Big Bang 2.0.1
Steinn Sigurðsson
Astro 120-2 - Jan ’17
Starting from first principles...
The Earth is the natural center of the universe - Ptolemaic system
The Copernican Principle asserted that the Earth is not the center of the universe
everything else generalises from that...
Sun not the center of the universe either, not even center of the galaxy
Galaxy not the center of much anything either
Center does not hold...
Eugene Alvin Villar (wiki)
see also http://www.malinc.se/math/trigonometry/
geocentrismen.php
iBleedOrange ©
from http://drawingwithnumbers.artisart.org/tag/
spirograph/
Reason Redux
We assume the universe is reasonable this may be wrong, but testable
the universe appears amenable to quantitative
logical reasoning, and to be well described by
mathematics
this is not necessarily true and a bit surprising
“unreasonable effectiveness” of math
this gives us predicitive power
science tries to make quantitative predictions
Cosmological Principle
Cosmological Principle: The Universe is
(roughly) homogenous and isotropic
Perfect Cosmological Principle: Universe
is homogenous and isotropic and
homogenous in time
Mediocrity Principle: there is nothing
special about us, the Earth, the Solar
System, the Milky Way or about our time
and place in the Universe
Perfection?
Cosmological Principle holds on large scales
Perfect Cosmological Principle appears
wrong
Principle of Mediocrity - uncertain.
Plausible but there is very high bias in
determining it.
Anthropic Principle?
caveat Teleological Fallacy
Unreasonable reasonableness?
Big Clue
Olber’s Paradox - why is the sky dark?
http://en.wikipedia.org/wiki/Olbers'_paradox
https://www.youtube.com/watch?v=GGPEEU5CSIY
== is the (observable) Universe finite?
in space? or in time?
Or, has the Universe changed?
Relativism: not all cosmologies are equivalent!
Inconsistent with observations…
STOP HERE