Physics
Astrophysics
Astrophysics is a branch of astronomy that applies the principles of physics and chemistry to understand the properties and behavior of celestial objects and the universe as a whole. It encompasses the study of stars, galaxies, black holes, and the cosmic microwave background, among other phenomena. Astrophysicists use mathematical models and observational data to explore the fundamental processes governing the cosmos.
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8 Key excerpts on "Astrophysics"
eBook - PDF- Cynthia Phillips, Shana Priwer(Authors)
- 2024(Publication Date)
- For Dummies(Publisher)
If you drop a can of beans on your toe, that’s gravity at work. Astronomy, on the other hand, is the study of everything in the sky, from planets to stars to galaxies. Astrophysics joins the party as a more quantitative study that combines the observations of astronomy (“what”) with the underlying theories of physics (“how”). Put simply, Astrophysics is the study of how the cosmos works from beginning to end. Astrophysics is, in many ways, a field that focuses on studying the intangible. Astrophysicists need to come up with specific ways of gathering information about phenomena that are, quite literally, out of this world. There are several ways in which scientists can tackle this problem: » Observations: Using Earth- and space-based telescopes and instrumentation, astrophysicists observe the universe at different wavelengths. » Laboratory work: Specially-designed equipment allows astrophysicists to simulate certain aspects of the cosmos right here at home. Assuming your home is an advanced-science lab, of course. » Theory: More than chalk on a blackboard, state-of-the-art supercomputers are used to run simulations on everything from the birth of a star to the end of the universe. Check out Chapter 4 for more information on each of these concepts. Let there be light! The electromagnetic spectrum The observational part of Astrophysics requires — surprise! — observations. Astrophysicists observe the universe using a variety of methods. Because we can’t (yet!) travel to other stars and galaxies, these observations are all based on detect- able information that distant objects send out into space. Most of this information comes in the form of electromagnetic radiation. 12 PART 1 Getting Started with Astrophysics Electromagnetic radiation (commonly known as light) is a way that energy travels through space, and it’s a critical concept for anyone conducting astrophysical observations.
eBook - PDF- Bradley W. Carroll, Dale A. Ostlie(Authors)
- 2017(Publication Date)
- Cambridge University Press(Publisher)
The application of physics to astronomy, Astrophysics , has proved very successful in explaining a wide range of observations, including strange and exotic objects and events, such as pulsating stars, supernovae, variable X-ray sources, black holes, quasars, gamma-ray bursts, and the Big Bang. As a part of our investigation of the science of astronomy, it will be necessary to study the details of celestial motions, the nature of light, the structure of the atom, and the shape of space itself. Rapid advances in astronomy over the past several decades have occurred because of advances in our understanding of fundamental physics and because of improve-ments in the tools we use to study the heavens: telescopes and computers. Essentially every area of physics plays an important role in some aspect of astronomy. Particle physics and Astrophysics merge in the study of the Big Bang; the basic question of the origin of the zoo of elementary particles, as well as the very nature of the fundamental forces, is intimately linked to how the universe was formed. Nuclear physics provides information about the types of reactions that are possible in the interiors of stars, and atomic physics describes how individual atoms interact with one another and with light, processes that are basic to a great many astrophysical phenomena. Condensed-matter physics plays a 20 Chapter 1 The Celestial Sphere role in the crusts of neutron stars and in the center of Jupiter. Thermodynamics is involved everywhere from the Big Bang to the interiors of stars. Even electronics plays an important role in the development of new detectors capable of giving a clearer view of the universe around us. With the advent of modern technology and the space age, telescopes have been built to study the heavens with ever-increasing sensitivity. No longer limited to detecting visible light, telescopes are now capable of “seeing” gamma rays, X-rays, ultraviolet light, infrared radiation, and radio signals.
eBook - PDF- Mendel Sachs(Author)
- 2010(Publication Date)
- ICP(Publisher)
1 Physics of the Universe Introduction Physics is the science of inanimate matter. Cosmology is the part of this science that deals with the universe as a whole. It is the oldest and the youngest branch of physics. It is the oldest because the heavens were studied in ancient times, in Greece and in Asia, and other parts of the world. It is the youngest because it has been re-invigorated in recent times due to observations with new, high-resolution astronomical instrumentation (such as the Hubble telescope) and theoretical analyses in the context of current thinking in particle physics and relativistic dynamics. Voluminous works have been written on the order of the night sky. ( The Greek word , ‘ Cosmology ’, means ‘ order ’ ( logos ) of the cosmos .) 1 Astronomical laboratories have been constructed since the ancient times to study this order. Examples include the Stonehenge monument, built by the ancient Britons thousands of years ago, and similar ancient astronomical viewing sites in India, China, Australia, Peru, Mexico and from other cultures in the different corners of the world, designed by the ancient and aboriginal peoples to see the star formations and their locations, the locations of the sun and the moon, at the different times of the year. In these ancient viewings, there was no magnification. Galileo, in the 16th century, was the first astronomer to use magnification, utilizing the telescope — a series of lenses that he 1 2 Physics of the Universe contrived to view the heavens. 2 Focusing mainly on our solar system, he saw the moons of Jupiter, the sun spots, the landscape of the moon, and he verified the conclusion of Copernicus that the earth moves ! However, Galileo went further than Copernicus, who theorized that the sun is at the absolute center of the universe, and that the earth orbits about it, along with the other planets of the solar system.
eBook - PDFAstrophysics through Computation
With Mathematica® Support
- Brian Koberlein, David Meisel(Authors)
- 2013(Publication Date)
- Cambridge University Press(Publisher)
1 Introduction Astrophysics draws upon a wide range of topics in astronomy and physics. Topics as widely ranging as observational techniques, thermodynamics, and general relativity are all central to the material covered in this text. Many readers, particularly undergraduate students, will have only passing experience with some of these foundational concepts. It is impossible for us to provide a comprehensive review of these within the scope of this text, but we begin with a basic overview of the most central topics necessary to approach the astrophysical subjects to be covered. In later chapters we build on these various terms in greater detail. Although we do assume more than a general background in physics and astronomy, we do not provide a comprehensive discussion of the basics, as these can be obtained elsewhere. Instead we present only those more advanced background concepts as needed to the task at hand. 1.1 Fundamental stellar properties One of the central goals of astronomy is the specification of the properties of the sun, stars, and other self-luminous bodies in the universe. Learning about the ranges of these properties and how the quantities characterizing them are determined are a major part of any astronomy course, so we only briefly discuss them here. 1.1.1 Cosmic distance scales The most fundamental property of a celestial object is its distance from another body. Usually the reference is the sun, the star nearest to Earth. Within the solar system, distances are specified using astronomical units (AU), equal to the mean distance between Earth and sun. Outside the solar system, distances are so large that one immediately switches to another unit, the parsec. The parsec was devised when distances to stars were first measured by the method of trigonometric parallax, and distance was determined from the annual shift of an object’s angular position in the sky.
eBook - PDF- Richard L. Myers(Author)
- 2005(Publication Date)
- Greenwood(Publisher)
Physics combined with other disciplines produces unique areas of study. Geophys- ics is physics of the Earth. Geophysicists use physics to study both the external and internal structure of the Earth. Biophysics applies the principles of physics to the study of life processes, for example, using ther- modynamics to study metabolism. Astro- physics applies physics to the study of the universe. The evolution of stars, the propa- gation of electromagnetic waves through interstellar space, and the structure of the universe are just a few areas that astrophys- ics addresses. Many distinct areas of science are highly dependent on physics. For exam- ple, meteorologists use physics to study the motion of the atmosphere and to understand weather patterns. Oceanographers apply physics to study wave motion and water cir- culation throughout the oceans. Engineers constantly apply physics to carry out tasks such as building bridges, designing cars, and refining oil. Numerous other disciplines uti- lize physics. In fact, it's difficult to think of any science or technical area that does not depend on physics to some degree. The Philosophical Foundation of Physics The development of modern science can be traced backed to ancient Greece and the desire to explain natural phenomena using rational logic. Before the fifth century B.C.E., Greek mythology served to explain phe- nomena such as seasons, floods, droughts, plagues, earthquakes, lightning, meteors, eclipses, and tides. Gods and goddesses in Greek mythology were the personification of natural phenomena. One area of Greek mythology that survives today is the obser- vation of the night sky and the identification of familiar constellations. Constellations such as Ursa Major (the Great Bear), Orion, Gemini, Leo, and Pegasus have individual stories, often several, associated with how they were formed. For example, Ursa Major, the Great Bear, lives in the northern skies.
eBook - PDFLet There Be Light: The Story Of Light From Atoms To Galaxies (2nd Edition)
The Story of Light from Atoms to Galaxies
- Alex Montwill, Ann Breslin(Authors)
- 2013(Publication Date)
- ICP(Publisher)
Chapter 5 Light from the Past — Astrophysics When Isaac Newton discovered the law of gravity, and that it applies equally to matter, whether on the earth, the moon or anywhere else in the universe, a completely new chapter was opened. It became possible to calculate the orbits of planets, even to predict the existence and motion of hitherto unseen planets. The science of Astrophysics was born. It now became possible, using the laws of physics, to trace the history of the universe back to the original Big Bang . It was later realized that the function of light as a messenger extended to bringing news of the first moments of the universe , when mas-sive energy was released in the form of electromagnetic radia-tion which is still around us. The laws of physics predict and explain other exciting things — among them the collapse and death of stars, seen as explosions of supernovae , and the existence of pulsars and even of ‘windows’ out of our universe, or black holes . 5.1 The birth of Astrophysics So far we have been dealing with the science of a stronomy — the study of the heavenly bodies and of their motion. Fascinating as has been the discovery of the order and organization of the solar system, we have not asked the questions: Why do the planets move as they do? Why do they move at all? Is there any explana-tion of Kepler’s laws, in particular the extraordinary relation 111 112 Let There Be Light 2nd Edition between the orbital radii and the orbital periods? The answers to these questions fall into the domain of Astrophysics. Isaac Newton and gravitation Isaac Newton (1642–1727) is very well known, throughout the scientific world and outside it, for his formulation of the mechanical laws of motion. His first law states that an object continues in a state of rest, or uniform motion in a straight line, provided that it is not sub-ject to the action of a force. We now know that the earth, the moon and the other planets are all in motion but not in a straight line.
eBook - PDF- Nelson Boli´var(Author)
- 2023(Publication Date)
- Arcler Press(Publisher)
COSMOLOGY AND MODERN Astrophysics 6 CONTENTS 6.1. Introduction .................................................................................... 172 6.2. Evidence of the Big Bang ................................................................ 172 6.3. Hubble’s Measurements .................................................................. 173 6.4. Cosmic Microwave Background Radiation ...................................... 177 6.5. Nucleosynthesis.............................................................................. 177 6.6. The Big Bang................................................................................... 179 6.7. Stellar Evolution.............................................................................. 184 6.8. The Ultimate Fate of Stars................................................................ 185 6.9. Astronomical Objects ..................................................................... 187 References ............................................................................................. 196 CHAPTER Developments in Modern Physics 172 6.1. INTRODUCTION The Big Bang, according to most scientists and astronomers, is the origin of our universe. We will show several of the quantitative data that support this notion in this section. We have delayed till now to teach cosmology since it is dependent on the theory of relativity and seems to have significant connections to basic particle physics. Our understanding of Astrophysics is growing, particularly in the last 20 years. The field is part of the unexplainable data and contradictory ideas in this section. Cosmology and current Astrophysics are inextricably linked, and most of what we provide in this section is about both (Shore, 2002; Carroll and Ostlie, 2006). The extent to which cosmology, as well as Astrophysics, are dependent on other domains of physics may surprise students when they first encounter these topics.
eBook - PDFThe New Walford Guide to Reference Resources
Volume 1: Science. Technology and Medicine
- R G Lester(Author)
- 2004(Publication Date)
- Facet Publishing(Publisher)
Covers co-ordinate transformations, the apparent place of a star, the positions of solar system bodies, eclipse predictions, etc. Clear explanations and examples of use. Willmann-Bell specialize in the publication of books and software for astronomers: www.willbell.com. Astrophysics & Cosmology almanacs • asteroids • astronomical winds • astrophysical formulas • big bang theory • black holes • brown dwarfs • cosmic radiation • cosmology • deep sky objects • extragalactic radio sources • galactic dust • galaxies • Hubble space telescope • infrared astronomy • Mars exploration • meteorites • naval observatories • near earth objects • nebulae • nothingness • observatories • planetary exploration • plasmas • quasars • radio telescopes • solar and stellar physics • solar winds • space agencies • space exploration • space physics • space research • space telescopes • steady state theory • string theory • ultraviolet astronomy • virtual observatories • weather in space • x-ray astronomy Introductions to the subject 692 Astronomy: a physical perspective M. Kutner 2nd edn, Cambridge University Press, 2003, 600pp. £35.00. ISBN 0521529271. A calculus-based text that explains astronomical phenomena, as well as how astronomers collect and interpret information about stars and the solar system. Very much a more advanced introduction. 693 Astronomy and Astrophysics in the new millennium National Research Council National Academy Press, 2001, 246pp. $34.95. ISBN 0309070317. Compilation of reports of panels charged with identifying the most important scientific goals in their respective areas: high-energy Astrophysics from space; optical and infrared astronomy from the ground; particle, nuclear, and gravitational-wave Astrophysics; radio and submillimetre-wave astronomy; solar astronomy; theory, computation, and data exploration; ultraviolet, optical, and infrared astronomy from space. 694 Astrophysical techniques C.R. Kitchin 4th edn, Institute of Physics Publishing, 2003, 493pp.
Index pages curate the most relevant extracts from our library of academic textbooks. They’ve been created using an in-house natural language model (NLM), each adding context and meaning to key research topics.
