astronomers-from-the-united-states

"Ibn al-Shatir’s forgotten model was rediscovered in the late 1950’s by E. S. Kennedy. .. In a preliminary work, the Commentariolus, he [Copernicus] employed an arrangement equivalent to Ibn al-Shatir's. Later, in De revolutionibus, he reverted to the use of eccentric orbits, adopting a model that was the sun-centered equivalent of the one developed at Maragha. Could Copernicus have been influenced by the Maragha astronomers or by Ibn al-Shatir? ...some of the al-Tusi material is known to have reached Rome in the 15th century (many Greek manuscripts were carried west after the fall of Constantinople in 1453), but there is no evidence that Copernicus ever saw It... . I personally believe he could have invented the method independently."

"Some of the al-Tusi material is known to have reached Rome in the 15th century... but there is no evidence that Copernicus ever saw it.…I personally believe he could have invented the method independently."

"In August, 1933, at the in Chicago, was founded with an enrollment of 57 charter members and and as the first President and Secretary-Treasurer, respectively. Within five years, the Society had doubled in size, with members from the U.S.A. and ten other nations. Annual meetings were suspended during World War II (1942 through 1945) and when it reconvened in 1946 the members adopted the name “”. By that time personal and professional antagonisms had arisen that threatened to fragment the Society and led, in 1949, to the resignation of Nininger and his wife. Throughout the 1950s the Society was widely regarded as a small, disorganized and essentially moribund organization. Revitalization of the Society began in the early 1960s after the advent of the when the Society steadily gained members with expertise in , , , and , and impact dynamics."

"Since the opening of the , images from have enabled us to map the surfaces of all the rocky planets and in the Solar System, thus transforming them from astronomical to geological objects. This progression of geology from being a strictly to one that is planetary-wide has provided us with a wealth of information on the evolutionary histories of other bodies and has supplied valuable new insights on the Earth itself. We have learned, for example, that the , and that the Moon subsequently accreted largely from debris of . The airless, waterless Moon still preserves a record of the impact events that have scarred its surface from the time its crust first formed. The much larger, volcanic Earth underwent a similar bombardment but most of the evidence was lost during the earliest 550 million years or so that elapsed before its first surviving systems of crustal rocks formed. Therefore, we decipher Earth's earliest history by investigating the record on the Moon. Lunar samples collected by the of the USA and the of the former USSR linked the Earth and Moon by their oxygen isotopic compositions and enabled us to construct a timescale of lunar events keyed to dated samples. They also permitted us to identify certain meteorites as fragments of the lunar crust that were projected to the Earth by impacts on the Moon. Similarly, analyses of the Martian surface soils and atmosphere by the and s led to the identification of meteorite fragments ejected by hypervelocity impacts on Mars. Images of Mars displayed land-forms wrought in the past by voluminous floodwaters, similar to those of the long-controversial of Washington State, USA. The record on Mars confirmed catastrophic flooding as a significant geomorphic process on at least one other planet. The first views of the Earth photographed by the crew of gave us the concept of and heightened international concern for protection of the global environment."

"Mainstream geology is founded upon enunciated by James Hutton (1726–1797) and Charles Lyell (1797–1875), who argued that, during unlimited expanses of time, the Earth has undergone slow, ceaseless change by processes we can observe in operation. In their view, we cannot call on any powers that are not natural to the globe, admit of any action of which we do not know the principle, nor allege extraordinary events to explain a common appearance. A , originating from outside the Earth, and wreaking change instantaneously. Such a process violates every tenet of uniformitarianism. Largely for this reason, hypotheses of impact origin for craters on the Earth and the moon were vigorously opposed for the better part of the past century. Space-age research now has established beyond doubt the authenticity of impact as a geologic process, but an abundance of evidence exists that a wide chasm still persists between the views of impact specialists and those of terrestrial geologists. A full realization of the ramifications of impact processes may have been delayed by the advent of , which engulfed the geological community in the late 1960s. Revolutionary as it appeared at that time, plate tectonics, which is envisioned as involving gradual changes generated by forces internal to the globe, fully conforms with uniformitarian principles. In contrast, impact processes, which have recently been cited to account for cataclysmic events such as massive tsunami deposits, incinerating wildfires, and global extinctions, carry genuinely revolutionary implications that are fatal to the uniformitarian principle itself."

"The , which measures the , together with the total energy density of the Universe, sets the size of the observable Universe, its age, and its radius of curvature. Excellent progress has been made recently toward the measurement of the Hubble constant: a number of different methods for measuring distances have been developed and refined, and a primary project of the has been the accurate calibration of this difficult-to-measure parameter. The recent progress in these measurements is summarized, and areas where further work is needed are discussed. Currently, for a wide range of possible s, the Universe appears to have a . Combined with current estimates of stellar ages, the results favor a . They are consistent with either an , or a with a non-zero value of the ."

"We are at an interesting juncture in cosmology. With new methods and technology, the accuracy in measurement of the has vastly improved, but a recent tension has arisen that is either signaling or as-yet unrecognized uncertainties. Just under a century ago, Edwin Hubble revolutionized cosmology with his discovery that the . Hubble found a relationship between radial velocity and the distance to nearby galaxies, determining the proportionality constant Ho (=v/r), that now bears his name. The Hubble constant remains one of the most important parameters in cosmology. An accurate value of Ho can provide a powerful constraint on the cosmological model describing the evolution of the universe. In addition, it characterizes the expansion rate of the Universe at the current time, defines the observable size of the Universe, and its inverse sets the ."

"... after finishing my postdoc, I became a faculty member at , and then ended up being the scientific leader of this project to measure the rate at which the universe is expanding. ... when that project finished, .. we .. resolved the issue. We went from a factor of 2 uncertainty — we measured an uncertainty of 10%."

"The , no less than the severest utilitarian, rejoices in every contribution of science to the arts, but he does not admit that the whole value of science is to be measured by any present applications. He puts in a demurrer to the conclusion that those portions of it are useless of which we do not see the utility. The use may be beyond our present sphere of vision, or, if coming within our cognizance, it may not admit of comparison with any standard of measure. Unlike the precious gem, which has an exchangeable but no intrinsic value, science bears no price in the market. It transcends all ideas of comparison and exchange. Its high utility lies in the breadth and dignity and sublime grandeur which it gives to the human mind."

"There are in astronomy refinements of method, both practical and theoretical, which can be appreciated only by rare gifts and profound study. But the elementary methods are quite within the reach of ordinary minds. The , which it was difficult to discover, may be very easily understood and its results readily traced. It might require a Newton or a La Place to unveil the mechanism of the heavens, but when that is once done every beholder may watch the wonderful evolutions."

"Dr. Caswell’s predilection was for and astronomy. During the period of twenty-eight and a half years (from December, 1831, to May, 1860) he made, with few interruptions, a regular series of meteorological observations at the same spot on . These observations, precise as regards temperature and pressure, and including also much information on winds, clouds, moisture, rain, storms, the , &c, have been published in detail in Vol. XII of the "Smithsonian Contributions to Knowledge," and fill 179 quarto pages. Dr. Caswell continued his observations in meteorology with unabated zeal to the end of 1876, covering, in all, the long period of forty-five years."

"# The trait that to me seems the most socially important about science, however, is that it is a major source of man's discontent with the status quo..."

"# Moreover, the pace of technological advance gravely threatens the bountiful and restorative power of nature to resist modification..."

"# Another trait of science that leads to much hostility or misunderstanding by the non-scientist is the fact that science is practiced by a small elite... (which) has cultural patterns discernibly different from those of the rest of society..."

"# Not only are the tenets of science constantly subject to challenge and revision, but its prophets are under challenge too..."

"… one does not expect a . To my mind, I was genuinely surprised because when you make a discovery of acceleration–well, what causes the acceleration? Well, we give it a name–'–but we don’t understand it yet. I would not be surprised if we don’t understand it during my lifetime. Without understanding it, I felt it wouldn’t be worthy of a Nobel Prize. The fact that it was given pretty timely–you know, I was only 44 last year–was a bit of surprise."

"# Further, the findings of science have an embarrassing way of turning out to be relevant to the customs and to the civil laws of men—requiring these customs and laws also to be revised..."

"Not only does it swallow anything that comes too near it but no one lives to tell the tale ... there are footprints leading in, and no footprints leading out ... If black holes weren’t real, I think the science-fiction writers would have wanted to invent them."

"Today we are able to make very precise measurements of the by measuring the distances and s of . The shift in a supernova’s due to the expansion of space gives its redshift (z) and the relation between redshift and distance is used to determine the expansion rate of the universe. Supernovae with greater redshifts, lying at greater distances, reveal the past expansion rate as their light was emitted at an epoch when the universe was younger. Supernovae Type Ia were the suitable candidate for these measurements as you need objects that are very luminous (thus can be observed even when they are very far) and highly uniform (so that intrinsic scatter doesn't blur the signal). Supernovae Type Ia are the most luminous of the common supernova types, peaking at 4 billion , and thus allowing us to look at extreme large distances."

"Having that bit of diabolical contrariness is a weird pleasure of being a scientist. You’re always trying to figure out, “OK, how could I be fooling myself into a wrong conclusion?” Because the more you get those things right, the more chances you have of catching the universe doing something that our brains never would’ve imagined. Scientists build out of what seems like a stance of weakness. So, one might think it’s terrible that scientists are always discovering new ways that they’re wrong, or it’s terrible that they’re only probabilistically sure of facts. But that’s really where scientists’ superpower has come from. We have been able to figure out amazing solutions to problems or surprises about the world. Much of that can be traced back to being willing to be wrong and being comfortable with finding the ways you’re wrong. And for this purpose, you want to build strong relationships with people who are going to tell you when you’re wrong, who will disagree with you, or who compete with you. They’re your best bet at figuring out where you’re making a mistake."

"# Certainly we have seen spectacular changes in the concept of private property and of national borders as we have moved into the space age..."

"The revealed the to have an unexpected richness of structure. Many of the observed features have now been identified as collective effects arising from the of the ring material. These effects include , the main topics of this review chapter. Both kinds of waves were first discussed in the astronomical literature in connection with the dynamics and structure of , and our discussion contrasts the similarities and differences between the and s. After developing the theory of free and forced waves of both types, we discuss how the observed waves can be used as diagnostics to obtain crucial parameters that characterize the physical state of the rings."

"have played a prominent role in astronomical thought since the discovery by in 1845 of the spiral structure of the ... Through the work of , , , and especially Hubble, by the late 1920s, it became known, and not just speculated, that such spirals were disk-like stellar systems coequal to our own Milky Way system. From the optical study of the kinematics of stars in the solar neighborhood, (1927) and Jan Oort (1927) deduced that the flattening of the galactic disk is due to rotation, and that this rotation occurred differentially, with the stars near the galactic center taking less time to go once around the center than the material farther out."

"I think . I never would have guessed it. Even as an undergraduate, once I’d learned a little physics, I would have thought that the universe was eternal, static, and always in equilibrium. So in graduate school when I found out that the universe was expanding, I was awestruck. Then I learned if we could measure the expanding universe, the way we record the growth of a child with marks on a doorframe ... , we could determine the age of the universe and predict its ultimate fate. This was staggering! I knew this is what I wanted to do. Since that time, charting the expanding universe to determine its nature has been my passion. Though I have to add: knowing what I know now, that the , I feel like King Alfonso X of Castile who saw Ptolemy’s and reportedly said “If the Lord Almighty had consulted me before embarking on creation thus, I should have recommended something simpler.”"

"is about the gravity of empty space, the gravity of the vacuum. And the vacuum is a concept that we address in and quantum mechanics. Quantum mechanics is physics on microscopic scales, while Einstein's theory of general relativity ... is physics on macroscopic scales. These two theories are both great, but they don't work together. We don't have what's called a quantum theory of gravity, the way the two are united. However, dark energy actually requires you to use both of these branches of physics. So our hope is that by observing how the universe actually does physics at that interface, we will learn how to unify those."

"Less than a century ago we had no idea that there was more to the universe than our own Milky Way. the immense size of the universe, the fact that it is expanding, the fact that it is populated with such things as – all this and more had to be discovered before we could do the work that led us to contemplate an ."

"As we discover , we suffer from a variety of s, both in our nearby and distant searches. The most significant effect is – a selection effect which leads brightness limited searches finding brighter than average objects near their sensitivity limit. This bias is caused by the larger volume in which bright objects can be uncovered compared to their fainter counterparts. Malmquist bias errors are proportional to the square of the intrinsic dispersion of the distance method, and because SN Ia are such accurate distance indicators, these errors are quite small – approximately 2%. We use s to estimate these effects, and remove their effects from our s."

"With the as an anchor, theory converged on a standard model of the universe, which was still in place in 1998, at the time of our discovery of the . This standard model was based on the theory of general relativity, and two assumptions. assumption one was that the , and assumption two that it is composed of normal , i.e. matter whose density falls directly in proportion to the volume of space, which it occupies. Within this framework, it was possible to devise observational tests of the overall theory, as well as provide values for the fundamental constants within this model – the current expansion rate (), and the average density of matter in the universe. For this model, it was also possible to directly relate the density of the universe to the rate of cosmic deceleration and the geometry of space. it stated that the more material the faster the deceleration, that above a critical density the universe has a and below this a ."

"# Science is constantly, systematically and inexorably revisionary. It is a self-correcting process and one that is self-destroying of its own errors..."

"# A related trait of science is its destruction of idols, destruction of the gods men live by... Science has no absolute right or absolute justice... To live comfortably with science it is necessary to live with a dynamically changing system of concepts... it has a way of weakening old and respected bonds..."

"The rich variety of stars live in our Galaxy mostly singly or in pairs ... Sometimes, however, hundreds or thousands of stars can be found in loose groups called s. The is a daily young open closer, and the which surrounds the famous "seven sisters" of this cluster attests to the fact that these stars must only recently have been born out of the surrounding gas and dust. The oldest stars in our Galaxy are found in tighter groups called s. Rich globular clusters may contain more than a million members."

"After completing her A.B. and A.M. degrees as a student of astronomer Mary Whitney at Vassar College, Caroline Furness became the first woman to earn a Ph.D. in astronomy at (1900). She collaborated with Whitney as her assistant between 1909 and 1911, each sending their variable star observations to . A member of the from 1911, Furness succeeded Whitney in 1913, and prepared for publication a volume of variable star observations made at Vassar from 1901 to 1912. In 1915 she authored the well-received An Introduction to the Study of Variable Stars."

"did not accept the but evolved one of his own in which he makes the planets revolve about the Sun, but the Sun carries them with itself about the Earth. Part of his observations he reduced himself, publishing among other things a book on the , one on comets, and one on the lunar theory, and an important star catalogue. He had planned several other valuable works, but his early death cut short his projects. He was the first to perceive the importance of applying refraction to observations. He improved the values of the Sun's and Moon's , he discovered two variations in the Moon's longitude in addition to those already known, and one in latitude. In short he improved many values which depended on accurate observation for their determination."

"... Suppose a large number of values, subject to variations on either side of a , and suppose these variations bound by no common law. Then, if a sufficiently large number of such values are taken into consideration, it will be found that the variations on either side of the mean value will counterbalance one another. If, then, we regard the absolute motions of the stars as subject to no common law, i.e., if we suppose the stars to be pursuing their courses independent of any common , and if a very large number of s are taken together, if would follow from this principle, that in the aggregate the peculiar proper motions would cancel one another, and the mean result would be unaffected by them and would give only the . This method of treatment, based upon the , is called the method of "," and is of wide application ..."

"A is one that undergoes a change in brightness. With some stars the change is as great as four or even six , while with others it may be only one magnitude, and in some cases as small as half a magnitude. This change in brightness is observed by comparing the light of the variable with the light of some standard star which is assumed to be constant in brightness, the comparison being made either directly, or through the medium of some sort of artificial star."

"Although banquets at professional meetings (like the chemists' "misogynists' dinner" of 1880) had long excluded women, the ban began to seem a little less intimidating around 1900, when several women scientists began in their own quiet way to challenge some of these age-old restrictions. Thus, for example, Mary Whitney of Vassar College, who had attended the founding meeting of the American Astronomical Society at in Wisconsin in 1899 with her protégée and successor, , was still not sure whether they would be welcome at the society's banquet in Washington, D.C., in 1902. President noticed her unease and wrote to assure her that they were indeed expected to attend ... Newcomb's encouragement induced these women to go, and thereby set a precedent for later meetings."

"At the we met , the Director, but were especially pleased to see who had made suck a name for herself by her work on . She was in charge of the reduction of the Paris astrographic plates, and we were interested to compare her computing bureau with the one at . She offered to escort us to to visit the venerable , and invitation which we were delighted to accept. We were charmed with picturesque dwelling, made from the stables of the old chateau, with its low-ceiled rooms and quaint winding passages. They made a fascinating setting for the indomitable old Frenchman, who in spite of his eighty years, was planning to make another ascent of that summer, even if he had to be carried to the summit in a chair. He also asked many questions about the college in America where young girls studied mathematical astronomy."

"At the present time we employ a for making certain observations which can best be made then, and for other work which is not possible at another time. The most important work, and one which demands the coöperation of at widely distant places, is the observation of s. These occur at other times, but only the brighter stars can be followed to the and such stars are not frequent in its path. During an eclipse, however, stars down to the eleventh are easily followed until they disappear, and any star whose position is accurately determned is available. If an Observatory has undertaken the investigation of the Moon's place, it takes advantage of a total eclipse and prepares a list of stars which are to be occulted at other distant observatoreis, and sends a circular requesting observations. Such a circular was issued by the , Russia, for the eclipse of March 10th. The time of an occultation is much less difficult to determine than a contact of an eclipse. The Moon has no atmosphere, so that the star disappears instantaneously."

"Firstly, we wish to know whence comes the comet and whither it goes. We wish to follow its path, as it sweeps its way through our solar system. As this orbit is controlled by the same law of gravity which controls all celestial motion, an exact knowledge of a comet's course among the planets, gives the basis of investigation regarding its relation to the solar system and to the realms of space beyond. Therefore one important line of investigation is the determination of the positions of the comet in the sky, from whence may be obtained its orbit in space. Secondly, the astronomer wished to know what are the nature and constitution of comets. The investigation of this question is of comparatively recent origin, and belongs to ."

"was established and equipped at the opening of the college in 1865. The has an of 12⅓ inches aperture and a focal length of 16¾ feet. It was originally made by }} of New York, but in 1872 the glass was re-cut by }}, and in 1888 the telescope was re-mounted by & }}. It was also at that time provided with electrical illumination for the . The magnifying powers, negative and positive, range from 150 to 600. A made by }} was added in 1890. This spectroscope has a prism for star spectra and a }} grating for the solar spectrum. There is also a }} direct-vision spectroscope. The has an objective aperture of 3¾ inches. It was made by }} of Philadelphia. In 1889 it was re-mounted by }}. The clock and chronograph are of }} manufacture."

"Mary Whitney … established a student-based research program at Vassar, focusing on observations of comets, s, and, after , on s. … In 1906 she developed an undergraduate course on variable stars, probably the first in the world, on which Caroline Furness based her 1915 textbook."

"We are so far from being able to move a good fraction of the population anywhere else. Even if Elon Musk and other private individuals manage to start sending humans to Mars, we may be a few hundred years away from putting any sizable population there—and we have to fix Earth right now. Eventually, if we’ve been irresponsible enough to create problems in our world, moving to a new one won’t necessarily solve the problem because we might do the same thing in the future."

"Looking from the astrobiology perspectives, life on Earth started early—just about as soon as it could. The more we learn about the origin of life, the more we realize it may be a likely outcome any time you have the right ingredients. However, if you look at the history of life on Earth, let’s say you put it on a twelve-hour clock, up until four o’clock it was just a world of microorganisms, from four to five o’clock that’s the era of plants coming onto land and animals and creatures in the sea, then after five o’clock until about ten o’clock this will be a world of only microorganisms again. So, in fact, our planet is in its late middle ages in terms of life on the surface. Then from ten o’clock until about midnight, the world will be completely desolate, devoid of life as the sun is running out of its nuclear fuel in the center and its outer atmosphere is expanding. The point is that our world has had big life for only a small slice of its existence and the portion of that which has had technology is even smaller. I think life is presumably abundant everywhere; the most common form is likely going to be microbial life. In addition, the distances are so vast that unless other civilizations have developed both a means of crossing those distances quickly and the desire to do so, plus the energy capability, I don’t know if we’ll see alien intelligence in our lifetime."

"… the technical question was, “Is the Big Bang the right story? Is the expanding universe the right story?” And there are a lot of sub-questions in that. If it is the right story, then how did the galaxies come? Where did they come from? Because it seemed quite mysterious. People were just beginning to realize that there was a structure that had been seen in the maps of where the galaxies are located, and that we had no clue what made that happen. So what is there to measure? Well, there’s not very many things to measure. You can measure the galaxies or you can look for this cosmic background radiation. And if you could measure it, it would tell you something that you never knew before."

"NASA’s Cosmic Background Explorer satellite mission, the COBE, laid the foundations for modern cosmology by measuring the spectrum and anisotropy of the and discovering the . ... The COBE observed the universe on the largest scales possible by mapping the cosmic microwave and infrared background radiation fields and determining their spectra. It produced conclusive evidence that the hot Big Bang theory of the early universe is correct, showed that the early universe was very uniform but not perfectly so, and that the total luminosity of post–Big Bang objects is twice as great as previously believed."

"The Cosmic Background Explorer (COBE) satellite, under study by NASA since 1976, will map the spectrum and the angular distribution of diffuse radiation from the universe over the entire wavelength range from 1 micron to 1.3 cm. It carries three instruments: a set of differential s (DMR) at 23.5, 31.4, 53, and 90 , a far infrared absolute (FIRAS) covering 1 to 100 cm-1, and a covering 1 to 300 s. They will use the ideal space environment, a one year lifetime, and standard instrument techniques to achieve orders of magnitude improvements in sensitivity and accuracy, providing a fundamental data base for cosmology. The instruments are united by common purpose as well as similar environmental and orbital requirements. The data from all three experiments will be analyzed together, to distinguish nearby sources of radiation from the cosmologically interesting diffuse background radiations."

"We talk about how diversity will open up new possibilities, and she’s a prime example of that. She thinks of stuff that no one has done and does it—pulls it off."

"The link between art and science for me is my love of color and my love of light."

"We know that molecular clouds are elaborate, and that their complex geometry is tied to star formation. But the images we have of them are flat — they’re inherently two-dimensional."

"We can never make assumptions about the entire universe based on what’s happening in our own backyard...we don’t want to have a theory of star formation just for the Milky Way — we want a universal theory."