Added note Nov. '05 I interpret science as observation, measurement and analysis of specific events. It includes conjectures that have often been precursors of further exploration, measurement and analysis. But it is always and evermore a study of what effects grow from specific describable causes. Taken in this light the Big Bang is the most colossal denial of science I can imagine; yet scientists have adopted it and devised mathematics to defend it. We are presented with the idea that, from nothing and without cause, there proceeded an eruption so powerful and extensive that the universe entire came from it. I have not been content with descriptions I have read of the Big Bang and have speculated on an alternative. To make my presentation here more compatible with conventional science, I have moved description of my speculations to the end of this web page.

Astronomy

Through our reception of energy we see this unending turmoil as a variety of concentrations of mass: extensive clouds of dust and particles, coalescing clouds in the process of generating new stars, stars during their life and in their death throes, explosions that disperse mass and thus take part in generating new clouds. Our science is beginning to discover and apply mathematics that allows understanding of part of what we see. It is indeed an immense caldron in which our view is strongly influenced by our line of sight and the orientation of the clouds and star systems with respect to our line of sight. And it is thus far perplexing.

Whatever the particles from those eruptions of nothingness, and how they may have combined, the most numerous particle resulting from condensation of primordial matter was the hydrogen atom. A sun the size of ours, after converting most of its hydrogen into helium in the fusion process, is expected to contract until the heat of compression ignites helium fusion; further depletion, contraction and temperature increase should produce heavier elements up to carbon and oxygen. A larger star may through successive contractions, each contraction igniting a heavier element as fuel, produce elements as heavy as iron. Our theory says a star as large as eight solar masses (Our Sun is one solar mass) ends its life in a supernova, a colossal explosion of extreme brilliance, blowing away most of its matter. But that matter isn’t lost; it is dispersed into space to become available to take part in forming new concentrations of gases and particles from which new stars can emerge.

The age of the Universe -- elapsed time since the Big Bang (or the most recent Bang) -- is taken as perhaps 13.7 billion years. The age of our Sun is taken as perhaps 4.7 billion years, roughly the same as the estimated age of Earth. Likely during those first nine billion years many local events, including supernovas, produced ever heavier elements so the nebula from which our solar system formed included heavy elements up to at least uranium, the heaviest element found in Earth’s crust. (In the reckonings of how many suns are orbited by planets capable of supporting life, it is evident that such a sun would have formed from remnants of a supernova; otherwise its planets could not have included the heavier elements that are necessary to life and to building a world. This consideration alone limits the number of stars in our galaxy that may claim planets that host life.)

Origin of our Milky Way

I have read no speculations of how things may have evolved from the Big Bang to the presence of galaxies and can only add my own speculation that, because matter was randomly dispersed in the Universe, centers of gravitational attraction arose and created galaxies. And, within those centers matter was randomly dispersed, giving rise to local accumulations that were drawn together by gravity to form individual stars (and perhaps whole solar systems).

Origin of the Solar System

Somehow the mass was set to spinning, doubtless due to spin of the vastly larger mass of our galaxy, of which our nebula was an infinitesimal part; and that spin resulted in a disc-shaped nebula, doubtless much thicker at the center than at the outer rim. We can only guess at the temperature distribution within regions of this disc, although reason tells us that the thicker central portion was hotter than matter radially farther out, and a line drawn laterally through the disc would show higher temperatures at the disc’s center. Within this disc gravity and centrifugal forces led to differentiation so the heavier elements tended to concentrate toward the center of rotation.

Whatever explanations are finally reached about formation of the solar system, there are irregularities that must be explained, such as lack of completion of concentration of the heavier elements in the center, departure of planetary ecliptic planes from radial alignment, retrograde planetary spins, formation of smaller bodies orbiting their hosts, . . .

Some think the planets were cast off by a forming sun; others think our planet and its siblings resulted from the gravitational pull of a celestial visitor passing near the Sun and stripping off chunks of matter; still others think an accretion disc containing all the matter of the solar system separated into rings. What led to separation of the disc into rings from which the planets could form by accretion is a matter of debate. I take the theory of disc formation and subsequent accretion of the Sun and planets as the more likely since there must be a balance between gravity and centrifugal force if stable orbits are to be produced. And the accretion theory leaves little question that the planets formed from the same source material as the Sun and likely resulted as an integral part of the process that produced the Sun.

Origin of Earth

If Earth was cast off or yanked away from a young Sun, its temperature was well above the melting point of all constituent materials. If the accretion disc separated into rings and collapsed to form planets while the Sun was coalescing, then Earth’s initial temperature may have been much lower, yet apparently adequate to melt all of its constituents. What gradients of temperature existed within the accretion disc due to gravitational compression and energies of impact during the accretion process? That and the growing surface of a dynamically forming planet are interesting exercises in speculation.

Formation of Earth was a coagulation, at first small, of particles and debris in our ring of the disc. As the ring was drawn together by gravity there resulted larger chunks, then asteroids; finally, with a growing sphere whose gravitational attraction became dominant, the disc collapsed although there was yet much debris to produce intense (and diminishing) bombardment for hundreds of millions of years. Somewhere along the way the Sun ignited. Whether Earth was molten due to the compression that eventually ignited the Sun, or whether its temperature was raised by the energies of collision as it accreted by meteorite or asteroid or planetesimal strikes, it was doubtless molten all the way from core to (a relatively smooth) surface, and gravity-induced differentiation led to concentration of iron toward the center.

Except for the products of radioactive decay (and relatively minor contributions from meteorites), the accretion disc contained all elements present in our Earth. While molten the heavier elements tended to sink toward the center; cooling to temperatures allowing solidification followed soon enough that Earth’s crust contained significant quantities of the heavy elements, including uranium.

Perhaps we should ask the question dealing with the age of Earth: At what point in its accretion should we say its origin was completed? Radiometric dating of some of the oldest meteorites known place the age of the meteorites at 4.7 billion years, but the age of a meteorite does not reveal when it struck Earth; accretion must have been nearly complete when it struck since it was not overlaid by later-arriving accreting materials. And there must have been a crust of thickness sufficient to absorb the blow and support the meteorite, as well as cool enough it did not re-melt, thus allowing the meteorite to retain its identity.

(While it is assumed the formation of Earth was essentially complete after a billion years, the accumulation of matter from space has not ended. Every year meteors and meteorites add some 200,000 tons of matter, scattered randomly. Because of estimated velocities of these fragments, it is felt they originate within the solar system and are not from deeper regions of space. Possibly including remnants of our primordial disc? And, from time to time Earth has been struck by a chunk large enough to disrupt processes at the surface. In most cases frictional heating in the atmosphere vaporizes a meteorite; it is a rare one that is large enough to reach the ground with an internal temperature modest enough that whatever life the meteorite supported was not destroyed during transit through Earth’s atmosphere.)

Radiation of energy is known to follow a fourth power law, so, as temperature drops, heat exchanges by radiation diminish rapidly. Within that ring, laterally out toward the edge, particles cooled toward the prevailing temperature of outer space. But toward the center they remained quite hot. Matter at various places joined and congealed into various sized chunks at various temperatures. So, as our sphere formed it was struck by particles large and small, hot and cold, from nearby and great distances, some with great impact energy. We have the surface of our moon as a model of surface deformation due to meteorite strikes; they are sporadic; they result in cratering and (with enough impact energy) remelting and flow. With slow conduction of heat along the surface, because of extent, temperature differences developed so some regions solidified while others remained molten. We can appreciate the early surface deformations leading to a crust of slightly uneven elevation.

Observation of other newly-formed suns suggests that ignition is followed by an outward wind that divests the sun of all gases not tightly bound gravitationally. Thus what remained of our uncollapsed disc was purged of its lighter gases, hydrogen and helium, and Earth was subjected to a solar wind that swept away gases not gravitationally bound or trapped in the Van Allen belts. Therefore what atmosphere Earth possesses today had, after the Sun's ignition and initial solar wind, escaped from Earth's interior, likely consisting mostly of carbon dioxide. And lighter gases, including hydrogen from dissociated water, were so energetic by virtue of their temperature as to escape Earth’s gravitational pull.

Distribution of elements within this sphere was obviously uneven although not enough to cause a discernible wobble in Earth’s daily rotation. Gravity produced a sphere of this molten blob and the centrifugal force of rotation produced an equatorial bulge and polar flattening. While gravitational differentiation within this melt concentrated the heavier elements toward the core, this process was slowed and interrupted by cooling and formation of a crust. With formation of a crust, the contraction that accompanied further cooling compressed a relatively incompressible interior so that the pressure led to volcanic activity. An atmosphere of unknown composition formed. Eventually water vapor was present. With enough krinkled crust, an atmosphere and water, the story constructed by geologists, paleontologists, paleobotanists and others can begin.

There are yet today at Earth's surface pockets of radioactive particles whose decay produces heat, so evidently there was initially enough radioactive decay that it contributed to Earth’s temperature. We can only speculate on the influence of radioactivity on Earth's thermal history, and we have no notion how much radioactive material exists in Earth's core.

We can’t know how long it took for Earth to cool enough to allow the initial molecular combinations that became the precursors of life, although the surface must have been well below the steam point so that there could have been rain and erosion (with its sludge) and significant bodies of water.

Early Earth

Earth’s inner core is supposed to be solid and enriched in iron; an outer core is molten, also enriched in iron^{3 To read footnote, click here}, and in motion (presumably something akin to massive rivers or perhaps like the Gulf Stream that flows like a river in the ocean). There is a magnetic field (presumably produced by this iron in motion) so that Earth behaves like a pole magnet with north and south at opposite ends. Over time the direction of that magnetic field has changed, even reversed, and it is difficult to imagine the kinds and magnitude of force that could so alter the flow of those rivers of iron in Earth’s core (unless it was uneven or irregular cooling so that obstructions to flow built up or shifted -- we certainly wouldn’t think the underside of the crust is smooth).

The charged particles in the solar wind, mostly protons (hydrogen nuclei) and electrons with some helium, travelling at 350-800 kilometers per second (and peaking at 2200 during solar flares) react with Earth's magnetic field to produce the Van Allen belts so Earth’s atmosphere is shielded from direct bombardment by the wind. Perhaps Earth’s early atmosphere of hydrogen was partially protected from the solar wind by the Van Allen belts although Earth’s temperature likely heated hydrogen enough that it escaped at low thermal velocities in spite of this shielding. (One result of the interaction between the solar wind and the inner Van Allen belt is the aurora seen at times in northern skies.)

What impact the solar wind? Presently the Van Allen belts leave only the poles exposed. It has been estimated that reversal in direction of Earth's magnetic field has occurred about four times each million years (and is now long overdue). Evidently reversal of magnetic field requires it to go through zero so for a time the surface is not protected by the Van Allen belts. With changing direction, and varying magnetic field strength, exposure at Earth's surface to the continued bombardment by particles in the solar wind must surely vary -- has varied many times -- (with effects not yet correlated with fossils).

Both the sun and moon attract oceanic water to produce tides, with lesser tides when their gravitational attractions are in opposition and higher tides when they are additive. Because the moon is very slowly orbiting farther and farther away from Earth, the moon was at one time much closer than it is today. So in the earlier days the tides had a ferocity greatly exceeding that of today.

Temperature at Earth’s surface is subject to a number of influences and not only varies greatly over its surface at any one time but has varied greatly with time in any one location. The radiant energy emanating from the Sun is essentially constant, and Earth’s distance from the Sun is essentially constant, so the radiant energy per square foot (or square meter) is essentially constant at the surface of the great sphere having the Sun at its center and Earth in its shell. But a patch of surface of our globe may be inclined to the incoming energy so the energy is spread over a larger area and results in less solar heating per unit of area; thus the poles are colder than the equator. And the tilt of Earth’s axis of rotation to the orbital plane produces seasons as Earth orbits the Sun. Moreover, rotation on its axis causes alternating heating (by day) and cooling (by night) of any patch of surface.

We can reflect on the consistent and gradual changes in Earth’s surface. The globe likely was never smooth, but meteorites and larger fragments caused varying but modest elevations in the early days of solid crust, and volcanic activity added to the unevenness of the surface. By the time Earth cooled enough to allow liquid water to settle on the surface, there were basins to collect it. With time, as Earth grew and cooled, the amount of dry land increased due to both accretion and volcanic activity, the depth of the atmosphere increased, the depth of waters increased and the depth of the crust increased. Over geologic time it was a slow progression of inexorable forces interacting in predictable -- and perhaps yet not suspected -- ways to produce our varied surface features.

Solar radiation includes the spectrum from far infrared through ultraviolet and X-ray while radiation from the ground is much lower temperature (longer wave length infrared). The gases carbon dioxide and methane (a by-product of life) allow unimpeded passage of near ultraviolet, visible and near infrared energies but reflect most infrared (except for several narrow windows). Taking the early composition of Earth’s atmosphere as mostly carbon dioxide, Earth intercepted vast quantities of solar energy but could not lose energy well because, at the longer wavelengths, heat from Earth’s surface was reflected back to the ground. Moreover, dust in the atmosphere, as from a volcanic eruption or a meteorite strike or a massive forest fire, may increase reflection of energy from both sources. Thus Earth’s surface temperature is strongly influenced by its atmosphere’s content; one consequence is that Earth has been subjected to temperature extremes that have produced a number of glacial epochs during which much of its water has been locked up in glaciers. Such reduction in the quantity of surface water has caused sea levels to drop, exposing immense areas to direct sunlight and weather effects. And the ice retreated from the last glacial period only a few (about twelve) thousand years ago. (Changes produced by the concentration of minerals as oceans evaporated to produce glaciers is outside the range of speculations I have read.)

Influencing life on the surface in two ways is the quantity of atmospheric oxygen. Of course, oxygen is necessary to animal life as we know it. Further, oxygen in the upper atmosphere produces an ozone shield that absorbs shorter (more energetic and therefore more harmful) ultraviolet radiation to protect life on the surface. Because of its strong chemical affinity, oxygen was initially likely all bound up in the solid aggregates, so atmospheric oxygen must have been liberated by life processes (plant life) that absorb carbon dioxide and release oxygen.

Atmospheric composition is obviously influenced by the processes at (and underneath) the surface and is mostly a balance between production and consumption; composition has certainly not been constant and may have varied widely to as much as 30% oxygen. It is estimated it took 4 billion years for the oxygen content to reach 7%, from which it eventually settled at today’s 21% oxygen, 78% nitrogen and other gases including water vapor.

What is now North America was apparently, at 3.8 billion years ago (bya), at least half as large as it is today. All of the exposed land may have been concentrated in the super- continent of Pangea, or it may have been in two land masses, Gondwanaland in the south and Laurasia in the north. Or Pangea may have split and been reunited, but as early as 1.0 bya there were five independent continents. By another reckoning the one continent of Pangea existed at 250 million years ago (mya); it had split into Laurasia and Gondwanaland by 200 mya; at 135 mya Gondwanaland split between Africa and South America so the South Atlantic was opened; and at 60 mya the North Atlantic split into Europe and North America. Mountain building, rifting and opening and closing of the oceans have all played a part in the history of Earth’s flora and fauna.

In our times we have experienced storms, some very devastating in their effect. Frequency and fury seem to increase where the Sun’s energy is intercepted in greater quantities. It is almost terrifying to reflect on the severity of storms in those early millions of years of higher temperatures. We have also experienced floods; no doubt floods also figured prominently in Earth’s past, some minor and some devastating almost beyond belief. And during the last million years glaciers have advanced and retreated seven times.

The modern view of Earth is a solid core maintained by radioactivity in excess of 5500^oC. but cooling to 3700^oC) at the core’s outer limit, bounded by a melt from 1000^oC to 2500^oC; the solid mantle resting on this melt supports the tectonic plates on which ride our continents. In deep mines there is a measured rise in temperature of 2-3^oC for each 100 meters (33-50^oC per mile), but scientists have been unsuccessful in drilling and bringing up cores from great depths because drill bits cannot withstand the temperatures. With some 4000 miles from surface to center and depth of crust exceeding some 60 miles, Earth still retains immense quantities of heat energy. I have seen no estimate of the quantity of radioactive material in the core, whose decay will allow gradual reduction of core temperature.

We can only guess what enormous pressures must exist in those incompressible melts on which our continents ride, pressures that continue to expel materials through fissures between plates. But we understand that, as materials cool, they shrink; so the heat loss by conduction from the core through the mantle and thence radiation to space causes Earth to shrink (imperceptible to our instruments). Our picture of volcanic activity is that internal pressures force magna toward the surface into domes, and when the pressure in a dome exceeds the tensile strength of the dome's overburden, an eruption releases that pressure. Thus it is the inexorable shrinkage of our globe that produces volcanoes.

At the present balance of Earth’s internal temperatures, the surface rides on huge subterranean tectonic plates that are moving slowly but inexorably, possisbly due to river-like currents in the melt. Continents are changing in relative position. Earth’s dry land was apparently joined together in its early days, then separated through motion of the tectonic plates and then rejoined before separating toward their present positions. Lines along which there is volcanic activity coincide with edges of adjacent plates where they are being pushed together or pulled apart by underlying forces. And new surface rocks and soil are being created by solids vented from volcanoes.

Earth’s surface features have been influenced as one plate forces another to rise (or sink), by volcanic activity, by weathering and erosion, by build-up layer by layer of sediments and their subsequent torture by forces from within Earth. The fossil record has, in fact, been found in these layers, and correlations of content of the layers has enabled construction of much of our knowledge of past flora and fauna as well as the epochs during which they populated Earth. These same correlations have also been used in dating newly uncovered strata so that dating strata and identifying fossil finds have reinforced each other.

Geology and the Fossil Record

Fossil finds have been unearthed in earth-moving operations involved in developments of highways, high-rise buildings and shopping centers, but these are relatively trivial motions of Earth’s surface. For the most part fossil finds occur in sedimentary rock that has been exposed in mountain ranges, or along rivers where erosion has worn down a face of the rock, or in erosion gorges with strata tilted due to earth movement or mountain building.

We can perhaps appreciate the value of sedimentary rocks in studying life -- plant and animal -- in pre-history. Sediments containing the newly-living are laid down under water, buried, compressed into rock, and in the fullness of time because of the forces of nature brought to the surface again. In studying the content of layer after layer a time sequence of organisms can be constructed. Through various techniques a time line has been established and comparisons with the results of study of other strata located elsewhere in the world has allowed the gradual elucidation of life forms -- and their time sequence -- long disappeared.

Before there was enough surface water to create erosion and sediments of erosion products -- well, we just have to look for other kinds of clues. Radioactive decay. Meteorites in those rare locations we feel have not been disturbed since the early crust formed. (Origin and dating and analyses of meteorites is a fascinating study in its own right, but we wish not to be distracted from our story of Earth’s development.) We must appreciate the very special conditions required for preservation of fossils and the length of time they must have been preserved despite the on-going saga of weather, glaciations, volcanism and earthquakes, continual overlaying by deposits from space. It is in the sediments we have found clues, and it is surprising that the fossil record has been developed as completely as it has.

We can only speculate on the interplay of chemical reactions, erosion and creation of sediments as that early crust formed and during the continued cooling of our glob of matter. But we can know of a certainty that it was initially hot and very slowly cooling.

To give some idea of the simplicity (or complexity) of the simplest organisms, consider that a molecule of salt (sodium chloride) measures some 0.3 millimicrons in diameter, while the smallest viruses susceptible to examination are some 20 millimicrons in diameter. They are rod-shaped and consist of nucleic acid surrounded by a protein sheath. Evidently such a small virus consists of hundreds of molecules (thousands of atoms arranged in specific patterns). In the microscopic world of today we know there are viruses that invade bacteria; there may be yet smaller units that invade viruses. Statistically, the odds against such a chance arrangement of molecules, in the simplest life-possessing units we know, are astronomical, so, in the search for the steps leading to the generation of life, we must look for a group of intermediate hunks of matter yet simpler than the smallest virus known.

We can accept with no uncertainty that there were intermediate stages between a very hot Earth, with its slurry of chemicals, to the simplest molecular combinations that bridged the gap from non-living and living.

Origin of Life on Earth

In our chemistry of today we see organic compounds as both necessary to life and the product of life. It is a circle; life is necessary to the generation of life. But early Earth was entirely inorganic; it was devoid of organic compounds.

There has to be a point at which life is recognized as having taken hold. In searching for the origination of life, we must declare how we perceive a definition of life. We take the defining characteristics of life to be metabolism (receiving nourishment and divesting wastes) and reproduction (producing more of like kind). The simplest form of reproduction as we view it today is division of an organism by splitting of its nucleus with each portion taking along a portion of the sheath and other structures. And we note that the nature of Nature seems to be for each organism to multiply either to the extent of available nourishment or until some other organism uses it for food in its own life processes.

I note that life has been discovered in what we had earlier felt were very unlikely places such as volcanic vents at extreme ocean depths -- extreme pressure and temperature -- which suggests that life will arise wherever there is energy and nourishment. Chemists suspect that ammonia, methane and water vapor in the early atmosphere (assuming Earth’s atmosphere was then similar to that of Jupiter today) may have combined, under the influence of ultraviolet radiation, or the energy of lightning, to form amino acids. Amino acids form chains to make protein, which is the structural stuff of life. Amino acids and other chemicals collected together in pools to make an organic soup from which the very complex molecules of life may have built up from simpler precursors. Or clays at hydrothermal springs on the sea floor may have catalyzed assembly of RNA molecules.

During the past few decades chemists have demonstrated the simplicity of generation of amino acids, and they have, under carefully controlled conditions, produced chains of acids to form simple proteins. And sufficiently long chains spontaneously form structures. What is the smallest, simplest combination of molecules capable of self-replication? My guess is that it will be a surprise if and when man finally divines a sequence of chemical combinations and reactions that can produce something capable of self-replication -- life. Weather and surface deformations before that time are irrelevant to the story of life. I am sure there was considerable elapsed time, possibly hundreds of millions of years, before this new life grew in complexity sufficient to leave traces that have been or can be recognized.

To make my presentation more compatible with conventional science, I have moved description of my speculations to the end of this web page.

Defining Life

Let's examine relative sizes using bacteria as a base line, noting that our most powerful microscopes are limited to modestly-sized molecules.

	-	hair	-	10 x cell or 100 x bacteria
		cell		10 x bacteria
bacteria		10-6 m (.001 mm or 106 nanometers)
		virus		1/10 of bacteria
		DNA		1/10 of virus or 1/100 of bacteria
		molecule		1/5 of DNA
		atom		1/10 of molecule or 10-10 m or 10 nanometers

Cells are the smallest structural units capable of functioning independently.
Viruses are not alive in the strict sense of the word but reproduce and have an intimate relationship with living organisms.
It is difficult to conceive even the simplest DNA or virus arising spontaneously from the primordial slurry of chemicals, so there must have been precursors that have escaped our attention or may have disappeared with the advent of DNA.

The simplest cells are enormously complex, including a surrounding membrane and whole collections of specialized structures within. The simpler cells do not have nuclei although multi-cellular organisms require cells with nuclei and other structures; all cells have in common DNA strands organized in chromosomes of various lengths, each chromosome housing its peculiar strand. DNA consists of sequences of only four protein molecules although a strand may be millions of molecules long; yet DNA contains the distinct blueprint for each species of the millions of plant and animal species inhabiting Earth. And the most complex organism, man, is initiated from a single cell.

What portions of those DNA strands comprise which gene that determines some structure and what induces various genes to turn on and off in the proper sequence are mysteries yet to be solved. (Some few genes have been identified, and even replaced with healthier genes.) But discovery of that double helix was only the beginning of unravelling the mysteries Nature solved eons ago.

Evolution

The earliest suspected evidence of life is algal -- plant life. Evidently a primitive chlorophyll formed and may have taken part in or been captured by the sheaths. And the simplest cells that have been identified are prokaryotic bacteria, which are housed within a membrane and include DNA but have little internal structure. I have no idea whatsoever what proteins may arise spontaneously in a petri dish laced with the correct chemicals, but I have no doubt some are known. Those hundreds of millions of years before the first life has been detected consist of how many bacterial life-times? Certainly enough for zillions of combinations to form. And it only required one event that could repeat itself for life to be on its way. My intuitive feeling is that it was inevitable that life should start, likely under water where the protective ozone shield was unnecessary.

Composition of Earth's atmosphere is both cause and consequence of events at or near the surface. Obviously, water vapor. And carbon dioxide for consumption by plants, and oxygen for consumption by animals. Atmospheric oxygen was a later development so we assume plant life (with single celled organisms arising first) preceded animals.

We can after a fashion place in sequence developments in life forms along the path to the appearance of mammals. The primacy of water is evident; in fact the oxygen we breathe is dissolved in the water in our lungs in order to penetrate the blood vessels to cleanse our blood. If early creatures required oxygen for their life cycle, then oxygen had to be available either as gas in the atmosphere or dissolved in the water from some ore -- and recall the slow increase in atmospheric oxygen.

For the theologically-minded, we must ask at what point the deity was sufficiently organized to begin bringing some influence to bear on developments. Considering the relative lateness of the origin of our Sun, it seems more reasonable to assume the origin of deity preceded the origin of the Sun. It is entirely possible that life did not originate on Earth but arrived here by way of interstellar visitors. Perhaps a meteorite was ejected by a supernova in some distant nebula and over the millennia journeyed to Earth. (Let us ignore both the temperature associated with the energy released by the supernova and the temperature reached in our atmosphere, which would have destroyed most vestiges of life). Be that as it may, that gives us no excuse to cease our search for knowledge of how that life may have come about. (I would guess that the deity was constrained to work within the physical characteristics of the materials at His disposal. As opposed to inventing characteristics as He went along.)

We shall shortly be concerned for fossils. Perhaps we should recognize that biologists have divided all known life forms into categories (kingdoms) -- with some remaining controversy about kingdoms and assigning simpler life forms to their appropriate kingdoms.
Metazoa (animals)
Plants (of the lowest group of plants, thallophyta, some are algae and some are fungi)
Fungi
Protistans (mostly single eukaryotic cells: amoeba, algae; includes seaweed)
Monera (single prokaryotic cells), which have more recently been sub-divided into archae (bacteria) and eubacteria
Although enormously complex, prokaryotic cells are the simpler; they possess DNA, although there is no nucleus to contain it, and there is little internal structure. Eukaryotic cells are larger and have a complex internal organization including a nucleus which houses the DNA in chromosomes, and specialized structures include organelles that are responsible for such processes as digestion, initiation of division, excretion, etc. Plants have chloroplasts which house the chlorophyll. Granted only that there must be provision for nourishment and waste, each cell contains all internal machinery necessary to survive as an individual life form.

(Initially biologists divided life into two kingdoms: plant and animal. That proved inadequate so it was proposed to divide life into five kingdoms -- above. Other biologists felt this also inadequate and proposed dividing life into eight kingdoms.) In any case the kingdoms of life forms are divided into phyla (or groupings) following anatomical characteristics of each life form. Botany is the study of plants, of which there are six major groups. Bacteriology is the study of bacteria. Zoology is the study of animals, of which there are recognized today some 25 major groups or phyla.

Evidently, our best hope for finding fossils lies with plants and animals; it is highly unlikely that smaller organisms will have left physical bodies or body parts that we will be able to detect. Both size and lack of solid structures hinder us although -- speaking of size -- there has been effort to study pollen found in fossilized animal spoor.

It would be interesting to correlate changing geographical characteristics of the globe (including tectonics), changing weather, rising and falling of the oceans as glaciers grow and retreat in eras of warmth and cold, the gradual increase in complexity of life forms influenced by these changes, and the actual life forms and fossils arising from these variables. I leave this for the professionals.

GEOLOGIC TIME

The Archean eon persisted for 1.5 billion years or until 2.5 bya. There is evidence of oceans and the first evidence that might be construed as life at 3.8 bya. The oldest suggestions of fossils was at 3.5 bya. The thickness of Earth's crust is estimated at 70 miles.

The Proterozoic eon persisted for nearly 2.0 billion years, or until 0.57 bya (570 mya). The oldest algal reefs are placed at 2.0 bya and the first green algae at 1.0 bya. Before about 2.3 bya, when oxygen in the atmosphere began to increase, there were only single-celled organisms; the first eukaryotes emerged about then. Mitochondria in the eukaryotes emerged between 2.3 and 1.8 bya, not long after the rise in oxygen concentration, and may have been the catalyst for increase in the number of cell types. The split between plants and animals has been estimated at 1.6 bya. Plastids, the plant component that enables them to produce oxygen by photosynthesis, originated about 1.5 bya. Eukaryotes with up to ten cell types emerged by 1.5 bya; with up to 50 cell types by 1.0 bya. (Plants and animals today have more than 100 cell types.) During the last 30 million years of the Proterozoic eon (the Vendian era) there arose the oldest soft-bodied animals (jellyfish, worms, anthropod-like forms). There had been massive glaciation around 950-900 mya, again around 750 mya, and the Proterozoic eon apprently ended with massive glaciation at 600 mya.

Taken together, the Hadean, Archean and Proterozoic are the Precambrian eon.

The Phanerozoic eon extends from the Cambrian onward to today and is subdivided into the Paleozoic era (to 225 mya -- million years ago), Mesozoic (to 65 mya) and Cenozoic; for convenience these are further subdivided into periods.

The 70 million years of the Cambrian period gave rise to every phylum of flora and fauna recognized today; the increase in number of distinct species has been called the ‘Cambrian Explosion.’

Let us interrupt the saga to insert here the divisions of geologic time and the developments that characterize the divisions.

The Paleozoic era is divided into periods:
Cambrian (from 570 million years ago -- mya -- to 500 mya) during which there were shallow seas and the first abundant record of marine life, especially trilobites and shellfish; evidence of all plant and animal phyla; while the seas were teeming with life, the land was a vast desert with at most a veneer of primitive vegetation (around water) and no animals.
Ordovician (500 to 425 mya): mountains elevated in New England with volcanoes along the Atlantic coast; much limestone deposited in shallow seas; great invertebrate animals; the first marine vertebrates (including jawless fish).
Silurian (425 to 405 mya): mountains formed in NW Europe, the first small land plants appeared (reproduction by spores), corals built reefs in northern seas, shelled cephalopods were abundant, and the first jawed fish appeared.
Devonian (405 to 345 mya): Age of fishes; New England mountains raised, land plants evolved rapidly, seed plants and large trees appeared; first sharks, insects, land animals and amphibians appeared.
Carboniferous period is divided into the
Mississippian (345 to 310 mya): land plants became diversified, sharks of relatively modern types appeared, land animals little known
Pennsylvanian (310 to 280 mya): mountains grew along the east coast of North America and in central Europe, coal swamp forests flourished, seed-bearing ferns abundant, cockroaches and first reptiles appeared
Permian (280 to 230 mya): folding of Appalachians and central European mountains, glaciers in the south and reefs in warm northern seas, trees of coal forests declined, ferns abundant, conifers present, first cycads and ammonites appeared, reptiles surpassed amphibians; trilobites extinct.
The Paleozoic era ended with a mass extinction that destroyed 96% of species of marine animals and 70% of species of land animals. (The Permian/Triassic extinction has been more accurately dated at 252.6 mya.)

The Mesozoic era is divided into periods:
Triassic (230 to 180 mya): lava flows in eastern North America, ferns and cycads dominant among plants, modern corals and some insects of modern types appeared, expansion of reptiles including earliest dinosaurs
Jurassic (180 to 135 mya): Sierra Nevada Mountains uplifted, primitive birds appeared
Cretaceous (135 to 65 mya): Rocky Mountains began to rise; most plants, invertebrate animals, fish and birds were of modern types; dinosaurs reached maximum development and became extinct, and mammals were small and very primitive. It has been suggested that, during portions of this period, CO₂ was 2%, O₂ 30% and atmospheric pressure 20% higher than today.
The Mesozoic era ended with extinction of the dinosaurs (and more than half the biological families). Presumably extinction resulted from a massive meteorite striking Earth; perhaps it was due to loss of the Van Allen belts as Earth's magnetic field reversed, leaving Earth exposed to the solar wind as the field passed through zero. That extinction allowed mammals to proliferate.

The Cenozoic era is divided into the Tertiary period (65 to 0.6 mya) and the Quarternary period (600 thousand years ago -- tya -- to recent times). Epochs in the Cenozoic era are:
Tertiary:
Paleocene (65 to 55 mya): primitive animals developed.
Eocene (55 to 35 mya): Rocky, Andes, Alps, Himalaya mountains raised, primitive horses appeared.
Oligocene (35 to 25 mya): many older types of mammals became extinct; mastodons, monkeys and apes appeared.
Miocene (25 to 10 mya): renewed uplift of Rockies and other mountains; great lava flows in western U.S., mammals began to acquire modern characteristics; dogs, modern horse, man-like apes appeared.
Pliocene (10 mya to 600 tya): earliest ape-like man appeared in Africa.
Quarternary:
Pleistocene (600 tya to 12 tya): glaciation, great mammals, modern man late in system.
Recent (12 tya to today): glaciers only in Antarctica and Greenland, many giant mammals became extinct, spread and development of modern human cultures. The discovery and development of agriculture, so that the quest for food did not monopolize our time, allowed leisure to pursue intellectual activities, which has led in turn to exploitation of natural resources for our convenience and pleasure, as well as extension of our physical and observational powers.
Today: It is important to note that geologic time has not ended, but today is part of the chain of development^{2 To view footnote, click here} Mankind (1) stands on the threshold of extending his mental powers through use of the computer and enhancing his innate capabilities through knowledge of the human genome and (2) possesses the capability of either extending his exploration to other worlds or destroying himself and all his intellect has produced.

We are accustomed to indicating time by elapsed time to the present, but let us turn it around to elapsed time since the formation of Earth. At 4.6 billion years for Earth’s age, it was 0.85 billion years before those deposits in Greenland (Isua), or 1.0 billion before sediments suggest actual cells, or 2.5 billion for algal reefs, or 3.2 billion before cells of more than a very simple design, or 3.5 billion for green algae. Some 4.0 billion years before evidence of multi-cellular creatures (soft-bodied animals). All calcareous fossils (those with shells or bones) were produced in the last 600 million years.

FOSSILS

If the primeval gases were swept away then the early atmosphere was likely rich in carbon dioxide, water vapor, hydrogen sulfide, hydrogen chloride, carbon monoxide and hydrogen although the free hydrogen as well as hydrogen resulting from breakdown of water may have escaped. Free oxygen was likely not a part.

The oldest sedimentary rocks are dated at some 3.8 bya -- Isua, Greenland -- and they include deposits that are arguably evidence of organic life because the ratio carbon12 to carbon13 is taken as evidence of photosynthesis. Sediments dated at 3.5-3.6 bya include actual cells -- structures that are today associated with blue-green algae, which are unquestionably plants. By 2.8 bya there were very fine filamentary structures, which are almost certainly of biological origin. There was still very little free oxygen in the atmosphere, but evidently enough to form sufficient shielding from ozone to protect the surface from harmful radiations from space. But until some 1.4 bya all evidence suggests very simple single-celled creatures; it was at 1.4 bya that single-celled organisms of a more complex design emerged. (Barely before the Cambrian explosion of diversity, the multi-cellular creatures found at Ediacara may reflect a failed experiment in multi-cellular design.) By .67 bya the oxygen level had reached perhaps 7%, and there is evidence of abundant but primitive life.

The Burgess find, dated at some 530 mya (million years ago) -- .53 bya -- is likely the most complete of that period as yet found. The Burgess shales reveal a tremendous proliferation of multi-cellular soft-bodied fauna including variations in body design that now have long been extinct. Undoubtedly single-celled creatures preceded them and the Burgess reveals the flowering of very diverse patterns for life. There were many basic designs for life in the Burgess Shales, but other designs disappeared later in the Cambrian period and DNA survived to become the model for all multi-cellular life today, the dominant means of passing on bodily designs. But note that these are all soft-bodied creatures; preservation of patterns that can be construed as fossils depended on rapid in-filling or overlay by sediments that would withstand the ravages of time.

There has recently been discovered (2003) in the UK a fossil dated at 425 mya (Silurian period) of a soft-bodied creature exhibiting a penis, which indicates that sexual reproduction had come into being that early.

It is perhaps surprising that the fossil record has been developed as completely as it has. Combinations of the conditions for preservation are rare although dozens of sites were found during this past century. Hundreds of sites of varying antiquity are known, scattered over Earth's crust. Perhaps as we understand more fully the kinds of events and conditions that preserve fossils we will explore more deeply into that crust.

Examination of what fossils have been discovered reveals nothing in the way of transitions from one reptile to another: There have been many distinctly different dinosaurs but there is nothing to show the steps by which one evolved from an earlier creature; perhaps in time enough treasures will be uncovered to fill in such chains.

There seems no finality in the state of our knowledge of our own past. New finds alter our understandings, such as evidence found in Colorado that plant life rebounded more quickly (1.4 million years rather than 10+ million) than previously thought after the mass extinctions that ended the Mesozoic era.

Postscript

Regarding SETI (the Search for ExtraTerrestrial Intelligence), there can be no doubt there are in our galaxy alone millions (perhaps billions) of stars with planets of a temperature range appropriate to host life forms. But, considering that the Sun and its planetary system must have included the remnants of a supernova (perhaps even a second generation supernova) in order for it to have the heavier elements necessary for life processes, the number of prospective hosts is only a fraction of those with an appropriate temperature range. In my view there are likely at least thousands of planets in our galaxy that could host life based on carbon and water. And we should admit there may be other chemical bases for life despite the necessary characteristics of their pervasive fluid to share with water two necessary properties: (1) be a near-universal solvent and (2) expand upon freezing (so there can be space for gases between liquid and solid in order for atmospheric ingredients to circulate above, and participate in the life processes in, that fluid).

Regarding our solar system as a gigantic heat engine, we estimate that our Sun should continue to provide reasonable warmth for billions of years, well beyond Earth's habitability. Earth's crust provides excellent insulation, but the heat from the core is radiating into space; lest there be an immense reservoir of radioactive material in the core -- which will eventually be spent -- our planet will continue to cool. But I think we can safely estimate that Earth will remain hospitable to human life for yet millions of years, possibly time enough to gain a complete understanding of our past and our surroundings -- if only we will exercise prudence in our husbandry of what our good fortune has provided.

Our civilization has not become aware of an earlier high civilization on Earth although earlier extinction events may have fatally disrupted its advance, or valleys between glaciers may have hosted developments that were destroyed by advancing or receding glaciers. Of course cultivation of high civilization may once again be interrupted by natural events (such as ended the dinosaur era) such as the volcano Toba or the culmination of conditions developing under Yellowstone. Perhaps, being forewarned, mankind will be enabled to foster the will and science to forestall such "extinction level events."

But it is now appropriate to enjoy a display of the creatures that have been found or inferred from the remains available to us.

It is well beyond my intent, nor indeed my educational preparation, to undertake correlations with the changing geological characteristics of Earth, changing weather, rise and fall of the oceans in eras of warmth and cold, and the gradual increase in complexity of life forms influenced by these changes. That is the domain of the professional who has committed his life to exploring, studying and correlating these complexities.

This was written with the expectation it would be the introductory chapter of a book of photographs and artistic renditions of fossils and ancient creatures. However, in view of my age and other present interests, I doubt my life span will allow the extended travels necessary to accumulation of photographs and their presentation; hence, this work ends here. I am still hopeful of finding a text that correlates datings of geologic strata and fossil finds, especially from the Jurassic period to modern times.

It seems true that, the more we learn, the more we realize how great our ignorance. There will forever be mysteries enough to attract those of exploratory bent. It is an adventure of mind that continues to unfold.

For Contents of Ken Wear's web site, click here.
If you are of a theological bent, you may understand and appreciate this essay [click here] dealing with evolution, Evolutionism, Creationism and Intelligent Design.
For comment on the effects of modern medical practices on evolution, click here.
Or a lecture on the beginning of stars and end of intelligence appears if you click here.
Since religions form the backdrop against which knowledge is interpreted, the religious events I have experienced are outlined in my Religious Odyssey and the resultant description of Reality is presented as Rational Theism.
I can be reached by e-mail by clicking here.

May 22, 2009 47-million year old fossil said to be in the human line of evolution. This hurts! Found, apparently in 1983 in a shale pit in Germany by private collectors, the find was split and sold on separate "plates." The lesser plate was bought by a private museum in this country (in Wyoming) and was "restored" to make it look more complete. The more complete plate recently came to light in a museum in Oslo. I am distressed that personal greed resulted in a "restored" fossil (Ida) that is now judged to be in the human evolutionary chain, partly, I suppose, based on the "restorer's" efforts in keeping with their notions of the salability of their interpretation of the fossil. Lost to us is confidence in the message the fossil yields.

Description of an alternate beginning

Then and now, here and there in the seething caldron of nothingness there is an event resulting in emanation of particles and/or energy. For the most part these particles recombine instantaneously to leave an undisturbed nothingness as before. But occasionally two or more events occur close enough together in time and space that they influence each other in some way and therefore cannot mutually annihilate all products of the events. There is a residue of matter and/or energy. It should be expected that, with time and despite an exponential decay in generation as space fills, particles and energies accumulate and interact to produce matter -- protons, electrons, leptons and other combinations, some of which may have escaped our observation.

From nothing, over incalculable stretches of time, there arose a collection of particles and energies producing enough matter that gravity asserted itself and brought together large and larger masses. It was a very uneven or non-homogeneous sea of particles. And, being non-homogeneous, there were various centers of gravitational attraction, some in time accumulating enough mass to compress and ignite the fusion process. Perhaps many such accumulations combining for a Bang or two here and there. Perhaps a Modest Bang. Perhaps expanding until gravity dictated otherwise, arrested expansion and drew the matter back together for a Bigger Bang. Perhaps Bangs of various sizes at various regions in that unimaginable expanse of what used to be nothingness. (The virtual aspects may have combined to become organized as legions of beings possessed of intelligence.)

So that is my picture of how it all began -- an inevitable outgrowth of the initial nothingness. A more elaborate presentation, Was the Big Bang the Ultimate Beginning, appears if you click here. (If you wish, assume a deity arose from the same nothingness, perhaps through other combinations of non-matter or virtual aspects of that seething caldron.) Considering the uneven distribution of matter that led to galaxies and such, this model seems more consistent with observation than one central event and an ensuing 'inflation.'

Doubtless theoretical minds can work both sides of this fence and generate theories in support or in contradiction. I am more content with the gradual creation and evolution of the Universe over trackless time than I am with the sudden explosion, with no preceding preparation, and of such magnitude as to generate in one swoop (in 10^-40 or less seconds) all that we have been able to see with our telescopes.

Speculations on the origin of life

Proteins, those strings of amino acids, are generated by living things and living things consist of proteins; life generates life. Simple proteins have been generated in the laboratory under violent conditions thought to resemble those of early Earth. By extension other proteins arose spontaneously and circulated in the ooze. The simplest known cells are enormously complex collections of proteins and other chemicals and it is difficult to visualize the processes by which they may have been formed. But their constituent amino acids and resultant proteins were evidently assembled as constituents of that chemical ooze and would readily adhere to a host rod substrate. (It seems pointless for me, untrained in organic chemistry, to attempt to be detailed in such a gross speculation as this: indeed what proteins were generated, how did they interact and how were they deposited? The underpinning of my speculation is the rod as host to various deposits.)

The restless and energetic nature of the surface, with the constant churning of waters with their varying chemical solutes and likely chemical reactions, crystal growths and chance interfaces, provides a reasonable backdrop and mechanism for production of myriad trial formulations of chemicals and crystals. The vastness of the seas (or ooze), the possible chemical exchanges and the extended time allow endless events to produce multiple precursors of something akin to life. And many of those precursors must have been strange indeed compared with what modern biologists observe. The double helix seems to be the key to reproduction and, analogous to the division of DNA into chromosomes, there likely were at first modest lengths of DNA or it precursors. It seems reasonable to suppose chains of development in various directions: precursors to precursors. But, once the double helix arose, it seems the development of life was unstoppable.

²Footnote 2:
Contemporary geological changes: In view of contemporary controversies about the direction of climate change, it is well to re-examine what we know of the changes toward the end of the named geologic periods and during recent times. Our science is presently searching for understanding of what controls Earth's average temperature and how our civilization influences that direction. Let us consider a few salient facts:

The temperature in which we exist -- our comfort zone -- results from a balance between energy received from beyond Earth, mostly from our Sun, (plus energy released by man's activities) and energy radiated from Earth to regions beyond. In our daily existence we experience the variations created by night and day, by the seasons, and by weather events. Over the centuries and millennia there have been trends that produce a setting in which these temporal variations occur.

White reflects; the snow and ice of glaciations prevent absorption at the ground of energy from the Sun. Green absorbs that energy. Yet, during the last million years glaciations have advanced and retreated repeatedly; with that glacial coating sufficient energy was absorbed to melt it; and in the absence of snow and ice temperature dropped enough for ice to form. Earth's core continues to lose heat by conduction to the surface and apparently makes a major contribution to surface temperature. We presently seem to be in the warm valley between glacial epochs; and the rise of civilization, from wanderers seeking food where Nature provided it to today's agriculture and science, falls entirely within such a window following glacial retreat. It is evident there are forces at play that have been only partially accounted for by our science.

What effect our efforts? "Greenhouse gases" are a topic of concern. Escaping attention is the heat energy released in producing those greenhouse gases, as well as energy rejected as useless in the generation of electricity, denudation of forests that once absorbed carbon dioxide, and building dams that result in methane production in the anaerobic decay of the stumps. I do not have numbers to compare energy received from the Sun with energy released by man's activities but suppose man's efforts are relatively puny.

Within recorded history there have been warm periods and cold periods without adequate explanation. Massive volcanic activity may flood the atmosphere with dust that keeps the Sun's energy from reaching the ground; nuclear warfare would undoubtedly result in massive energy release as well as atmospheric disturbance and consequent cooling at the surface.

For a more complete discussion of global warming, click here.

Your BACK buttorn will return you to the text.

2-26-10 Recent geological research following adoption of the idea of tectonic plates (1970s) suggests that Earth consists of a central core of solidified iron surrounded by molten iron (perhaps including a mix of other elements to form molten rock), which is then surrounded by solidified rock on which rests our continents. Pressure and temperature increase with depth from the surface and reach levels where rock is molten and flows like a highly viscous fluid. Doubtless it is the motion underneath that causes those tectonic plates to move relative to each other, resulting (over vast stretches of time) in volcanoes, earthquakes and mountains. The Atlantic Ocean is widening by an inch or so each year while the Pacific Ocean is becoming narrower by a few inches a year. Volcanoes erupt and earthquakes occur largely where tectonic plates scrub together, some rising and some subducting at their boundary. Research is continuing to elucidate specifics.

My printer takes 18 pages or 9 sheets of paper to print this document.