Origin and Formation of the Universe

1. Origin and Formation of the Universe

2. “I CAN” Statements Origin/Formation of the Universe Identify and Compare the two theories of universe formation [L2] Describe the evidences supporting the Big Bang Theory and universe expansion [L3] Abundance of light elements Describe the formation of Cosmic Background Radiation Summarize the Doppler Effect and Define Redshift Describe the possible fates of the Universe [L2] 2

3. How do scientists know about Earth’s formation? Scientists use direct observation and theoretical models to try to understand how the universe formed. 3

4. Theories [models]of Universe Formation Big Bang Theory Steady State Theory 4

5. The Big Bang Theory The most widely accepted theory for the formation of the Universe 5

6. The Big Bang Theory All matter was once compacted in a tiny, dense particle, smaller than a piece of dust. The particle was compacted by extreme pressure and temperature 6

7. Building a Universe • an expansive event called the big bang instantaneously filled space with all matter and energy

8. The Big Bang Theory The Big Bang Theory DOES NOTstate that the universe was created from a“giant explosion”!!! 8

9. The Big Bang Theory 10-43sec Initial, hyper-(super fast) expansion, NOT an explosion! Matter and energy are propelled outward in all directions 10-32sec Hot soup of electrons, quarks and other particles 9

10. The Big Bang Theory 10-6sec Rapid cooling allows quarks to clump into protons and neutrons 3minutes protons and neutrons combine into atomic nuclei 300,000years electrons join nuclei to make atoms (mostly Hydrogen and Helium); light (photons) is emitted 10

11. The Big Bang Theory 1 billion years Gravity brings together atoms of H and He forming giant clouds that will become galaxies. 11

12. Galaxies, families of billions of stars 12

13. OUR galaxy, the Milky Way, a spiral galaxy 13

14. Big Bang Timeline 14

15. The Big Bang Theory Over the next 13.7 billion years, inflation continued and the universe cooled [-270C] Inflation continues today, and according to the BBT, inflation should never end… 15

16. Consequences of the Big Bang • If the universe did come into existence through an expansive event. there should be some evidences: • The mix of the elements should be known • The universe should have a measurable Temp. • The universe should be expanding

17. Abundance of Light Elements Elemental composition of the present universe closely matches the predictions made by the BBT: 17

18. Big Bang “After Glow” In the early moments following the BB, the universe was giving off large amounts of IR radiation (thermal energy) and visible light. As the universe expanded, it cooled. Weak radiation should be dispersed in all direction of space. 18

19. Arno Penzias and Robert Wilson Early 1960s - Penzias and Wilson are hired by Bell Labs to evaluate the performance of the new radio telescope to be used in trans-Atlantic telephone communications. They found a small, unexplained signal regardless of the direction the telescope is pointed. It is not enough to be a problem, but they are curious. 1964 - They become aware that the noise in their telescope is the cosmic background radiation predicted by the Big Bang theory. Bell Labs’ radio telescope. 19

20. COsmic Background Explorer • In 1992, COBE announced a measurement that showed that the background radiation was ALMOST uniform This measurement confirmed the temperature to be app. 2.73K

21. Remnant echo of the BB image of the (extremely tiny) anisotropies in the cosmic background radiation

22. Expanding Universe THE BALLOON ANALOGYSPACE between galaxies is increasing

23. Cluster of galaxies do not increase in size, but the galaxies move further apart

24. In the 1920s, Edwin Hubble determines that the galaxies are: Moving away from the Earth in all directions and The father away they are, the faster they move outward Hubble’s Law states that:as the distance increases, so does the velocity. This implies that the universe is UNIFORMELY expanding. Edwin Hubble with his cat Nikolus Copernicus. (Colliers Magazine, 1949) 26

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26. Hubble used a phenomenon first discovered by the Austrian mathematician and physicist, Christian Doppler (1803-53). The pitch of a note is how high or low it sounds. It depends on the frequency of the wave. Higher the frequency of a sound wave, shorter its wavelength, higher its pitch. How was this known??? 28

27. As the police car approaches, the SW from its siren are compressed towards the observer.The intervals between waves diminish, which translates into an increase in frequency or pitch. 29

28. Conversely as the police car recedes, the SW are stretched relative to the observer, causing the siren's pitch to decrease. 30

29. By the change in pitch of the siren, you can determine if the car is coming nearer or speeding away. 31

30. A change in pitch results from a change/shift in the frequency of the sound waves is referred to as the DOPPLER EFFECT.

31. Doppler Effect [Light] • As the light from a galaxy travels away from us, the distance between us and that galaxy increases, thus light is “stretched” appearing redder. • Red has a longer wavelength than Blue

33. Red Shift and Blue Shift • The waves emitted by an object moving toward an observer are squeezed; its frequency appears to increase and is therefore said to be blueshifted. (shorter wavelength)] • In contrast, the waves emitted by an object moving away are stretched or redshifted. (shorter frequency, longer wavelength) • Blueshifts and redshifts exhibited by stars, galaxies and gas clouds also indicate their motions with respect to the observer. 35

34. Hubble and Redshift He recorded emission spectra for distant galaxies and stars, then matched spectroscopic pattern of emission spectrum with particular element, and observed that spectra did not match up with any known spectra, but appeared to be a SHIFTED hydrogen emission spectrum 36

35. Redshift This is hydrogen spectrum here On earth Small shift Far away Large shift VERY far away 37

36. The Universe is EXPANDING and SPEEDING UP

37. Galaxy’s velocity is proportional to its distance galaxies that are twice as far from us move twice as fast Every galaxy took the same amount of time to move from a common starting position to its current position

38. Einstein lecturing on the General Theory of Relativity in Pasadena, California, 1932. Albert Einstein developed the general theory of relativity (GTR) in 1915. It predicted that space had to be either expanding or contracting. Einstein was still a bit unsure about what he had come up with and thus believed this to be incorrect and changed his theory. 40

39. Expansion of Space 1916 - Einstein’s general theory of relativity predicts that space must be either expanding or contracting. Einstein does not believe this and tries to “fix” the theory. 1920s - Other astronomers and physicists show that all versions of the GTR require either the expansion or contraction of space. 1929 - Hubble’s Law. 1930 - Arthur Eddington explains Hubble’s Law as the expansion of space as described by the GTR. 1930 - Einstein calls his not accepting his original theory “the greatest blunder of my scientific career.” 41

40. STEADY-STATE THEORY • Infinite Universe Theory • No definite beginning • The Universe is expanding, but it always looked, and will look the same • this implies that its density remains constant

41. STEADY-STATE UNIVERSE

42. The Future of the Universe The rate of expansion of the universeis increasing. The universe will continue to expand forever, as suggested by the BBT, and stars making up the galaxies will age and die. as more stars die over billions of years, the universe will eventually grow cold and dark OR 44

43. The Future of the Universe The expansion will slow down as new matter is “formed” [E=mC^2], and will eventually stop It will begin to contract and collapse until the universe contracts back to a single point in a big crunch! PULSATING (OSCILLATING) THEORY 45

44. Big Theory Video