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Books > Science & Mathematics > Astronomy, space & time > General
Pulsar timing is a promising method for detecting gravitational
waves in the nano-Hertz band. In his prize winning Ph.D. thesis
Rutger van Haasteren deals with how one takes thousands of
seemingly random timing residuals which are measured by pulsar
observers, and extracts information about the presence and
character of the gravitational waves in the nano-Hertz band that
are washing over our Galaxy. The author presents a sophisticated
mathematical algorithm that deals with this issue. His algorithm is
probably the most well-developed of those that are currently in use
in the Pulsar Timing Array community. In chapter 3, the
gravitational-wave memory effect is described. This is one of the
first descriptions of this interesting effect in relation with
pulsar timing, which may become observable in future Pulsar Timing
Array projects. The last part of the work is dedicated to an effort
to combine the European pulsar timing data sets in order to search
for gravitational waves. This study has placed the most stringent
limit to date on the intensity of gravitational waves that are
produced by pairs of supermassive black holes dancing around each
other in distant galaxies, as well as those that may be produced by
vibrating cosmic strings. Rutger van Haasteren has won the 2011
GWIC Thesis Prize of the Gravitational Wave International Community
for his innovative work in various directions of the search for
gravitational waves by pulsar timing. The work is presented in this
Ph.D. thesis.
This book offers review chapters written by invited speakers of the
3rd Session of the Sant Cugat Forum on Astrophysics - Gravitational
Waves Astrophysics. All chapters have been peer reviewed. The book
goes beyond normal conference proceedings in that it provides a
wide panorama of the astrophysics of gravitational waves and serves
as a reference work for researchers in the field.
In this thesis, ultimate sensitive measurement for weak force
imposed on a suspended mirror is performed with the help of a laser
and an optical cavity for the development of gravitational-wave
detectors. According to the Heisenberg uncertainty principle, such
measurements are subject to a fundamental noise called quantum
noise, which arises from the quantum nature of a probe (light) and
a measured object (mirror). One of the sources of quantum noise is
the quantum back-action, which arises from the vacuum fluctuation
of the light. It sways the mirror via the momentum transferred to
the mirror upon its reflection for the measurement. The author
discusses a fundamental trade-off between sensitivity and stability
in the macroscopic system, and suggests using a triangular cavity
that can avoid this trade-off. The development of an optical
triangular cavity is described and its characterization of the
optomechanical effect in the triangular cavity is demonstrated. As
a result, for the first time in the world the quantum back-action
imposed on the 5-mg suspended mirror is significantly evaluated.
This work contributes to overcoming the standard quantum limit in
the future.
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 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.
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.
The zodiac was first clearly defined by the Babylonians some 2500
years ago, but until recently the basis of this original definition
remained unknown. This zodiac of the Babylonians, known as the
sidereal zodiac because it is specified in direct relation to the
stars (Latin sideris, 'starry'), was used for centuries throughout
the ancient world, all the way to India, and must be distinguished
from the tropical zodiac in widespread use by astrologers in the
West today, which was introduced only in the middle of the second
century A.D. by the Greek astronomer Claudius Ptolemy. Such was
Ptolemy's influence, however, that the tropical zodiac gained
prominence and, except for its survival (in a variant form) in
India, knowledge of the sidereal zodiac was lost. In this thrilling
study of the history of the zodiac, first submitted in 2004 as his
Ph.D. thesis, Robert Powell rescues the the sidereal zodiac from
the dusts of time, tracing it back to the Babylonians in the
sixth/fifth centuries B.C. The implications of this discovery-among
them the restitution of the sideral zodiac to its rightful place at
the heart of astrology-are immense, they key point being that the
signs of the sidereal zodiac, each thirty degrees long, coincide
closely with the twelve astronomical constellations of the same
name, whereas the signs of the tropical zodiac, since they are
defined in relation to the vernal point, now have no direct
relationship to the corresponding zodiacal constellations, owing to
the precession of the equinoxes.This revolutionary history of the
zodiac includes chapters on the Egyptian decans and the Hindu
nakshatras, showing how these sidereal divisions, which originated
in Egypt and India, are related to the original Babylonian zodiac.
It also sheds light on the controversy surrounding the 'zodiac
question' (tropical vs. sidereal), illuminating the history of the
tropical zodiac-showing that originally it was not a zodiac at all,
but a calendar for describing the course of the seasons This book,
the fruit of thirty years of research, is intended not only for
scholars but for general readers as well, and offers the clearest
and most comprehensive study of the history of the zodiac yet
published.
How does it happen that billions of stars can cooperate to produce
the beautiful spirals that characterize so many galaxies, including
ours? This book reviews the history behind the discovery of spiral
galaxies and the problems faced when trying to explain the
existence of spiral structure within them. In the book, subjects
such as galaxy morphology and structure are addressed as well as
several models for spiral structure. The evidence in favor or
against these models is discussed. The book ends by discussing how
spiral structure can be used as a proxy for other properties of
spiral galaxies, such as their dark matter content and their
central supermassive black hole masses, and why this is important.
Nature is characterized by a number of physical laws and
fundamental dimensionless couplings. These determine the properties
of our physical universe, from the size of atoms, cells and
mountains to the ultimate fate of the universe as a whole. Yet it
is rather remarkable how little we know about them. The constancy
of physical laws is one of the cornerstones of the scientific
research method, but for fundamental couplings this is an
assumption with no other justification than a historical
assumption. There is no 'theory of constants' describing their role
in the underlying theories and how they relate to one another or
how many of them are truly fundamental. Studying the behaviour of
these quantities throughout the history of the universe is an
effective way to probe fundamental physics. This explains why the
ESA and ESO include varying fundamental constants among their key
science drivers for the next generation of facilities. This
symposium discussed the state-of-the-art in the field, as well as
the key developments anticipated for the coming years.
A physicist and an inventor, Jules Janssen (1824-1907) devoted his
life to astronomical research. He spent many years traveling around
the world to observe total Solar eclipses, demonstrating that a new
era of science had just come thanks to the use of both spectroscopy
and photography, and persuading the French Government of the
necessity of founding a new observatory near Paris. He became its
director in 1875. There, at Meudon, he began routine photographic
recordings of the Sun surface and had a big refractor and a big
reflector built. Meanwhile, he also succeeded in building an
Observatory at the summit of Mont-Blanc. The story of this untiring
and stubborn globe-trotter is enriched by extracts of the
unpublished correspondence with his wife. One can thus understand
why Henriette often complained of the solitude in which she was
left by her peripatetic husband: "There are men who leave their
wives for mistresses; you do it for journeys!" ... Basking in the
glow of his success, Janssen was able to undertake the construction
of the great astrophysical observatory of which he had dreamed. It
was at Meudon that he had it built.
In a series of illuminating lectures, Joseph A. Seiss presents a
clear picture of astronomical occurrences and inspirations to be
found in the Biblical New Testament and Gospels. A superbly
insightful Bible commentary, this book contains seventeen lectures,
each of which focuses upon a specific astronomical occurrence in
the New Testament. Events which draw specific influence from the
constellations of the stars are charted, with each star sign
identified as important to separate events depicted in the
scriptures of the gospels. The nativity of Jesus Christ, wherein
the Star of Bethlehem appears to the three wise men, is perhaps the
most obvious incident of the astronomical. However, Seiss
demonstrates that the stars above are richly significant and play a
role in many of the most famous tales of the Bible. For example,
when Seiss recounts the story of St. Peter's fishing, he compares
the sign of Pisces, which was already widely known in the Biblical
era.
The large telescope at Meudon has become legendary. When it was
conceived, after 1870, astronomy as a whole was limited to visual
observation. Knowledge of the sky was limited to what one could
see, assisted only by optical means. The large telescopes produced
at this time produced larger images, permitting close-up views: the
Meudon telescope was able to accomplish this perfectly. At Meudon,
which became the Mecca of visual observation, the major planets
were examined in a way that no other telescope had previously been
able to. The telescope monitored the state of their atmospheres and
mapped the appearance of their surfaces. Through the telescope, one
could obtain photographs showing the nuclei of comets, revealing
their very small size, and by using an eyepiece one could measure
the separation of double stars. With a marvellous little
instrument, the polarimeter, the nature of clouds in planetary
atmospheres has been determined, and the type of surface material
identified. Many more results were obtained, while photography,
universally adopted, revolutionized other knowledge about the
world. The sensitive emulsion, combined with large aperture
reflecting telescopes, revealed the deepness and richness of the
cosmos. The vast telescope of Meudon, which was the largest
refracting telescope in Europe, became a legendary instrument and
was symbolic of a new way to practice astronomy. Audouin Dollfus, a
renowned astronomer, describes the great years of the Meudon
telescope. He gives us the entire story of this instrument, from
the birth of the concept that drove Jules Janssen at the end of the
nineteenth century, to the idea that French astronomy could provide
an outstanding telescope which would approach the limits of
technical and industrial resources. The telescope remained
unchanged until 2006, when the first steps toward restoration and
public reopening were taken.
The invention of the semiconductor laser along with silica glass
fiber has enabled an incredible revolution in global communication
infrastructure of direct benefit to all. Development of devices and
system concepts that exploit the same fundamental light-matter
interaction continues. Researchers and technologists are pursuing a
broad range of emerging applications, everything from automobile
collision avoidance to secure quantum key distribution. This book
sets out to summarize key aspects of semiconductor laser device
physics and principles of laser operation. It provides a convenient
reference and essential knowledge to be understood before exploring
more sophisticated device concepts. The contents serve as a
foundation for scientists and engineers, without the need to invest
in specialized detailed study. Supplementary material in the form
of MATLAB is available for numerically generated figures.
This book is a collection of essays written by the very
scientists and engineers who have led, and continue to lead, the
scientific quest known as SETI, the search for extraterrestrial
intelligence. Divided into three parts, the first section, 'The
Spirit of SETI Past', written by the surviving pioneers of this
then emerging discipline, reviews the major projects undertaken
during the first 50 years of SETI science and the results of that
research.
In the second section, 'The Spirit of SETI Present', the
present-day science and technology is discussed in detail,
providing the technical background to contemporary SETI
instruments, experiments, and analytical techniques, including the
processing of the received signals to extract potential alien
communications.
In the third and final section, 'The Spirit of SETI Future', the
book looks ahead to the possible directions that SETI will take in
the next 50 years, addressing such important topics as interstellar
message construction, the risks and assumptions of interstellar
communications, when we might make contact, what aliens might look
like and what is likely to happen in the aftermath of such a
contact.
This book is the result of a working group sponsored by ISSI in
Bern, which was initially created to study possible ways to
calibrate a Far Ultraviolet (FUV) instrument after launch. In most
cases, ultraviolet instruments are well calibrated on the ground,
but unfortunately, optics and detectors in the FUV are very
sensitive to contaminants and it is very challenging to prevent
contamination before and during the test and launch sequences of a
space mission. Therefore, ground calibrations need to be confirmed
after launch and it is necessary to keep track of the temporal
evolution of the sensitivity of the instrument during the mission.
The studies presented here cover various fields of FUV
spectroscopy, including a catalog of stellar spectra, datasets of
Moon Irradiance, observations of comets and measurements of the
interplanetary background. Detailed modelling of the interplanetary
background is presented as well. This work also includes
comparisons of older datasets with current ones. This raises the
question of the consistency of the existing datasets. Previous
experiments have been calibrated independently and comparison of
the datasets may lead to inconsistencies. The authors have tried to
check that possibility in the datasets and when relevant suggest a
correction factor for the corresponding data."
..".The Multiversal book series is equally unique, providing
book-length extensions of the lectures with enough additional depth
for those who truly want to explore these fields, while also
providing thekind of clarity that is appropriate for interested lay
people to grasp the general principles involved." - Lawrence M.
Krauss
Cosmic Update Covers: A novel approach to uncover the dark faces
of the Standard Model of cosmology.The possibility that Dark Energy
and Dark Matter are manifestations of the inhomogeneous geometry of
our Universe.On the history of cosmological model building and the
general architecture of cosmological modes.Illustrations on the
Large Scale Structure of the Universe.A new perspective on the
classical static Einstein Cosmos.Global properties of World Models
including their Topology.The Arrow of Time in a Universe with a
Positive Cosmological Constant.Exploring the consequences of a
fundamental Cosmological Constant for our Universe. Exploring why
the current observed acceleration of the Universe may not be its
final destiny.Demonstrating that nature forbids the existence of a
pure Cosmological Constant.Our current understanding of the long
term (in time scales that greatly exceed the current age of the
Universe) future of the Universe.The long term fate and eventual
destruction of the astrophysical objects that populate the universe
--including clusters, galaxies, stars, planets, and black
holes.
The material is presented in a layperson-friendly language
followed by addition technical sections that explain the basic
equations and principles. This feature is very attractive to
readers who want to learn more about the theories involved beyond
the basic description.
"Multiversal Journeys is a trademark of Farzad Nekoogar and
Multiversal Journeys, a 501 (c) (3) nonprofit organization.""
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