured the spectra (light) of many galaxies • found nearly all galaxies are red-shifted • Redshift (Z) Andromeda galaxy Z = [(1+ v/c)/(1+ v/c)]1/2 - 1

16. Quasars & Cosmology Redshift Redshift happens when light seen coming from an object that is moving away has shifted (towards the red end of the spectrum) Department of Physics, Applied Physics & Astronomy, RPI

17. Do you know what Red Shift is? • R • Remember: the Red is the longest wavelength while Purple is the shortest.

19. What does Redshift mean for the BIG BANG Theory? • If all of the galaxies are redshifted, then they are ALL moving apart from each other!! • (This is proof that the Universe is expanding)

20. 2. Hubble’s Law • Galaxies are moving away from us. B. The farther away the faster they go!

21. Expanding Universe • If galaxies are all moving away, then at some point they were all much closer. • Hubble’s Law implies the Universe is expanding.

22. 3. Cosmic Background Radiation • CBR is radiation left over from the explosion of the Big Bang discovered by Arno A. Penzias and Robert W. Wilson. • It is similar to the radiation leftover after a nuclear bomb.

23. Look back Time • We see everything as it once was. Present Young Early

24. Age of the Universe • Since all galaxies are moving away from us, how long has it been since all galaxies were together? time = distance / velocity velocity = Ho x distance time = distance / (Ho x distance) time = 1/Ho “An expanding universe does not preclude a creator, but it does place limits on when he might have carried out his job.” -Steven Hawking, A Brief History of Time

25. The End of the Universe • Will the universe expand forever? • Depends on the density of the Universe. • Too big: Big Crunch • Closed Universe • Bound Universe • Too small: Big Freeze • Open Universe • Unbound Universe

26. Hubble Space Telescope • Use HST to find Cepheids in other galaxies.

27. V=HoD V Present Past Distance (Lookback time) Are We Slowing Down? • In our experience, things slow down over time. • Is the Universe slowing down at all? • Plot distance versus velocity. • Use supernovae as “standard candles.” • Distant supernovae (large lookback time). Slowing Accelerating

28. Slowing Accelerating Are We Slowing Down? • Unseen mass making stars move fast: Dark Matter • Unseen energy accelerating galaxies: Dark Energy

29. We are not made of the same type of matter as most of the Universe!