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Welcome to
Physics 43!
Classical Mechanics!
Study of the motion of objects and
mechanical systems that are large
relative to atoms and move at speeds
much slower than the speed of light.
You can’t get to Modern Physics
without doing Classical Physics!
The fundamental laws and
principles of Classical Physics
are the basis Modern Physics.
Some
Physical Models
of the Universe
A Brief History
of Physics
Physics seeks a single theory of
Everything….
Bubble Universes
Superstrings
Theory of Everything (TOE)
Let no one unversed in geometry enter here.
The Universe is made of pure mathematical ideas – the Platonic
Solids. Plato believed that the stars, planets, Sun and Moon move
round the Earth in crystalline spheres.
Earth and the universe were seen as constructed out of five basic
elements: earth, water, air, fire, and ether. The natural place of the
motionless Earth was at the center of that universe. The stars in the
heavens were made up of an indestructible substance called ether
(aether) and were considered as eternal and unchanging. The laws of
nature of the Earth were different from those of the Heavens.
The Sun and the planets would
revolve in small circles whose
centers revolve in large circles about
the Earth ("epicycles") which is at
rest and at the center of the Universe.
From our perspective, the sun and stars appear
to orbit us!
Ptolemy's geocentric
system, adopted by
the Roman Catholic
Church, dominated
western thought until
the time of
Copernicus, 14
centuries later…..
5th-15th Centuries
European Enlightenment
Renaissance
14th & 15th Century
The Vitruvian Man 1490
Copernicus put the Sun at the center of the solar system with the Earth
orbiting around the Sun, thus proposing a heliocentric cosmology.
Like Aristotle and Ptolemy, Copernicus retained the conventional idea
that the planets moved in perfectly circular orbits and continued to
believe that the stars were fixed and unchanging.
REVOLUTION!
I hold that the Sun is located at the centre of the
revolutions of the heavenly orbs and does not change
place, and that the Earth rotates on itself and moves
around it.
Heliocentric Heretics
Rome, Campo de'fiori: The monument to
Giordano Bruno, burnt at the stake here.
Based on observational data he derived three laws
of planetary motion that put the sun at he center of
the universe with elliptical orbits.
Isaac Newton
(1642 -1727)
Using his Calculus, Newton derives Kepler’s
three laws of planetary motion from his own
three laws of motion and his Universal Law of
Gravity. Newton is the man of the millennium.
In Principia (1687 ) Newton
•Invented Calculus
•3 Laws of Motion
•Universal Law of Gravity
NOT ONLY
is the Earth not immobile!
The Earth Moves through Solar System at
30Km/sec!!!
Milky Way Galaxy
At the turn
of the 20th
century we
did not know
that there
were other
galaxies in
the
Universe!!!
Orbital Speed of Solar System: 220 km/s
Orbital Period: 225 Million Years
• Gas Particles are in constant RANDOM motion
• Particles have different speeds
• Pressure is given by the momentum transferred by particles colliding
• Average KE of each particle is ~ T
2nd Law of Thermo
• Heat flows spontaneously from a substance at a
higher temperature to a substance at a lower
temperature and does not flow spontaneously in
the reverse direction.
• Heat flows from hot to cold.
• Alternative: Irreversible processes must have an
increase in Entropy; Reversible processes have no
change in Entropy.
• Entropy is a measure of disorder in a system
Conservation of Energy
Energy can neither be created nor destroyed.
It may change in form or be transferred from
one system to another.
The total amount of energy in the Universe
is constant and can never change.
Ei = E f
Except for VERY brief amounts of time according to the Heisenberg Uncertainty Principle.
1860: E&M was Solved!
(Vector Form)
James Clerk Maxwell
1860s
Light is wave. The medium is the Ether.
c=
1
μ 0ε o
= 3.0 x108 m / s
What is the World Made of?
Why a discrete spectrum?
Why THIS spectrum?
Why this shape?
Why the drop?
Classical vs Modern
•Laws of Physics are deterministic.
•Space and time are absolute.
•Particles are Localized in Space and
have mass and momentum.
•Waves are non-localized in space and
do not have mass or momentum.
•Superposition: Two particles cannot
occupy the same space at the same
time! But Waves can! Waves add in
space and show interference.
•Laws of Physics are statistical.
•Space and time are relative.
•The speed of light is absolute.
•Particles are wave-like
•Waves are particle-like
Modern Physics:
Quantum Physics & Relativity
Unsolved Mysteries of 1900’s
that gave birth to Modern Physics
•Where is the ether?
•Is light particle or wave?
•What is matter made of?
•How and why do atoms radiate discrete
spectra?
•Are nebulae within our galaxy or are
they other galaxies?
•Is space & time finite? Infinite?
Born 1879
Galilean Relativity
The force on a moving charge depends on the Frame.
Charge Rest Frame
Wire Rest Frame
(moving with charge)
(moving with wire)
F =0
F = qvB sin θ
Einstein realized this inconsistency and could have chosen either:
•Keep Maxwell's Laws of Electromagnetism, and abandon Galileo's
Spacetime
•or, keep Galileo's Spacetime, and abandon the Maxwell Laws.
Newton’s Principia in 1687.
Galilean Relativity
Space and Time are ABSOLUTE!
Velocities add:
V= U +V'
V’= 25m/s
V = 45m/s
U = 20 m/s
Time is Relative!
Space is Relative!
Only the SPEED
OF LIGHT is
Absolute!
Lorentz Contraction in Wire
Moving charges in the wire cause a Lorentz contraction in the distance
between the moving charges in the wire so that from the rest frame of
the charge outside the wire (or at rest in the wire) the moving charges
bunch up and thus give a net charge to the wire.
Eisntein Saves Maxwell!
The force on a moving charge does NOT depend on the Frame.
Charge Rest Frame
Wire Rest Frame
(moving with charge)
(moving with wire)
F = qvB sin θ
F = kq1q2 / r
2
From the rest frame of the charge, the wire is charged and it feels a
Coulomb force. The forces in each frame are equal though they are
due to different causes!
On the Electrodynamics of Moving Bodies
1905
Energy is Converted into Mass
E=
2
mc
Fission
Heavy elements FISSION into lighter elements, releasing energy
in the process by E = Δmc2, where Δm is the difference in mass
between the parent and products.
~ 25 MeV is released in this reaction
Most of the Energy is released in the form of Kinetic Energy (heat).
Nuclear Weapons
Albert Einstein
1916
Mass warps space-time.
The Field Equation:
Evolution of Life in the Universe
Cepheids
Hubble
V = Ho d
Andromeda
Galaxy
Space and Time were created in
the Big Bang!
The Quantum Gang
Particles!
The Universe is made of…
Regular Matter: 5%
Dark Matter: 25%
Dark Energy: 70%
Dark Energy: Accelerating the
Universe toward the Future
Future Evolution?
Quantum Entanglement
Quantum Computing
The Qubit
At the heart of the realm of quantum computation is the
qubit. The quantum bit, by analogy with the binary digit, the
bit, used by everyday computers, the qubit is the quantum
computer's unit of currency. Instead of being in a 1 or zero
state, a qubit can be in a superposition of both states.
Quantum Teleportation??
Black Holes & Worm Holes
Gravity Waves
LISA
Parallel Universes
Multiverse
String Theory
Quantum Quackery?
The Final Frontier: Consciousness
Each caged electron is a
qubit in a nanoscale
quantum dot. We have a
billion billion of them
enslaved by coherent near
electromagnetic brain fields
of low frequency . This forms
a mind-brain hologram.
There is direct back-reaction
of the coherent phased array
of single electron dipoles on
their mental pilot landscape
field. This generates our
inner conscious experience.
- Jack Sarfatti
A Quantum Model of
Consciousness