How the universe began


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Topic introduction to The Cosmic Engine

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How the universe began

  1. 1. How the universe began<br />Year 11 Physics – The Cosmic Engine<br />
  2. 2. Admin stuff<br />Syllabus<br />Glossary<br />
  3. 3. Syllabus references<br />Outline the discovery of the expansion of the Universe by Hubble, following its earlier prediction by Friedmann<br />Identify that Einstein described the equivalence of energy and mass<br />Identify data sources and gather secondary information to describe the probable origins of the Universe<br />
  4. 4. Where did the universe come from?<br />
  5. 5. The Big Bang theory<br />The expanding universe<br />Cosmic background radiation<br />
  6. 6. The expanding universe<br />Scientists who have contributed to the expanding universe<br />Albert Einstein<br />AleksandrFriedmann<br />Edwin Hubble<br />
  7. 7. Albert Einstein<br />Special theory of relativity<br />The speed of light<br />Equivalence of energy & mass<br />Energy can be converted into mass<br />Mass can be converted into energy<br />E = mc2<br />
  8. 8. Evidence for Einstein’s theory<br />Predicted that light rays can be warped by space-time and should curl around stars (gravitational lensing)<br />Gravitational lensing of distant quasars has been studied by astronomers using the Hubble telescope<br />Predicts that time should run slower near an object as large as a planet<br />Tested and verified in 1962<br />Predicted that the universe is expanding but Einstein believed in static universe so he put a cosmological constant in the equation to make the universe static<br />
  9. 9. AleksandrFriedmann<br />Read Einstein’s work but thought his cosmological constant was wrong, so he tried to solve Einstein’s equations<br />Assumed that the universe is the same no matter where we look<br />Friedmann’s maths proposed two models: (1) closed universe and (2) open universe<br />
  10. 10. Closed universe<br />Time and space have a beginning and an end<br />Time and space both began with a big bang and will end when gravity stops the universe and pulls everything back into one point – “ the big squeeze”<br />The universe is finite and the expanding universe is due to space expanding<br />
  11. 11. Open universe<br />Universe began with a big bang and will continue to expand forever<br />Time and space has no end<br />
  12. 12. How do we know the universe is expanding?<br />In 1912, VestoSlipher examined the spectrum of light produced from a nebulae<br />Found that the light from the nebulae had frequencies lower than normal light<br />The light from the nebulae was more shifted towards the red end of the spectrum – red shift<br />
  13. 13. What is redshift?<br />Remember: light travels at the same speed regardless of how fast you are travelling<br />Light is made up of different colours; red has the lowest frequency and blue/purple has the highest frequency<br />Redshift is when light moves towards the red end of the visible light spectrum<br />
  14. 14. The electromagnetic spectrum<br />
  15. 15. Redshift continued ...<br /><br />
  16. 16. Redshift in the universe<br />The left spectrum is the transmitted frequency of light from a star<br />The right spectrum is the observed frequency of the star from Earth<br />The spectral lines are shifted towards the red end<br />Shows star is moving away from us<br />
  17. 17. Edwin Hubble<br />Hubble used the redshift idea to propose his expanding universe model where the universe is like an exploding bomb<br />He also came up with the Hubble constant (Ho)<br />Rate at which universe is expanding<br />Used to estimate the size of the universe<br />
  18. 18. Summary<br />The big bang theory proposes that the universe exploded out of a hot dense point.<br />The big bang theory is supported by the expanding universe model which various scientists have contributed to<br />Einstein – equivalence of energy and mass (E = mc2)<br />Friedmann – closed and open universe<br />Hubble – spectral lines and Hubble constant<br />
  19. 19. Redshift demonstration<br />Go to<br />Save code: X03RO<br />