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Stephen Hawkins - property of expanding universe PDF file

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Authors    Hawking, Stephen Advisors Sciama, Dennis Date 1966-03-15 Awarding Institution University of Cambridge Author Affiliation Faculty of Mathematics. Applied Mathematics and Theoretical Physics Qualification PhD Type Thesis Metadata Show full item record Citation Hawking, S.   (1966).  Properties of expanding universes  (doctoral thesis).  https://doi.org/10.17863/CAM.11283 Description This thesis has been made openly available with the kind permission of Professor Stephen Hawking. Abstract Some implications and consequences of the expansion of the universe are examined. In Chapter 1 it is shown that this expansion creates grave difficulties for the Hoyle-Narlikar theory of gravitation. Chapter 2 deals with perturbations of an expanding homogeneous and isotropic universe. The conclusion is reached that galaxies cannot be formed as a result of the growth of perturbations that were initially small. The propogation
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Archaeologists find gates of Hell in Saudi Arabia

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When researchers are searching for remnants of structures and settlements constructed by ancient peoples they typically focus on areas that are hospitable to human life. A new discovery in Saudi Arabia goes firmly against that notion, with archaeologists revealing the existence of hundreds of stone “gates” situated in and around ancient lava domes, in an area that is little more than a hellish landscape devoid of vegetation and water. The structures, which measure anywhere from 40 feet to nearly 1,700 feet in length, are crude in their construction, built of rough rocks that have withstood thousands of years of wear and tear. What’s most interesting is that it appears that the lava fields these structures were built upon was still active at the time, with hardened lava appearing to have flowed over some of the gates. “Gates are found almost exclusively in bleak, inhospitable lava fields with scant water or vegetation, places seemingly amongst the most unwelcoming to our species,” D
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How do Scientists Read Chromosomes?

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To "read" a set of chromosomes, scientists use three key features to identify their similarities and differences: Size.  This is the easiest way to tell chromosomes apart. Banding pattern.  The size and location of Giemsa bands make each chromosome unique. Centromere position.  Centromeres appear as a constriction. They have a role in the separation of chromosomes into daughter cells during cell division (mitosis and meiosis). Using these key features, scientists can identify all 46 chromosomes — one set of 23 from each parent What are centromeres for? Centromeres are required for chromosome separation during cell division. The centromeres are attachement points for microtubules, which are protein fibers that pull duplicate chromosomes toward opposite ends of the cell before it divides. This separation ensures that each daughter cell will have a full set of chromosomes. Each chromosome has only one centromere. During cell division, microtubule
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The top three scientific explanations for ghost sighting

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From ghosts to ghouls, witches to wizards, Halloween is the one time of the year when people come together to celebrate everything supernatural. But beyond the fancy dress and trick or treating, belief in ghosts is actually relatively common – with  38% of people classifying themselves as believers  and a similar number having actually reported seeing one. The term “ghost” refers to the idea that the spirits of the dead – human and animal – influence the physical world. And the idea of a haunting can often include anything from a sensed presence, or objects moving, to spirit activity. But in a world filled with science and reason, these “hauntings” can often boil down to a very simple explanation. So with Halloween just round the corner, here are the top three scientific and psychological explanations for hauntings, spirits, spookiness and all things supernatural – although it should be noted that many important questions have yet to be resolved … 1. Because I told you so Atte
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Why do we dream?

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The human  brain  is a mysterious little ball of gray matter. After all these years, researchers are still baffled by many aspects of how and why it operates like it does. Scientists have been performing sleep and  dream  studies for decades now, and we still aren't 100 percent sure about the function of  sleep , or exactly how and why we dream. We do know that our dream cycle is typically most abundant and best remembered during the REM stage of sleep. It's also pretty commonly accepted among the scientific community that we all dream, though the frequency in which dreams are remembered varies from person to person. The question of whether dreams actually have a physiological, biological or psychological function has yet to be answered. But that hasn't stopped scientists from researching and speculating. There are several theories as to why we dream. One is that dreams work hand in hand with sleep to help the brain sort through everything it collects during the
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Monotremata - monotremes

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  Short-beaked echidna taxidermy Short-beaked echidna skeleton Platypus taxidermy The   order   Monotremata   is the only   extant   group within the subclass Prototheria   - the   oldest living   taxon   of the class Mammalia . Whilst there has never been much doubt that monotremes split off from other mammal group at an early stage, due to their many ancestral reptilian characters (see below), the mid 20 th -Century saw much dispute regarding the evolutionary positioning of the other two major groups of mammal - the metatherians (marsupials) and the eutherians (placental mammals) - with respect to the monotremes. The question was whether the metatherians were the   sister clade   of the monotremes or of the eutherians. This proved a difficult question to answer, as much of our understanding of mammalian   phylogeny   has been gained through comparisons of tooth morphology, yet monotremes are toothless - a character that is certainly not ancestral. Howev
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Introduction to Calculus

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Calculus is all about  changes . Sam and Alex are travelling in the car ... but the speedometer is broken. Alex: "Hey Sam! How fast are we going now?" Sam: "Wait a minute ..." "Well in the last minute we went 1.2 km, so we are going:" 1.2 km per minute x 60 minutes in an hour =  72 km/h Alex: "No, Sam! Not our  average  for the last minute, or even the last second, I want to know our speed RIGHT NOW." Sam: "OK, let us measure it up here ... at this road sign... NOW!" "OK, we were AT the sign for  zero seconds , and the distance was ...  zero metres !" The speed is 0m / 0s = 0/0 =  I Don't Know ! "I can't calculate it Sam! I need to know  some  distance over  some  time, and you are saying the time should be zero? Can't be done." That is pretty amazing ... you'd think it is easy to work out the speed of a car at any point in time, but it isn't. Even
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