2. The Big Bang Theory (Part I) How the Universe began. Mike Stuckey Warren East High School

3. Assumptions Made Assumption 1 : The universality of physical laws -> The laws of physics are the same everywhere F G  G M 1 M 2 d 2 F G  G M 1 M 2 d 2 and

4. Assumptions Made Assumption 1 : The universality of physical laws Assumption 2 : The cosmos is homogeneous ->Matter and radiation are spread out uniformly w/ no large gaps or bunches.

5. Assumptions Made Assumption 1 : The universality of physical laws Assumption 2 : The cosmos is homogeneous Assumption 3: The universe is isotropic ->same properties in all directions -> no center and no direction

6. Assumptions Made Assumption 1 : The universality of physical laws Assumption 2 : The cosmos is homogeneous Assumption 3: The universe is isotropic

7. Cosmology The study of the nature and evolution of the universe. Not the study of Bill CosbyNot the study of cosmetics and beauty supplies.

8. Imagine NOTHING Nothing to see ! Nothing to hear ! Nothing to feel ! Nothing to think ! No Matter ! No Energy ! No Time ! No Pizza !!!!!!!!! Let’s Create The Universe !! NOTHING Then, about 13.7 billion years ago, something happened ….. A large “explosion”. A big bang. This is where and when the universe began. Energy and time are created, but no matter !!!

10. Primeval Fireball (The Beginning) The universe is in an extremely high state of energy, with temperatures estimated to be greater than 10 32 K. It is just #$?! hot !!!! But this ball of energy quickly expands and cools, decreasing the temperature of the universe.

11. Energy & Temperature There is a close relationship between energy and temperature. The more concentrated energy there is in a substance the higher that substance’s temperature will be. The higher a substance’s temperature is the more concentrated energy it has. Since the universe is expanding the energy of the universe spreads out decreasing the temperature of the universe. This is a key thing to remember!!!!!!!!!!!!

13. Heavy Particle Era The temperature is greater than 10 12 K Less than 0.000001 seconds after the Big Bang At these high temperatures (energy), photons collide to produce massive particles and antiparticles The most important particles formed are protons and antiprotons.

14. Matter & Energy Conversion A matter-antimatter pair is two subatomic particles which are identical in every way except they have opposite charges. The antimatter equivalent to a proton is an antiproton. An antiproton has the same properties as a proton but it has a negative charge. The antimatter equivalent to an electron is a positron. A positron has the same properties as an electron except it is positively charged.

15. Matter & Energy Conversion At these high temperatures (energy), photons collide to produce massive particles and antiparticles like protons and antiprotons. The amount of matter, m, produced in this collision of photons is determined by the amount of energy, E, of the photons. E = mc 2 If there is more energy available, then more massive particles can be produced !!!

16. Heavy Particle Era The temperature is greater than 10 12 K Less than 0.000001 seconds after the Big Bang At the end of this era, the universe is a thick soup of heavy particles, antiparticles and energy. The most important particles present are the protons.

18. Light Particle Era The temperature is greater than 6x10 9 K Less than 6 seconds after the Big Bang Because of the lower temperatures during this era, the photons present can’t produce anymore heavy particles. These photons can collide to produce light particles and antiparticles, like electrons and positrons. During this era protons and electrons interact to form neutrons. Antiprotons and positrons interact in the same way. At the end of this era the temperature of the universe is below the point where there is enough energy for matter & antimatter to form from colliding photons. The universe consists of heavy and light particles (protons & electrons) and neutrons. Just what is needed to start to make atoms!!! Some of the neutrons decay back into protons and electrons. The neutrons which survive are very important for the next era.

20. Nucleosynthesis Era (Part I) The temperature is around 10 9 K Less than 300 seconds after the Big Bang The neutrons which remain react with the protons to form an isotope of Hydrogen called Deuterium. (1 proton and 1 neutron) The neutrons that don’t form deuterium decay back into an electron & a proton. Deuterium fuses to form Helium. At this point the total mass of the Helium formed is about 25% the total mass of the universe. Some Tritium (Hydrogen with 2 neutrons), Lithium and Berylium also form. In the first 5 minutes after the Big Bang, the protons & neutrons that formed earlier have formed the first stable nuclei of small atoms. These atoms still have not captured the electrons because the temperature is too high at this time.

22. Nucleosynthesis Era (Part II) The temperature is around 3000 K About 329,000 years after the Big Bang At these low temperatures the nuclei which have formed can now capture electrons and become neutral. This allows light and radiation to pass through the neutral atoms and expand throughout the universe cooling to around 2.7 K

24. Matter Era The temperature is less than 3000 K Over 1 million years after the Big Bang With the radiation and matter freed from each other, the pressures which kept the matter from clumping together is now greatly reduced. Matter is able to clump together forming galaxies, stars, and the Earth. We are still in this era.