cosmology

"I shall try to sum up the main obstacles which arrested the progress of science for such an immeasurable time. The first was the splitting of the world into two spheres, and the mental split which resulted from it. The second was the geocentric dogma, the blind eye turned on the promising line of thought which had started with the Pythagoreans and stopped abruptly with Aristarchus of Samos. The third was the dogma of uniform motion in perfect circles. The fourth was the divorcement of science from mathematics. The fifth was the inability to realize that a body at rest tended to stay at rest, a body in motion tended to stay in motion. The main achievement of the first part of the scientific revolution was the removal of these five cardinal obstacles. This was done chiefly by three men: Copernicus, Kepler and Galileo. After that, the road was open to the Newtonian synthesis; from there on the journey led with rapidly gaining speed to the atomic age."

"It may be true that and (not science and evolution) are among the causes of atheism and materialism. It is at least equally true that biblical literalism, from its earlier flat-earth and geocentric forms to its recent young-earth and flood-geology forms, is one of the major causes of atheism and materialism. Many scientists and intellectuals have simply taken the literalists at their word and rejected biblical materials as being superseded or contradicted by modern science. Without having in hand a clear and persuasive alternative, they have concluded that it is nobler to be damned by the literalists than to dismiss the best testimony of research and reason. Intellectual honesty and integrity demand it."

"These seven bodies were the Sun, the Moon, Mercury, Venus, Mars, Jupiter, and Saturn, all of which were documented by the Babylonians over three thousand years ago. Until the sixteenth century, the most commonly held view was that the Earth was at the centre of the Universe and that the seven bodies revolved around the Earth."

"The odd thing about this story is that the heliocentric view was known in Europe long before Copernicus but, for various reasons, was totally ignored by the "established" dogma... All this time all kinds of absurdities were written about the heavens, the celestial spheres, the Empyrean and so on, which constituted the “established” view. And all the time the real knowledge was there and all those schoolmen, could, with some practical observation and sensible application of Mathematics, have found out that the Ptolemaic system was not true. But they did not: they preferred to argue about such weighty matters as how many angles could sit on the point of a pin. And when the proofs were presented to them in black and white, hard and irrefutable mathematical demonstrations, they still rejected them preferring the comforts of the ‘‘established” dogma. Theology (and Church interests) decided what was acceptable, not Mathematics."

"Let us... examine the point on which Newton, apparently with sound reasons, rests his distinction of absolute and relative motion. If the earth is affected with an absolute rotation about its axis, centrifugal forces are set up in the earth: it assumes an oblate form, the acceleration of gravity is diminished at the equator, the plane of Foucault's pendulum rotates, and so on. All these phenomena disappear if the earth is at rest and the other heavenly bodies are affected with absolute motion round it, such that the same relative rotation is produced. This is, indeed, the case, if we start ab initio from the idea of absolute space. But if we take our stand on the basis of facts, we shall find we have knowledge only of relative spaces and motions. Relatively, not considering the unknown and neglected medium of space, the motions of the universe are the same whether we adopt the Ptolemaic or the Copernican mode of view. Both views are, indeed, equally correct; only the latter is more simple and more practical. The universe is not twice given, with an earth at rest and an earth in motion; but only once, with its relative motions, alone determinable. It is, accordingly, not permitted us to say how things would be if the earth did not rotate. We may interpret the one case that is given us, in different ways. If, however, we so interpret it that we come into conflict with experience, our interpretation is simply wrong. The principles of mechanics can, indeed, be so conceived, that even for relative rotations centrifugal forces arise."

"The fundamental core of contemporary Darwinism, the theory of DNA-based reproduction and evolution, is now beyond dispute among scientists. It demonstrates its power every day, contributing crucially to the explanation of planet-sized facts of geology and meteorology, through middle-sized facts of ecology and agronomy, down to the latest microscopic facts of genetic engineering. It unifies all of biology and the history of our planet into a single grand story. Like Gulliver tied down in Lilliput, it is unbudgable, not because of some one or two huge chains of argument that might — hope against hope — have weak links in them, but because it is securely tied by thousands of threads of evidence anchoring it to virtually every other area of human knowledge. New discoveries may conceivably lead to dramatic, even "revolutionary" shifts in the Darwinian theory, but the hope that it will be "refuted" by some shattering breakthrough is about as reasonable as the hope that we will return to a geocentric vision and discard Copernicus."

"The present revolution of scientific thought follows in natural sequence on the great revolutions at earlier epochs in the history of science. Einstein's special theory of relativity, which explains the indeterminateness of the frame of space and time, crowns the work of Copernicus who first led us to give up our insistence on a geocentric outlook on nature; Einstein's general theory of relativity, which reveals the curvature or non-Euclidean geometry of space and time, carries forward the rudimentary thought of those earlier astronomers who first contemplated the possibility that their existence lay on something which was not flat. These earlier revolutions are still a source of perplexity in childhood, which we soon outgrow; and a time will come when Einstein's amazing revelations have likewise sunk into the commonplaces of educated thought."

"The Greek philosopher, Plato, in the fourth century B.C. asked his students if they could devise a theory or explanation to explain this erratic planetary motion using some form of circular motion. Being keen observers, the Greeks came up with the most logical and obvious conclusions; namely, that the earth was the center about which the sun, the moon, planets, and the stars rotated. This model of the universe is called a geocentric or earth-centered model. It satisfactorily explained the daily motion of the stars and sun by assuming that they were attached to invisible crystalline spheres that rotated about the earth. The axis of the sphere of the sun was tilted with respect to that of the stars to account for the variation of the sun's height at with the various seasons. Since the sun appears to move through the stars and was brighter, it was assumed to be nearer to the earth than the stars. The spheres of the Moon, Mercury, and Venus were placed within the sphere of the sun while those of Mars, Jupiter, and Saturn were placed outside the sphere of the sun but within the sphere of the stars."

"Fundamental changes in science have always been accompanied by deeper digging toward the philosophical foundations. Changes like the transition from the Ptolemaic to the Copernican system, from Euclidean to non-Euclidean geometry, from Newtonian to relativistic mechanics... have brought about a radical change in our common-sense explanation of the world. From all these considerations everyone who is to get a satisfactory understanding of twentieth century science will have to absorb a good deal of philosophical thought. But he will soon feel the same thing holds for a thorough understanding of the science which originated in any period of history."

"Ptolemy... against the champions of this or that cosmology of the heavens... had dared to claim that it is legitimate to interpret the facts of astronomy by the simplest geometrical scheme which will 'save the phenomena,' no matter whose metaphysics might be upset. His conception of the physical structure of the earth, however, prevented him from carrying through in earnest this principle of relativity, as his objections to the hypothesis that the earth moves amply show."

"Galileo had the experience of beholding the heavens as they actually are for perhaps the first time, and wherever he looked he found evidence to support the Copernican system against the Ptolemaic, or at least weaken the authority of the ancients. This shattering experience—of observing the depths of the universe, of being the first mortal to know what the heavens are actually like—made so deep an impression... that it is only by considering the events of 1609... that one can understand the subsequent direction of his life."

"Both ancient and medieval observers had noted that in many respects nature appeared to be governed by the principle of simplicity, and they had recorded the substance of their observations to this effect in the form of proverbial s which had become currently accepted bits of man's conception of the world. That falling bodies moved perpendicularly towards the earth, that light travelled in straight lines, that projectiles did not vary from the direction in which they were impelled, and countless other familiar facts of experience, had given rise to such common proverbs as: 'Natura semper agit per vias brevissimas'; 'natura nihil facit frustra'; 'natura neque redundat in superfluis neque deficit in necessariis' [Nature always acts by the shortest path; nature does nothing in vain; nature never overflows into the unnecessary, nor is she deficient in what is necessary]. This notion, that nature performs her duties in the most commodious fashion, without extra labour, would have tended to decrease somewhat the repulsion which most minds must have felt at Copernicus; the cumbrous epicycles had been decreased in number, various irregularities in the Ptolemaic scheme were eliminated... That such a tremendous shift in the point of reference could be legitimate was a suggestion quite beyond the grasp of people trained for centuries to think in terms of a homocentric philosophy and a geocentric physics. ...Copernicus could take the step because... he had definitely placed himself in... [the] dissenting Platonic movement. ...It was no accident that he became familiar with the remains of the early Pythagoreans, who almost alone among the ancients had ventured to suggest a non-geocentric astronomy."

"Persisting in their original resolve to destroy me and everything mine by any means they can think of, these men are aware of my views in astronomy and philosophy. They know that as to the arrangement of the parts of the universe, I hold the sun to be situated motionless in the center of the revolution of the celestial orbs while the earth revolves about the sun. They know also that I support this position not only by refuting the arguments of Ptolemy and Aristotle, but by producing many counter-arguments; in particular, some which relate to physical effects whose causes can perhaps be assigned in no other way. In addition there are astronomical arguments derived from many things in my new celestial discoveries that plainly confute the Ptolemaic system while admirably agreeing with and confirming the contrary hypothesis."

"Extra spatial dimensions could be a good thing. ... In a nongravitational theory, the spacetime geometry is a rigid background on which the dynamics takes place. In that setup, the fact that we observe four-dimensional Minkowski spacetime is a compelling argument to formulate the theory in that background geometry. As you know very well, this is part of the story of the Standard Model. However, in a gravitational theory that abides by the general principles laid out by Einstein, the spacetime geometry is determined by the dynamical equations. In such a setup extra dimensions can make sense provided that the equations of the theory have a solution for which the geometry is the product of four-dimensional Minkowski spacetime and a compact manifold that is sufficiently small to have eluded detection. It turns out that there are many such solutions. Moreover, the details of the compact manifold play a crucial role in determining the symmetries and particle content of the effective low-energy theory in four dimensions, even when the compact dimensions are much too small to observe directly."

"Why try to unite the four forces in a single theory? Why not simply use Einstein’s theory of general relativity to govern big things and quantum mechanics for little ones? Some concepts, such as the Big Bang or how black holes form, live in both domains. When we combine equations of the four forces to describe these ideas, our answers usually end up being either zero or infinity. … Here’s where string theory comes to the rescue. By adding seven hidden dimensions to the familiar three and another for time, plus antiparticles and a mirror set of particles called superparticles, the math starts to make sense. The force of gravity is diluted because it permeates into one or more of the hidden dimensions. Dark matter and dark energy also may invisibly shape our universe from these phantom dimensions."

"Miró... showed a series of canvases in which form submitted to strong colouring expressed a new two-dimensional cosmogony, in no way related to abstraction."

"Perhaps, with the introduction of more rational views of cosmogony and anthropology, and broader and more generous principles of psychology into our elementary text-books, through the union of a sounder physics with a larger metaphysics, our children's children may finally learn that there are inalienable animal as well as human rights, and that, in respect to the ties of moral obligation and the claims to kind and just treatment which they imply, not only "all nations of men," as Paul affirmed on Mar's Hill, but, as the Indian sage declared, "all living creatures are of one blood." "Metempsychosis", p. 164"

"The cosmogony of the Manava Dharmashastra is the broadest and most comprehensive we have thus far encountered."

"Uru and Svati are found in cosmogony. The signs of approaching Aquarius and its combination with Saturn are again being repeated. One can see once more how the cosmogony of the Atlanteans was on the right path. Not only was the chemism of the rays known at that time, but also the actual cooperation of the luminaries. After long wanderings, humanity again approaches just that. 516."

"Urusvati knows that cosmogony and religion should be carefully studied. One should appreciate the words of the Great Pilgrim when He said that He had come to fulfill the previous Law. 170."

"Your accepted conceptions of cosmogony — whether from the theological or scientific standpoints —do not enable you to solve a single anthropological or even ethical problem and they stand in your way whenever you attempt to solve the problem of the races on this planet... Go on saying, Our planet and man were created — and you will be fighting against hard facts for ever, analyzing and losing time over trifling details—unable to even grasp the whole. But once admit that... both planets and man are — states for a given time; that their present appearance — geological and anthropological — is transitory and but a condition concomitant of that stage of evolution at which they have arrived in the descending cycle — and all will become plain. You will easily understand what is meant by the one and only element or principle in the universe and that androgynous; the seven-headed serpent Ananda of Vishnu, the Nag around Buddha, the great dragon eternity biting with its active head, its passive tail, from the emanations of which spring worlds, beings and things. You will comprehend the reason why the first philosopher proclaimed all — maya..."

"Man hath ever made a cosmogony in keeping with his views in physics; a scheme of government in keeping with his cosmogony; a theory of ethics in keeping with his government, and a code of law and theology in keeping with his ethics. Every perception of the human mind modifies human practice. Science is but the theory of art."

"Amid all the beliefs of Europe, and of Asia, that of the Indian Brahmins seems to me infinitely the most alluring. And the reason why I love the Brahmin more than the other schools of Asiatic thought is because it seems to me to contain them all. Greater than all European philosophies, it is even capable of adjusting itself to the vast hypotheses of modern science. Our Christian religions have tried in vain, when there were no other choice open to them, to adapt themselves to the progress of science. But after having allowed myself to be swept away by the powerful rhythm of Brahmin thought, along the curve or life, with its movement of alternating ascent and return, I come back to my own century, and while finding therein the immense projections of a new cosmogony, offspring of the genius of Einstein, or deriving freely from the discoveries, I yet do not feel that I enter a strange land. I yet can hear resounding still the cosmic symphony of all those planets which forever succeed each other, are extinguished and once more illumined, with their living souls, their humanities, their gods – according to the laws of the eternal To Become, the Brahmin Samsara – I hear Siva dancing, dancing in the heart of the world, in my own heart."

"If Gods are made in the image of men, cosmogonies reflect the forms of terrestrial states. In an empire ruled absolutely by one man the notion of an universe under the control of a single God seemed obvious and reasonable.... The Christian God was a magnified and somewhat flattering portrait of Tiberius and Caligula."

"Radha’s elevated status, her role as a cosmic queen equal to or superior Krishna giving her a central role in the cosmogony in the Brahma Vivarta Purana... As creator of the universe we find Radha playing a role that is extremely atypical of her earlier history, the role of a mother. In the Brahma Vaivarta Purana, however, she is often called by names that suggest that her motherly role, vis-à-vis the created world. She is called mother of Vishnu, mother of the world, and mother of all."

"Pythagorean mathematics, the theory of the four elements of Thales of Miletus, Epicurean materialism, Platonic idealism, Judaism, Islam, and modern science are rooted in Egyptian cosmogony and science."

"Two principles, according to the Settembrinian cosmogony, were in perpetual conflict for possession of the world: force and justice, tyranny and freedom, superstition and knowledge; the law of permanence and the law of change, of ceaseless fermentation issuing in progress."

"The most natural expectation away from asymptotic limits in moduli space of supergravity theories is the desert scenario, where there are few states between massless fields and the quantum gravity cutoff. In this paper we initiate a systematic study of these regions deep in the moduli space, and use it to place a bound on the number of massless modes by relating it to the black hole species problem. There exists a consistent sub-Planckian UV cutoff (the species scale) which resolves the black hole species problem without bounding the number of light modes. We reevaluate this in the context of supersymmetric string vacua in the desert region and show that even though heuristically the species scale is compatible with expectations, the BPS states of the actual string vacua lead to a stronger dependence of the cutoff scale on the number of massless modes. We propose that this discrepancy, which can be captured by the “BPS desert conjecture”, resurrects the idea of a uniform bound on the number of light modes as a way to avoid the black hole species problem. This conjecture also implies a stronger form of the Tadpole Conjecture, which leads to an obstruction in stabilizing all moduli semi-classically for large number of moduli in flux compactifications."

"Since 1974, the guiding principle for building extensions of the standard model has been the so-called desert hypothesis. ... Its premise is that there is no new physics between the energy scales of electroweak unification (109 GeV or 1 TeV) and the vicinity of the Planck mass MPl (1019 GeV). That implies an enormous "desert," 16 orders of magnitude wide, where one would expect to encounter nothing new. MPl is the mass at which a particle's Compton wavelength becomes equal to its Schwarzschild radius—a realm where one can't do without a quantum theory of gravity. ... The leading contender for the elaboration of the desert picture has been the supersymmetric extension of the standard model ..."

"Let me come finally to the question that is of more direct interest to the audience here: ‘what are the scales of string unification?’ or put more provocatively, ‘will we see strings and extra dimensions at the LHC?’ (this is also discussed in Peskin’s talk ...) The conventional (and conservative) hypothesis is that the string, compactification and Planck scales lie all to within two or three orders of magnitude from each other, and are hence far beyond direct experimental reach. The non-gravitational physics at lower energies is thus described by a 4d supersymmetric quantum field theory (SQFT), which must at least include in it the MSSM. This conventional hypothesis is supported by the following three solid facts : (i) Softly broken SQFTs can indeed be extrapolated consistently to near-Planckian energies without destabilizing the electroweak scale ; (ii) the hypothesis is (almost) automatic in the weakly-coupled heterotic string theory, and (iii) the minimal (or ‘desert’) string-unification assumption is in remarkable agreement with some of the measured low-energy parameters of our world."

"An ash I know there stands, Yggdrasill is its name, a tall tree, showered with shining loam. From there come the dews that drop in the valleys. It stands forever green over Urðr's well."

"Where did you get this Christmas tree?" "Nowhere." "Did you cut down the Yggdrasil?" "Maybe..."

"Does Yggdrasil drink from it because it is the Well of Wisdom, or is it the Well of Wisdom because Yggdrasil drinks from it?"

"I know that I hung on the windy tree Nine full nights, Pierced by a spear offered to Odin Myself to myself of which none knows Upon that tree Where its roots run..."

"General relativity"

"Quasars were several hundred times more numerous when the universe was much younger. They were most numerous when the universe was about twenty percent of its current age, a time in the history of the universe sometimes called "cosmic noon"."

"LOFAR is a new European radio interferometer operating at frequencies 15–240 MHz (van Haarlem et al., 2013) and represents a milestone in terms of radio survey speed compared to existing telescopes. The LOFAR Surveys Key Science Project aims to carry out a tiered survey. ... These surveys will open the low-frequency electromagnetic spectrum for exploration, allowing unprecedented studies of the radio population across cosmic time and opening up new parameter space for searches for rare, unusual objects such as high-z radio quasars in a systematic way. Perhaps, one of the most tantalizing prospects are the 21 cm absorption line measurements using LOFAR along sight lines toward z > 6 radio quasars."

"The continuum spectrum of a quasar can often be described, over a broad frequency range, by a power law of the form S\nu \propto \nu–\alpha ... where \alpha is the spectral index. \alpha = 0 corresponds to a flat spectrum, whereas \alpha = 1 describes a spectrum in which the same energy is emitted in every logarithmic frequency interval."

"We seem to live in a remarkably economical X-ray universe, in that the observed cosmic X-ray background (CXRB) is produced with almost the least cosmic effort possible. It is not dominated by luminous obscured quasars thundering out huge amounts of power at z ≈ 2–4 but rather by moderate-luminosity, obscured AGNs at z ≈ 0.5–2."

"It is now clear that astronomers came across indirect manifestations of the CMB long before the 1960s. In 1941, Andrew McKellar discovered cyanide molecules (HCN) in interstellar space. ... As the object of research, McKellar chose absorption lines caused by cyanide molecules in the star 'ε' of Ophiuchis. He concluded that these lines could only be caused by absorption of light by rotating molecules. Relatively simple calculations allowed McKellar to conclude that the excitation of rotational degrees of freedom of cyanide molecules required the presence of external radiation with an effective temperature of 2.3 K. Neither McKellar himself, nor anyone else, suspected that he had stumbled on a manifestation of the cosmic microwave background."

"The standard Friedmann-Lemaître-Robertson-Walker (FLRW) cosmology is based on the cosmological principle, which posits that the universe is homogeneous and isotropic on large scales. This assumption is supported by the smoothness of the CMB, which has temperature fluctuations of only ∼ 1 part in 100,000 on small angular scales. These higher multipoles of the CMB angular power spectrum are attributed to Gaussian density fluctuations created in the early universe with a nearly scale-invariant spectrum, which have grown through gravitational instability to create the large-scale structure in the present universe. The dipole anisotropy of the CMB is however much larger, being ∼ 1 part in 1000 as observed in the heliocentric rest frame. This is interpreted as due to our motion with respect to the rest frame in which the CMB is isotropic, and is thus called the kinematic dipole."

"... we know in particular that for the first 380,000 years of the universe it was filled with a fireball. And we know this for sure because we've seen the fireball. In fact we've seen it , and we've take a photograph of it. This is called the cosmic microwave background radiation, but a much better name for it is the Fireball That Filled the Universe When It Was Much Younger."

"It is hard to understand how this infinitely dense singularity can evaporate into nothing. For matter inside the black hole to leak out into the universe requires that it travel faster than the speed of light."

"The subject of this book is the structure of space-time on length-scales from 10-13 cm, the radius of an elementary particle, up to 1028 cm, the radius of the universe. ...we base our treatment on Einstein's General Theory of Relativity. This theory leads to two remarkable predictions about the universe: first, that the final fate of massive stars is to collapse behind an event horizon to form a 'black hole' which will contain a singularity; and secondly, that there is a singularity in our past which constitutes, in some sense, a beginning to the universe."

"So Einstein was wrong when he said, "God does not play dice." Consideration of black holes suggests, not only that God does play dice, but that he sometimes confuses us by throwing them where they can't be seen."

"I'm sorry to disappoint science fiction fans, but if information is preserved, there is no possibility of using black holes to travel to other universes. If you jump into a black hole, your mass energy will be returned to our universe but in a mangled form which contains the information about what you were like but in a state where it can not be easily recognized. It is like burning an encyclopedia. Information is not lost, if one keeps the smoke and the ashes. But it is difficult to read. In practice, it would be too difficult to re-build a macroscopic object like an encyclopedia that fell inside a black hole from information in the radiation, but the information preserving result is important for microscopic processes involving virtual black holes."

"[F]or a physicist, the upper limit to entropy... is a critical, almost sacred quantity. ...the Bekenstein and Hawking result tells us that a theory that includes gravity is, in some sense, simpler than a theory that doesn't. ...If the maximum entropy in any given region of space is proportional to the region's surface area and not its volume, then perhaps the true, fundamental degrees of freedom—the attributes that have the potential to give rise to that disorder—actually reside on the region's surface and not within its volume. Maybe... the universe's physical processes take place on a thin, distant surface that surrounds us, and all we see and experience is merely a projection of those processes. Maybe... the universe is rather like a hologram."

"Black holes ain't as black as they are painted. They are not the eternal prisons they were once thought. Things can get out of a black hole, both to the outside, and possibly to another universe. So if you feel you are in a black hole, don't give up. There's a way out."

"Black holes have the universe's most inscrutable poker faces. ...When you've seen one black hole with a given mass, charge, and spin (though you've learned these thing indirectly, through their effect on surrounding gas and stars...) you've definitely seen them all. ...black holes contain the highest possible ...a measure of the number of rearrangements of an object's internal constituents that have no effect on its appearance. ...Black holes have a monopoly on maximal disorder. ...As matter takes the plunge across a black hole's ravenous , not only does the black hole's entropy increase, but its size increases as well. ...the amount of entropy ...tells us something about space itself: the maximum entropy that can be crammed into a region of space—any region of space, anywhere, anytime—is equal to the entropy contained within a black hole whose size equals the region in question."

"A natural guess is that... a black hole's entropy is... proportional to its volume. But in the 1970s and Stephen Hawking discovered that this isn't right. Their... analyses showed that the entropy... is proportional to the area of its event horizon... less than what we'd naïvely guess. ...Berkenstein and Hawking found that... each square being one by one Planck length... the black hole's entropy equals the number of such squares that can fit on its surface... each Planck square is a minimal unit of space, and each carries a minimal, single unit of entropy. This suggests that there is nothing, even in principle, that can take place within a Planck square, because any such activity could support disorder and hence the Planck square could contain more than a single unit of entropy... Once again... we are led to the notion of an elemental spatial entity."