thursday august 30, 2012 (the big bang theory and general relativity; the doppler effect and red...
TRANSCRIPT
ThursdayAugust 30, 2012
(The Big Bang Theory and General Relativity; The Doppler Effect and
Red Shift)
The Launch PadThursday, 8/30/12
Which of the following best describes the Big Bang Theory?
A. The Universe has always existed as it is today, and always will.
B. Matter and energy suddenly exploded into already existing space
and time.C. Time, space, matter, and energy all
came into being at the same time and something was created from
nothing.D. Matter and energy cannot be created
nor destroyed.
Announcements• Please remember that we will
have our first Quiz tomorrow.• All serious ESS students should
now be in possession of a science journal.
Assignment Currently Open
Summative or
Formative?Date Issued Date Due Date Into
GradeSpeed Final Day
ESS Class Information Sheet F 8/27 8/28
ESS Class Procedures and
ExpectationsF 8/27 8/29
There's a rare `blue moon' tomorrow, a fitting tribute to Neil Armstrong by the cosmic calendar. That's the day of a private
service for Armstrong, the first man to walk on the moon, who died last Saturday in Ohio at age 82. A blue moon occurs when there's a second full moon in one calendar month. It won't happen again
until July 2015. The full moon cycle is 29.5 days so a blue moon is uncommon and has come to mean something rare. The moon
actually won't be colored blue. Armstrong's family has suggested paying tribute to him by looking at the moon and giving the
astronaut a wink.
Recent Events in Science
The Big Bang TheoryThe Big Bang model, or theory, is the
prevailing cosmological theory of the early development of the universe, and attempts to explain
some of the earliest events in the universe.
According to the theory, the universe was once in an extremely hot and dense state that expanded rapidly
(a "Big Bang").
As there is little consensus among physicists about the origins of the universe, the Big Bang theory
explains only that such a rapid expansion caused the young universe to cool and resulted in its present
continuously expanding state.
According to recent measurements, the original state of the universe existed around 13.8 billion years ago,
to which some physicists refer as the time that the Big Bang occurred.
Physicists have attempted to establish the theory's validity through scientific evidence and observations.
The Big Bang Theory
The framework for the model relies on Albert Einstein's Theory of
General Relativity.
http://www.youtube.com/watch?v=30KfPtHec4s
General relativity is a geometrical theory of gravity developed by
Einstein in which gravity's effects are a consequence of the curvature of four-dimensional “space-time.”
According to this theory, the energy and momentum of all matter and radiation cause
curvature in space-time.
The Big Bang Theory
This curvature also opens the possibility that the universe is closed, having finite volume but without
any boundary.
Among the many experimentally
confirmed consequences of
general relativity are the perihelion
precession of the planet Mercury, the bending of light in a
gravitational field, and the slowing of time in a gravitational field.
The Big Bang Theory
In 1929,Edwin Hubble discovered that the distances to far away galaxies were
generally proportional to their redshifts.
http://www.youtube.com/watch?v=FhfnqboacV0
Hubble's observation was taken to indicate that all very distant galaxies
and clusters have an apparent velocity directly away from our vantage point:
the farther away, the higher the apparent velocity.
The Doppler Effect
• The Doppler Effect is the apparent change in frequency of waves (pitch) due to the motion of the source or observer.
– Note: The higher the frequency the higher the pitch.
• A great example is an ambulance’s siren coming toward you and then passing you. The pitch drops as the ambulance passes.
The Doppler Effect