Formation of the Universe
“In the very beginning, there was a void, a curious form of
vacuum, nothingness containing no space, no time, no
matter, no light, no sound. Yet the laws of nature were in
place and this curious vacuum held potential. A story
logically begins at the beginning, but this story is about the
universe and unfortunately there are no data for the
beginnings—none, zero. We don’t know anything about the
universe until reaches the mature age of a billion of a
trillionth of a second. That is, some very short time after
creation in the big bang. When you read or hear anything
about the birth of the universe, someone is making it up—
we are in the realm of philosophy. Only God knows what
happened at the very beginning.”
--Taken from The God Particle by Leon Lederman, a Nobel
Prize winner
Cosmology

Cosmology is the study of the
Nature,
 Structure,
 Origin,
 And fate of the universe.

The Structure of Everything
Universe in a Nutshell
Quarks: SN
(10-16 meters)
p+ = 2 up + 1 down
n = 2 down + 1 up
Subatomic Particles: SN
(10-15 meters)
Atoms: EM
(10-13 meters)
There are four fundamental forces in nature
1. Gravity
2. Electromagnetic (EM)
3. Strong Nuclear (SN)
4. Weak Nuclear
Molecules: EM
(10-9 meters)
Matter (stuff): Gravity
(100 meters)
Planets: Gravity
(107 meters)
Solar System: Gravity
(1014 meters)
Star Clusters: Gravity
(1018 meters)
Galaxies: Gravity
(1020 meters)
Galaxy Clusters: Gravity
(1021 meters)
Super Clusters: Gravity
(1023 meters)
Universe: Gravity
(1025 meters)
Big Bang Theory

The Big Bang Theory was first proposed in
the late 1920’s.

It states that there was an infinitely small,
infinitely dense point that contained
everything that is the universe.

This singularity was incredibly dense and
hot.
Big Bang Theory

The Big Bang is believed to have occurred
between 10 and 15 billion years ago.
(Most scientists agree that the universe is
13.7 billion years old.)

Two elements, hydrogen and helium were
created in the primordial fireball, along
with small amounts of lithium and
beryllium.
Georges Henri Lemaitre

Late 1920’s

Belgian Astronomer and Jesuit Priest

Known as the “Father of the Big Bang”

First suggested that the universe formed
from a singularity but had no evidence.
Edwin Hubble

1929

Studied light given off by galaxies.

Noticed that light from most galaxies was shifted
to the red end of the electromagnetic spectrum.

Proposed Hubble’s Law after studying these
galaxies.
Hubble’s Law

The rate at which a galaxy is moving is
directly proportional to its distance from
us.

In other words, the farther away a galaxy
is from us, the faster it travels away from
us.

Thus the universe is expanding.
Electromagnetic Spectrum
Emission Lines
Spectral Lines and how they correspond to Absorption lines
Hubble’s Law


All Galaxies
exhibit redshifts
of spectral lines.
More Distant
Galaxies Recede
Faster
The universe is expanding…
Cosmic Microwave Background
Radiation

Long-wavelength radiation that fills all space.

Can be detected using special antenna. (1% of
this can be detected in the static on your TV
set.)

George Gamow (1940’s) predicted there should
be “echoes” of the Big Bang “explosion.”
Bell Laboratories

Penzias and Wilson (1965)
were radio astronomers
who worked for Bell
Telephone Laboratories.

Found a mysterious
microwave signal causing
background noise in their
radio telescope.

The signal came from
everywhere.
Arno Penzias
Robert Wilson
COBE

Cosmic Background Explorer (1989)

Probe that looked 15 billion light years into
space to detect tiny temperature changes.

These temperature changes were
evidence of the heat left over from the Big
Bang.
WMAP

In June 2001,
Wilkinson Microwave
Anisotropy Probe
(WMAP) captured the
“glow” of the Big Bang
by detecting
temperature changes
just like COBE.

WMAP was much
more precise.
Historical Observations of the CMB and Anisotropy
Steady State Theory

Opposes the Big Bang Theory

Steady State Theory states that the
universe has always been essentially the
same as it is today and that it will continue
that way forever.
Steady State Theory

As matter moves apart, new matter is
created to fill the gaps.

Cosmic Background Radiation in the
universe ruled out the Steady State
Theory.
Evidence of the Big Bang
1. The expansion of the universe
Edwin Hubble's 1929 observation that
galaxies were generally receding from us
provided the first clue that the Big Bang theory
might be right.
Evidence of the Big Bang
2. The abundance of
the light elements H,
He, Li
The Big Bang theory
predicts that these
light elements should
have been fused from
protons and neutrons
in the first few
minutes after the Big
Bang.

Predicted abundance of elements heavier than
hydrogen, as a function of the density of baryons in
the universe (expressed in terms of the fraction of
critical density in baryons, Omega_B and the
Hubble constant)
Evidence of the Big Bang
3. The cosmic microwave background
(CMB) radiation
The early universe should have been very
hot. The cosmic microwave background
radiation is the remnant heat leftover from
the Big Bang.
Limitations of the Big Bang
1. Structure in the universe
The Big Bang theory makes no attempt to
explain how structures like stars and
galaxies came to exist in the universe.
Limitations of the Big Bang
2. Fluctuations in the cosmic microwave
background (CMB) radiation
The temperature of the CMB is observed
to vary slightly across the sky. What
produced these fluctuations and how do
they relate to stars and galaxies?
Limitations of the Big Bang
3. The inflationary universe
A very short, but especially rapid burst of
growth in the very early universe
(“inflation”) provides an elegant, yet
untested, explanation of the previous
puzzles.
Big Picture Timeline
What’s the Universe Made Of?

4 % Atoms

22% Cold Dark Matter

74% Dark Energy
What is Dark Matter?

Dark matter: this generally refers to
"exotic" matter that interacts only weakly
with ordinary matter. While no such matter
has ever been directly observed in the
laboratory, its existence has long been
suspected.
What is Dark Energy?

Dark energy: this is a truly bizarre form of
matter, or perhaps a property of the
vacuum itself, that is characterized by a
large, negative pressure (repelling force).
This is the only form of matter that can
cause the expansion of the universe to
accelerate, or speed up.

Dark Energy Explained

WMAP data reveals that its
contents include 4.6% atoms, the
building blocks of stars and
planets. Dark matter comprises
23% of the universe. This matter,
different from atoms, does not
emit or absorb light. It has only
been detected indirectly by its
gravity. 72% of the universe, is
composed of "dark energy", that
acts as a sort of an anti-gravity.
This energy, distinct from dark
matter, is responsible for the
present-day acceleration of the
universal expansion. WMAP data
is accurate to two digits, so the
total of these numbers is not
100%. This reflects the current
limits of WMAP's ability to define
Dark Matter and Dark Energy.
Fates of the Universe

Open Universe

Closed Universe

Flat Universe

Accelerating Universe
Fates of the Universe

Open Universe – little gravity that outward
expansion goes on forever

Closed Universe – gravity will eventually
halt the expansion and draw everything.
Also known as the Big Crunch
Fates of the Universe

Flat Universe – expansion slows down but
never stops

Accelerating Universe - expansion of the
universe will speed up. (Most accepted
theory because of dark energy.)
Light

A light year is defined as the distance that
light travels in one earth year.

Light travels at
300,000 km/s or
 186,000 mi/s

Remember…
Time and Space are Inseparable…
 Light travels at a finite speed (3 x 108 m/s)
 When you look into the night sky, you look
into the past…
 The farther out you look, the farther back
in time you see…
 The sequence of events in the evolution of
the universe are “written” in space like an
eternal movie…

Into the Past
Time Required for Light to Travel to
the Earth
Moon
1.25 seconds
Sun
8.5 minutes
Centrari
4.5 years
Betelgeuse
1200 years
Milky Way
100,000 years
Andromeda
2.2 million years
Virgo Cluster
60 million years
Hydra Super Cluster
3 billion years
Quasars
13 billion years
Cosmic Microwave Background
Radiation (CMB)
13.5 billion years