The AAVSO is an international non-profit organization of variable star observers whose mission is:

to observe and analyze variable stars
to collect and archive observations for worldwide access
to forge strong collaborations between amateur and professional astronomers
to promote scientific research and education using variable star data.

Assessments of lysergic acid diethylamide (LSD) in the treatment of alcoholism have not been based on quantitative meta-analysis. Hence, we performed a meta-analysis of randomized controlled trials in order to evaluate the clinical efficacy of LSD in the treatment of alcoholism. Two reviewers independently extracted the data, pooling the effects using odds ratios (ORs) by a generic inverse variance, random effects model. We identified six eligible trials, including 536 participants. There was evidence for a beneficial effect of LSD on alcohol misuse (OR, 1.96; 95% CI, 1.36–2.84; p = 0.0003). Between-trial heterogeneity for the treatment effects was negligible (I² = 0%). Secondary outcomes, risk of bias and limitations are discussed. A single dose of LSD, in the context of various alcoholism treatment programs, is associated with a decrease in alcohol misuse.

PyEphem provides scientific-grade astronomical computations for the Python programming language. Given a date and location on the Earth’s surface, it can compute the positions of the Sun and Moon, of the planets and their moons, and of any asteroids, comets, or earth satellites whose orbital elements the user can provide. Additional functions are provided to compute the angular separation between two objects in the sky, to determine the constellation in which an object lies, and to find the times at which an object rises, transits, and sets on a particular day.

the opening paragraph of the article Mindless Statistics by Gerd Gigerenzer

It is argued that it is possible to give operational meaning to free will and the process of making a choice without employing metaphysics.

The circumgalactic medium (CGM) is fed by galaxy outflows and accretion of intergalactic gas, but its mass, heavy element enrichment, and relation to galaxy properties are poorly constrained by observations. In a survey of the outskirts of 42 galaxies with the Cosmic Origins Spectrograph onboard the Hubble Space Telescope, we detected ubiquitous, large (150-kiloparsec) halos of ionized oxygen surrounding star-forming galaxies; we found much less ionized oxygen around galaxies with little or no star formation. This ionized CGM contains a substantial mass of heavy elements and gas, perhaps far exceeding the reservoirs of gas in the galaxies themselves. Our data indicate that it is a basic component of nearly all star-forming galaxies that is removed or transformed during the quenching of star formation and the transition to passive evolution.

To our best knowledge, there are no problem books on cosmology yet, that would include its spectacular recent achievements. We believe there is a strong need for such now, when cosmology is swiftly becoming a strict and vast science, and the book would be extremely useful for the youth pouring in this area of research. Indeed, the only way to rise over the popular level in any science is to master its alphabet, that is, to learn to solve problems.
Of course, most of modern textbooks on cosmology include problems. However, a reader, exhausted by high theory, may often be thwarted by the lack of time and strength to solve them. Might it be worth sometimes to change the tactics and just throw those who wish to learn to swim into the water?
The proposed problems constitute our contribution to this cause. There are over 1000 problems, divided into 14 chapters, covering topics from the dynamics of the expanding Universe and CMB to cosmology beyond the Lambda-CDM model and holography. We intend to publish their solutions in later editions. The reader, however, is encouraged to look for answers independently, even though - or especially so because - the problems range from easy to not quite and from elements of scientific folklore already to those with answers not quite settled.

Follow the adventures in the life of a Welsh astrophysicist sent into exile to a small island in the middle of the ocean. A blog by a scientist that almost certainly won't be about science, but will be very facetious.

The Art of Penguin Science Fiction

GNU Data Language (GDL) is a free/libre/open source incremental compiler compatible with IDL and to some extent with PV-WAVE. Together with its library routines it serves as a tool for data analysis and visualization in such disciplines as astronomy, geosciences and medical imaging. GDL is free software licensed under the GPL. GDL is developed by an international team of volunteers led by Marc Schellens - the project's founder

HPC Techreport
A brief introduction to Python (for scientific computing)

We have prepared a comprehensive critically evaluated compilation of the most accurate wavelength measurements for classified lines of neutral neon (Ne I) in its natural isotopic abundance. Data from 19 sources spanning the region 256 Å to 54 931 Å are included. Based on this line list we have derived optimized values for the energy levels of neutral neon. Tabular data for 1595 classified lines and 374 energy levels are provided. In addition to the observed wavelengths, we present revised wavelengths calculated from the optimized energy levels for all lines that have been previously recommended for use as secondary wavelength standards. © 2005 by the U.S. Secretary of Commerce on behalf of the United States. All rights reserved.

The Great Observatories Origins Deep Survey (GOODS) is a public, multiwavelength survey which originally covered two 150 square arcmin fields, centered around the HDF-N (Hubble Deep Field North) and the CDF-S (Chandra Deep Field South). It is a coordinated effort to combine the deepest survey data over the widest wavelength range (from X-ray through radio) from NASA’s Great Observatories (HST, Chandra, Sptizer), ESA’s XMM-Newton, and the largest ground-based observatories, namely ESO-VLT, Keck, Gemini in the optical/nearIR region, VLA in the radio, etc. Observations were designed to promote major advances in following primary science areas:

Software is a cornerstone of science. Without software, twenty-first century science would be impossible. Without better software, science cannot progress.

Vereiningung für Jugendarbeit in der Astronomie e.V.

Events on the world lines of two theoretical physicists, from the horizon to timelike infinity. A scientifically minded blog with varying amounts of entertainment, distractions, and every day trivialities.

Life is unique in nature in complexity and in its drive for self-propagation. We are part of life, implying a human purpose to safeguard and propagate life. For this purpose we may settle the Solar System, and seed with life new solar systems, solar nebulae and star-forming interstellar clouds. Directed panspermia to these targets can carry colonizing cyanobacteria, extremophile microorganisms, and eggs of multicellular rotifers to start higher evolution. The technical requirements for launching, targeting, deceleration and capture, and the probability of success were evaluated. The results show that directed panspermia can be accomplished with present technology. These programs will also serve the drive of life to occupy all habitats, and protect life from various threats, including ultimately the red giant Sun. ...

Welcome to the Sloan Digital Sky Survey III Science Archive Server. The SDSS-III is a large imaging and spectroscopic survey of the Northern sky, using a 2.5m optical telescope at Apache Point Observatory in New Mexico. The SAS serves images and spectra generated by the survey to astronomers and the general public alike. Please see the main survey site for full details and documentation.

The OPERA neutrino experiment at the underground Gran Sasso Laboratory has measured the velocity of neutrinos from the CERN CNGS beam over a baseline of about 730 km with much higher accuracy than previous studies conducted with accelerator neutrinos. The measurement is based on high-statistics data taken by OPERA in the years 2009, 2010 and 2011. Dedicated upgrades of the CNGS timing system and of the OPERA detector, as well as a high precision geodesy campaign for the measurement of the neutrino baseline, allowed reaching comparable systematic and statistical accuracies. An early arrival time of CNGS muon neutrinos with respect to the one computed assuming the speed of light in vacuum of (60.7 \pm 6.9 (stat.) \pm 7.4 (sys.)) ns was measured. This anomaly corresponds to a relative difference of the muon neutrino velocity with respect to the speed of light (v-c)/c = (2.48 \pm 0.28 (stat.) \pm 0.30 (sys.)) \times 10-5.

SDSS images of selected RC3 galaxies

In the late 1960s British mathematician John Conway invented a virtual mathematical machine that operates on a two-dimensional array of square cell. Each cell takes two states, live and dead. The cells’ states are updated simultaneously and in discrete time. A dead cell comes to life if it has exactly three live neighbours. A live cell remains alive if two or three of its neighbours are alive, otherwise the cell dies. The Conway’s Game of Life became the most programmed solitary game and the most known cellular automaton. The book brings together results of forty years of study into computational, mathematical, physical and engineering aspects of the Game of Life cellular automata. Selected topics include phenomenology and statistical behaviour; space-time dynamics on Penrose tilling and hyperbolic spaces; generation of music; algebraic properties; modelling of financial markets; semi-quantum extensions; predicting emergence; dual-graph based analysis; fuzzy, limit behaviour and ...

If you have astronomical imaging of the sky with celestial coordinates you do not know—or do not trust—then Astrometry.net is for you. Input an image and we'll give you back astrometric calibration meta-data, plus lists of known objects falling inside the field of view.

This page, updated monthly, will let you know some of the things that you can look out for in the night sky. It lists the phases of the Moon, where you will see the naked-eye planets and describes some of the prominent constellations in the night sky during the month

In the late 1960s British mathematician John Conway invented a virtual mathematical machine that operates on a two-dimensional array of square cell. Each cell takes two states, live and dead. The cells’ states are updated simultaneously and in discrete time. A dead cell comes to life if it has exactly three live neighbours. A live cell remains alive if two or three of its neighbours are alive, otherwise the cell dies. The Conway’s Game of Life became the most programmed solitary game and the most known cellular automaton. The book brings together results of forty years of study into computational, mathematical, physical and engineering aspects of the Game of Life cellular automata.

LifeWiki is a wiki designed with the hope of collecting all information about Conway's Game of Life together in one place. It contains a comprehensive catalogue of patterns as well as a glossary and general information about the game.

The aim of this book is to explain and exemplify the basic concepts and phenomena of quantum mechanics by means of visualization. Unlike classical mechanics, for which students have already developed an intuition based on everyday experience, the phenomena of quantum mechanics often defy intuition.

Naïve upsampling of pixel art images leads to unsatisfactory results. Our algorithm extracts a smooth, resolution-independent vector representation from the image which is suitable for high-resolution display devices

xyscan is a tool for scientist in the need to extract data points, i.e. numeric values, from a plot. It allows to scan the plots and extract data points including the size of the error bars (both in x and y). It can handle plots with linear and logarithmic scales. In fact xyscan can be used for extracting numeric values from any kind of 2D technical drawings.

A User’s Guide to the Universe: Surviving the Perils of Black Holes, Time Paradoxes, and Quantum Uncertainty” answers the sorts of the questions that we (as physicists) have been drunkenly asked at cocktail parties, but lacked the wherewithal to coherently answer.

We report on the experimental quantum teleportation of strongly nonclassical wave packets of light. To perform this full quantum operation while preserving and retrieving the fragile nonclassicality of the input state, we have developed a broadband, zero-dispersion teleportation apparatus that works in conjunction with time-resolved state preparation equipment. Our approach brings within experimental reach a whole new set of hybrid protocols involving discrete- and continuous-variable techniques in quantum information processing for optical sciences.

10 NASA Inventions You Might Use Every Day

The purpose of this web site is to act as a community knowledge base for performing astronomy research with Python. It provides lists of useful resources, a forum for general discussion, advice, or relevant news items, collecting users' code snippets or scripts, and longer tutorials on specific topics. The topics within these pages are presented in a list view with the ability to sort by date or topic. A traditional "blog" view of the most recently posted topics is visible from the site Home page.

This book covers the main topics concerned with interpolation and approximation by polynomials. This subject can be traced back to the precalculus era but has enjoyed most of its growth and development since the end of the nineteenth century and is still a lively and flourishing part of mathematics. In addition to coverage of univariate interpolation and approximation, the text includes material on multivariate interpolation and multivariate numerical integration, a generalization of the Bernstein polynomials that has not previously appeared in book form, and a greater coverage of Peano kernel theory than is found in most textbooks. There are many worked examples and each section ends with a number of carefully selected problems that extend the student's understanding of the text.

From the best-selling author of The Elegant Universe and The Fabric of the Cosmos comes his most expansive and accessible book to date—a book that takes on the grandest question: Is ours the only universe?

Dimensions takes important places, events and things, and overlays them onto a map of where you are.

IBI-Weblog

Weblog am Institut für Bibliotheks- und Informationswissenschaft der Humboldt-Universität zu Berlin

n this outlook we describe what could be the next steps of the direct characterization of habitable exoplanets after first the medium and large mission projects and investigate the benefits of the spectroscopic and direct imaging approaches. We show that after third and fourth generation missions foreseeable for the next 100 years, we will face a very long era before being able to see directly the morphology of extrasolar organisms.

So, why do you talk to your dog about physics?

Lots of reasons, but the main one is that I'm a physics professor. Talking about physics is what I do. Sooner or later I talk to everybody about physics.

Welcome to Visual6502.org! Here we'll slowly but surely present our small team's effort to preserve, study, and document historic computers. We aim to present our work in a visual, intuitive manner for education and inspiration, and to serve as a solid verifiable reference for classic computer systems. See our slides for an introduction and some fun images.

Up to date and comprehensive in its coverage, Neutrinos in Particle Physics, Astrophysics and Cosmology reviews the whole landscape of neutrino physics, from state-of-the-art experiments to the latest phenomenological and theoretical developments to future advances.

Nature 427, 388-389 (29 January 2004) | doi:10.1038/427388a (restricted)

A reclusive Russian claims to have solved a century-old mathematical problem — but his enigmatic personality is adding a fresh dimension to the proof-checking process. Emily Singer reports.

Quantum mechanics describes strange phenomena far beyond the realm of everyday experience. Computer visualization is sometimes the only method to observe what cannot be seen by any other means.

This is a collection of movie clips in which Mathematics appears. I'm collecting DVDs and VHS tapes of such movies. This is a working document to be extended over time. I started this page during spring break 2006. See also the page "Begin of lectures in college teaching" and "End of lectures in college teaching" and "Examples of good talks". To see the movies larger, to see it on the iphone or include it ina presentation, chose the quicktime ipod version, which are files with .m4v extension. (Media RSS link).

IDLWAVE is an add-on mode for GNU Emacs and XEmacs which enables feature-rich development and interaction with IDL®, the Interactive Data Language, produced by ITT Visual Information Solutions. It provides a compelling, full-featured alternative to the IDLDE development environment bundled with IDL.

Emission lines provide a powerful tool to study the physical properties and chemical compositions of astrophysical objects in the Universe, from the first stars to objects in our Galaxy. The analysis of emission lines allows us to estimate the star formation rate and initial mass function of ionizing stellar populations, and the properties of active galactic nuclei. This book presents lectures from the eighteenth Winter School of the Canary Islands Astrophysics Institute (IAC), devoted to emission lines and the astrophysical objects that produce them. Written by prestigious researchers and experienced observers, it covers the formation of emission lines and the different sources that produce them. It shows how emission lines in different wavelengths, from ultraviolet to near infrared, can provide essential information on understanding the formation and evolution of astrophysical objects. It also includes practical tutorials for data reduction, making this a valuable reference

"eine äußerst hilfreiche Anleitung zur Bewältigung technischer Klippen bereits weit im Vorfeld des öffentlichen Ernstfalles"
(Physik in unserer Zeit)

AcaWiki is like "Wikipedia for academic research" designed to increase the impact of scholars, students, and bloggers by enabling them to share summaries and discuss academic papers online. AcaWiki turns research hidden in academic journals into something more dynamic and accessible.

Wer als Schüler, Student, Ingenieur oder Wissenschaftler Datenreihen und mathematischen Funktionen darstellen will und über elementare Python-Kenntnisse verfügt, der sollte sich diesen Artikel einmal genauer ansehen.

Veusz is a scientific plotting and graphing package written in Python. It uses PyQt (Wiki) and Numpy. Veusz is designed to produce publication-ready Postscript/PDF output. Veusz runs under Unix/Linux, Windows and Mac OS X.

With this unique traveler's guide, you'll learn about 128 destinations around the world where discoveries in science, mathematics, or technology occurred or is happening now. Travel to Munich to see the world's largest science museum, watch Foucault's pendulum swinging in Paris, ponder a descendant of Newton's apple tree at Trinity College, Cambridge, and more. Each site in The Geek Atlas focuses on discoveries or inventions, and includes information about the people and the science behind them.

This timely and concise account of the early universe from the first light to reionization links the latest theories and experiments. Written by a scientist with much experience in research and writing, this is equally suited to young researchers and master and PhD students.

SM is a plotting programme written by Robert Lupton (

tIt is well known that interstellar travel is bounded by the finite speed of light, but on very large scales any rocketeer would also need to consider the influence of cosmological expansion on their journey. This paper examines accelerated journeys within the framework of Friedmann- Lemaitre-Robertson-Walker universes, illustrating how the duration of a fixed acceleration sharply divides exploration over interstellar and intergalactic distances. Furthermore, we show how the universal expansion increases the difficulty of intergalactic navigation, with small uncertainties in cosmological parameters resulting in significantly large deviations. This paper also shows that, contrary to simplistic ideas, the motion of any rocketeer is indistinguishable from Newtonian gravity if the acceleration is kept small.

Formulae for the line-of-sight and transverse comoving distances, proper motion distance, angular diameter distance, luminosity distance, k-correction, distance modulus, comoving volume, lookback time, age, and object intersection probability are all given, some with justifications. Some attempt is made to rationalize disparate terminologies, or at least abuse bad usage.

The Net Advance of Physics: COSMOLOGY

The gathering and analysis of experimental data are fundamental activities in science and engineering. Mathematica in the Laboratory is a hands-on guide which shows how to harness the power and flexibility of Mathematica in the control of data-acquisition equipment and the analysis of experimental data. It is fully compatible with Mathematica 3.0. Many practical examples are given, which can either be used directly or adapted to suit a particular application. The book sets out clearly how Mathematica can provide a truly unified data-handling environment, and will be invaluable to anyone who collects or analyzes experimental data, including astronomers, biologists, chemists, mathematicians, geologists, physicists, and engineers.

Astronomy provides a laboratory for extreme physics, a window into environments at extremes of distance, temperature and density that often can't be reproduced in Earth laboratories, or at least not right away. A surprising amount of the science we understand today started out as solutions to problems in astronomy. Some of this science was key in the development of many technologies which we enjoy today. This paper describes some of these connections between astronomy and technology and their history.

"Astrophysics Updates" is intended to serve the information needs of professional astronomers and postgraduate students about areas of astronomy, astrophysics and cosmology that are rich and active research spheres. Observational methods and the latest results of astronomical research are presented as well as their theoretical foundations and interrelations. The contributed commissioned articles are written by leading exponents in a format that will appeal to professional astronomers and astrophysicists who are interested in topics outside their own specific areas of research. This collection of timely reviews may also attract the interest of advanced amateur astronomers seeking scientifically rigorous coverage.

We describe a new formula capable of quantitatively characterizing the Hubble sequence of spiral galaxies including grand design and barred spirals. Special shapes such as ring galaxies with inward and outward arms are also described by the analytic continuation of the same formula. The formula is r(φ) =A/log [B tan (φ/2N)] . This function intrinsically generates a bar in a continuous, fixed relationship relative to an arm of arbitrary winding sweep. A is simply a scale parameter while B, together with N, determines the spiral pitch. Roughly, greater N results in tighter winding. Greater B results in greater arm sweep and smaller bar/bulge, while smaller B fits larger bar/bulge with a sharper bar/arm junction. Thus B controls the 'bar/bulge-to-arm' size, while N controls the tightness much like the Hubble scheme. The formula can be recast in a form dependent only on a unique point of turnover angle of pitch – essentially a one-parameter fit [...]

We present reduced and calibrated high resolution Lyman-alpha (Lya) images for a sample of 6 local star forming galaxies. [...]

The exploration of the first billion years of the history of the Universe, from the so-called Dark Ages to cosmic reionisation, represents one of the great challenges of contemporary astrophysics and one of the main drivers for future observational facilities.

The book contains the elaborated notes of lectures given at the 36th Saas-Fee Advanced Course "First Light in the Universe" by three eminent scientists in the field: Abraham Loeb, Andrea Ferrara, and Richard Ellis. The formation of the first stars and black holes, the initial mass function, feedback effects, early dust formation, the history of cosmic star formation, distant galaxies, cosmic reionisation and the cosmic infrared background are the main topics treated. This book provides an accessible and up-to-date review of the field and will be useful to graduate students of astronomy, cosmologists, physicists and researchers.

We present stellar population modeling results for ten newly discovered Lyman alpha emitting galaxies (LAEs), as well as four previously known LAEs at z ~ 4.5 in the Chandra Deep Field-South. We fit stellar population models to these objects in order to specifically learn if there exists more than one class of LAE. Past observational and theoretical evidence has shown that while many LAEs appear to be young, they may be much older, with Lyα equivalent widths enhanced due to resonant scattering of Lyα photons in a clumpy interstellar medium (ISM). [...]

APLpy (the Astronomical Plotting Library in Python) is a Python module aimed at producing publication-quality plots of astronomical imaging data in FITS format. The module uses Matplotlib, a powerful and interactive plotting package. It is capable of creating output files in several graphical formats, including EPS, PDF, PS, PNG, and SVG.

Welcome to my Galaxy Luminosity Function Engine. You can use the form below to create your own B-band luminosity function (LF) of a volume-limited galaxy population. The assumption is that the shapes of the type-specific LF of ellipticals (E), lenticulars (S0), spirals (Sp), dwarf irregulars (dIrr), and dwarf ellipticals (dE) are invariant of the environment and thus the observed variation of the overall LFs from galaxy clusters to the field has its origin in the different type mixtures (known as the morphology-density relation).

I present an elementary essay on some issues related to nonrelativistic quantum mechanics, which is written in the spirit of extreme simplicity, making it an easy-to-read paper. Moreover, one can find a useful collection of ideas and opinions expressed by many well-known authors in this vast research field

Kalzium is an application which will show you some information about the periodic system of the elements. Therefore you could use it as an information database.

Exemplar allows you to see how a particular term or phrase is used in peer-reviewed, published literature. Need the full text? It’s one click to the source.

How do you spark off an interest in maths when the curriculum seems dreary? It's all about mystery, big stories and journeys to infinity and beyond, says Marcus du Sautoy

The way galaxies assemble their mass to form the well-defined Hubble sequence is amongst the most debated topic in modern cosmology. One difficulty is to link distant galaxies to those at present epoch. We aim at establishing how were the galaxies of the Hubble sequence, 6 Gyrs ago. We intend to derive a past Hubble sequence that can be causally linked to the present-day one. We selected samples of nearby galaxies from the SDSS and of distant galaxies from the GOODS survey. We verified that each sample is representative of galaxies. We further showed that the observational conditions necessary to retrieve their morphological classification are similar in an unbiased way. Morphological analysis has been done in an identical way for all galaxies in the two samples. We found an absence of number evolution for elliptical and lenticular galaxies, which strikingly contrasts with the strong evolution of spiral and peculiar galaxies. Spiral galaxies were 2.3 times less abundant in the past ...

We describe a new library (AST) which provides a flexible high-level programming interface for handling world coordinate systems in astronomy and for producing graphical output. It includes, but is not limited to, a wide range of celestial coordinate systems and supports the Digitised Sky Survey plate solutions and the draft FITS WCS proposals amongst other possibilities. AST is portable and environment independent.