Billions of Years -- a scientific theory

Time is the motion of particles relative to each other. From a scientific perspective, without motion and without matter there is no time. If the material universe had a beginning, time as we know it began when the universe began. But science can postulate no such beginning.

None of us, including scientists, grasps reality in its entirety. With incomplete knowledge, physicists grasp the universe as energy (E), equal to mass (M) times the speed of light (C) squared (Emc2). Any mass, including rock, has energy, detectable when its atoms are split. And, astronomers gather that the universe is expanding, that galaxies have been moving away from a dense central configuration for the past 15 billion years since the "big bang."

Scientists have mapped celestial bodies. Nearest to our galaxy -- the Milky Way -- is the Canis Major Dwarf Galaxy, 25,000 light-years from our solar system, a distance that would take 250,000 years to cover traveling at one-tenth the speed of light: 67,064,760 miles per hour). The farthest object from us that we know of is a distance of about 10 billion light years. In other words, the light from this object that we see today left there 10 billion years ago.

Getting more local, geologists claim that the sun and earth are around 4.55 billion years old, and they describe the sun as moving around our galaxy at roughly 500,000 miles per hour. One revolution around the galaxy is said to take 200 million years. Dividing 4,550 by 200 makes 23 revolutions around our galaxy since the sun and earth formed. This means that since the end of the last major ice age -- some ten thousand years ago, the Earth has moved only one twenty-thousandth of a revolution through our galaxy.

Geologists describe the earth as having come together gravitationally. Hot and fluid energy was condensing into what we now see as the solids around us. The denser matter (iron and nickel) settled at the center. The less dense matter, in the form of rocks, rose to the surface. And, as the earth gave off heat, its outer layers cooled, leaving Earth's interior hot and molten. Gasses bubbled to the surface, eventually to become atmosphere. When the temperature was right, gasses in the atmosphere produced clouds that contained moisture -- hydrogen and oxygen. It began to rain, and water began to cover much of the earth's surface.

Biologists claim that earliest forms of life consisted of carbon, water, nitrogen, oxygen, phosphor (sic), sulfur and other materials. Although they were not discovered until the 19th century.

Among the chemicals on the Earth's surface were two nucleic acids: DNA (deoxyribonucleic acid) and RNA (ribonucleic acid). These acids could divide and replicate themselves.

About 3,800 million years ago there were on earth simple cells that lacked a nucleus: bacteria.

About 3,000 million years ago photosynthesis developed. Photosynthesis occurred when sunlight acted upon a certain kind of bacteria and unicellular algae.

Photosynthesis is the source of carbon within organic compounds, and it gave off oxygen into the atmosphere. About 2,400 million years ago, photosynthesis began to oxygenate the earth's atmosphere.

About 2,000 million years ago organisms developed that were cells with complex structures enclosed within membranes -- eukaryotes cells.

Proteins within a cell, in a region called dehydrons, became unstable in a watery environment. With this instability, "sticky" proteins were more likely to work together in building more complex networks of gene and protein interractions. Around 1,000 million years ago multicellular life began.

Nearly all life was dependent on photosynthesis, which converted energy from the sun into food for an organism.

Vegetable life in the form of algae transferred out of water and became more complex plant life -- and plant life eventually became nutrition for creatures that crawled out of the ocean.

Around 600 million years ago organisms called simple animals appeared -- organisms that acquired energy by devouring other organisms.

Some people see design in these developments -- a creation by a centralized intelligence. Some others see chaos. A tree exists where conditions permit. It has a chaos of branches that reach out unevenly with leaves exposed to what the tree needs. A chaos of creeks meander from various directions to a lower elevation and forms a georgeous lake surrounded by a chaos of vegetation.

The genetic mutations of organisms has also been viewed as chaos rather than as planned. Biologists today see genetic mutations in micro-organisms. Knowledge of this has progressed to the point where biologists can now alter or add a characteristic to an animal's DNA, fluorescence for example, that will be passed to their offspring.

Creatures with jointed bone structures, called arthropods, are estimated to have come into existence around 570 million years ago. And around 500 million years ago fish appeared, followed 25 million years later by land plants.

Scientists calculate that around 400 million years ago, sea temperatures fell to levels near today's temperatures, creating a more hospitable environment for species to flourish. In what is today Poland, the footprints of four-legged creatures -- surmised to have been crocodile-like -- have been found preserved in carbonate rock, the footprints are estimated to be 397 million years old. Another estimation is that 300 million years ago, spiders appeared that had the ability to make silk but not to make webs. No matter: there were not yet flying insects to catch.

Around 360 million years ago came amphibians. Sixty million years later reptiles appeared, and 100 millions years after that came the first mammals.

Plant life was able to survive without a brain, but creatures that needed to make an effort to get nutrition and to protect themselves would not have survived without a brain to give them the ability to decide when and where to move.

Around 230 to 220 million years ago dinosaurs first appeared. Paleontologists estimate that the age of the dinosaurs (the Jurassic Period) began 20 million years later. Approximately 80 million years later mammals first appeared -- in the form of small nocturnal creatures that fed on insects and nursed their young. Paleontologists estimate that dinosaurs became extinct 65 million years ago, while birds and other smaller creatures better able to survive flourished. Scientists calculate that 38 million years ago primates appeared -- creatures resembling monkeys and apes.

Biologists speak of variation between species and within species -- a specie being creatures that can interbreed. Within a specie, imprecise replications occur from parent to offspring -- unlike cloning, which creates identical genetic duplicates. Across a great span of time, some variations survived and other variations did not.

The fossilized bones of an ape that lived around 10 million years ago was discovered in a volcanic mud deposit in what is today northern Kenya. It is considered among those primates that preceded gorillas, chimps and humans. To quote the science reporter for the BBC, Helen Briggs, "Genetic studies suggest that the ancestors of humans and chimpanzees went along their separate pathways of evolution about five million to seven million years ago."

According to findings at an archaeological dig in what today is southeastern Spain, 1.8 million years ago the following creatures lived side by side: giant hyenas, saber-toothed cats, zebras, giraffes, gazelles, wolves, wild boar and lynx (BBC, October 30, 2007).

DNA analysis suggests that the common ancestor of modern humans (Homo sapiens) and Neanderthals lived between 800,000 and 520,000 years ago and that around 700,000 years ago human-kind and Neanderthal-kind began diverging. Humans (homo sapiens) are said to have lived about 60 thousand years ago in Africa.

Biologically, humans are a work in survival. The species of animal that we call human developed across thousands of years. They many characteristics of other animals, including those that lived in trees, but their ancestor-species had become too big to live comfortably there. Their legs had become longer and their pelvis reshaped, both of which helped them walk and run upright, which was more energy efficient and helped them run across ground after game. Their skin was exposed, keeping them cooler with sweat and evaporation and allowing them to run farther without suffering heat stroke as did their prey. Unlike chimpanzees, they had broad shoulders that allowed them to throw stones and spears with deadly force. They benefited from a growth in brain size, needed in adapting to the ups and downs of climate change across the thousands of years.

Humans have a body chemistry that made fighting and empathy possible, the latter allowing them to live in a group, which added to their ability to survive. They were able to survive because they were few in number. Hunting and gathering required access to great stretches of land that was not occupied by other humans. Enough game was left to them by other predators. They could gather food that grew wild, and they had access to drinkable water.

As with other creatures that move around to get nourishment, they had the ability to make choices. Unlike chimpanzees, their genes structured their brain in a way that allowed complex verbalization. They made generalizations, and this made imagination possible. They had the ability to reflect on their activities and actions. They invented tools. They accurately apprended their surroundings, and they made mistakes. They imagined a humanlike will in everything that moved. They invented or imagined beings beyond their ability to comprehend.

Humans imagined beings that were a contrast to themselves -- a contrast that sharpened the image of humanity's condition. These were angels, unchallenged by nature and divorced from the biological development of animals. Angels did not need to struggle as did humans. Humans struggled for nourishment with an imperfect ability to digest what was available as food. This imperfection in digestion made excretion necessary for all earthbound creatures including humans, and along with procreation activities these activities were thought of as not angelic, helping to set the angels apart from humans.

Micro-organisms were also challenged by nature. Like humans they need moisture to survive. Viruses cannot survive long without a host. Unlike the angels imagined by humans, the human body is in an unending struggle with microscopic organisms, armed with an immune system in that unending war.

And humans need to have been born with the right body chemistry for their minds to contend with life. If they don't have it, they are dependent on others who do. It is easier in today's affluence to care for these "special needs" individuals. It was not so easy before humanity began leading a settled and affluent existence.

But given the brain they inherited, humans have been better able than other species to manipulate their surroundings. Unlike other creatures they have altered landscapes and the atmosphere.