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Origin of Universe - Big Bang

Origin of Universe - Big Bang. Dr. Charles Ophardt EDU 370. Expanding Universe. Big Bang Theory Universe began 15 billion years ago Began as a huge expansion known as the Big Bang Space and Time came into existence All matter started to expand. Big Bang.

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Origin of Universe - Big Bang

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  1. Origin of Universe - Big Bang Dr. Charles Ophardt EDU 370

  2. Expanding Universe • Big Bang Theory • Universe began 15 billion years ago • Began as a huge expansion known as the Big Bang • Space and Time came into existence • All matter started to expand

  3. Big Bang • Big Bang Event created space and time • No time before and no space outside of it • Explosion occurred everywhere filling all space from the beginning with energy. • At instant of Big Bang, universe was infinitely dense and hot

  4. Big Bang II • Immediately after Big Bang: • Universe consisted of primarily radiation with some matter • From extremely dense and hot beginning, universe expands and the matter begins to cool • As it expands matter dominates within 1,000 years of the beginning

  5. Big Bang III • First few seconds: • Photons of radiation collide and convert energy into mass • Protons, electrons, and neutrons formed • Universe cooled from 100 million trillion trillion degrees to 10 billion degrees

  6. Big Bang IV • After three minutes: • Temperature falls to one billion degrees • Protons and neutrons combine to form the nuclei of helium, deutrium, and a few other light nuclei. • Temperatures were too high for other elements to form

  7. Big Bang V • After 300,000 years: • Universe cooled to 3000 degrees • Electrons combine with atomic nuclei to form neutral atoms • Proton + electron = H atom • 2 p + 2 n + 2 electron = He atom • From this time radiation is unable to interact with gas. • Background microwave radiation now at 3 degrees Kelvin

  8. Big Bang VI • Stars and Galaxies: • After one billion years: • Small perturbations in the matter resulted in condensation • Stars formed from condensation of matter • Stars have conditions to form the rest of the elements.

  9. Big Bang is a Testable Model • Basic Assumptions are plausible • Empirical support • Reasonable sound physical basis • Real test • Does the Big Bang Model explain and make predictions that can be tested against observations?

  10. Evidence for Big Bang • 1. Universe is expanding and cooling • 2. Theory predicts 25 % of total mass should be helium • 3. Cosmic Background Radiation • 4. Collapse of matter to form galaxies and stars

  11. Universe is Expanding • Hubble Expansion Law • 1929 - almost all galaxies appeared to moving away from us • Observation - red shift in spectrum • Red shift larger in faint galaxies (further away and moving faster)

  12. Universe is Expanding II • Hubble Law • H = v / d • H = Hubble Constant • V = velocity • D = distance • Hard to measure the Hubble Constant need velocity from red shift and distance from earth

  13. Red Shift or Doppler Effect • If object moving away-light waves are stretched toward red spectrum • If object moving toward -waves are compressed toward blue spectrum

  14. Doppler Shift • Lines in spectra move left for blue shift and move right for red shift • Blue shorter wavelength, red longer

  15. Red Shift or Doppler Effect II • Amount of shift depends on speed • The faster an object moves, the greater the doppler shift • Example: an emission line of hydrogen is shifted less by close galaxies than faraway ones. • This means faraway galaxies are moving faster than nearby ones. • Sound of train whistle works the same

  16. Abundance of Light Elements • Observed abundances of: • Hydrogen Deuterium, helium, and lithium • Formed in first 3 minutes of big bang • Helium calculated to be 25% and observed in that amount • These elements are not produced in required quantities in observed stellar fusion

  17. Cosmic Microwave Background • The thermal spectrum of CMB was predicted before its observation • Expansion caused the hot universe to cool as it spread out • Radiation thinly spread to its present temperature of 2.7 degrees Kelvin • Observed as uniform background microwave radiation at peak wavelength of 1 mm- detected with a RadioTelescope

  18. Formation of Galaxies • At 10,000 years, temperatures fall so that massive particles begin to dominate • Gravitational forces begin to dominate • Stars form from the increasing density of matter • Clusters of stars form galaxies

  19. Other Theories • Steady State Model • Postulate no origin to universe • Large scale features are constant • Maintain an average density of galaxies • Whole new galaxies must be popping into existence between old ones

  20. Steady State II • To explain Cosmic Background Radiation • A whole new class of weak microwave emitting sources must exist (about 100,000 times the total visible galaxies) • Lacks supporting evidence

  21. Conclusion • The Big Bang theory is one of the most strongly supported theories in all of science. • It explains the observed facts • It has made successful predictions; It has stood the test of time; • There is no alternate theory that the professional scientific community deems valid.

  22. Questions I • Describe the universe as a system. Which statement is false? • A. The universe consists of all matter and energy that exists. • B. The universe is that it is mostly empty space • C. The matter of the universe tends to occur in clumps • D. The empty space is small compared to the size of the objects • themselves.

  23. Questions II • Which statement about the evidence for the Big Bang Theory is false? • A. Universe is expanding and cooling • B. Theory predicts 25 % of total mass of universe should be helium • C. Cosmic Background Radiation is a measure of the background infrared light • D. Matter collapsed to form galaxies and stars

  24. Questions III • Which statement about the Big Bang Theory is false? • A. Photons of radiation collide and convert energy into mass • B. Protons combine with electrons to form neutrons • C. A proton combines with an electron to form a hydrogen atom • D. A helium atom is formed from 2 p + 2 n + 2 electron

  25. Questions IV • Which statement about the Hubble Law is false? • A. Almost all galaxies appeared to moving away from us • B. Hubble Law is based upon the observation of a red shift in spectrum of galaxies and stars • C. The red shift is smaller in faint galaxies since they are further away and moving faster • D. The most inaccurate term in the Hubble Constant is the distance to the object.

  26. Questions V • Which statement about the Red Shift is false? • A. If object is moving away the light waves are compressed toward the red spectrum • B. If object is moving toward you the light waves are shifted toward blue spectrum • C. Amount of red shift depends on speed • D. The faster an object moves, the greater the doppler shift

  27. Questions VI • Which statement about the CMB is false? • A. The thermal spectrum of CMB was not predicted before its observation • B. Expansion caused the hot universe to cool as it spread out • C. Radiation thinly spread to its present temperature of 2.7 degrees Kelvin • D. CMB is observed as uniform background microwave radiation at peak wavelength of 1 mm

  28. References • http://www.astronomynotes.com • http://www.pparc.ac.uk/Ed/Notes/Bbwebpage.asp

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