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Special theory of relativity (1905) general theory of relativity M.C. Chang Dept of Phys.

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Presentation on theme: "Special theory of relativity (1905) general theory of relativity M.C. Chang Dept of Phys."— Presentation transcript:

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2 Special theory of relativity (1905) general theory of relativity M.C. Chang Dept of Phys

3 Space and time NewtonPost-Newton

4 Inertial frame and noninertial frame

5 The velocity of light 100+200=300 C+C=2C? C=299792458 m/s The velocity of light is the same to all observers (in inertial frames)

6 Simultaneity There is no unique “now”.

7 Time dilation (a moving clock ticks slower) ct vt ct’ An optical clock ct’

8 In 1971, experimenters from the U.S. Naval Observatory undertook an experiment to test time dilation. time dilation Eastward JourneyWestward Journey Predicted-40 +/- 23 ns+ 275 +/- 21 ns Measured-59 +/- 10 ns+ 273 +/- 7 ns

9 The twin paradox

10 Relative point of view Length contraction (a moving object shrinks)

11 The barn-pole paradox

12 Relativistic mass (a moving object becomes heavier) Nothing moves fasterthan the speed of light

13 The most famous formula in the world

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15 由氘及氚組成的靶 Nuclear fusion deuterium tritium

16 L. Livermore National Lab. 核融合設施 (NIF)

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18 Special theory of relativity general theory of relativity (the theory of gravity, 1916)

19 Objects of different weights fall at the same speed

20 The principle of equivalence =

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22 The bending of light by gravity

23 Gravitational lens

24 Relativity in GPS (Global Positioning System) with on-board atomic clocks Accuracy: 30 nanosecond → 15 meters USD 350

25 Relativistic effect: Faster by -7+45=38 microsec per day = an error of 11 km! (g/4) Gravity slows down a clock

26 Gravity balanced by pressure

27 a space-time singularity Gravitational collapse will always occur on any star over 5 solar masses, inevitably producing a black hole Schwarzschild radius (1916) Black hole

28 Binary black hole mergers Gravitational wave spectrum, and possible sources From K. Thorn’s lecture note

29 LIGO Laser Interferometer Gravitational Wave Observatory, Hanford, WA + Livingston, LA Detecting gravitational wave

30 Lisa (launch > 2018 ) 20xx? Laser Interferometer Space Antenna a resolution of 20 picometers over a distance of 5 million kilometers !!

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32 The milky way

33 Our galaxy

34 2.6 ± 0.2 million times the mass of the Sun

35 Super-massive black hole

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37 2.5 MLYs away 0.2 MLYs in diameter 10^12 stars

38 Cluster of galaxy

39 Large-scale structure of the universe (each blue dot is a galaxy!) "Space is big. Really big. You just won't believe how vastly, hugely, mind-bogglingly big it is." The Hitchhiker's Guide to the Galaxy

40 Shape of the universe Einstein’s field equation Cosmological constant ( vacuum energy) http://abyss.uoregon.edu/~js/cosmo/lectures/lec15.html Λ>0 leads to repulsion

41 Hubble’s law (1929) Red shift 1 pc=3.26 ly

42 (The name was given by Hoyle, 1950)

43 From Mather’s slide

44 Age ~ 13 billion yrs Oldest galaxy known

45 Penzias and Wilson 1978

46 Background radiation (COBE satellite) Dipole due to earth motion 10 -3 Galactic plane 10 -5 1% TV static

47 2006 The universe at age 389000 years Mather & Smoot COBE (launched 1989) WMAP (launched 2001) angular resolution ~ 0.3°

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50 Space travel Caution: Slippery ahead

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53 The matricide (or grandpa) paradox

54 Thank you


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