Nature

"God be thanked for the Milky Way that runs across the sky, That's the path that my feet would tread whenever I have to die. Some folks call it a Silver Sword, and some a Pearly Crown, But the only thing I think it is, is Main Street, Heaventown."

"The stars are words and all the innumerable worlds in the Milky Way are words, and so is this world too. And I realize that no matter where I am, whether in a little room full of thought, or in this endless universe of stars and mountains, it’s all in my mind."

"Now, almost one hundred years later [in 1916 when Einstein began to apply his theory to describe the universe as a whole], it is difficult to fully appreciate how much our picture of the universe has changed in the span of a single human lifetime. As far as the scientific community in 1917 was concerned, the universe was static and eternal, and consisted of a one single galaxy, our Milky Way, surrounded by vast, infinite, dark, and empty space This is, after all, what you would guess by looking up at the night sky with your eyes, or with a small telescope, and at the time there was little reason to suspect otherwise."

"A broad and ample road, whose dust is gold, And pavement stars—as starts to thee appear Soon in the galaxy, that Milky Way Which mightily as a circling zone thou seest Powder'd with stars."

"The Sun is no lonelier than its neighbors; indeed, it is a very common-place star,—dwarfish, though not minute,—like hundreds, nay thousands, of others. By accident the brighter component of Alpha Centauri (which is double) is almost the Sun's twin in brightness, mass, and size. Could this Earth be transported to its vicinity by some supernatural power, and set revolving about it, at a little less than a hundred million miles' distance, the star would heat and light the world just as the Sun does, and life and civilization might go on with no radical change. The Milky Way would girdle the heavens as before; some of our familiar constellations, such as Orion, would be little changed, though others would be greatly altered by the shifting of the nearer stars. An unfamiliar brilliant star, between Cassiopeia and Perseus would be—the Sun. Looking back at it with our telescopes, we could photograph its spectrum, observe its motion among the stars, and convince ourselves that it was the same old Sun; but what had happened to the rest of our planetary system we would not know."

"But tell me, did you sail across the sun? Did you make it to the Milky Way? to see the lights all faded... And that Heaven is overrated? And tell me, did you fall for a shooting star? One without a permanent scar, and did you miss me While you were looking for yourself out there?"

"We come no nearer the infinitude of the creative power of God, if we enclose the space of its revelation within a sphere described with the radius of the Milky Way, than if we were to limit it to a ball an inch in diameter. All that is finite, whatever has limits and a definite relation to unity, is equally far removed from the infinite... Eternity is not sufficient to embrace the manifestations of the Supreme Being, if it is not combined with the infinitude of space."

"The brain is waking and with it the mind is returning. It is as if the Milky Way entered upon some cosmic dance. Swiftly the head-mass becomes an enchanted loom where millions of flashing shuttles weave a dissolving pattern, always a meaningful pattern though never an abiding one; a shifting harmony of subpatterns."

"The Milky Way was a familiar sight to all, snaking across the heavens with its light and dark patches forming recognizable shapes. The sky also contained numerous isolated faint and fuzzy objects (nebulae), fixed among the stars, as well as bright wandering stars (planets), and of course the moon, dominating the night sky, lighting the way by night and rendering many of its fainter companions temporarily invisible."

"There is a point of view among astronomical researchers that is generally referred to as the Principle of Mediocrity. … If the Sun and its retinue of worlds is only one system among many, then many other systems will be like ours: home to life. Indeed, to the extent that this is true, we should be prepared for the possibility that, even in the Milky Way galaxy, billions of planets may be carpeted by the dirty, nasty business known as life."

"We have finally established the contours that define the supercluster of galaxies we can call home … This is not unlike finding out for the first time that your hometown is actually part of much larger country that borders other nations."

"The cosmos is extremely complex....Earth is nothing but a speck of dust, and it is insignificant. Yet within this there are innumerable and complex structures. What are these structures of dimensions like?...Which level of dimension does our humankind live-in ? We live in the surface matter comprised of the biggest layer of molecular particles; we live in between molecules and planets—a planet is also a particle, and within the vast cosmos, it, too, is a trivial speck of dust. The Milky Way Galaxy is also a trivial speck of dust. This universe—the small universe I just described—is also but a trivial speck of dust. The largest particles that our human see are the planets, and the smallest particles visible to humankind are molecules. We humans exist in between the particles of molecules and planets. Being in this dimension, you think it is vast; from a different perspective, it is actually extremely narrow and tiny."

"The nebula is another stellar disc, composed of billions of suns, and constituting the Milky Way of some unknown firmament. Herschel has counted more than two thousand nebulae. Our Milky Way is the dwelling; the nebulae are the city."

"The Milky Way is a most extensive stratum of stars of various sizes admits no longer of the least doubt and our sun is actually one of the heavenly bodies belonging to it as evident. I have now viewed this shining zone in almost every direction, and find it composed of stars, whose number, by the account of these gages, constantly increases and decreases in proportion to its apparent brightness to the naked eye."

"We may also draw a very important additional conclusion from the gradual dissolution of the Milky Way; for the state into which the incessant action of the clustering power [presumably, gravity] has brought it at present, is a kind of chronometer that may be used to measure the time of its past and future existence; and although we do not know the rate of going of this mysterious chronometer, it is nevertheless certain, that since the breaking up of the parts of the milky way affords a proof that it cannot last for ever, it equally bears witness that its past duration cannot be admitted to the infinite."

"Time will come no doubt, When the sun shall die, the planet will freeze, and The air on them; frozen gases, white flakes of air Will be the dust: which no wind ever will stir; this very dust in dim starlight glistening Is dead wind, the white corpse of wind. Also, the galaxy will die; the glitter of the Milky Way, our universe, all the stars that have names are dead. Vast is the night. How you have grown, dear night, Walking your empty halls, how tall!"

"What of the scientists who assumed that continents were stable, that the hereditary material was protein, or that all other galaxies lay within the Milky Way? These false and abandoned efforts were pursued with passion by brilliant and honoura le scientists."

"Scientists previously placed the Milky Way in the Virgo Supercluster, but under Tully and colleagues' definition, this region becomes just an appendage of the much larger Laniakea, which is 160 million parsecs (520 million light years) across and contains the mass of 100 million billion Suns."

"Exalted Manna, gladness of the best, Heaven in ordinary, man well dressed, The milky way, the bird of Paradise, Church bells beyond the stars heard, the soul's blood, The land of spices something understood."

"As we are used (says he) to call the appearance of the heavens, where it is surrounded with a bright zone, the milky-way, it may not be amiss to point out some other very remarkable nebulae, which cannot well be less, but are probably much larger, than our own system ; and being extended, the inhabitants of the planets that attend the stars which compose them, must likewise perceive the same phenomenon; for which reason that may also be called milky-ways, by way of distinction."

"Space is not space between the earth and the sun to one who looks down from the windows of the Milky Way."

"...the old man looked up At a black eyelet in the white of the Milky Way, and he thought with wonder: "There — or thereabout — Cloaked in thick darkness in his power's dust-cloud, There is the hub and heavy nucleus, the ringmaster. Of all this million-shining whirlwind of dancers, the stars of this end of heaven, it is strange, truly, That great and small, the atoms of grain of sand and the suns of planets, and all the galactic universes. Are organized on one pattern, the eternal roundabout, the heavy nucleus and whirling electrons the leashed, And panting runners going nowhere; frustrated flight, unrelieved of strain endless return – all- -all."

"It was first surmised by the ancient philosopher, Democritus, that the faintly white zone which spans the sky under the name of the Milky Way, might be only a dense collection of stars too remote to be distinguished. This conjecture has been verified by the instruments of modern astronomers, and some speculation of a remarkable kind have been formed in connection with it."

"Most known extrasolar planets (exoplanets) have been discovered using the radial velocity, or transit methods. Both are biased towards planets that are relatively close to their parent stars, and studies find that around 17–30% of solar-like stars host a planet. Gravitational microlensing, on the other hand, probes planets that are further away from their stars. Recently, a population of planets that are unbound or very far from their stars was discovered by microlensing. These planets are at least as numerous as the stars in the Milky Way."

"I can never look now at the Milky Way without wondering from which of those banked clouds of stars the emissaries are coming. If you will pardon so commonplace a simile, we have set off the fire alarm and have nothing to do but to wait. I do not think we will have to wait for long."

"We cast the message to the cosmos. It is likely to survive a billion years into our future. When our civilization is profoundly altered and the surface of the Earth may be vastly changed. Of the 200 billion stars in the Milky Way galaxy, some — perhaps many — may have inhabited planets and space faring."

"This Voyager spacecraft was constructed by the United States of America. We are a community of 240 million human beings among the more than 4 billion who inhabit the planet Earth. We human beings are still divided into nation states, but these states are rapidly becoming a single global civilization. We cast this message into the cosmos. It is likely to survive a billion years into our future, when our civilization is profoundly altered and the surface of the Earth may be vastly changed. Of the 200 billion stars in the Milky Way galaxy, some--perhaps many--may have inhabited planets and space faring civilizations. If one such civilization intercepts Voyager and can understand these recorded contents, here is our message: "This is a present from a small distant world, a token of our sounds, our science, our images, our music, our thoughts, and our feelings. We are attempting to survive our time so we may live into yours. We hope someday, having solved the problems we face, to join a community of galactic civilizations. This record represents our hope and our determination, and our good will in a vast and awesome universe”."

"Galileo claimed to have seen mountains on the Moon, to have proved the Milky Way was made up of tiny stars, and to have seen four small bodies orbiting Jupiter. These last, with an eye to getting a position in Florence, he quickly named 'the Medicean stars'."

"Fascinated by its symmetry the geometer may at times have been too exclusively engrossed with his science, forgetful of its applications; he may have exalted it into his idol and worshipped it; he may have degraded it into the toy– when he should have been hard at work with it, using it mankind and the glory of his creator....But ascend with me above the dust, above the cloud, to the realms of the higher geometry, where the heavens are never clouded, where there is no impure vapour and no delusive or imperfect observation, where the new truths are already arisen, while they are yet dimly dawning on the world below, where the earth is a little planet; where the sun has dwindled to a star; where all the stars are lost in the Milky Way to which they belong ; where the Milky Way is seen floating through space, like any other nebula; where the whole great girdle of the nebulae has diminished to an atom and has become as readily and completely submissive to the pen of geometer, and the slave of his formula, as the single drop, which falls from the clouds instinct with all forces of the material world. Try with me the precision of measure with which the universe has been meted out; observe how exactly all the parts are fitted to the whole and to each other, and then declare who was present in the council-chamber when the Lord laid the foundations of the earth."

"Sjelfva vintergatan är idel verldar, hvilkas sken som knappast räcker til oss."

"It may seem rash indeed to draw conclusions valid for the whole universe from what we can see from the small corner to which we are confined. Who knows that the whole visible universe is not like a drop of water at the surface of the earth? Inhabitants of that drop of water, as small relative to it as we are relative to the Milky Way, could not possibly imagine that beside the drop of water there might be a piece of iron or a living tissue, in which the properties of matter are entirely different."

"What was observed by us in the third place is the nature or matter of the Milky Way itself, which, with the aid of the spyglass, may be observed so well that all the disputes that for so many generations have vexed philosophers are destroyed by visible certainty, and we are liberated from wordy arguments."

"Astronomers have mapped the cosmic watershed in which our Milky Way Galaxy is a droplet. The massive structure, which the research team dubs the Laniakea Supercluster, extends more than 500 million light-years and contains 100,000 large galaxies. The work, published in the September 4th Nature, is the first to trace our local supercluster on such a large scale. It also provides a physical way to define what a supercluster actually is."

"If you want to see a black hole tonight, tonight just look in the direction of Sagittarius, the constellation. That's the center of the Milky Way Galaxy and there's a raging black hole at the very center of that constellation that holds the galaxy together."

"It suggests a nebulous dim puff of star dust lost in the blaze of the Milky Way. Properly, the Jew ought hardly to be heard of; but he is heard of, has always been heard of. He is as prominent on the planet as any other people, and his importance is extravagantly out of proportion to the smallness of his bulk."

"As, pricked out with less and greater lights, between the poles of the universe, the Milky Way so gleameth white as to set very sages questioning."

"For the Milky Way, we find that the orbital speed increases and then remains roughly constant. This implies that we are still within the body of the Milky Way, even at the largest distances from the center of the Milky Way. We have not yet located the edge of the Milky Way; the Milky Way extends much further than the edge of the disk of stars (the visible disk)! The mass contained in the Milky Way (in the visible disk) is 2x1011 M(Sun). The mass contained in the Milky Way galaxy (out to as far as we can see HI gas) is 6x1011 M(Sun)."

"The Milky Way is a spiral disk galaxy, similar to many others we see in the sky. This surprisingly beautiful shape is so common among galaxies that the universe almost seems to delight in building them. The end product is especially remarkable in the light of what is believed to be the starting point: nebulous blobs of gas."

"...the mass where we can see stars is only 1/3 of the mass of the entire Galaxy. This suggests that a lot of mass in the Milky Way is in some form which does not radiate large amounts of light (Dark Matter)."

"The gas blobs that evolved into the Milky Way consisted merely of hydrogen and helium (and a smattering of lithium), the elements that were created in the Big Bang. All the other elements were literally created by the stars. Unlike the medieval alchemists, the stars can actually transmute one element into another—they are prodigious chemical factories. Nevertheless, even today hydrogen and helium make up about 98 percent of the normal matter in the universe. It’s the distribution of the elements that make up the final 2 percent that makes all the difference to studies of galactic evolution."

"The GAIA project, which [was] slated to be launched by the European Space Agency by 2012, holds great promise for our attempts to solve the puzzle of the Milky Way’s formation. The GAIA satellite will be taking a massive stellar census, measuring the positions, motions and chemical compositions of more than a billion stars. It will, in effect, provide a three-dimensional map of our galaxy with unprecedented accuracy and resolution."

"More observations are needed before we can refine our models of the Milky Way’s evolution. For one thing, we are still uncertain about the formation timescale For the thin disk outside the w:Local Interstellar Cloud}solar neighborhood because we lack precise observational constraint."

"The granddaddy of galactic-formation models was conceived in the early 1960s by three astronomers: Olin Eggen, Donald Lynden-Bell and Allan Sandage. Their 1962 publication played a seminal role in the field and is now simply referred to by the authors’ initials: ELS....According to ELS, the Milky Way began as a spherical cloud of gas—a protogalaxy—that was born collapsing toward its center.The original gas was poor in metals, and so stars formed as the cloud was collapsing would also be metal poor.These newly made stars maintained the kinematic properties of the gas in the collapsing cloud, and so followed eccentric orbits around the center of the Galaxy, forming the population II stars of the halo and the globular clusters. As the cloud contracted, some of its energy would have been lost to heat in a dissipative collapse;"

"There is another type of exploding supernova that also seeds the Galaxy with elements. This is the type Iasupernova. This explosion involves a binary system in which a white dwarf star and an intermediate-mass star (a red giant) orbit each other. The two stars are so close to each other that the white dwarf gradually pulls a considerable amount of material from the outer envelope of the expanding red giant. At a certain point the white dwarf will acquire so much mass that it collapses under its own weight and produces an explosion that blasts the bulk of its material into the interstellar medium—mostly in the form of iron, but also some sulfur, silicon and calcium. Such explosions contributed about 70 percent of the iron we see today in the Galaxy....three processes hold an important key to understanding the evolution of the Milky Way precisely because they occur on very different timescales. By measuring specific abundance ratios in stars from different parts of the Galaxy, astronomers can discover how fast the metal enrichment proceeded and the timescale over which the region was formed."

"In the decades that followed, a number of observations indicated that the Galaxy could not have formed in such a rapid collapse. The ELS model, as originally proposed,could not be right. One notable alternative was suggested by the American astronomers Leonard Searle and Robert Zinn in 1978… Instead of a single-cloud collapse, Searle and Zinn proposed that the halo of the Milky Way formed by the aggregation of many cloud fragments, each of which may have already formed stars and globular clusters"

"As we arbitrarily divide the human body into a torso with a head and limbs, so we can conceptually separate the Galaxy into various components. The flying-saucer shape—consisting of the central bulge and the spiral disk—is only the most obvious part of the Galaxy. The spiral disk itself can be subdivided into a thin disk, which rises about 1,000 light-years above and below the galactic mid-plane, and a thick disk, which extends to about 3,500 light-years on either side of the plane. The relative flatness of our galaxy is evident when one considers that the galactic disk is generally thought to be about 120,000 light-years across. Our sun resides in the thin disk about 28,000 light-years from the galactic center... About 200 globular clusters are known, and they appear to be some of the oldest objects in the Galaxy. It took many decades of careful study to tease apart the various regions of the Milky Way, and the process of dissecting out fine-scale subregions continues even today.One of the reasons it’s so difficult is that we cannot measure the properties of all the stars in the Galaxy—they are simply too far away....the different orbits of the stars, their kinematic properties, provide a crucial distinction between stars that belong to different regions of the Galaxy"

"Although the development of new technologies has improved the quality of the observations and so refined the constraints on astronomers’ models, we are still far from a complete understanding of our galaxy’s evolution. Like our galaxy, the field itself is still evolving."

"A star’s kinematic properties are one of the ways that astronomers can recognize an interloper from another part of the Galaxy. ...The most metal-poor star ever observed in our galaxy is located in the halo. It is old and has a metallicity [Fe/H] of about -4.0, or about 10,000 times less than the Sun!"

"It appears, however, that our galaxy’s formation was neither smooth nor continuous."

"He (Sikandar) offered up suitable thanksgivings for his success, and the royal troops spoiled and plundered in all directions, rooting up all the trees of the gardens which shaded Dhulpur to the distance of seven kos."