Universal Beginnings

I. Definitions

	The Universe consists of all objects and phenomenon observed or 
	postulated. 	[Encyclopedia Britannica]

	Scale Of the Universe

		Distance from sun to earth = 500 Light Seconds (93 Million 
		Miles)

		Distance to nearest star (Proxima Centauri) = 4.3 Light Years

		Diameter of Local Galaxy = 100,000 Light Years

		Nearest Large Galaxy (Andromeda) = 2 Million Light Years

		Distance to Quasi Stellar Objects = 

	Mythology for our purpose is a peoples attempt to explain 
	observed or postulated phenomenon by the best means they have 
	available to them

II. Ancient Mythology

	To explain the origins of the world as they knew it, the ancient 
	people postulated creation by beings or powers greater than themselves

	Types of Ancient Creation Myth

		Creation by a supreme being often a sky god

			All Powerful, Pre-existent

			Primoral matter in chaotic state

			Creation a conscious act

			Judeo-Christian creation stories in Genesis

		Creation through emergence

			Gradual creation from chaotic situation under the 
			earth

			Navaho Emergence Myth

			Movement from lower to higher levels

		Creation by world Parents

			Primordial mother and father

			Chaos before coming of world parents

			World Parents bear lesser gods who sometimes rebel and 
			take over

			Babylonian Myth - Enuma elish

		Creation from the cosmic egg

			Primoral chaos compared to an egg with the germs of 
			creation

			Japanese and Chinese creation stories

		Creation by earth divers

			Cosmic waters present before creation

			Animal dives into water to secure a portion of the 
			earth

	Common Threads

		Primoral matter in form of chaos

		Some agent separates the chaotic matter and creates the earth 
		and all on it

		Men and Women highest order of creation

		Creation of the Earth, Sun, and Moon were the main act of 
		creation

		Everything else was secondary

III. Modern Mythology

	Steady State Universe postulated by British school in 1948

		Based on astronomical knowledge of the time??

		Universe has always existed as it is and will continue that 
		way

		Observation has since indicated this may be wrong

			Beginning and End of the Universe Possible Conclusion

	Hubbell's Law

		Postulated by Edwin Hubble

		On a large scale, Galaxies appear to be moving away from one 
		another at a rate proportional to their distance from us

			Red shift phenomenon

		Tracing location of galaxies back in time Hubble concluded 
		that 10 to 15 Billion years ago, all matter was in the same 
		place packed in an incredibly dense state

	Big Bang Creation

		At that time everything exploded in a Big Bang which began 
		the expansion seen today

		Evidence supported by steady, uniform microwave background 
		radiation detected by radio telescopes

			Believed to be remains of light of primeval fireball

	Measurement problem

		Since objects at the extremes of the universe are so far away, 
		we are seeing them as they were up to billions of years ago

		Requires very careful evaluation to understand state of the 
		universe

	Future of the Universe Presently Not Known

		Will expansion continue, achieve a steady expansion velocity, 
		or contract again??

		Need to know mass of universe to answer

		At present time, the total mass of the universe is not known

		With what we know today, the universe will continue to expand, 
		but theoretical physicists are learning more all the time

			Latest work I have seen indicates Neutrinos may have 
			mass which will significantly change estimates

	Questions and doubts

		Religious Objections

		Present state of knowledge

			mass calculations very tentative and being revised on 
			a regular basis

The Formation of the Stars

I First Generation Stars

	Temperature of universe about a few thousand degrees C around 300,000 
	years after the big bang

		At that point, hydrogen and helium atoms form by capture of 
		electrons by protons

		Cosmic background radiation emitted and universe became 
		electrically neutral

	First Stars began to form about 12 billion years ago and hydrogen 
	atoms fuse into helium

		Elements up to iron form in the interior of stars

		Elements up to uranium form in supernova explosions

	The forming and explosion of this first generation of stars created 
	the materials from which later stars including our sun were formed

The Sun and The Solar System

I. Definition

	The Solar System consists of the sun, nine known planets and their 
	satellites, countless asteroids and comets and the interplanetary 
	medium.

II Origins Of the Solar System

	Observed Process

		Solar system began with the gravitational collapse of an 
		interstellar cloud of gas and dust possibly started by density 
		fluctuations within the cloud

		Initial shape roughly spherical

		Outer edge moves slower than inner, thus as it collapses, it 
		begins to rotate

		As cloud contracts, it flattens - more away from the center 
		than close to it  	[called solar nebula]

		As the cloud condenses, it heats up as its potential energy is 
		eventually converted to heat

		As temperatures become high enough at the center, nuclear 
		reactions start and a star is born

		This process takes about 10 million years

		In the case of our sun, this happened about 4.6 Billion Years 
		Ago based on lead isotope decay measurements

	The Formation of Planets

		Attraction and Collision in the disk forms larger objects

		Collisions relatively low velocity due to rotation so gravity 
		often holds the colliding objects together

		Dichotomy in planet growth

		The Inner Planets

			Planets close to the sun formed where temperatures 
			were above the freezing point of water and became 
			small rocky bodies with a density of about 3 gm/cc

			Hydrogen, Helium, and some of the Water Vapor escape 
			back into space

			Inner Planets formed in about 100 Million Years

			Continued collision with large bodies caused 
			significant effects

				retrograde rotation of Venus

				loss of atmosphere on Mars

			Heavy bombardment continued for about 600 Million 
			Years further changing planetary features

		The Outer Planets

			Planets forming outside the freezing point become very 
			large, low density objects large enough to retain 
			Hydrogen and Helium

			Availability of Ice resulted in very large planets

			At about 10 time mass of earth, they can retain 
			Hydrogen and Helium

			Since Hydrogen and Helium are most common elements in 
			the universe, the outer planets can become very large 
			but with densities of about 1.2 gm/cc

			Large planetary systems formed as minor solar systems

			Some moons added by capture

		Strong solar wind later cleared much of the remaining dust 
		out of the system

		Rocky asteroids formed in gap between Mars and Jupiter

			source of meteorites

		Icy bodies formed outside orbit of Neptune and Pluto 
		(Oort Cloud)

			source of comets

The Formation of the Earth

I. Age

	The Earth, like the Solar System formed about 4.6 Billion Years Ago

	Based on Lead Isotope measurements

II. Differentiation and Crust Formation

	Energy of formation and collisions resulted in mostly molten early 
	earth

	Heavy elements like iron and nickel sank to the center and remained 
	molten

	Lighter elements rose toward the top and formed an early crust over 
	the molten interior

	The lightest ones that probably formed the first atmosphere escaped 
	into space

	A secondary atmosphere then formed by outgassing associated with 
	surface volcanic activity

	Continued bombardment of bodies from space added more energy and 
	probably destroyed the earliest crust

		Oldest rocks on earth date to about 3.9 Billion Years Ago

III. The Atmosphere

	Assume gases emitted by early volcanoes same as today

	No free oxygen in secondary atmosphere (anoxygenic)

	Evolution of Free Oxygen

		Ultraviolet radiation broke up water vapor

			Hydrogen escaped, Oxygen stayed in atmosphere

			mostly captured by iron and other elements

		Once life appeared, photosynthesis became predominant 
		form of oxygen production

			Blue-green algae known to exist about 3.5 Billion 
			Years ago

		Early iron absorbed much of oxygen in forming ferric 
		iron ores

		Excess iron in oceans probably cleared about 1.7 Billion 
		Years Ago

		Oxygen levels at beginning of Precambrian period about 2.2 
		Billion years ago were about 1% of today's levels

		Oxygen content of atmosphere at end of Precambrian period 
		650 Million Years ago were about 10% of today's levels

		When first land plants appeared about 400 Million Years ago, 
		present levels had been reached and they have stayed there

IV. The Oceans

	Volcanic output includes water vapor

	Once the surface cooled to less than 100 degree C about 3.5 Billion 
	Years ago, the vapor began to condense

	Oceans achieved modern chemical characteristics about 2 Billion Years 
	ago once deposition of iron slowed due to slowing of volcanic activity

	Most of iron precipitated out about 1 Billion Years ago

	During the last 570 Million years, the oceans have been essentially 
	steady state chemical systems

Plate Tectonics

I Theory

	About 1908 a German, Alfred Wegener proposed a theory of continental 
	drift based on a match of the profiles of South America and Africa

	Theory not generally accepted

	Findings of seafloor studies after World War II

		Mid Ocean Ridge

		Oceanic trenches

		Earthquake and Volcanism Zones identified at trenches

	Seafloor spreading model 

	Developed about 1960 by Henry Hess

	New crust formed at mid ocean ridges

		Dealt only with ocean crust (basaltic)

	Crust flows into the trenches where it melts and is recycled

	This melt also indicated by zones of volcanoes

	Total crust produced at the ridges is equal to that destroyed in 
	the trenches

	Can show rate and direction of movement in Pacific Island Chains

	Evidence to support theory in magnetic anomalies tied to earth 
	field polarity reversal

		As crust cools, magnetic particle in it align with the earth 
		field

		Result is stripes parallel to ridges

		Produces about 140 million years of evidence in ocean crust

II. Continental Movement

	Continental mass less than ocean crust, thus rides on top of it

	Collision of continental masses produce mountain ranges

		Effects seen today in Western Americas and North of India

	Rate and direction can be inferred from locations of glacial deposits, 
	chalk beds, coal beds, Etc.

	Projections to the past

		Assumes that the plates do not deform

		Present day movements and indicators show much of land 
		together 240 Million years ago in continent called Pangaea

		Less certain projections also indicate an earlier giant 
		continent of Godwana about 390 million years ago

		It is estimated that when the earth was hotter, there was 
		more movement as the ridges expanded at a higher rate

III. Effects of Plate Movement

	Climactic effects due to changes in ocean currents

	Less diversity of life when the continents were joined

	Movement of diverse life forms when they join together

		North and South America example

IV. Unanswered Question

	What drives the movement?

The Beginnings of Life On Earth

I. Reducing atmosphere of early earth fostered formation of building blocks 
   of life

	Allowed production of amino acids and other building blocks of life 

	Chemical process driven by ultraviolet light exposure and lightning

	Over time more complex proteins developed from the early building 
	blocks

II. About .1 to 1.5 Billion Years ago self replicating, mutable systems 
    developed out of the primoral soup of the early ocean

	Early life forms probably lived deep enough in the oceans to avoid 
	UV light

	They along with other processes produced oxygen that gradually built 
	up in the atmosphere

	As Oxygen and Ozone built up, UV exposure reduced and life forms 
	moved toward the surface

	Vertebrate life forms appear in the fossil record beginning about 600 
	million years ago

	Land life forms appear about 500 million years ago

	They very quickly adapted and spread to all corners of the earth

Theory of Evolution

I. Definition

	A theory that animals and plants have origins in earlier types and 
	mutate over long time spans

	All plants and animals derive from bacteria-like microorganisms that 
	originated about 3 billion years ago

II. Darwin's Theory

	"On the Origin of Species by Means of Natural Selection" Published 
	in 1859

	Expanded to Humans in 1871

	Natural selection the driving force of change as organisms move to 
	new environments or their environment changes

	Offshoots of Darwin's theory regarding species

		Herbert Spencer - survival of the fittest

			rejected by Darwin

		Social Darwinism of the late 19th and early 20th centuries

	Marxist theories of economic/political evolution

III. Mendelian Genetics

	Synthetic Theory of Evolution came from this development

	Work on Peas published by Gregor Mendel in 1866

		Developed principles of inheritance/heredity

	Tied to Origin of Species by Theodosius Dobzhansky in 1937 publication 
	"Genetics and the Origin of Species"

	Widely accepted by about 1950

IV. Evidence for Evolution

	Comparative Studies of living organisms by Darwin and others

	Fossil Remains of similar and extinct species

		Shows succession of organisms through time

			Bacteria - 3.5 Billion Years Ago

			Soft body worms - 700 Million Years Ago

			Vertebrates - 400 Million Years Ago

			Mammals - 200 Million Years Ago

			Hominoid Australopithecus - 3 to 4 Million Years Ago

			Homo Habilis - 1.5 to 2 Million Years Ago

			Homo sapiens sapiens - 100,000 Years Ago

		Structural Similarities

			Bone structure of vertebrates very similar

			Inheritance from common ancestor makes sense

	DNA Evidence

		Structure DNA deduced in 1953 by James Watson and Francis Crick

		Similarities in Genetic code in DNA indicate common origins

		Example cytochrome c grouping of amino acids

			humans and chimps have 104 amino acids in the same 
			order

			rhesus monkeys have one different

			Horses have 11 additional amino acids

			Tuna fish have 21 added

		Comparison shows recency of common ancestors

		Hundreds of such groups have been tested with similar results

	Theory resisted by fundamentalist religions as a denial of God

		began very early after Darwin's publication

		Liberal religious interpretation is that God acts through 
		natural causes

Conclusions

Beginning with the formation of the universe in the Big Bang about 13 Billion 
Years ago, the universe has continued to expand.  

About 4.6 Billion years ago the solar system and the earth were formed.  

Life appeared on earth about 3 Billion years ago and all life on earth has 
developed from those first life forms.  

Hominoid life forms appeared about 4 million years ago and the Homo Sapien 
sub-species about 50,000 years ago.  

We will discuss the developments by homo sapiens in the period before 
historical recording began in the next lesson.