Eye to Eye With Einstein Lecture I: Einsteins Relativity Theories Professor Henry Greenside Duke Uni - PowerPoint PPT Presentation

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Title: Eye to Eye With Einstein Lecture I: Einsteins Relativity Theories Professor Henry Greenside Duke Uni


1
Eye to Eye With EinsteinLecture I Einsteins
Relativity TheoriesProfessor Henry
GreensideDuke University
Albert Einstein 1879-1955
2
Three Talks About Einsteins 1905
DiscoveriesImplications For Our 21st World
  • Today Relativity and Emc2.
  • October 9 What is light? Einsteins concept of
    the photon and a glimpse of the quantum world.
  • October 23 What is matter made of? Einsteins
    idea to use Brownian motion to establish the
    existence and properties of atoms.

3
Brief Outline of Einsteins Life
1879 Born March 14 in Ulm, Germany. 1895 Fails
entrance exam to Swiss Federal Institute of
Technology (ETH) Zurich. 1902 Appointed 3rd class
technical expert at Bern patent office. 1901
Becomes Swiss citizen, declared unfit for
military duty because of flat feet and
varicose veins. 1904 First son, Hans Albert, is
born 1905 Annus mirabilis PhD thesis and four
papers on relativity, quantum theory, Brownian
motion. 1907 Has happiest thought of my life,
gravity equivalent to acceleration. 1911 Full
professor at German University of Prague, works
out bending of light during solar eclipse. 1915
Completes general theory of relativity. 1922 Wins
Nobel Prize in Physics for explanation of the
photoelectric effect. 1933 Leaves Germany for
Princeton, NJ after Nazis take power. 1939 Signs
letter to President Roosevelt warning about
dangers of an atomic bomb. 1940 Becomes US
citizen while retaining Swiss citizenship. 1952
Turns down offer to become president of
Israel. 1955 Dies in Princeton University,
donates brain to science, his remains are
cremated.
4
What Is Physics?
5
Start in 1873 with the Maxwell Equations That
Describe All Electrical and Magnetic Phenomena
James Clerk Maxwell 1831-1879
6
Puzzles Associated With Light
Light is an electromagnetic wave that travels at
300,000,000 meters in a second (denoted by letter
c after the Latin word celeritas). But what is
waving as light moves through space? What is
the speed of light measured with respect to?
7
Special Relativity
  • Complements rather than supplants Newtons ideas,
    only important when speeds become close to speed
    of light.
  • Assumptions
  • Laws of physics are same in all inertial frames
    of reference.
  • Deductions
  • Speed of light same for all observers.
  • A material object can never go faster than the
    speed of light, information can not be sent
    faster than light.
  • Speeds add in a funny way .6c .6c is .88c, not
    1.2c.
  • There is no ether light travels through empty
    space.
  • Time slows down the faster you move!
  • Lengths become shorter the faster an object
    moves!
  • Emc2 mass can be interchange with one another.
  • Simultaneity is not absolute.
  • Mass increases the faster you move!

8
Not All is Relative
  • Speed of light is an absolute.
  • Acceleration is an absolute.
  • Simultaneity at same point in space is absolute.

9
The Speed of Light c Is the Maximum Possible
Speed and Is the Same for All Observers
10
Relative Motion at Low Relative Speeds
11
Relative Motion at Light Speed
Speed of light is same for you and Jackie!
12
Simultaneity Is Not Absolute
13
Implication 1 of Speed of Light Limits to
Computing, Need for Parallel Computing
In one nanosecond (one billionth of a second),
light travels about 0.3 m (1 foot) so all parts
of computer must be within 1 foot radius to avoid
waiting for information to arrive. Hard to
remove heat from many circuit elements close
together.
14
Implication 2 of Speed of Light Travel to the
Stars is Hard
Fastest current man-made object Voyager 1,
launched in 1970s, now moving at 3.6 AU/year
(40,000 mph) and nearest star is 250,000 AU away
(4.4 light-years) so time to get to Alpha
Centauri would be about 70,000 years. Voyager is
presently about 100 AU from the Sun. Tennis ball
demo to give sense of what 1 AU means
15
Implication 3 of Speed of Light Existence of
Black Holes
16
How Black Holes Are Observed
17
Time Dilation The Faster an Object, The Slower
the Passage of Time on the Object
18
Time Dilation Thought Experiment
19
Relativistic Length Contraction
v0.8c gives 0.6 contraction v0.995c gives
0.1 contraction
20
Implication 1 of Time Dilation Synchronizing
Accurate Clocks Requires Relativity Global
Position System (GPS)
Atomic clock, size of rice grain.
21
Implication 2 Travel to Stars Makes You Younger
Compared to Someone On Earth
With rocket moving at 0.999c, round-trip time to
Vega about 25 light-years away would be 50 years
for someone on Earth. But person on rocket sees
distance to Vega contracted to 1 ly so time to go
to Vega and back would be about 2 years. If the
twins were 30 years old at launch time, one would
be 80 years old, the other 32 years old when
reunited!
22
Recommended Novel
23
Implication 3 Design of 21st Century Research
Devices
Large Hadron Collider (LHC) 27 km (17 miles) long
ring on Swiss-French border.
24
Neat Relativistic Effectshttp//www.anu.edu.au/Ph
ysics/Searle/
25
Emc2 Mass and Energy Are Interchangeable
26
Implication 1 of Emc2 Compressing A Spring
Increases Its Mass!
27
Implication 2 of Emc2 Small Amount of Mass Can
Release Enormous Amount of Energy
Energy from one grain of salt (0.1 mg) could lift
the space shuttle about ten kilometers up from
Earth.
28
Implication 3 of Emc2 How Stars Generate So
Much Energy For So Long
Mass of 4 H nuclei 6.690 x 10-27 kg Mass of
He nucleus 6.643 x 10-27 kg Difference in
mass 0.047 x 10-27 kg
0.7 of original mass Four million
metric tons H transformed into solar energy each
second!
29
Sun is Huge Compared to Planets
30
Implication 4 Understanding Conversion of Energy
to Matter and Antimatter
2005
1950s
31
Positron Emission Tomography PET Scan
Healthy Alzheimer
32
Where is All the Antimatter?
33
Conclusion of Talk I
  • Einstein was brilliant by thinking in new
    directions.
  • Relativity follows from simple and innocent
    assumption laws of nature are the same in all
    inertial frames of reference.
  • Relativity stunning example of ability to
    understand world by thinking about its
    properties.
  • All the crazy implications have been tested many
    times and are well established time does slow
    down, lengths do contract, and energy can be
    converted into matter and vice versa.
  • Relativity used daily by many scientists and
    engineers, especially important for astronomy and
    cosmology.
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