Cosmo%20Book%20Report.pdf

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Why Aren’t Black Holes Black? Authors: Robert Hazen and Maxine Singer Anchor Publishing 320 Pages Kathleen Kelly Abstract: Hazen and Singer explore the worlds of physics, earth sciences, chemistry, and biochemistry to examine the questions for which science has not answered and the current methods being used to pursue new knowledge. While discussing major breakthroughs and current knowledge, the authors also emphasize the many things scientists have not discovered and the limitations of modern technology. This book relates to the course through the discussion of certain cosmological concepts and with the shared idea that science is an ever-evolving field.

The main author, Robert M. Hazen is Senior Staff Scientist at the Carnegie Institution’s Geophysical Lab and Clarence Robinson Professor of Earth Sciences at George Mason University. He received his B.S. and S.M. in Geology at the Massachusetts Institute of Technology, his PhD in Earth Sciences at Harvard, and was NATO Postdoctoral fellow at Cambridge University. His recent research examines the roles of minerals in life’s origins. Hazen is a qualified professional with more than four decades of mineralogical research. The author writes about a large variety of scientific topics to demonstrate that scientific questions vary in scope and content and to demonstrate the limitations of modern science and technology. This book is interesting because, in his discussion of biology and chemistry, he reinforces how and why physics and cosmology impact other fields. Evidently, this book relates to Physics 10240 because chapters about the universe and cosmology are related to topics discussed in class. This book helped me work towards my goal of broadening my understanding of sciences–which is the same goal I had in mind when I enrolled in this course. Chapter 1 explores dark matter. Scientists know that dark matter exists because the visible mass of the galaxy–multiplying the number of visible stars by the average mass per star–is not the same as the dynamical mass of the galaxy–observing how stars move based on gravitational forces and measuring the position and orbital speed of stars and/or clouds of gas as they orbit the galactic center. Further, the outer parts of spiral galaxies moved 2-3 times faster than they should based on the gravity from visible sources. Scientists do not know for sure what dark matter is made out of. Some of the most likely explanations are massive compact halo objects (MACHOs), snowballs of hydrogen ice, black holes, hot dark matter, cold dark matter. However, MACHOs only represent about 20% of suspected dark matter in our galaxy. Additionally, hot dark matter and cold dark matter are hard to examine because they can’t have an electric charge, can’t interact with light or other forms of electromagnetic radiation, must be very small, and have significant mass. The next chapter examines the history of the universe–as seen through the light emitted from distant galaxies many billions of years before the Earth was born–in hopes of guessing its ultimate fate. We believe the universe to be expanding based on the redshifts of galaxies. Proof of the Big Bang theory and a static universe lies in the constant cosmic microwave background radiation, and the changing contents of the universe. We can determine the age of the universe by examining the spectra and chemical makeup of distant stars and by looking at radioactive isotopes and their decay rates. We do not know for sure how the universe will end, but there are three possible situations: an open universe that expands forever, the closed universe that falls back in on itself, and the flat universe in which the expansion rate slows to almost zero. The study of the universe as it was, is, and shall be is a question involving philosophy and belief. Chapters 1 and 2 are closely related to our class content, but expanded my cosmological knowledge about a variety of new topics. The third chapter describes the search for a “theory of everything”, a single set of equations that describes the properties and behavior of all kinds of matter and forces. We must understand the arrangement of matter’s fundamental particles and how nature's four

forces–gravity, electromagnetic force, and the strong and weak nuclear forces–act between particles. The standard model is not a complete theory because it only describes three of the four forces, fails to explain dark matter, and does not incorporate gravity. Chapter 4 describes our incomplete knowledge of atoms. Chemists cannot anticipate even a small portion of all the possible arrangements of atoms and their properties. Scientists must look at many different ratios of elements at different temperatures, cooking times, cooling rates, and pressures. As they learn more, some trends emerge that allow scientists to accurately predict some results. Future research about atoms might take place through virtual simulations, predicts the author. This chapter also describes how atoms bond and how electrons impact this process. The next chapter describes types of energy–potential, kinetic, and heat–and the first two laws of thermodynamics. Due to our energy usage, humans are running into the concerns of atmospheric pollution. This chapter briefly considers other forms of energy: nuclear, wind, water, and sunlight. However, there are still concerns regarding the technological development, costs, and implementation of such sources of energy. According to chapter 6, we lack knowledge of the Earth’s center because no known materials can withstand the intensity of the Earth’s deep interior. Understanding Earth’s interior provides information on its surface. Thus, scientists attempt to make geophysical models of the Earth. We can determine the Earth’s mass using the orbital velocities of the moon and satellites, and we can measure the total internal heat supply with special thermometers. The next chapter examines the limits to the number of human beings the planet can support. Natural habitats are being destroyed, species are going extinct, and human activities cause air, water, and soil pollution. To monitor the current state of the world, we rely on the Earth Observing System, a system of satellites. It is hard to study small ecosystems due to the lack of control we have over the natural world and because it is difficult to determine causal relationships in nature. Chapter 8 delves into the unanswered question of how life originated on Earth. The biological community cannot agree on a single definition of life, about whether or not life was inevitable, or if it can be duplicated. Most biologists do agree that a self-replicating cell arose on Earth about 4 billion years ago and life has been evolving from that cell ever since. In this field, scientists analyze the most primitive cells that currently exist on Earth, but this is limited because atmospheric conditions have changed. Then, Chapter 9 describes the incredible processes that our DNA manages with coded instructions for a different kind of protein–including metabolism, cellular defense, communication, and reproduction. Genetics is very important to the study of evolution–genes are the pathway for heredity and mutations are the mechanism behind evolutionary change. Next, Hazen describes the historic theories on evolution and the mechanisms of evolution are random variation and natural selection. This chapter also explores whether or not another lethal asteroid will hit the earth. Based on the observations of previous asteroids, scientists agree that another giant asteroid will hit the Earth, the only question is when.

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Chapter 11 looks at developmental biology. Additionally, Hazen discusses the study of long-lived organisms that teach us about aging and the purpose of telomeres at the end of chromosomes. Cancer and germ cells have an enzyme that allows them to rebuild the telomeres, which gives them much longer lives. In the next chapter Hazen describes neurons, dendrites, axons, and synapses. Researchers are limited in the experiments they can complete for technical and ethical reasons. Psychologists look between the physical brain and human behavior, and other scientists are able to dissect brains. Hazen also describes specific areas of the brain that are related to memory function–a lot of this knowledge comes from studying people with brain injuries and animals. Next, chapter 13 reinforces the idea that there are pros and cons to scientific knowledge; while scientific knowledge can cure disease, feed the hungry, and contribute to economic well-being, it can also expose the world to new hazards (such as pollution, radiation, and deadly weapons). The pursuit of science can also lead to dangerous human experimentation. The last chapter describes the likelihood of the existence of planets similar to Earth. Hazen outlines seven factors that contribute to the probability that intelligent life exists on other planets: 1) the number of sunlike stars, 2) which sunlike stars have solar systems, 3) which solar systems have earthlike planets, 4) what fraction of earthlike planets have life, 5) how often life leads to intelligence, 6) whether intelligent life-forms attempt to communicate or not, and 7) how long advanced societies will remain communicative. This chapter also discusses the difficulties of searching for extraterrestrial intelligence using radio waves and microwaves. This was a good book because it explained a lot of diverse topics. This book is helpful to provide exposure to many different topics and encourage readers to continue learning about topics that intrigued them. Also, as someone without a background or major in science, there were many topics that I had heard about before, but had never taken the time to learn about. Therefore, it was a good way to broaden my knowledge of the universe, Earth, and atoms. Lastly, I thought this book was good because it was really interesting to consider the limitations of modern science and the relationship between science and philosophy. According to the author, philosophy and religion tend to take over when science reaches its limits, only for science to sometimes take its place again as we develop new theories and technology. I really enjoyed reading about dark matter and the big bang theory. My least favorite chapter was the chapter about how life originated because I had a hard time imagining the world that long ago. I think the difficulty level of the book was medium. I didn’t need to have a deep understanding of science in order to understand the book, but for certain chapters it definitely helped that we had discussed certain topics in class, but it wasn’t necessary. It was well written and understandable. Additionally, it was written with an interesting perspective on the limitations of science. However, the biggest downside of this book is that it is limited by its age. It was published in 1997–about 25 years ago.