Digamon IT1(DK1) presentation

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Digamon IT1(DK1) presentation

  1. 1. Space and Time Can Warp Your Mind
  2. 2. Space <ul><li>What is space? </li></ul><ul><ul><li>Gridwork for measuring distances </li></ul></ul><ul><ul><li>Everything – planets, stars, galaxies, and the universe </li></ul></ul><ul><li>Is space infinite? </li></ul>
  3. 3. Time <ul><li>What is time? </li></ul><ul><ul><li>The constant drumbeat of existence </li></ul></ul><ul><ul><li>“ Time is what happens when nothing else does.” </li></ul></ul><ul><li>Measured with atomic clocks to one part in 10 15 </li></ul><ul><ul><li>One second since the demise of the dinosaurs </li></ul></ul><ul><li>Does time have a beginning? An end? </li></ul>
  4. 4. Motion <ul><li>Change of position in space over time </li></ul><ul><ul><li>Change in space </li></ul></ul><ul><ul><li>Change in time </li></ul></ul><ul><li>Motion through space variable </li></ul><ul><li>Motion through time constant </li></ul><ul><li>Change within fixed framework </li></ul>
  5. 5. Motion is Relative <ul><li>Motion measured compared to fixed frame of reference </li></ul><ul><ul><li>Which frame is fixed? Which is moving? </li></ul></ul><ul><li>Why you can’t sit still </li></ul><ul><ul><li>Earth’s rotation – 800 mph </li></ul></ul><ul><ul><li>Earth’s orbit – 65,000 mph </li></ul></ul><ul><ul><li>Sun’s orbit – 450,000 mph </li></ul></ul><ul><ul><li>Milky Way’s motion – 1,300,000 mph </li></ul></ul>
  6. 6. Speed of Light
  7. 7. Speed of Light <ul><li>Finite </li></ul><ul><li>186,000 miles per second </li></ul><ul><ul><li>670 million mph </li></ul></ul><ul><li>Light travel distances </li></ul><ul><ul><li>Earth-Sun distance is 93 million miles </li></ul></ul><ul><ul><li>500 seconds of light travel time </li></ul></ul><ul><ul><li>1 light-year = 6 trillion miles </li></ul></ul>
  8. 8. Time-Warped View <ul><li>Proxima Centauri – 4.2 ly </li></ul><ul><li>Center of Milky Way – 27 thousand ly </li></ul><ul><li>Andromeda galaxy – 2.5 million ly </li></ul><ul><li>Fornax cluster – 65 million ly </li></ul><ul><li>Most distant objects – 13 billion ly </li></ul><ul><li>Looking out in space = back in time </li></ul>
  9. 10. Observable Universe <ul><li>Finite speed of light </li></ul><ul><li>Finite age of the universe </li></ul><ul><li>Finite volume observable </li></ul><ul><li>Properties </li></ul><ul><ul><li>Spherical </li></ul></ul><ul><ul><li>Centered on the observer </li></ul></ul><ul><ul><li>Horizon, not edge </li></ul></ul>
  10. 13. Special Theory of Relativity
  11. 14. Special Theory of Relativity <ul><li>Speed of light is an absolute - c </li></ul><ul><li>Physics is the same to all observers </li></ul><ul><ul><li>Observer at rest </li></ul></ul><ul><ul><li>Observer in motion </li></ul></ul><ul><ul><li>Inertial reference frame </li></ul></ul><ul><ul><li>Our reference frame has considerable motion </li></ul></ul>
  12. 15. Non-relativistic Motion <ul><li>Velocities add together </li></ul>20 mph 2 mph Total 22 mph
  13. 16. Relativistic Motion <ul><li>Motions don’t add linearly </li></ul>0.95 c 0.1 c Total 1.05 c - WRONG Relativistic sum = 0.96 c (0.1 + 0.95) c (1 + 0.1*0.95)
  14. 17. Special Theory of Relativity <ul><li>Thought experiments </li></ul><ul><ul><li>Deduce relativistic behavior </li></ul></ul><ul><ul><li>Observer at rest vs. observer in motion </li></ul></ul><ul><li>Speed of light is constant </li></ul><ul><ul><li>Change in space different </li></ul></ul><ul><ul><li>Change in time different </li></ul></ul>
  15. 18. Thought Experiment - rest light mirror <ul><li>Measure distance </li></ul><ul><li>Measure time </li></ul><ul><li>Calculate speed of light </li></ul>
  16. 19. Thought Experiment - motion mirror light <ul><li>Measure distance </li></ul><ul><li>Measure time </li></ul><ul><li>Calculate speed of light </li></ul>
  17. 20. Shrinking Space <ul><li>Length contraction </li></ul><ul><ul><li>The length of an object appears shorter when measured by a moving observer </li></ul></ul><ul><li>Spaceship pilot flying at 0.99c would measure football field as 14 yards long </li></ul><ul><li>Crowd would measure spaceship to be 1/7 as long as pilot thinks </li></ul><ul><li>Relativistic diet tip: If you move fast, other people think you’re thinner </li></ul>
  18. 21. Stretching Time <ul><li>Time dialation </li></ul><ul><ul><li>Time appears to slow down when measured by a moving observer </li></ul></ul><ul><li>Travel to Proxima Centauri at 0.99 c would take 4.25 years </li></ul><ul><li>Pilot would only age (4.25/7) years, about 7 months </li></ul><ul><li>One way time travel to the future </li></ul>
  19. 22. Light doesn’t exist? <ul><li>At speed of light, lengths go to zero </li></ul><ul><li>At speed of light, time stands still </li></ul><ul><li>Photon of light doesn’t experience space or time </li></ul><ul><ul><li>Emitted </li></ul></ul><ul><ul><li>Instantaneously crosses any amount of space </li></ul></ul><ul><ul><li>Absorbed </li></ul></ul><ul><li>In its own frame of reference, light doesn’t exist in space or time </li></ul>
  20. 23. Special Theory of Relativity One’s view of space and time depends on one’s motion
  21. 24. General Theory of Relativity
  22. 25. General Theory of Relativity <ul><li>Matter warps space </li></ul><ul><li>Re-interpret gravity as geometry </li></ul><ul><ul><li>Straight paths, but in curved space </li></ul></ul><ul><ul><li>Geodesic </li></ul></ul><ul><li>Extends special relativity to handle non-inertial frames of reference </li></ul>
  23. 26. Warped Space
  24. 27. Warped Space <ul><li>Matter tells space how to curve </li></ul><ul><li>Curved space tells matter how to move </li></ul>
  25. 28. Gravitational Lenses <ul><li>More mass, more warp </li></ul><ul><li>Warped space can act like a glass lens </li></ul>
  26. 32. Slowing Time <ul><li>Gravitational time dilation </li></ul><ul><ul><li>Clocks run slower in a larger gravitational field </li></ul></ul><ul><li>Tested by flying atomic clock in plane </li></ul><ul><ul><li>Slower due to special relativity </li></ul></ul><ul><ul><li>Faster due to general relativity </li></ul></ul><ul><li>Today’s atomic clocks can measure altitude difference of 1 yard </li></ul>
  27. 33. General Theory of Relativity One’s view of space and time depends on how much matter is around and how it is distributed
  28. 34. Expansion of Space
  29. 35. Einstein’s Greatest Mistake <ul><li>Equations for the universe unstable </li></ul><ul><li>Einstein added an energy of space (cosmological constant) term to create stable solution </li></ul><ul><li>Missed predicting the expansion of the universe </li></ul>Energy of motion Energy of matter Energy of space = +
  30. 36. Expansion of Space <ul><li>Hubble measured motions of galaxies </li></ul><ul><ul><li>All appear to move away from us </li></ul></ul><ul><ul><li>Cosmic cooties? </li></ul></ul><ul><li>Expansion through space - WRONG </li></ul><ul><ul><li>Galaxies moving away from center </li></ul></ul><ul><ul><li>No measurements show a center </li></ul></ul><ul><ul><li>Copernican hypothesis underlies astronomy, and all science </li></ul></ul>
  31. 37. Expansion of Space <ul><li>Expansion of space </li></ul><ul><ul><li>Galaxies at rest </li></ul></ul><ul><ul><li>Space between galaxies expanding </li></ul></ul><ul><ul><li>All galaxies see every other galaxy moving away </li></ul></ul><ul><ul><li>No center </li></ul></ul><ul><li>Different kind of relative motion </li></ul><ul><ul><li>Observers at rest </li></ul></ul><ul><ul><li>Reference frame in motion </li></ul></ul>
  32. 38. Big Bang <ul><li>The Universe has expanded … </li></ul><ul><ul><li>from small to big </li></ul></ul><ul><ul><li>from hot to cold </li></ul></ul><ul><ul><li>from dense to rarified </li></ul></ul><ul><li>Standard framework of cosmology </li></ul><ul><ul><li>Only hypothesis that fits observations </li></ul></ul><ul><ul><li>Scientific theory </li></ul></ul>
  33. 39. Big Bang Observation <ul><li>Cosmic Microwave Background </li></ul><ul><ul><li>Remnant glow from hot early universe </li></ul></ul><ul><ul><li>Seen in every direction on the sky </li></ul></ul><ul><ul><li>Perfect thermal spectrum </li></ul></ul><ul><ul><li>Time: half a million years after big bang </li></ul></ul><ul><ul><li>Temperature: 3000 degrees </li></ul></ul><ul><ul><li>Size: 1/1000 th present size </li></ul></ul><ul><li>Observational evidence that the universe was smaller, denser, and hotter in the past </li></ul>
  34. 40. Expansion of Space One’s view of space and time depends on when in the history of the universe one is observing
  35. 41. SOME say the world will end in fire, Some say in ice. From what I’ve tasted of desire I hold with those who favor fire. But if it had to perish twice, I think I know enough of hate To know that for destruction ice Is also great And would suffice. Fire and Ice - Robert Frost
  36. 42. “ Thank You”

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