1. http://www.wimp.com/bigbang/ Ever ask yourself the question… How did this all begin?

2. Gravity is what is responsible for the formation of our Universe Universe  Galaxies  Solar System  Earth Our Galaxy  The Milky Way

3. Our Solar System

4. Relative Sizes of the Planets to the Sun 109 EARTHS FIT ACROSS THE DIAMETER OF THE SUN

5. Stellar Evolution of Sun- what is the fate of our sun? 0.08M

6. How do stars evolve and what determines how they die? THEIR INITIAL MASS!!!!!!

10. How does a star form? All stars are made up of predominantly Hydrogen and Helium

11. ProtostarProtostar clump of interstellar material; a star in its infancy/conception stagesclump of interstellar material; a star in its infancy/conception stages formed from dark nebulae (clouds of dust that are so opaque that they block all visible light)formed from dark nebulae (clouds of dust that are so opaque that they block all visible light) Two forces need to act on the interstellar material to condense and form a starTwo forces need to act on the interstellar material to condense and form a star 1.Force of gravity – pulls the interstellar materials together 2.Internal Pressure – pushes the material apart (the materials become so tightly packed that they begin repelling each other) Formation of Stars: STAGE 1

12. How do stars shine? Nuclear fusion!!!!!!! Hydrogen fusion happens in the very core of all MS stars It combines particles into bigger particles This process releases HUGE quantities of energy

13. Hydrogen Fusion Hydrogen

14. Nuclear FissionNuclear Fusion Definition Fission is the splitting of a large atom into two or more smaller ones. Fusion is the fusing of two or more lighter atoms into a larger one. Natural occurrence of the process Fission reaction does not normally occur in nature. (but used in nuclear bombs) Fusion occurs in stars, such as the sun. Conditions Critical mass of the substance and high-speed neutrons are required. High density, high temperature environment is required. Energy Released The energy released by fission is a million times greater than that released in chemical reactions, but lower than the energy released by nuclear fusion. The energy released by fusion is three to four times greater than the energy released by fission. Both give off huge amounts of energy!

15. The Main Sequence As the protostar compresses, it forms a dense core Once it is hot enough, Hydrogen fusion starts A star enters the “Main Sequence” (MS) when Hydrogen fusion begins The MS is the longest stage of a star’s life –90% of all stars are in this stage

16. During the MS A star is in “equilibrium” It’s size stays constant –compression from gravity = the outward pressure from the gas DURING THE MAIN SEQUENCE

17. Increasing Temperature HR Diagram Increasing Luminosity “Brightness” BRIGHT DIM COOLHOT

18. Hertzsprung- Russell Diagram is an important chart that displays how the temperature and luminosity of a star can be represented. There are a few general points to note (and can be seen from the diagram) Bluer stars are hotter and redder stars are cooler (just like the hottest part of a flame is the blue part). The more massive a star is the hotter it is (so the bluer it appears) and the more luminous (the more light it gives off). Once nuclear fusion begins a star is ‘born’ it enters the Main Sequence phase of its life. A star spends 90% of its life on the main sequence. Once stars have used up their hydrogen, once they stop fusing hydrogen, they are no longer classified as a main sequence star.

19. What about the Big Bang? What about Universal Expansion? http://www.teachersdomain.org/resource/phy03.sci.phys.fund.hubble2/

21. Different elements emit different wavelengths of light So light tells us about composition - what the star is made of

22. The Doppler Effect Objects moving AWAY FROM EACH OTHER experience RED SHIFT Objects moving TOWARDS EACH OTHER experience BLUE SHIFT

23. The Doppler Effect – indicates if a star is moving towards us or away from us. Moving away from us! Moving toward us!

24. What the line emission spectrum tells us- what light tells us SUMMARY (1.) Composition- what the star is made of – which elements (2.) Movement- we see a redshift of the spectral lines if the star is moving away and a blue shift if the star is moving towards us

25. Hubble’s Law: The farther the galaxy, the faster it is moving away from Earth. (distance from and speed moving away from are directly proportional)

26. Edwin Hubble Revolutionized our view of the universe.

28. Hubble- Summary- why is he important? 1 st : He made us realize ours was not the only galaxy 2 nd : He made us realize the universe is much much larger than people had previously believed 3 rd : His data showed that all galaxies are accelerating away from us!

29. The Big Bang Theory http://www.imdb.com/video/cbs/vi1889142553/

30. Big Bang What is the Big Bang and what is our evidence for it? The Big Bang is Cosmological theory explaining the development of the universe. 13.7 billion years ago the universe began as a hot, dense, tiny ball of pure energy (singularity) –Space-time was created, began expanding outward –Cooled while expanding Subatomic particle creation –Eventually, gas and dust combined to form planets and stars Heavier elements formed in the core of evolving stars

32. Image constructed from Wilkinson Microwave Anisotropy Probe (WMAP)

33. … evidence for Big Bang CMBR has been redshifted due to expansion all the way to radio end of the spectrum. WMAP is a map of all CMBR we are receiving. We are receiving it from all directions uniformly, so if you ‘press rewind’ this would indicate that at one time all of this light came from same place

34. 3 pieces of evidence for the Big Bang (1.) CMBR- left over light from the Big Bang (2.) Hubbles law- the fact that the universe is expanding tells us it was once much smaller (3.) The abundance of H and He observed today matches the predictions of this theory