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Books > Science & Mathematics > Astronomy, space & time
It has been known for a long time that stars are similar to our
Sun. But it was only in 1810 that they were shown to be made of an
incandescent gas. The chemical composition of this gas began to be
determined in 1860. In 1940, it was demonstrated that the energy
radiated by the stars is of thermonuclear origin. How stars form
from interstellar matter and how they evolve and die was understood
only recently, with our knowledge still incomplete. It was also
realized recently that close double stars present a wide variety of
extraordinary phenomena, which are far from being completely
explored.This book explains all these aspects, and also discusses
how the evolution of stars determine that of galaxies. The most
interesting observations are illustrated by spectacular images,
while the theory is explained as simply as possible, without
however avoiding some mathematical or physical developments when
they are necessary for a good understanding of what happens in
stars. Without being a textbook for specialists, this book can be
profitably read by students or amateurs possessing some basic
scientific knowledge, who would like to be initiated in-depth to
the fascinating world of stars.The author, an emeritus astronomer
of the Paris Observatory, worked in various domains of astronomy
connected with the subject of this book: interstellar matter and
evolution of stars and galaxies. He directed the Marseilles
observatory from 1983 to 1988 and served for fifteen years as Chief
Editor of the professional European journal Astronomy &
Astrophysics. He has written many articles and books about physics
and astronomy at different levels.
This thesis describes the essential features of Moon-plasma
interactions with a particular emphasis on the Earth's magnetotail
plasma regime from both observational and theoretical standpoints.
The Moon lacks a dense atmosphere as well as a strong intrinsic
magnetic field. As a result, its interactions with the ambient
plasma are drastically different from solar-wind interactions with
magnetized planets such as Earth. The Moon encounters a wide range
of plasma regime from the relatively dense, cold, supersonic
solar-wind plasma to the low-density, hot, subsonic plasma in the
geomagnetic tail. In this book, the author presents a series of new
observations from recent lunar missions (i.e., Kaguya, ARTEMIS, and
Chandrayaan-1), demonstrating the importance of the electron
gyro-scale dynamics, plasma of lunar origin, and hot plasma
interactions with lunar magnetic anomalies. The similarity and
difference between the Moon-plasma interactions in the geomagnetic
tail and those in the solar wind are discussed throughout the
thesis. The basic knowledge presented in this book can be applied
to plasma interactions with airless bodies throughout the solar
system and beyond.
This thesis brings together the various techniques of X-ray
spectral analysis in order to examine the properties of black holes
that vary in mass by several orders of magnitude. In all these
systems it is widely accepted that the X-ray emission is produced
by Compton up-scattering of lower energy seed photons in a hot
corona or accretion flow, and here these processes are examined
through a study of the X-ray spectral variability of each source. A
new technique is introduced, in which models are fitted to over 2
million X-ray spectra on time-scales as short as 16 ms, and
subsequently it is shown that the nature of the correlation between
intensity and spectral index is strongly dependent upon the
spectral state of the black hole. Finally, the results of an
extensive survey of nearby galactic nuclei using the Chandra X-ray
telescope are presented in the form of images and spectra, and
these results are used along with data from the literature to
search for Compton-thick nuclei.
This is the first comprehensive bibliography of temporal
scholarship-research on the subject of time and the phenomenon of
time itself. As the author notes in his introduction, the nature of
research insights on the subject of time is difficult to comprehend
within the confines of any specific discipline since relevant
materials are scattered throughout the literature in numerous
scholarly fields. By bringing together the most significant
published works in a wide variety of disciplines, this unique
compendium enables scholars and researchers to look beyond their
own particular area of expertise when selecting appropriate
resource materials. Throughout, the focus is on the time dimension
itself as a problematic or researchable phenomenon rather than on
narrow topics such as time management, time series analysis, or
forecasting.
Organized by discipline, the work begins with an initial chapter
that lists general works on the time dimension. Nineteen chapters
then list works in particular disciplines ranging from anthropology
and culture to biology, economics, futures studies, history,
linguistics, management studies, psychology, and more. The final
chapter lists miscellaneous entries which could not be categorized
into any of the specific disciplinary headings. Within each
chapter, entries are arranged alphabetically by author or editor.
Nearly all sources are from scholarly journals and books.
The series of texts composing this book is based on the lectures
presented during the II Jose Plinio Baptista School of Cosmology,
held in Pedra Azul (Espirito Santo, Brazil) between 9 and 14 March
2014. This II JBPCosmo has been entirely devoted to the problem of
understanding theoretical and observational aspects of Cosmic
Background Radiation (CMB).The CMB is one of the most important
phenomena in Physics and a fundamental probe of our Universe when
it was only 400,000 years old. It is an extraordinary laboratory
where we can learn from particle physics to cosmology; its
discovery in 1965 has been a landmark event in the history of
physics.The observations of the anisotropy of the cosmic microwave
background radiation through the satellites COBE, WMAP and Planck
provided a huge amount of data which are being analyzed in order to
discover important informations regarding the composition of our
universe and the process of structure formation.
God and Time is a collection of previously unpublished essays written by leading philosophers about God's relation to time. The essays have been selected to represent current debates written between those who believe God to be atemporal and those who do not. The essays highlight issues such as how the nature of time is relevant to whether God is temporal and how God's other attributes are compatible with his mode of temporal being. By focusing on the metaphysical aspects of time and temporal existence, God and Time will make a unique contribution to the current resurgence of interest in philosophical theology within the analytic tradition.
The main focus of this book is on the interconnection of two
unorthodox scientific ideas, the varying-gravity hypothesis and the
expanding-earth hypothesis. As such, it provides a fascinating
insight into a nearly forgotten chapter in both the history of
cosmology and the history of the earth sciences. The hypothesis
that the force of gravity decreases over cosmic time was first
proposed by Paul Dirac in 1937. In this book the author examines in
detail the historical development of Dirac's hypothesis and its
consequences for the structure and history of the earth, the most
important of which was that the earth must have been smaller in the
past.
William Gascoigne (c.1612-44) was the inventor of the telescopic
sight and micrometer (instruments crucial to the advance of
astronomy). His name is now known to historians of science around
the world. For some considerable time after his tragic death at the
age of 32 in the English Civil War, however, it seemed as if his
achievements would be consigned to oblivion. Most of his papers
were lost and even the few that survived have largely disappeared.
This is the story of how his work was rescued. Into this story is
woven an account of the state of astronomy and optics during
Gascoigne's lifetime, so that the reader can appreciate the
significance of his discoveries.
This book presents three major studies covering exomoon and
exoplanet detection and characterisation. Firstly, it reports the
observations and analysis of the atmosphere of the hot Neptune
GJ3470b, one of the lowest-mass planets with a measured atmosphere,
using transmission spectroscopy techniques. The result provided
improved measurements of Rayleigh scattering in the atmosphere and
the first limits on additional planetary companions in the system.
The second part discusses modeling a Kepler-like satellite's
ability of a to detect exomoons by looking for transit timing
variations and transit duration variations, demonstrating how
exomoons can unambiguously be identified from such data.Lastly, the
book examines the development of a state-of-the-art Galactic
microlensing simulator, which has been made publicly available. It
was used to compare with the largest published sample of
microlensing events from the MOA-II survey.
This thesis develops new and powerful methods for identifying
planetary signals in the presence of "noise" generated by stellar
activity, and explores the physical origin of stellar intrinsic
variability, using unique observations of the Sun seen as a star.
In particular, it establishes that the intrinsic stellar
radial-velocity variations mainly arise from suppression of
photospheric convection by magnetic fields. With the advent of
powerful telescopes and instruments we are now on the verge of
discovering real Earth twins in orbit around other stars. The
intrinsic variability of the host stars themselves, however,
currently remains the main obstacle to determining the masses of
such small planets. The methods developed here combine
Gaussian-process regression for modeling the correlated signals
arising from evolving active regions on a rotating star, and
Bayesian model selection methods for distinguishing genuine
planetary signals from false positives produced by stellar magnetic
activity. The findings of this thesis represent a significant step
towards determining the masses of potentially habitable planets
orbiting Sun-like stars.
The Square Kilometre Array (SKA) radio telescope is set to become
the largest telescope on Earth, and also the largest science
project in Africa. From September 2011 to August 2012, the SKA
featured regularly in the South African media. In The Stars in Our
Eyes, author Michael Gastrow dissects the representation of the SKA
in the South African media in the period under discussion. Who were
the main actors in this unfolding narrative? Who held the stage and
who were marginalised? Where did gatekeeping occur and why? What
was the relationship between journalists and scientists? How did
the story unfold in the social media as opposed to the print media?
Drawing on mass communication theory and science communication
theory, The Stars in Our Eyes: Representations of the Square
kilometre Array Telescope in the South African Media addresses
critical gaps in the literature on science communication,
particularly with respect to science communication in an African
context.
This thesis presents accurate analyses of the spin-orbit angle
for many remarkable transiting exoplanetary systems, including the
first measurement of the Rossiter-McLaughlin effect for a multiple
transiting system.
The author presents the observational methods needed to probe
the spin-orbit angle, the relation between the stellar spin axis
and planetary orbital axis. Measurements of the spin-orbit angle
provide us a unique and valuable opportunity to understand the
origin of close-in giant exoplanets, called "hot Jupiters."
The first method introduced involves observations of the
Rossiter-McLaughlin effect (RM effect). The author points out the
issues with the previous theoretical modeling of the RM effect and
derives a new and improved theory. Applications of the new theory
to observational data are also presented for a number of remarkable
systems, and the author shows that the new theory minimizes the
systematic errors by applying it to the observational data.
The author also describes another method for constraining the
spin-orbit angle: by combining the measurements of stellar flux
variations due to dark spots on the stellar surface, with the
projected stellar rotational velocity measured via spectroscopy,
the spin-orbit angles "along the line-of-sight" are constrained for
the transiting exoplanetary systems reported by the Kepler space
telescope."
The development of the orbits theory lags behind the development of
satellite technology. This book provides, for the first time in the
history of human satellite development, the complete third order
solution of the orbits under all possible disturbances. It
describes the theory of satellite orbits, derives the complete
solutions of the orbital disturbances, describes the algorithms of
orbits determination based on the theory, describes the
applications of the theory to the phenomenon of the satellite
formation physically. The subjects include: Orbits Motion
Equations, Disturbance theory, Solutions of the differential
Equations, Algorithms of Orbits determinations, Applications of the
theory to the satellite formation.
This book presents the proceedings of the 2nd Karl Schwarzschild
Meeting on Gravitational Physics, focused on the general theme of
black holes, gravity and information.Specialists in the field of
black hole physics and rising young researchers present the latest
findings on the broad topic of black holes, gravity, and
information, highlighting its applications to astrophysics,
cosmology, particle physics, and strongly correlated systems.
This book, which is a reworked and updated version of Steven
Bloemen's original PhD thesis, reports on several high-precision
studies of compact variable stars. Its strength lies in the large
variety of observational, theoretical and instrumentation
techniques that are presented and used and paves the way towards
new and detailed asteroseismic applications of single and binary
subdwarf stars. Close binary stars are studied using high cadence
spectroscopic datasets collected with state of the art electron
multiplying CCDs and analysed using Doppler tomography
visualization techniques. The work touches upon instrumentation,
presenting the calibration of a new fast, multi-colour camera
installed at the Mercator Telescope on La Palma. The thesis also
includes theoretical work on the computation of the temperature
range in which stellar oscillations can be driven in subdwarf
B-stars. Finally, the highlight of the thesis is the measurement of
velocities of stars using only photometric data from NASA's Kepler
satellite. Doppler beaming causes stars to appear slightly brighter
when they move towards us in their orbits, and this subtle effect
can be seen in Kepler's brightness measurements. The thesis
presents the first validation of such velocity measurements using
independent spectroscopic measurements. Since the detection and
validation of this Doppler beaming effect, it has been used in tens
of studies to detect and characterize binary star systems, which
are key calibrators in stellar astronomy.
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