Basic observed parameters

Age: 13.7 By measured by the spacecraft WMAP Data from the cosmic microwave background radiation

(CMBR)

Diameter: Best model is 45 Bly

Composition: 73% dark energy 23% dark matter 4% atomic (baryonic) material

75% H, 25% He (originally)

Critical density Ω = 1.0 measured by WMAP data Measured density of universe to the value at infinite

expansion This means the universe is inflationary (expansion was faster

than known physical laws allow)

Early chronology of the universe

The first instant of the Big Bang model of the universe is not observable since our understanding physics allows only the baryonic (atomic) certainty to begin at the Planck time = 10-43 sec

From this early start, the universe entered an inflationary expansion of 50 orders of magnitude in 10-32 sec Called the inflation period

First to appear were the forces, but combined into a single force The first to separate was the weakest - gravity

Energy and matter condensed as the universe cooled

First “stuff” to form were the constituents of atomic particles Quarks and leptons

Quarks Heavy particles are ruled by the strong nuclear

force

Leptons Light particles are ruled by the weak force

Quarks

Make up the particle family known as hadrons which include two families

Baryons – composed of three quarksProtons and neutronsStable

Mesons – composed of two quarksShort lived

Quarks

Quarks come in 6 varieties (flavors), each with an anti-particle

Up – 1st generation - lightest Down - 1st generation Charm – 2nd generation - heavier Strange – 2nd generation Top – 3rd generation - heaviest Bottom – 3rd generation

Quarks 2nd and 3rd generation quarks are short lived and

decay into the 1st generation particles through the weak interaction

Quarks bound by the strong force (gluon)

Strong force is unusual in that it becomes stronger with increasing distance No single quarks exist unless at extremely high

energies

Atomic/baryonic nuclei are all up/down quarks

Leptons – lighter particle family that includes:

1. Electrons (1 type of electron, plus antielectron)

2. Muons (2 types of muon that include tau and mu, and their antiparticles)

3. Neutrinos (3 types of neutrinos that include the electron, mu and tau species, and their antineutrinos)

Participate in weak force but not in strong force

Created or absorbed in quark transformations

Quarks and leptons are shown in the diagram as 1st, 2nd, or 3rd generation particles, along with the forces portrayed on the right as force carriers

Particle and force details, including spin (upper right) and rest mass energy (bottom)

T + 10-40 sec  -  First stuff forms

Building blocks for "elementary" particles - quarks, gluons, etc.

Basic four physical forces established and act as a unified field

Gravity separates from the rest of the forces

T + 10-35 sec  - Inflationary phase of expansion

A phase transition in the energy/material expands the universe by a factor of 1050 in 10-32 sec

Strong force separates from the remaining electro-weak force

T + 10-20 sec  -  Baryonic particles form

p+,  e-, no, ν (protons, electrons, neutrons, neutrinos)

Universe is composed of a mixture of electromagnetic (EM) radiation (photons) and charged particles (p+, e-)

Brief condition that allows fusion of particles produces proton-to-neutron ratio that results in a 75% H and 25% He mix (plus a very little deuterium (2H), 3He, and lithium)

T +  1 sec  -  Nucleus formation begins

Temperatures sufficiently low to begin forming proton-neutron pairs and triplets

T + 385,000 yr  -  Particle and EM radiation mix expands and cools to form first neutral atoms

p+ and e- cool sufficiently to form hydrogen which dominated the early baryonic (atomic) universe

The universe quickly becomes transparent (uncoupling of mass and energy)

Cosmic background radiation (CBR) created at this time and at a temperature of about 3,000 K Ionization temperature of hydrogen

T + 400 Myr -  First stars form

Hydrogen and helium gas in dense pockets cool enough to form the first stars that are: Massive since there is no efficient method of

cooling Massive since there is a large critical density to

overcome the high thermal pressure

Recent star formation is much easier and faster since metals (anything heavier than helium) helps cool the molecular gas clouds for collapse into stars

The lights in the universe turn on for the first time since they dimmed at T + 500,000 years

T + 109 yr  -  First small galaxies form

Formation site of these dwarf galaxies takes place in the higher density regions implied by the CMBR maps showing elevated density

Dwarf galaxies become the building blocks of larger galaxies similar to planetesimals accreting to form planets and moons

Hubble deep-field images show ragged, blue dwarf galaxies at the largest distance (earliest age)

Large structures

The first stars and galaxies to form were in enhanced density regions that later became the dominant clusters and superclusters of galaxies

Mass dominated by dark matter

T + 10x109 yr (10 By)        Solar system forms

Molecular gas cloud dominated by hydrogen fragments and collapses into a star and planetary disk

Enrichment of 5% dust and metals from dying stars including supernova (large stars) and planetary nebulae (medium or small stars)

T + 13.7x109 yr (13.7 By)    Today

Cosmic background radiation now 2.73 K

Expansion of universe measurable on scale of millions of light years but not on smaller scales because of the gravitational grip on close and/or clustered galaxies

Universe expansion is accelerating, caused possibly by dark energy

Cosmic background radiation

The beginning of the universe was a violent expansion with a near-infinite density and temperature that rapidly expanded and cooled

Pure energy contained in the hot matter soon formed the first particles and forces

The production of particles included the baryons made of quarks, and leptons that include electrons and light, short-lived particles These makes up the atomic world we are familiar

with, but has a variety of other particles

Formation of baryons (primarily protons and neutrons) occurred after the quarks cooled sufficiently – approximately 10-20 sec after the Big Bang

Hydrogen was fused into helium in the first few seconds

Further expansion and cooling of the universe reached the 3,000 K ionization temperature of hydrogen after approximately 380,000 years

Because the particle universe was dominated by hydrogen, the neutral hydrogen atoms released the electromagnetic energy (light) strongly held by the previously charged particles

The uncoupled light still contained the signature of the hydrogen, helium, as well as the remaining electrons, the dark matter and dark energy, the acoustic waves, and much more

As the light and mass continued to expand, the light was reduced in temperature, going from 3,000 K to roughly 3 K in 13.7 By

This is the 3 K cosmic microwave background radiation that still contains the secrets of the formation of the early universe

The 2.73 K cosmic background radiation has a peak emission in the microwave band near 90 GHz

The radiation has become known as the cosmic microwave background radiation (CMBR) because of its frequency range

Sensitive receiver in orbiting spacecraft are needed to measure the CMBR with enough sensitivity to determine the small variations imprinted by the early universe

The first maps made of the CMBR were done in patches using balloon-borne instruments

The first dedicated satellite used to map the CMBR was the Cosmic Background Explorer (COBE) launched in November 1989

A more accurate and sensitive spacecraft named the Wilkinson Microwave Anisotropy Probe (WMAP) was launched in 2001 and placed in the Sun-Earth L2 Lagrange point (WMAP shown on the right)

Comparison maps of the older COBE data and the newer WMAP data

While the data presented in the full-sky map of the WMAP output appears chaotic, plotting a power spectrum of the positions, angle of separation, and number of data peaks produces a curve representing the influences of various states of mass and energy, as well as time

The power spectrum shown on the right includes the compiled data from WMAP (blue continuous line) in addition to data from earlier spacecraft and balloon-borne missions

By fitting the influence of various parameters to the actual day, specific values for the age of the universe, the density of the universe, the composition of the universe, and a host of other physical characteristics can be determined

The plot shown on the right for example shows an obviously poor fit of an “open” universe in which the universe continues to expand forever to the actual CMBR data

CMBR Spectral Fit

Interpretation Observations

Earliest dataUniverse is limited in age Night sky is dark (Obler's paradox)

Early quantitative results

Edwin HubbleUniverse is expanding

Galaxy expansion increases with distance

Penzias & WilsonCosmic fireball exists

Heat left behind by the Big Band is now the cosmic microwave background radiation (CMBR) at 2.73 K

Interpretation Observations

Recent results

Universe expansion is inflationary CMBR pattern, accurate supernova measurements in distant galaxies

Dark energy dominates universe (73% of mass/energy)

CMBR pattern, accurate supernova measurements in distant galaxies

Age of universe is 13.7 ± 0.1 By CMBR pattern, universe expansion rate, oldest stars

Small percentage of atomic (visible) material makes up the universe

CMBR pattern, galaxy dynamics, galaxy clusters, H/He ratio, inflationary expansion

Dark matter dominates galaxies and clusters

CMBR pattern, galaxy dynamics, galaxy cluster dynamics, galaxy evolution

The first stars formed after approximately 400 million years

CMBR pattern

Dark energy Details unknown, but is contained in “empty space” Accelerates expanding universe after first 5 By that

was first slowing down from self-gravity

Dark matter Details of material unknown Contained in large galaxies and clusters of galaxies Makes up roughly 90% of all large galaxies’ mass

Both dark energy and dark matter are observed by their gravitational effects on both light (EM radiation) and on baryonic (atomic) material

First stars

Universe expanded and cooled sufficiently to allow gas concentrations to form massive stars Approximately 400,000 My after Big Bang

First stars were 100 Mo to 500 Mo (solar masses) Pure hydrogen and helium (75/25) Short lifetimes

<1 My Created first atoms heavier than He Can be observed indirectly by their bright UV light

ionizing the surrounding gas May be observed in the James Webb Next Generation

Telescope that replaces the Hubble space Telescope

Evolution of the universe

Standard Model baryonic content stable since protons have >1033 yr This means that there is a lifetime of the universe with three

possibilities for its end

1  Open universeDensity is less than that required to recollapse the universe after its explosive beginning and continues to expand without limit - not supported by the WMAP data

2  Closed universeDensity of the universe is greater than critical density and will recollapse to produce one or possibly many cycles - not supported by the WMAP data

3  Inflationary (flat) universeThe universe is exactly balanced in potential and kinetic energy and continues expanding, but only until it reaches an infinite radius at infinite time - supported by the WMAP data

Standard Model

The Standard Model of particles and forces does have limitations

The simplicity of the model cannot account for quantum gravity, one of the most difficult problems confronting physicists today

The Standard Model provides no insight into the matter-antimatter asymmetry of the universe (all particles, few or no antiparticle mass remains)

Extensions of the Standard Model have been more successful at reaching a successful theory of all particles and forces

Standard Model

Even with the more comprehensive treatment of gravity and mass, and with other important details from super symmetry, string and superstring theory, and inflation theory, have not yet answered the question of dark energy and dark matter, nor of quantum-scale gravity

What first surfaced as Albert Einstein's controversial cosmological constant Λ, the dark (vacuum) energy that permeates empty space has a profound implication for the model of mass, energy and forces

Understanding dark energy and dark matter may lead to the successful theory of "everything“ – a complete set of consistent equations of particles, forces, and energies

Standard Model of particles and forces

1. What is gravity?  

How does it relate to the other forces?

What determines gravitational mass?

How does gravity relate to dark energy?

How does gravity relate to dark mass?

How is gravity defined in collapsed matter (black holes)?

2. What is dark matter and what are its physical laws?

To date, what is known is that it:

Can be measured by its gravitational affect  on galaxies

Collects in galaxies, galaxy groups, and galaxy clusters

Is not observed in small galaxies or on a scale smaller than a galaxy

Has a "cold" character since it would quickly dissipate if it were warm/hot

3. What is dark energy and what are its physical laws?

All that is known is that dark energy:

Dominates the universe’s total mass and energy

Is measurable over the largest scales

Appeared approximately 5 By after the Big Bang

4. What is the nature of the inflationary event that expanded the initial universe and that continues today?