Big Bang

1. Big Bang A Trip to the Beginning of the Universe by Stefan Diehl

2. Overview • Introduction • History of the Big-Bang-Theory • Trip to the Big-Bang • From the Plank - Epoch to the formation of galaxies

3. Introduction Today: ~ 14 billion years after the Big Bang The Earth is home to many different animals and plants But the mankind is the only one who asks the question, where we came from and where we go to

4. How did the idea came up, that everything started with a Big Bang? 1929 Edwin Hubbel: The distance to far away galaxies is genarally proportional to their redshifts • Very distant galaxies have an velocity directly away from our vantage point • The farther away, the higher the velocity By the redshift of galxies we can meassure their velocity

5. If the distance between galaxy clusters is increasing today, everything must have been closer together in the past Big Bang

6. Another proof for the Big Bang … 1965:Arno Penzias and Robert Wilson discovered the cosmic background radiation Picture of the universe 379.000 years after the Big-Bang, when recombination of photons and matter ended … The redshift of this radiation is a proof for the expansion of the universe

7. Let`s start our Trip starting point today

8. How everything started … • The earliest phases of the universe are subject to much speculation • Most common models: • Incredibly high energy density • Huge temperatures and pressures • Time and space lost their status as a continuum (didn`t exist any more) Theory of quantum gravitation

9. The Plank – Epoch < 10-34 s All fundamental forces were united in one elementary force weak nuclear force gravi- tation electro-magnetic force strong nuclear force interaction of Quarks Beta -radiation

10. After this time: A very fast expansion started The gravitation splits of from the other forces GUT – force (Grand Unified Theorie) We don‘t know much about this time and the particles which existed in it

11. Inflation and Quark - Epoch A phase transition caused a cosmic inflation Universe expanded exponentially Strong nuclear force split of from the GUT - force When inflation stopped: • The universe consisted of a quark-gluon plasma, as well as all other elementary particles • Temperatures were so high (1013 K) that the random motions of particles were at relativistic speeds • Particle-antiparticle pairs of all kinds were being continuously created and destroyed in collisions

12. Quark - Epoch At some point: Beginning of the baryogenesis Leaded to a very small excess of quarks and leptons over antiquarks and anti-leptons (about 1 part in 30 million) Result: Predominance of matter over antimatter in the present universe Thank to this asymmetry for our life

13. Four Fundamental Forces electroweak force split of weak nuclear force electromagneticforce All fundamental forces we know, existed in this moment

14. Formation of the Basic Particles of Matter • One part in a billion of a second after the Big Bang: • Quarks and gluons combined to form baryons (protons and neutrons) • The temperature of 1013 K was no longer high enough to create new proton-antiproton pairs mass annihilation only a small part of the original protons and neutrons survived, but none of their antiparticles

15. Formation of the Basic Particles of Matter • Around one second after the Big Bang a similar process happened for electrons and positrons Quarks and gluons didn`t exist as free particles any more • At this point we have all the particles we need to construct elements • Protons • Neutrons • Elektrons Why don`t we start ?

16. Beginning of the Nucleosynthesis … A few minutes after the beginning of the expansion • The temperature was about one billion Kelvin and the density was about that of air • Beginning of the „Big Bang“ nucleosynthesis • Neutrons combined with protons to form the universe's first deuterium and helium nuclei • 75 % Protons • 25 % Helium-4 • 0,001 % Deuterium • Lithium, Beryllium

17. The First Hydrogen Atoms • After about 379,000 years … • Temperature was fallen under 3000 K Electrons and nuclei combined into atoms (mostly hydrogen) radiation decoupled from matter and continued passing through space since today • This relic radiation is known as the cosmic microwave background radiation today By the expansion of the universe the wavelength of this radiation increased redshift

18. Let`s lock on our map: starting point today our actual position

19. How Galaxies were Built Over a long period of time … • Denser regions of the nearly uniformly distributed matter gravitationally attracted other matter They grew even denser Gas clouds were formed

20. How the First Stars begin to Burn • If a part of such a cloud has reached a special density, the other parts collaps into it • Temperature increases up to 106 K • Fusion of deuterium starts and produces more energy temperature increases A star is born, in which the fusion continues with other elements

21. Is there a limit for Nuclear Fusion? Nuclear fusion can only produce the elements up to iron Fusion of heavy nucleons needs energy

22. Where did the other Elements come from? • Supernova • Explosion of a heavy star • Very high energy and density • In this situation neutrons can be captured by havy nuclei and transformed into protons by emission of beta radiation • Heavy elements like uranium exist on earth All of us are a relict of a supernova many many years ago

23. We have reached our goal … starting point today

24. But, how will the trip go on? • Will there be a Big Crunch sometime? • Will the expansion slow down, but go on forever? Many open questions … But one thing is sure: Mankind is only a very small point in the history of time and space

25. References • www.gsi.de • Prof. Cassing Talk 2 „Physik im Blick 2007“ • www.wikipedia.org • www.nasa.org (pictures) Thank you for your attention!