Download 4tuesCosmo

Tuesday, week 4
• Arney on Systems and more
• Zita on Astrophysics in crisis
• Kuhn and Social constructionism
• This week – Library workshop #2
• Next week - Research proposals (in teams)
- midquarter conferences (seminar teams)
Arney on Systems
Where is the Life we have lost in living?
Where is the wisdom we have lost in knowledge?
Where is the knowledge we have lost in information?
The cycles of Heaven in twenty centuries
Bring us farther from God and nearer to the Dust.
T. S. Eliot, "Two Choruses from the Rock"
Kuhn on
revolutions
Original paradigm:
good framework for solving
old puzzles
Anomalies: outstanding problems, inconsistencies?
Crisis: proliferation of theories
New paradigm: how can it replace the old?
Astrophysics in
crisis
Black holes:
what have you heard?
Big Bang: You’ve heard that “the laws of physics
break down” in the earliest moment.
Black holes can help us understand what that
means.
Evidence for the Big Bang
The 3-degree background radiation reveals
the origin of structure in the universe
More evidence for the Big Bang
Expansion of the universe: further galaxies
are receding faster
Amount of Hydrogen and Helium in the
universe: beginning was very hot
3K radiation: universe has cooled to the
present
Questions about the Big Bang
What happened in the first tenth of a millionth
of a billionth of a billionth of a billionth of
a billionth of a second (10-43 sec)?
The universe was very small, so ask
Quantum Mechanics.
The universe was very massive and dense, so
ask General Relativity (theory of gravity).
Current paradigms in physics
Quantum Mechanics
explains the very
small
http://www.phys.lsu.edu/dept/gifs/quantum.gif
General Relativity
explains the very
massive (theory of
gravity)
http://fusionanomaly.net/quantummechanics.html
How big was the universe
in the beginning?
R
http://academic.evergreen.edu/curricular/astro/astro2005/lectures/LastLecture.ppt
General Relativity (gravity)
The early universe was a singularity – like a
black hole.
R
BH
Event horizon R = distance inside which
everything is trapped
Quantum Mechanics
The early universe was very small – a point.
DR
Small quantum objects have an uncertain size
or wavelength
Problem: the early singularity could
be outside its own event horizon?!
DR
R
“Laws of physics break down”
We need a new
theory of “quantum gravity”
String theory?
http://www.columbia.edu/cu/record/archives/vol23/vol23_iss18/28c.gif
Loop quantum gravity?
http://www.cpt.univ-mrs.fr/~rovelli/rovelli.html
Will one of these resolve the crisis and
become our new paradigm? GUT?
Outstanding cosmological questions
What physics operated before the Planck time?
What is gravity? Higgs? Graviton? Other?
What is dark matter? Neutrino mass? Wimps?
What is dark energy? Why does universe’s
expansion accelerate?
How to unite gravity with QM? Loop quantum
gravity? Superstrings? D-branes?
Supersymmetric particles?
How to choose which model?
Criteria:
* New model answers
old Q
* Predictions pass tests
* New puzzles solvable
* Simplicity, beauty
* More?
My generation articulated this problem. Your generation will solve it.
Can science discover truth?
Facts are “theory-laden”?
Theories are created by humans and reflect
their biases, language, culture…?
In what sense can science be objective, if it
is socially constructed?
Stay tuned…
Tuesday
Wednesday
Thursday