CosMos
the world or universe regarded as an orderly, harmonious system
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Course notes, BE170A2, Formation of a Planetary Biosystem, University of Arizona.
The Universe probably began with quantum fluctuations, followed by a period of inflation during the first trillion trillion trillionth of a second. The Universe then expanded uniformly for 14 billion years due to a delicate balance of three expanding forces with the inward force of gravity. Although telescopes and mathematics can look backward in time and track the 14 billion years of the universe, scientific instruments cannot peer into the unknown time before the beginning of the universe and thus, unfortunately, science cannot explain how or why the universe began. Similarly, scientists have derived the progression of matter and energy since the first photons and elementary particles in the first trillionth of a second, but they have not determined how matter and energy originated in the first place. As with the universe, science has revealed the natural history of the solar system, earth, life, animals, and humanity, but there are still some unanswered questions.
This course begins with the development of space and matter (Chapters 1 and 2) during the first 9 billion years of the universe. Then, in a relatively brief segment of time, the sun, protoplanetary disk, and planets originated in a giant dark cloud in the Milky Way Galaxy (Chapters 3-5). Photosynthetic life and plants evolved in the 3.4 billion years of the Precambrian (Chapter 6). There was a dramatic change in climate (Chapter 7) at the end of the Precambrian, which enabled animal life in the Cambrian. Sea anemones evolved in the Avalon Explosion in the sea, and insects, mollusks, and other arthropod invertebrates evolved from them (Chapter 8). Vertebrate fish with their advanced vertebrate characteristics suddenly appeared in the Cambrian (Chapter 9), and then reptiles and birds evolved (Chapter 10) from them in the Paleozoic and Mesozoic eras. Primitive mammals evolved advanced intelligence and senses in the hostile world of the dinosaurs (Chapter 11). An asteroid and giant magma event wiped out the dinosaurs, and then modern mammals evolved and diversified in the Cenozoic Era (Chapter 12). Humans evolved from the primates in the last four million years (Chapter 13). The end of this evolutionary process may have been the point at which God transformed intelligent homo sapiens into spiritual and eternal humans. The next two steps in human history dramatically changed our planetary biosystem. When human population grew, and food requirements exceeded natural food sources, people in various parts of the world turned to agriculture and began the Neolithic Revolution (Chapter 14). Finally, great civilizations formed in the river valleys of the world (Chapter 15) and eventually converted almost all of the arable land in the world to production of food and other resources for humans.
The last section (CosMoses, not required) includes four PDFs. The first two provide the perspective of 19th century member of the National Academy of Sciences Arnold Guyot, who related natural history with Moses' descriptions of the origin of the universe to a habitable planet and the origin of animals to humans. The third PDF compares Neolithic archaeology and geology with Moses' description of Adam and Eve to Noah's Flood. The fourth PDF compares Moses' description of the Middle East with Bronze Age archaeology.
Table of Contents
Chapter links and summaries
Chapters 1 to 3 Summary.mp4Summary of chapters 1-3
Nicolaus Copernicus and Georges Lemaitre made the two greatest cosmological discoveries in history. They combined obscure observational data with complex mathematics, which few of their contemporaries could follow, to radically change our conception of the universe. In the Copernican model, the earth was no longer the center of the universe, but it was one small planet in an enormous universe. In Lemaitre's Big Bang model, the universe began as a quantum fluctuation and then expanded. Modern scientists added a brief period at the beginning when the universe expanded faster than the speed of light during a trillion trillion trillionth of a second.
People have always wondered about the nature of matter and energy. After a long debate over two millennia, the scientific revolution revealed the atomic structure of matter. In the early 19th century, scientists discovered the properties of the atom. In the late 19th century, scientists combined theoretical physics with experiments in supercolliders and developed the Standard Model of Particle Physics. Scientists also discovered that most of the matter and energy in the universe is dark matter and dark energy. The next frontier in particle physics is string theory or other small particles that are the foundation of matter.
One of the most amazing things about the universe is that chaotic dark molecular clouds collapse and form highly organized stars, planets, and life. Giant blue stars formed in the early universe and became the black holes at the cores of galaxies. Spiral galaxies like the Milky Way continually form stellar nurseries and clusters of new stars within them. Scientists classify stars with the Hertzsprung-Russell diagram, which classifies stars based on their mass and color. Based on its position in the Hertzsprung-Russell diagram, scientists know that in 5 billion years the sun will become a red giant and then a white dwarf.
Chapter 4 to 6 Summary.mp4Summary of chapters 4-6
Protoplanetary disks form around young stars, and planets form within them. Likewise, the circumsolar disk formed around the sun and the planets in the solar system formed within it. The solid particles (ices and dust) gather at the midplane of the disk and then gather together and form planetesimals and then planets. The ALMA telescope array in South America is one of the most amazing technological achievements in history. With it, astronomers can view protoplanetary disks. They can even view the chemicals within the disks. As scientists learn about other disks, they are trying to piece together our disk's history.
Planetesimals form through one of three processes: accretion, disk fragmentation, or streaming instability. The most likely scenario in the inner solar system was streaming instability. In 2009, Hanson determined that a gap in the circumsolar disk explain the architecture of the inner solar system planets. There have been many attempts to explain the cause of this gap and the differences between inner and outer planets. A recent study in Science indicates that planetesimals in the inner solar system formed early when the inner disk was still wet, and radioactive aluminum 26 dried out the planetesimals that formed Earth.
Science is often like a family jigsaw puzzle saga. Nobody makes any progress for a long time, and then somebody organizes some pieces and fills in a section of the puzzle. After some time, someone else fills in another part of the puzzle, and so on, and on, and on. This was never more true than in origin of life research. In the 1950s, Miller and Urey, found the first piece when they formed amino acids from chemicals. In the 1960s, scientists realized that RNA could function as a protein or information system, thus the RNA world hypothesis. In 2009, Sutherland discovered cyanosulfidic chemistry, which forms all of life's compounds.
Chapters 7 to 9 Summary.mp4Summary of chapters 7-9
For 1.5 billion years, algae photosynthesis added oxygen to the atmosphere and ocean. At the end of the Archaean Eon (2.5 Ga), the atmosphere became oxidized, which removed the orange haze that covered the earth.. The oxidized atmosphere at the beginning of Proterozoic Eon caused equatorial glaciations. There is a great controversy about the cause of these glaciations during the Proterozoic Eon (2.5 Ga to 542 Ma). One hypothesis is a different tilt of Earth's axis. The other is snowball Earth. During the last 575 million years, Earth has had a stable and habitable climate for plants and animals but with periodic extinctions.
Although there were some supposed animals prior to 575 Ma, most paleontologists now think that animal life began with the Avalon Explosion, which began 575 Ma and led to the evolution of sea anemones by 560 Ma. Analysis of DNA and the fossil record indicates that major animal phyla evolved from sea anemones by the beginning of the Cambrian (541 Ma). At this point, invertebrate animals increased in complexity and phyla such as mollusks, arthropod crustaceans, and annelid worms gradually appeared in the Cambrian seas. Insect evolved from crustaceans (arthropods) and entered the land during the Devonian.
The vertebrates include fish (Chapter 9), reptiles and birds (Chapter 10), mammals (Chapters 11-12), and humans (Chapter 13). They have advanced sensory systems, internal bone structure, large brain, complex nervous systems, and organs that allowed them to grow large and live on land.. All vertebrates descended from early vertebrate jawless fish that were discovered in the Chengjiang Lagerstatten (517 Ma). This chapter considers the origin of the early vertebrates as well as the evolution of jawed fish and bony fish from the Cambrian to Devonian periods. The origin of the vertebrates remains a complete mystery.
Chapter 10 VoiceThread.mp4The Age of Reptiles began with the evolution of amphibians in the Carboniferous Period and extended until the the End Cretaceous Extinction. Mammal ancestors (synapsids) ruled the Permian; however the Great Permian extinction wiped out the large, carnivorous synapsids. Beginning with the Triassic, archosaurs ruled the earth during the Mesozoic Era (Triassic, Jurassic, and Cretaceous periods). Scientists classify archosaurs into two groups: archosaurs closer to crocodiles, and archosaurs closer to birds. The reason is that birds and crocodiles are the only archosaurs that survived the End Cretaceous extinction.
During the Permian Period, mammal ancestors (synapsids) began to evolve temperature regulatory systems, a higher efficiency respiratory system, mammalian teeth, and a vertical gait; however, it was difficult for these animals to survive in the low oxygen environment of the early Triassic after the Great Permian extinction. A few tiny mammals survived and evolved superior sensory systems and intelligence in the world of archosaurs. The eutherian mammals split off from other mammals approximately 180 Ma. They survived the End Cretaceous extinction, somehow became placental, and became the modern mammals.
The Cenozoic Era of the Phanerozoic Eon began 66 Ma with the End Cretaceous extinction and the elimination of the dinosaurs. It is called the Age of Mammals because mammals dominated the Cenozoic, but it was also the age of birds, insects, sharks, bony fish, turtles, snakes, lizards, and mammals. Modern mammal groups evolved to occupy the ecological niches left behind by the dinosaurs. This chapter first reviews the climate, geology, and paleontology of the Cenozoic. It then focuses on the evolution of four of the more interesting groups of modern mammals: marsupials, horses, whales, and primates.
Hominids split from apes approximately 7 Ma when they began to walk on two legs. Bipedalism triggered hand-eye coordination and intelligence. The brain started to grow 2.5 Ma when humans began to make tools. Brain size steadily increased until the appearance of Neanderthals and Homo sapiens. There was a "dynamic period of innovation" between 100,000 and 70,000 years ago in southern Africa. this may have been the point at which God transformed intelligent homo sapiens into spiritual and eternal humans. This was also the point in time when humans left Africa and crossed into Europe, Asia, the Americas, and Australia.
As populations grew and climates changed, wild animal and wild vegetation food sources became limited. In order to supplement their diet, Mesolithic hunter-gatherer groups gradually shifted from following herds and gathering wild vegetation to raising crops and domesticating animals. This shift to an agricultural lifestyle started between 12,000 and 7,000 years ago in most parts of the world and is called the Neolithic (New Stone Age) Revolution. Neolithic communities were typically innovative, peaceful, and egalitarian, and there is little evidence of the use of weapons of war or other negative features of civilization.
Approximately 5,000 years ago, small agricultural communities in the large river valleys of the world began the transition to cities and civilizations. Civilization has had many benefits, but civilizations on all continents typically had a central ruling bureaucracy, class system, hoarding of wealth, abuse of the poor, frequent wars, lack of freedom, and pollution. Acknowledging these common characteristics, this chapter generally focuses on the positive accomplishments of civilizations, such as writing, science, mathematics, engineering, monetary systems, food production, transportation, art, religion, and education.
This section compares the writings of Moses with scientific and archaeological data. Moses dealt with questions such as the origin of the universe, origin of animals, and origin of humans. Did God intervene in these origins or was it evolution? Moses didn't have a consistent answer. Were Adam and Eve the first humans? Not necessarily. Why do Jews and Canaanites have 50% Chalcolithic Zagros DNA from Iran? Well, either Noah or his sons seem to have married women from this area. Did fire and brimstone rain down on Sodom and Gomorrah? Earthquakes in the region release hydrogen-sulfide, which smells like matches.
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Nicolas Copernicus. Credit: Jan Matejko. Public domain. Definition of cosmos from Dictionary.com
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