Автор: Jean-Louis Tassoul
Издательство: Cambridge University Press
Год издания: 2000
isbn: 0511009631
Количество страниц: 273
Язык: english
Формат: PDF
In the mid-1970s, we had no direct information about the internal rotation of the Sun. Little was known about the rotation of main-sequence stars of spectral type G and later, although it was already well established that the surface rotation rate of these stars decayed as the inverse square root of their age. We certainly had much more information about axial rotation in the upper-main-sequence stars, but the actual distribution of specific angular momentum within these stars was still largely unknown. On the theoretical side, important progress in the study of rotating stars had been made by direct numerical integration of the partial differential equations of stellar structure. However, because there was no clear expectation for the actual rotation law in an early-type star, the angular momentum distribution always had to be specified in an ad hoc manner. The presence of large-scale meridional currents in a stellar radiative zone was also a serious problem: All solutions presented to date had unwanted mathematical singularities at the boundaries, and the back reaction of these currents on the rotational motion had never been properly taken into account. As far as I remember, there was only one bright spot that was emerging from this rather gloomy picture of stellar rotation: The observed degree of synchronism and orbital circularization in the short-period close binaries appeared to be in reasonable agreement with the (then current) theoretical views on tidal interaction in close binary systems. The year was 1977 and, as I said, we did not realize that the tide was turning fast.
Автор: Перельман Я.И.
Издательство: Артистическое заведение Т-ва А.Ф.Маркс
Год издания: 1919
Количество страниц: 82
Язык: русский
Формат: DJVU
Мысль о полетах в глубины вселенной и достижении иных миров автор не считает праздной мечтой. Она полна высокого интереса для науки и для жизни. Было время, когда признавалось невозможным переплыть океан; нынешняя всеобщая вера в недосягаемость небесных светил в сущности столь же безосновательна, как и убеждение наших предков в недостижимости антиподов. Правильный путь к разрешению проблемы заатмосферного летания и межпланетных путешествий уже намечен; к чести русской науки, он предуказан человечеству русским ученым. Практическое же разрешение этой грандиозной задачи, невыполнимое сейчас, может осуществиться не в столь далеком будущем. Этой маленькой экскурсией в область космической физики автор надеется также до некоторой степени рассеять существующее в публике предубеждение против небесной механики и физики, как знаний слишком отвлеченных, неспособных будто бы дать пищу живому уму. Наука, которая открывает возможность успешно соперничать в полете воображения с фантазией остроумнейших романистов, проверять и исправлять их смелые замыслы - такая наука должна перестать казаться сухой и скучной. И если те простейшие сведения из этой области знания, которые рассеяны в настоящей книге, заронят в уме любознательного читателя искру интереса к изучению механики и физики вселенной, если они возбудят желание поближе познакомиться с фундаментом величественной науки о небе, то цель автора будет достигнута вдвойне. Чтение этой книги не требует никаких специальных познаний. Материал, предназначаемый для более сведущих читателей, отнесен в отдел «Прибавлений».
Автор: Malcolm S.Longair
Издательство: Springer
Год издания: 2008
isbn: 3540734775
Количество страниц: 738
Язык: english
Формат: PDF
This is the second edition of my book Galaxy Formation.Many people liked the first edition which appeared in 1998, just before the explosion of magnificent new data which have completely changed the face of astrophysical cosmology. Many of the agonies which had to be gone through in the first edition have disappeared and, to many people’s amazement, including mine, there is now a concordance model for cosmology, the cosmologist’s equivalent of the particle physicist’s standard model. Just like the standard model, however, the concordance model creates as many problems as it solves. This is not a cause for concern, but rather one for celebration because we are now able to ask much better and deeper questions than in the past. These questions indicate clearly the need for physics and astrophysics ‘Beyond the Concordance Model’.
Автор: B. G. Sidharth
Издательство: World Scientific Publishing Company
Год издания: 2009
isbn: 9814277819
Количество страниц: 200
Язык: english
Формат: PDF
This book addresses some of the baffling questions encountered at the final frontier of space and time related to particle physics and cosmology in the context of recent iconoclastic observations and developments. When particle physics stagnated in the early seventies, a new development emerged - String Theory. For the past 25 years, String Theory, popularly called the Theory of Everything, has mesmerized not just scientists, but also the general public. Yet a closer scrutiny today reveals that it is no more than a mathematical marvel. It has neither predicted anything nor has it been anywhere near verification. We are essentially where we were in the early seventies. Another chronic problem that Einstein had abandoned was the unified description of his theory of General Relativity that deals with the Universe at large and Electromagnetism which is to do with particles. Such a description is necessary even if it warrants a radical departure from our time-honoured ideas of space and time. A bright spot has now appeared in Cosmology. Iconoclastic observations in the past years have shown that the Universe is actually accelerating, driven by a mysterious Dark Energy. This book takes the lay reader through these uncharted waters and mind-boggling developments on an unimaginable journey from the ultra small to the farthest stretches conceivable, via such imagination defying concepts as extra dimensions and multiple universes.
Автор: Giles Sparrow
Издательство: Dorling Kindersley Publishers Ltd
Год издания: 2007
isbn: 140531818X
Количество страниц: 320
Язык: english
Формат: PDF
At last, an illustration-rich, very well edited history of spaceflight. "Beautiful" because the pictures and computer-aided graphics are extensive, attractive, and many of the pictures are new to me. (And I have seen lots of spacecraft pictures.)
Автор: John Fielding
Издательство: adio Society of Great Britain
Год издания: 2006
isbn: 1905086164
Количество страниц: 320
Язык: english
Формат: PDF
Explore the contributions of radio amateurs to the science of radio astronomy and how the average amateur can make and set up equipment to study the signals coming from space. Contents include: * Receiving radio signals from outer space * A historical perspective of radio astronomy needed to become active * Paramaters required for the antenna and receiver through practical low noise amplifiers * Advice on assembling a receiving station and practical information to put together your own * A practical design for a "hydrogen line receiver" aimed at at 1420 MHz The author has achieved a great balance between historical narrative and technical information. Amateur Radio Astronomy is not only "a great read" but a practical technical reference for this fascinating topic.
Автор: Зигель Ф.Ю.
Издательство: Наука
Год издания: 1980
Количество страниц: 312
Язык: русский
Формат: DJVU
Популярный рассказ о звездном небе, о его делении на созвездия, какие созвездия видны зимой, весной, летом и осенью. Читатель узнает из книги о главных достопримечательностях каждого созвездия - двойных переменных звездах, звездных скоплениях, туманностях и других объектах. Отдельные главы посвящены звездному небу Антарктиды, Млечному пути и телам Солнечной системы. Особое внимание уделено Луне и первоначальному знакомству с лунной топографией. В новом издании книги учтены Открытия последних лет в области звездной астрономии, рассказано о квазарах, «черных дырах», о новейших данных по морфологии галактик. Для учащихся средней школы и широкого круга любителей астрономии.
Автор: Gregory Vogt
Издательство: Lerner Publications
Год издания: 2010
isbn: 0822590824
Количество страниц: 44
Язык: english
Формат: PDF
There is no gravity in space. The North Star never changes its position in the sky. Earth's shadow causes the phases of the moon. You may have heard these common sayings or beliefs before. But are they really true? Can they be proven using science? Let's investigate seventeen statements about space and find out which ones are right, which ones are wrong, and which ones still stump scientists! Find out whether astronauts really landed on the moon! Discover whether it's true that the same side of the Moon is always dark! See if you can tell the difference between fact and fiction with Is That a Fact?
Автор: Alvaro Israel, Rachel Einav, Joseph Seckbach
Издательство: Springer
Год издания: 2010
isbn: 9048185688
Количество страниц: 600
Язык: english
Формат: PDF
Global warming is accelerating faster than the ability for natural repair, and environmental stresses are damaging ecosystems, all affecting physical and biological systems on Earth. A new Nasa-led study shows that human activity has caused climate changes resulting in permafrost thawing, acid rain, and lower productivity in lakes as well as increased emissions of greenhouse gases, including CO2, N20, CH4, CF3, and CFC. Marine plants play a vital role in maintaining the balance of marine environments, while serving as a source of food for humankind and important chemical compounds. Microalgae and seaweed have enormous potential for reducing global warming and climate change. During photosynthesis algae grow, draw CO2 from the atmosphere, release oxygen, and produce solar biofuel. Experts in the life of marine plant ecosystems in globally changing environments contributed chapters to this book. The target readers are phycologists, ecologists, atmospheric scholars, conservationists, environmentalists, and ecologically aware laymen.
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