Physical Sciences

X-ray Astronomy at Goddard:
Early History

From 1965 to 1972 there were over a dozen balloon-borne experiments (mostly from New Mexico), including the first such to take place from Australia (1966), one in which hard X-ray emission was discovered (albeit with crude angular resolution) from a region towards the galactic center whose centroid is located among subsequently identified sources GX1+4, GX3+1, and GX5-1. A balloon-borne experiment in 1968 was based on the multi-anode multi-layer xenon gas proportional chamber that had recently been developed in our lab and represented the first use of such a high performance instrument for X-ray astronomy.

Nearly 10'000 links to books on philosophy, science, classics, literature, history, economics, etc. Multilingual. Several Search programs on author, title, language, words, etc.

This paper deals with the English rejection of the Gregorian calendar in 1583, seeking to set this episode in its cultural, political and intellectual context. It concentrates particularly upon the work of John Dee, whose treatise of advice to the queen on the calendar reform is almost the only one of his major writings which has not (as far as I am aware) been studied in any depth in published writings.

This web site is an online gateway to the extraordinary library resources of Harvard University and serves as an important research tool for Harvard's current students, faculty, staff, and researchers who hold Harvard IDs and PINs. The site also provides practical information on each of the more than 90 libraries that form the Harvard system. Visitors and guests should consult the Library's Frequently Asked Questions before navigating the sit

This was the first (but is not not the latest and greatest, for most purposes) online atlas of Mars. It lets you choose a site by various means and will show the locations (as footprints) of thousands of high-resolution Viking Orbiter images.

From around 3000 BC onwards, astronomy in its most primitive form had developed. The sun, moon and changing seasons would have already been well studied. Perhaps the chief difference in thinking at that time was that the earth was flat. People genuinely believed that if you went far enough you would fall off the edge.

Plimpton 322 is part of a baked clay tablet made in Babylon between 1900 and 1600 BC, probably found at Senkereh in the 1920's,and now in the G.A. Plimpton Collection in Columbia University Library, New York. It is the oldest preserved document on number theory. It is written in cuneiform script using sexagecimal notation. It was first deciphered by Neugebauer and Sachs in 1945. It lists 15 Pythagorean triples and is the complete classification of such triples under certain hypotheses. The lecture will describe the tablet and explain the underlying mathematics.

Founded in December 1904 by George Ellery Hale as one of the original scientific enterprises of the Carnegie Institution of Washington, Mt. Wilson Observatory is completing its first century as one of the world’s premier astronomical observatories. During the first half of the twentieth century Mt. Wilson was successively home to the world’s two largest telescopes as well as the most powerful facilities in existence for studying the sun

They developed a form of writing based on cuneiform (i.e. wedge-shaped) symbols. Their symbols were written on wet clay tablets which were baked in the hot sun and many thousands of these tablets have survived to be read by us today. It was the use of a stylus on a clay medium that led to the use of cuneiform symbols since curved lines could not be drawn.