Galakser og stjerner

Den verdenskendte kosmolog og bestsellerforfatter til En kort historie om tid har efterladt os sine sidste tanker om universets største spørgsmål i dette betagende posthume værk. Hvordan opstod universet? Kan menneskeheden overleve på Jorden? Findes der intelligent liv uden for vores solsystem? Kommer kunstig intelligens til at udkonkurrere os? Igennem sin enestående karriere udvidede Stephen Hawking vores forståelse af universet og opklarede nogle af dets største mysterier. Men selv når hans teoretiske arbejde med sorte huller, imaginær tid og multivers førte hans tanker til rummets yderste grænser, troede Hawking fuldt og fast på, at videnskaben skulle spille en rolle i løsningen af Jordens største problemer. Nu hvor vi står over for potentielt katastrofale forandringer – herunder klimaforandringer, truslen om atomkrig og udviklingen af kunstig super-intelligens – har Stephen Hawking rettet sin opmærksomhed mod menneskehedens mest presserende anliggender. Med en fascinerende argumentation og karakteristisk humor er 'Korte svar på de store spørgsmål' den sidste bog fra en af historiens største begavelser, en intellektuelt stimulerende tour de force fra universets uendelige vidder til de allermest vedkommende udfordringer, som vi og vores klode står over for. En procentdel af indtægterne fra bogen går til velgørende formål.

Gyldendals stjernekort er et let anvendeligt redskab til at orientere sig i stjernevrimlen. Kortet kan bruges året rundt: Den øverste plastskive drejes, således at dato og klokkeslet kommer til at stå ud for hinanden, og den aktuelle stjernehimmel for det pågældende tidspunkt fremkommer. Sammen med kortet følger en grundig vejledning, som giver eksempler på de for årstiden karakteristiske stjernebilleder. Kortet er tegnet til at kunne bruges i Danmark, men kan med god nøjagtighed anvendes i det øvrige Skandinavien.

Der er ikke otte, men milliarder af planeter i Universet, og mange af dem ligger i et lunt smørhul, hvor de potentielt kan huse liv. Den opdagelse er en af de største i den moderne astronomi, og vi er kun lige begyndt at forstå, hvad der egentlig gemmer sig derude i kosmos af bizarre kloder. 'Fjerne kloder' beskriver erkendelsesrejsen, fra Giordano Bruno blev brændt på bålet i år 1600 for sin kætterske idé om uendelig mange planeter – og til konstruktionen af små satellitter, som måske kan besøge de nærmeste af disse exoplaneter og lede efter livstegn på dem. Undervejs møder vi forskerne ved fronten, som kigger hinsides solsystemet og kæmper for at besvare det ultimative spørgsmål: Er vi alene?

En dag befinder Frederik Dirks Gottlieb sig i sin fars gamle sommerhus. Han er taget derop, fordi faren er død, og midt i alt flytterodet finder han nogle gamle kasser med farens efterladte papirer og bunker af ufo-blade. Uden at vide det, er det begyndelsen til en ny og vild drejning i Frederiks liv.Kasserne gemmer nemlig på hemmeligheder, Frederik ikke kendte til. Nu begynder han en intensiv jagt efter svar på, hvem faren var, og før han aner det, har han kilder i røret fra Pentagon. Hvad er det, faren vidste? Og holder nogen noget hemmeligt for os?Ufo-mysteriet er en virkelig fortælling om mystik og dybe hemmeligheder. Det er en historie om mennesker, der hele deres liv er blevet hånet for at have troet på liv i rummet, men som endelig får oprejsning.Mens Frederik Dirks Gottlieb søger efter svar, tager han læserne med gennem ufoernes historie og fortæller om de folk, der gennem tusindvis af år har søgt svar på spørgsmålet over alle spørgsmål: Er vi alene?

Avi Loeb, ledende astrofysiker ved Harvard University, fremlægger sin kontroversielle teori om, at vores solsystem for nylig blev besøgt af avanceret og fremmed teknologi fra en fjern stjerne. I slutningen af 2017 fik nogle forskere på et observatorium i Hawaii øje på et objekt, der kom flyvende gennem vores indre solsystem og bevægede sig så hurtigt, at det nødvendigvis måtte stamme fra en anden stjerne. Avi Loeb påviste, at det ikke kunne være en asteroide. Objektet bevægede sig ganske enkelt for hurtigt og langs en underlig bane – og det forsvandt sporløst. Bogen er en tankevækkende rejse til videnskabens og den menneskelige forestillingsevnes yderste grænser.

Teorien om Big Bang er den bedste model, vi i øjeblikket har om universets skabelse; men det betyder ikke, at det er den endelige sandhed. Men hvorfor er der stort set enighed om, at universet for 13,7 milliarder år siden blev skabt af en tætpakket klump, der rummede al energi og alt stof? Og eksisterede der noget inden Big Bang? Astrofysikeren Anja C. Andersen formidler teorier og forskningsresultater udogmatisk og letforståeligt.

Porphyrin Sensitizers for Solar Cells" by Jonnadula V S Krishna is a comprehensive guide to the applications of porphyrin-based dyes in dye-sensitized solar cells (DSSCs). The book covers the various aspects of porphyrin sensitizers and their potential use in solar cells, including their synthesis, characterization, and performance in solar cells. The book begins with an introduction to the principles of solar energy conversion and an overview of different types of solar cells. It then focuses on the design and synthesis of porphyrin sensitizers, including their electronic and photophysical properties. The author also discusses various techniques for characterizing porphyrin sensitizers, such as UV-vis absorption, fluorescence, and electrochemical methods. The book then delves into the performance of porphyrin sensitizers in solar cells, including their efficiency, stability, and compatibility with different types of electrolytes. The author also explores the various factors that can affect the performance of porphyrin-based solar cells, such as the nature of the sensitizers, the thickness of the dye layer, and the composition of the electrolyte. Overall, "Porphyrin Sensitizers for Solar Cells" is an essential resource for researchers and engineers working in the field of solar energy conversion, as well as for graduate students and advanced undergraduates in chemistry, materials science, and physics. The book provides a thorough and up-to-date overview of the latest research on porphyrin sensitizers, making it an invaluable reference for anyone interested in this exciting field.

'If you want to remember why you once fell in love with the idea of the cosmos, or want to fall in love with it for the first time, then this book is for you' ObserverFrom Carlo Rovelli, the bestselling author of Seven Brief Lessons on Physics, this is a story of wonder, new worlds and why the end is just the beginningLet us journey into the heart of a black hole. Let us slip beyond its boundary, the horizon, and tumble - on and on - down this crack in the universe. As we plunge, we'll see geometry fold, we'll feel the equations draw tight around us. Eventually, we'll pass it: the remains of a star, deep and dense and falling further far. And then - the bottom. Where time and space end, and the white hole is born . . .With lightness and magic, here Carlo Rovelli traces the ongoing adventure of his own cutting-edge research, of the uncertainty and joy of going where we've not yet been. Guiding us to the edge of theory and experiment, he invites us to go beyond, to experience the fever and the disquiet of science. Here is the extraordinary life of a white hole.A BOOK OF THE YEAR ACCORDING TO THE FINANCIAL TIMES * SUNDAY TELEGRAPH * NEW STATESMAN * NEW SCIENTIST

Like in the past cosmic rays (CR) may help us extend our knowledge of Particle Physics. Such a case is the nature of Dark Matter (DM). That question lies in the intersection of particle physics and astrophysics. It involves both questions of particle physics modeling, as well as of production and propagation of cosmic rays.Cold dark matter (CDM) has been established by many evidence as the stan-dard paradigm for the missing matter of the universe. Beginning with early obser-vations of velocity dispersions of galaxies in clusters [358], and later measurements of galactic rotation curves [296, 295], CDM has been supported by numerous ad- ditional observations. These include strong lensing of background galaxies [339],x-ray emission from galaxy clusters [91], the combination of CMB and type Ia supernovae data [313], measurements of the distributions of galaxies [118, 334], as well as the highly remarkable recent study of the bullet cluster [117].Measurementsof the CMB, the need for early structure growth, and the success of big-bang nu-cleosynthesis rule out baryonic matter as being the dark matter, necessitating anew particle beyond the standard model.

"Stargazing is a perfect hobby. It can be done any time of year from anywhere, and it's easy to share with friends and family of all ages. For decades, Mike Lynch has been building telescopes, teaching classes on astronomy, and guiding tours of the stars. Let the beloved WCCO Radio meteorologist help you begin stargazing with the new edition of Stars: A Month-by-Month Tour of the Constellations. Written in Mike's casual, friendly tone, the guide provides a monthly look at the night sky-complete with sky charts and detailed descriptions of what you can expect to see. Plus, you'll learn all about two or three specific constellations each month"--

Winds form an integral part of astronomy ¿ from regulating rotation of stars through enriching galaxies with fresh materials. Outflowing winds persist during the entire lives of stars and play a key role in shaping the exoplanet demographics we observe. In massive stars, their winds are a vital ingredient of their evolution, from the main sequence to the pre-supernova stage, determining black hole masses as measured from gravitational waves. In the case of low-mass stars, their winds dictate rotational evolution, which affect angular momentum distribution within the stellar interior and thus the generation of magnetic fields. In the case of planets, winds take the form of atmospheric escape, which can strongly affect their atmospheric evolution. IAU Symposium 370 brings together researchers on winds of exoplanets and stars, including the solar wind, to share insights into the physics and modelling tools used by these different communities.

By the star physicist and author of multiple #1 Sunday Times bestsellers, a major and definitive narrative work on black holes and how they can help us understand the universe. At the heart of our galaxy lies a monster so deadly it can bend space, throwing vast jets of radiation millions of light years out into the cosmos. Its kind were the very first inhabitants of the universe, the black holes.Today, across the universe, at the heart of every galaxy, and dotted throughout, mature black holes are creating chaos. And in a quiet part of the universe, the Swift satellite has picked up evidence of a gruesome death caused by one of these dark powers. High energy X-ray flares shooting out from deep within the Draco constellation are thought to be the dying cries of a white dwarf star being ripped apart by the intense tides of a supermassive black hole ? heating it to millions of degrees as it is shredded at the event horizon.They have the power to wipe out any of the universe's other inhabitants, but no one has ever seen a black hole itself die. But 1.8 billion light years away, the LIGO instruments have recently detected something that could be the closest a black hole gets to death. Gravitational waves given off as two enormous black holes merge together. And now scientists think that these gravitational waves could be evidence of two black holes connecting to form a wormhole ? a link through space and time. It seems outlandish, but today's physicists are daring to think the unthinkable ? that black holes could connect us to another universe.At their very heart, black holes are also where Einstein's Theory of General Relativity is stretched in almost unimaginable ways, revealing black holes as the key to our understanding of the fundamentals of our universe and perhaps all other universes.Join Professors Brian Cox and Jeff Forshaw in exploring our universe's most mysterious inhabitants, how they are formed, why they are essential components of every galaxy, including our own, and what secrets they still hold, waiting to be discovered.

This book, the world's first complete (and stereoscopic) atlas of an asteroid, is the result of a unique collaboration between OSIRIS-REx mission leader Dante Lauretta and Brian May's London Stereoscopic Company. Lauretta's colleagues include Carina Bennett, Kenneth Coles, and Cat Wolner, as well as Brian May and Claudia Manzoni, who became part of the ultimately successful effort to find a safe landing site for sampling. The text details the data collected by the mission so far, and the stereo images have been meticulously created by Manzoni and May from original images collected by the OSIRIS-REx cameras.

Following on from the hugely popular Treasury of Folklore: Seas and Rivers and Woodlands and Forests comes Treasury of Folklore: Stars and Skies, an exploration of the mysteries of the stars, skies and heavens above.People have gazed up at the same stars for millennia, trading stories about them; conjuring gods and goddesses; mapping the constellations; and navigating the complex human world below. The tales, traditions and myths included here traverse countries and continents and have been chosen to highlight how humans are linked through time and place, with shared dreams, fears and ways of rationalising the unknown.Under 'Stars and Heavens' Willow delves into rosy fingered dawn and the hubris of Icarus, the Greek myths surrounding the constellations and the omen of meteors, the trials of the Hawaiian goddess Hina and the legend of the rabbit in the moon. In the section on 'Skies' we are introduced to winged Pegasus and the trials of the Firebird, the Witch of Westray and stories of storms, the mysteries of the Northern Lights and unexplained UFOs. Treasury of Folklore: Stars and Skies is a fascinating portal into a rich history of myths surrounding the sky, an aspect of the natural world that continues to fascinate and confound.

Much has been said and written about the value of space exploration from a worldview that is primarily Western, Caucasian, male, and politically libertarian. Reclaiming Space aims to incubate, illuminate, and illustrate a more diverse and inclusive conversation about space travel. Featuring twenty-seven essays written by a diverse array of contributors, Reclaiming Space offers perspectives on subjects such as spaceflight's history; the links between science fiction, space art and imagery, and space policy; and spaceflight as a tool for social progress.

Discover 15 stars, planets and constellations, and learn how to spot them in the night sky.

Every night, above our heads, a drama of epic proportions is playing out. Diamond planets, zombie stars, black holes heavier than a billion Suns. The cast of characters is extraordinary, and each one has its own incredible story to tell.

By the star physicist and author of multiple #1 Sunday Times bestsellers, a major and definitive narrative work on black holes and how they can help us understand the universe. At the heart of our galaxy lies a monster so deadly it can bend space, throwing vast jets of radiation millions of light years out into the cosmos. Its kind were the very first inhabitants of the universe, the black holes.Today, across the universe, at the heart of every galaxy, and dotted throughout, mature black holes are creating chaos. And in a quiet part of the universe, the Swift satellite has picked up evidence of a gruesome death caused by one of these dark powers. High energy X-ray flares shooting out from deep within the Draco constellation are thought to be the dying cries of a white dwarf star being ripped apart by the intense tides of a supermassive black hole ? heating it to millions of degrees as it is shredded at the event horizon.They have the power to wipe out any of the universe's other inhabitants, but no one has ever seen a black hole itself die. But 1.8 billion light years away, the LIGO instruments have recently detected something that could be the closest a black hole gets to death. Gravitational waves given off as two enormous black holes merge together. And now scientists think that these gravitational waves could be evidence of two black holes connecting to form a wormhole ? a link through space and time. It seems outlandish, but today's physicists are daring to think the unthinkable ? that black holes could connect us to another universe.At their very heart, black holes are also where Einstein's Theory of General Relativity is stretched in almost unimaginable ways, revealing black holes as the key to our understanding of the fundamentals of our universe and perhaps all other universes.Join Professors Brian Cox and Jeff Forshaw in exploring our universe's most mysterious inhabitants, how they are formed, why they are essential components of every galaxy, including our own, and what secrets they still hold, waiting to be discovered.

Studienarbeit aus dem Jahr 2014 im Fachbereich Physik - Astronomie, Note: 1,0, , Sprache: Deutsch, Abstract: Wie sind Galaxien entstanden? Wie sind Galaxien aufgebaut? Was für Arten von Galaxien gibt es? Was passiert, wenn zwei Galaxien kollidieren? Wie Entwickeln sich Galaxien weiter? Was wird aus der Milchstraße?Diese Seminararbeit beschäftigt sich mit diesen Fragen und vergleicht, wie sie heute und vor 25 Jahren beantwortet wurden.In Spiralgalaxien kann man im Gegensatz zu elliptischen Galaxien sehr gut einzelne Strukturen erkennen, wie das Halo, welches kugelförmig die Galaxie umgibt und eine flache Scheibe, mit den Spiralarmen mit einem dichten Zentrum aus Sternen.Im Halo, welcher einen Radius von bis zu 200 000 LJ haben kann, bewegen sich vereinzelt Kugelsternhaufen, wodurch er relativ dunkel ist im Gegensatz zur Spirale. Einige Kugelsternhaufen bewegen sich aber auch außerhalb des Halos. Diese Sternhaufen können mehrere Millionen von Sternen, meist alte Rote Riesen welche schon erkaltet sind, enthalten und weisen Radien von bis zu 150 LJ auf. Ihre Bahnen verlaufen außerdem sehr exzentrisch um den Kern, bis zu 300 000 LJ über die Scheibenebene hinaus. Beim Durchkreuzen dieser Scheibe wird Gas an diese abgegeben, woraufhin die Roten Riesen zu weißen Zwergen werden. Die Arme der Scheibe, deren Radius oft das 50-fache ihrer Dicke beträgt, liegen eher lückenhaft und ohne klar definierbare Grenzen vor. Das Größenverhältnis zum Galaktischen Zentrum, oder auch Bulge genannt, ist von Galaxie zu Galaxie verschieden. Im Gegensatz zu den Sternen in der Scheibe sind diejenigen im Zentrum viel älter und bewegen sich auf Bahnen, welche weit aus der Scheibenebene herausführen, oder sogar im spitzen Winkel dazu verlaufen. In der Scheibe können jedoch auch noch Sterne durch das vorhandene Material, wie Staub und Gas, neu entstehen. Es konnte damals schon durch die Rotation der Galaxien die Existenz von dunkler Materie postuliert werden, welche wahrscheinlich um den Halo herum zu finden ist, aber über die Beschaffenheit kann nur gemutmaßt werden.

Proceedings of an ISSI Workshop, 26-30 January 1998, Bern, Switzerland

Proceedings of the 180th Symposium of the International Astronomical Union, held in Groningen, The Netherlands, August 26-30, 1996