From Sidney Harris, http://www.sciencecartoonsplus.com/originals2.html

There are two ways to slide easily through life; to believe everything or to doubt everything. Both ways save us from thinking. -Alfred Korzybski

A century ago thoughts about the beginnings of space and time could only be approached through theological avenues. It was assumed that all that was seen was the universe and that it was a static entity. Then it was viewed in this way- It is today as it always has been and as it always will be. Our study this week takes us to the heart of the origins matter as best we know it today. Be cautioned that a lot is known about the history of the expansion of the universe. But as that famous philosopher Anonymous has observed, “The Universe is mostly hydrogen and ignorance.” As you proceed through this material, enjoy the grand beauty of the realm of the galaxies. It is a remarkable testament to our curiosity as a species.

When you read or hear anything about the birth of the universe, someone is making it up…Only God knows what happened at the Very Beginning (and so far She hasn’t let on).

Nobel Laureate Leon Lederman, The God Particle

What is Cosmology…

Our universal “world view”

Our cosmological model

Cosmology is the study of the origin and evolution of the Universe. Newton was one of the first to approach cosmology on a scientific basis. He said"the hypothesis of matter, being at first evenly spread through the heavens, is in my opinion inconsistent with the hypothesis of innate gravity without a supernatural force to reconcile them" -- that is, he felt that matter would unavoidably be attracted into concentrations, unless God kept the matter spread through space.

Universe models formed in many cultures

Cosmology through the ages…

In Hindu mythology, the dance of Shiva Nataraja expresses the birth and death, and rebirth of the Universe

Chinese mythology: In the beginning, the universe was nothing but swirling vapors and chaos. From these vapors, the forces of Yin and Yang emerged. The two forces combined to create all things, and all things created contained elements of both. http://tlc.discovery.com/convergence/eden/myths/myths_10.html

Apollo, Greek god of the sun, http://www.forthnet.gr/olympics/athens1896/pictures/pics/apollo.jpg

We must walk along the path in darkness (superstitions, myths, etc.) before we see the light of truth…larry mascotti

2nd Century: Claudius Ptolemy (Physics of Aristotle)

Model: Earth-centered CosmologyBig Idea: Different laws for Earth and the cosmos

Astronomy has seen three scientific revolutions in cosmology

16th Century: Nicolaus Copernicus (Physics of Newton)

Model: Sun-centered CosmologyBig Idea: Universal physics; same laws everywhere

20th Century: Edwin Hubble (Physics of Einstein) Model: Big Bang Cosmology

Big Idea: Universe is changing, evolving

Our View of the Cosmos - the story of scientific models

Cosmic expansion:

Recall Hubble’s observation in 1929…

Z ~ distance everything is receding from everything else (on the whole)

The universe is expanding

In reference to the balloon,

where is the edge? The center?

Keep in mind that it’s a 2-D analogy…

1) Virtually all galaxies are moving away from us, e.g. they are redshifted.

2) The more distant the galaxy, the larger its redshift, that is the faster it is moving away.

Doppler shift

Standard Candle

Important: Velocities are measured by redshifts observed from galaxy spectra and distances are computed by using the Standard Candle Method.  Recall that in this technique known luminosities and measured brightness allow the inverse relationship between a light's appearance and it distance to be applied. Essentially when luminosity and brightness are know than faintness equals farness.

The top drawing would imply that the Universe expanded into "something" that preceded the beginning of the expansion. This "something", the condition before the event known as the Big Bang, is being theoretically explored but to date no experimental test support the condition of the "something" that came before the expansion phase of the Universe-everything we know. The expansion of the Universe is the beginning of time and space as we know it. In observing such a diagram as shown above it suggests that the observer, you, is viewing the balloon universe from a

place outside of this balloon universe. Where exactly is "outside the universe?"

This expansion is summarized in Hubble's Law:VR = H0 x d

VR = radial velocity, d=distanceH0 = Hubble's constant, about 70 Km/sec/Mpc

Hubble's Law, once it is calibrated, provides an easy way to measure the distance to a galaxy. Just take a spectrum and measure the redshift, use

it to calculate the velocity, and plug the result into Hubble's Law rearranged to solve for distance: d = VR/H0.

H0 is closely related to the age of the Universe:Distance = Velocity x time

v = d / tt = d/v

Hubble's Law: VR = d x H0 ==> d = VR/H0 VR t = (H0)(VR)

so 1/H0 is the age of the Universe (or more precisely, the length of time that the Universe has been expanding).

1/H0 ~ 13 billion years.

The big bang:

so the universe is expanding…

What if we trace the expansion backward in time? What would we expect?

Would we reach a “beginning?”

Is there a beginning?

This “beginning” is what cosmologists call the “big bang”

Back to class 10/22/04 Ian Shipsey

Primordial Soup

Nobel Laureate Leon Lederman, The God Particle

…if the metal of a car were melted, upon examining the liquid melt, you would have no way of knowing if the hot liquid came from a Ford or a Chevy…The Big Bang wiped out the evidence of what came before…

Designer?For a Scientist It Doesn’t Explain Anything…

If the Designer can create a Universe, why is c = 300,000 km/sec instead of 400,000?

If Designer had to have c = 300,000 km/sec, why? What (who?) dictated that, and why?

Russian Matryoshka Dolls

16

The Big Bang Theory describes how our Universe is evolving, not how it began. The Big Bang separates the preceding "bland condition" of zero time and space with the Universe we observe today. Our concept of time requires an event to "flow" from. It describes the history of the expansion of the universe.

Big Bang Theory

Image at Image at http://map.gsfc.nasa.gov/universe/bb_theory.html

• In 1915, Albert Einstein concluded that the universe could not be static based on his recently-discovered theory of relativity and added a "cosmological constant" to the theory of relativity because astronomers assured him that the universe was static

• Aleksandr Friedmann and Abbe George LeMaitre are credited with developing the basics of the Big Bang model between 1922 and 1927; their calculations suggested that universe is expanding, not static.

• Years later, Einstein called his cosmological constant the biggest mistake of his career

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Standard Big Bang Cosmology

• Sometime in the distant past there was nothing – space and time did not exist

• Vacuum fluctuations created a singularity that was very hot and dense

• The Universe expanded from this singularity• As it expanded, it cooled

– Photons became quarks– Quarks became neutrons and protons– Neutrons and protons made atoms– Atoms clumped together to make stars and galaxies

What holds the universe together?

• Gravity – very weak, but operates over incredibly long distances.

• Electromagnetism – strong, but operates only over moderate distances

• Strong force – the strongest, but only good for about 10-15 meter. Keeps nuclei together

• Weak force – regulates radioactive (fission) decay.

Phases of the Inflationary Universe (the Big Bang +)

• Supergravity era• First 10-44 seconds 1032 K• Universe is all energy, smaller than

an electron. Only 1 force exists.• Gravity separates from other 3

forces.

Grand Unified Theory Era• 10-35 seconds 1028 K• Universe is still all energy, still

smaller than an electron, but 1000x larger than before.

• Strong force separates.

Radiation Era

• Up to 10-10 seconds 1015 K• Universe expands fast (1 um)• Energy takes recognizable forms

(photons)• Electromagnetic & weak forces

separate. 4 Forces now !

Heavy Particle Era

• 10-7 seconds 1014 K• Universe expands to 1 km in size• High energy photons collide to make

protons, antiprotons, quarks, etc.• Some matter & antimatter annihilate

each other.

Light Particle Era

• 0.1 second 1012 K• Universe is 1,000,000 km wide• Photons collide to make electrons &

positrons• Photons are too sluggish to make

any more heavier particles

Nucleosynthesis Era

• 100 seconds to 10,000 years 1010 K• Universe is up to 1 LY wide• Protons & electrons collide to make

neutrons• Protons & neutrons begin to stick

together – make nuclei of light elements (H, He, Li, Be)

Matter Era

• 10,000 years to now• Up to present size (>10 billion LY)• Nuclei & electrons are now slow

enough that entire atoms form

Matter Era

• Density drops low enough that universe becomes transparent.

• Matter begins to clump (nebulae)• Stars form, clump to make galaxies

A Big Bang summary• 1. Universe is confined to a Singularity (a point)• 2. The Singularity explodes in a Big Bang• 3. Universe is born in rapid expansion of energy and space• 4. Universe cools and 4 forces form• 5. Some energy condenses to quarks and leptons• 6. Quarks and leptons combine into protons and neutrons• 7. Protons, neutrons and electrons combine to form atoms• 8. Gravity pulls atoms into clouds of gas and dust• 9. Stars and galaxies form from the clouds• 10. Solar systems evolve around the stars

Back to class 10/22/04 Ian Shipsey

Galaxiesborn

The process…

•Observation…•Tentative thoughts…•“Ladder of logic”…

Destination…The Theory

31

Predictions for the Big Bang Model

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.

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.

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.

04/21/23 Prof. Lynn Cominsky 33

Big Bang Nucleosynthesis

• Light elements (namely deuterium, helium, and lithium) were produced in the first few minutes of the Big Bang

• Elements heavier than 4He are produced in the stars and through supernovae

• However, enough helium and deuterium cannot be produced in stars to match what is observed because stars destroy deuterium in their cores

• So all the deuterium we see must have been made around three minutes after the big bang, when T~109 K

• BBN predicts that 25% of the matter in the Universe should be helium, and about 0.001% should be deterium, which is what we see

1948

Gamov early universe should be hot & dense

Should radiate as a black body

1949

Alpher and Herman large redshift would stretch the wavelength into the IR and radio

In 1948 George Gamow predicted that if the Big Bang had occurred, the radiation from it should be observable in the microwave portion of the spectrum. However, the technology for observing at these wavelengths did not yet exist. In the mid 1960s, microwave techniques had advanced to where they could be applied to astronomy. A group at Princeton decided to build detectors to look for the radiation from the Big Bang.

A few miles down the road from Princeton, Arlo Penzias and Robert Wilson were working for Bell Labs trying to improve the use of microwaves for carrying telephone calls. To their annoyance, their microwave receiver picked up some "static" regardless of where it was pointed. They learned of the Princeton group's research, and realized that their "static" was in fact the remnant radiation from the Big Bang. Penzias and Wilson received the Nobel Prize for their work.

(from Bell Labs, http://www.bell-labs.com/user/apenzias/nobel.html)

The COBE (Cosmic Background Explorer) satellite made very careful measurements of the shape of the spectrum of this emission. It is a perfect blackbody at a   temperature of 2.728K; it is often termed the "3K background". (From R. McCray, http://cosmos.colorado.edu/astr1120/lesson12.html)

04/21/23 Prof. Lynn Cominsky 37

Universe’s Baby Pictures

Red is warmer

Blue is Blue is coolercooler

Credit: NASA/WMAP

Note that the temperature variation on the Earth covers about 100°C while those measured by WMAP range only over about 0.0004 °C, a smaller range by a factor of a quarter of a million.

The edge-center problem:

Suppose the universe has an edge…

It wouldn’t be an edge to the distribution of matter – it would be an edge to space itself!

You couldn’t just reach past it and feel around…

Seems to violate common sense…

We assume it has no edge

No edge => no center

If the universe is infinite no center problem.

So what is this big bang?

If no edge, then no center

The big bang did not happen at some “spot,” it happened everywhere…

…and is still happening…

“Universe” vs. “observable universe”:

Minor distinction…

Universe = all that exists

Observable universe = all that we can “see”

The former could be infinite

The latter is most definitely finite

“All of astronomy is reasonably unreasonable.”

Reasonable assumptions often lead to unreasonable results…

Basic Principles

Big Bang: the universe began hot and dense and thereafter expanded and cooled.

Gravitational Instability: Stars, galaxies, clusters of galaxies ("Structure") formed from the gravitational pull of small density wrinkles in the early universe

Cosmological Expansion

Recession of the galaxies: distant objects appear to be moving away from us.

Cosmic Microwave Background: we are bathed in primordial light.

Properties of the Cosmic Light

3 degrees above absolute zero (-270 degrees Celsius)

mm-cm wavelength

400 photons per cubic centimeter

10 trillion photons per second per squared centimeter

A Brief History

Looking at distant objects, we look backwards in time.

Galaxies formed when the universe was a few billion years old

Microwave background radiation was emitted when the universe was about 300,000 years old

Before 300,000 years, the universe was a nearly smooth particle soup.

Temperature Sky Maps

Temperature anisotropies: small variations in the temperature of the microwave background from one direction on the sky to the other.

Temperature map: representation of the 3 dimensional sky in a 2 dimensional plane.

COBE: a satellite which detected the large features in the microwave background sky in 1992

WMAP: very high resolution satellite measurements of CMB in 2003

NASA/JPL-Caltech/A. Kashlinsky (GSFC)

Brief History of the Universe

Prediction: An expanding universe is evolving over time. If we look at the early universe, it should appear different.

Observation: Distant galaxies less evolved, physically and chemically.

Testing the Big Bang model

A view through space…and time!

The earliest known galaxies

Many of the galaxies we see at great distances (and Many of the galaxies we see at great distances (and early times) indeed look violently disturbedearly times) indeed look violently disturbed

Fermilab

For information about how the universe is not only probed by telescope but also with high energy particle accelerators. View: Science Now-Watch The Segment (left side of screen 12 minutes) and The Cosmic Perspective (Middle of screen)

http://www.pbs.org/wgbh/nova/sciencenow/3410/02.html

Dark Energy73%

Dark Matter23%

“Normal Matter”4%

Latest analysis of the properties of the universe:

Seems to be flat

Accelerating

Will expand forever

Age: 13.7 billion years

4% baryonic matter

23% dark matter

73% dark energy

H0 ~ 71 km/s/Mpc

Inflation on strong ground

Cosmological constant supported, but quintessence not entirely ruled out

Dark matter is of the “cold” variety in order to clump and produce the universe we see today

•The universe is 13.73±0.12 billion years old. That’s an uncertainty of only 0.9%.

•The rate of the universe’s expansion today, is 70.1±1.3 km per second per megaparsec.

•Whatever dark energy is, its behavior is becoming clearer. It’s not something that spreads out as space expands, as particles in space would, but is something inherent to space-time itself. A cubic centimeter of space always has the same amount of dark energy, no matter how much space has expanded.

http://www.youtube.com/watch?v=5NU2t5zlxQQ

Size of the universe

But what of the future?

Will the Universe exist forever, or will it someday

fade away into darknesss?

The process…

•Observation…•Tentative thoughts…•“Ladder of logic”…

Destination…The Theory

62

04/21/23 Prof. Lynn Cominsky 63

Standard Big Bang Cosmology

• Top reasons to believe big bang cosmology1. Hubble Expansion-Dynamic Universe. 2. Big Bang Nucleosynthesis-the chemical abundance of hydrogen and

helium match the predicted amounts. 3. Cosmic Microwave Background (CMB)-the “afterglow” that has

engulfed the universe has been measured and is in agreement with theoretical predictions.

4. Galactic Evolution-as viewed in the Hubble Ultra Deep Field Sky Surveys. Active galaxies, collisions and quasars were greater in the past than now.

5. Support from nuclear physics experiments.

http://janus.astro.umd.edu/astro/times/

Event When it happened

Big Bang January 1, midnight

First Atoms form January 1, 1:00a.m.

Stars and Galaxies form January 8, 7:00a.m.

Our Sun is born September 1, 8:00a.m.

Earth born September 11, 2:00a.m.

Moon formed September 13, 12:00p.m.

Earliest life on Earth September 30, 1:00p.m.

First multi-cellular life on Earth December 14, 11:00p.m.

Dinosaurs appear December 27, 3:00a.m.

Dinosaurs die December 30, 10:00a.m.

Humans arise December 31, 11:39p.m.

Humans migrate from Asia to America December 31, 11:59:30p.m.

First cities December 31, 11:59:49p.m.

Shang Dynasty in China December 31, 11:59:53p.m.

Pythagorian Age in Greece December 31, 11:59:55p.m.

1 A.D. December 31, 11:59:56p.m.

Fall of the Roman Empire December 31, 11:59:57p.m.

Columbus sails for America December 31, 11:59:59p.m.

Present Day next January 1, midnight

Sun becomes Red Giant next May 2, 4:00p.m.

Sun becomes White Dwarf next May 7, 1:00p.m.

Here is the history of the Universe compressed into a year                                                                                   

The Revised History of the Universe in 200 Words or Less

Quantum Fluctuation. Inflation. Expansion. Particle-Antiparticle Annihilation. Deuterium and Helium Production. Matter Domination. Recombination. Blackbody Radiation. Local Contraction. Large-Scale Structure Formation. Violent Relaxation. Virialization. Galaxy Formation. Turbulent Fragmentation. Contraction. Ionization. Massive Star Formation. Deuterium Ignition. Hydrogen Fusion. Hydrogen Depletion. Core Contraction. Envelope Expansion. Helium Fusion. Carbon, Oxygen, and Silicon Fusion. Iron Production. Implosion. Supernova Explosion. Metals Injection. Star Formation. Universal Acceleration. Supernova Explosions. Star Formation. Planetesimal Accretion. Planetary Differentiation. Crust Solidification. Volatile Gas Expulsion. Water Condensation. Carbon Dioxide Solution. Water Photodissociation. Escaping Hydrogen. Ozone Production. Ultraviolet Absorption. Polymerization. Coacervate Formation. Molecular Reproduction. Protein Construction. Fermentation. Photosynthetic Unicellular Organisms! Oxidation. Mutation. Evolution. Cell Differentiation. Respiration. Sexual Reproduction. Multicellular Organisms. Evolutionary Diversification. Fossilization. Trilobite Domination. Land Exploration. Comet Collision. Dinosaur Extinction. Mammal Expansion. Homo Sapiens Manifestation. Language Acquisition. Glaciation. Innovation. Religion. Animal Domestication. Fermentation. Food Surplus Production. Inscription. Civilization! Exploration. Warring Nations. Empire Creation and Destruction. Expansion. Scientific Explanation. Colonization. Revolution. Constitution. Vaccination. Industrialization. Emancipation. Invention. Mass Production. Urbanization. Migration. World Conflagration. Suffrage Extension. Penicillin. Depression. World Conflagration. Fission Explosions. Computerization. United Nations. Space Exploration. Population Explosion. Environmental Degradation. Superpower Confrontation. Liberation. Terrorism. Lunar Excursions. Resignation. Inflation. Internet Expansion. Globalization. Reunification. Dissolution. Union. World Wide Web Creation. Composition. Terrorism. Invasion. Extrapolation?

Copyright 1996-2000 by Eric Schulman http://members.bellatlantic.net/~vze3fs8i/hist/histcom.html

Thoughts from others…

Science attempts to describe/explain the evidence of the senses in the most elegant and economical way possible without evoking a supernatural cause.

Chet Raymo

A clear consensus on the reality of the universe would be an enormously valuable achievement…Any story of the universe will do if everyone around you shares it. But if different people you meet have different stories, no story will do…Consensus has to be based on something impartial, and science is the closest the modern world can come to that.

Joel R. Primack and Nancy Ellen Abrams

Like the ancients, modern people want to connect to the universe, but the strangeness of a creation story without human or animal personalities, one that is hard to visualize because things happen in it following unfamiliar laws-the kind of creation story may seem at odds with our intuitive sense of what makes a satisfying explanation…Our animal/human creation stories may have their place as metaphors for lives-but no longer for the universe beyond the solar system…

Joel R. Primack and Nancy Ellen Abrams

At last we have arrived at the beginning. This creation story is not only the truest story of our time, but the only one we know with any chance of being true. The opening characters are not Nun (The Primeval Water of Egyptian belief) or Adam and Eve, but neutrino and quark. Some parts of the story we are fairly sure we understand, and other parts we are less sure about. There are two different reasons for cosmological uncertainty: the first is simply that we don’t understand the physics; the second is that we understand the physics but the situation is too complicated for us to be sure we can use the basic principles properly…the period we are most confident about is from about one-thousandth of a second to about 400,000 years after the beginning…Cosmologists are uncertain about what occurred before the first ten-thousandth of a second, because the physics that was most relevant then is not yet fully understood…(after 400,00 years) But as time goes on, although the physical principles don’t change, the complexity of the universe becomes so great that our uncertainty increases again. When we get to events such as the intricately interacting processes by which galaxies like our Milky Way assemble and evolve, we can’t possibly reason it out from basic principles. What we do instead is to program into supercomputers the laws of physics and our best cosmological theories and let the universe evolve in cyberspace. Then we compare the result to actual astronomical observations to see if the cyberspace universe our theory produced is the kind of universe we actually live in…Since the cyberspace universe does indeed match the observed universe we see on the large scale, we know that our theories are on the right track…

Joel R. Primack and Nancy Ellen Abrams

…Is it not astonishing that nearly all the inhabitants of our planet …Down to our time …have lived and died without knowing where they are……and without the slightest conception of the marvels of the universe?

Camille Flammarion

Galaxy Song

http://www.youtube.com/watch?v=buqtdpuZxvk

For a beautiful view of earth through time view: http://www.lifethroughtime.com/