Touching The Limits Of
Cosmology and our View of the
Physical Cosmology, Part I,
Summary by Amy Lovell-Klar:
The Big Bang Theory is the widely accepted model
of the universe.
- We may be on the verge of another paradigm shift.
- We tend to pitch science against religion
- We may not need to be so antagonistic
- Judeo-Christian mythology
- "Let there be light" fits with today's
- One shot universe -- all begins at once.
- Northeast Indian mythology
- Sedi + Melo -- male and female forces
- Cyclical -- unity begets duality, duality
- Guinea mythology
- Death the Creator (life from death)
There are chasms between the different religions and between
science and religion. Science's theories and models are self-contained
and don't conflict with religion. Stories have meaning to help us determine
how we should live.
- As knowledge expands, so do the boundaries of the
unknown. New questions come from the answers to old ones.
Theories and Axioms
- Must take axioms as a base for knowledge (e.g.
- Goedel's Theory -- you can't prove
the axioms of a theory. Infinite Regress
- What's beyond what we know about our universe?
- We belong to the universe and have to explain ourselves
and our experience of the universe.
- The observable universe only includes light from places
that light is reaching us from, i.e. 30 billion light years, radius of 15
billion light years.
- Beginning of our observation and explanation is within
the observable universe.
- To measure is to compare to something we know. Base
measurements of universe on size of the earth.
- Models -- shrink everything by the same ratio
to replicate the actual universe
- Galaxies are closer to each other than stars are, relative
to their size.
- Galaxies are moving and will eventually run into
- Stars in galaxies are so far apart, they won't
even hit each other when the galaxies overlap.
- Speed of light -- 300,000 meters per second
- Light year -- distance light travels
in one year
- Center of the known universe -- appears to
be Earth from our vantage point.
- We're probably not in the center in
reality, because there is probably more than just the observable universe.
- Paradigm shifts about the center of the universe
- Copernican Revolution -- Sun in center
to Earth in center
- Herschel -- mapped stars, Earth appeared
- He wasn't aware of interstellar
medium -- fog between stars.
- Beginning of observation outside our
- We're not in the center of
the galaxy or the universe.
Light as a Time Machine
- Light from the sun is 8 minutes old, from Saturn
it's around 80 min. old
- By the time we observe light in the universe, the
event or the emission of light has already happened -- we're working
with outdated info.
- From the farthest point of the observable universe,
info is 15 billion years old.
- We use the "time machine" to watch galaxies
form that have been formed for many years. Use this info to understand how
comparable galaxies formed.
- Nothing can go faster than the speed of light.
- Not even a baseball thrown from a train
that is traveling at the speed of light.
- "You can't see the forest for the trees."
- Suppose universe is infinite AND infinitely old.
The sky would be completely full of stars and we would burn.
- Edwin Hubble used spectroscopy together with Cepheids
as distance indicators.
- Redshifts of Galaxies -- all of them are
moving away from us.
- Farther away galaxies move faster
- Universe is expanding
- Universe is moving into unknown space -- we get
info from light that is farther and farther away.
- Everything is moving away from the same point at the
same ratio of distance to speed.
- If you calculate backwards you can determine the age
of the universe
- The constant that connects speed and distance in
this calculation is called the Hubble constant.
The Big Question
How is the calculation of 10-14 billion years for the
age of the universe reconciled with the fact that we can see the oldest galaxies
at distances of almost 14 billion light years at the edges of the universe (when
they should have been close)?
May 15, 2000