摘要:

The 1960 spring meeting of the New York State Section of the American Physical Society was the second to be held under a revised system. Once again, a central theme was chosen, and some 170 members and guests were treated to a spirited and excellent survey of modern radio astronomy presented by several of the outstanding and active radio astronomers of the nation.

ISSN:0031-9228    

DOI:10.1063/1.3057495

出版商:AIP    

年代:1961

数据来源: AIP

摘要:

Before sketching the activities in radio astronomy elsewhere in the world, let me start with a brief historical survey. Radio astronomy had its beginnings in the United States, with the pioneer work of Jansky in the early 1930's, followed by Grote Reber in the late thirties and early forties. Jansky, in the course of radio atmospheric studies at the Bell Laboratories, showed that at meter wavelengths the dominating source of noise is not terrestrial but celestial, with the radio intensity at 15‐m wavelength varying as a function of position in the sky. The most intense radiation came from the Milky Way in the direction of Sagittarius, which was known to be the direction of the center of our galaxy. Reber, who worked in h:s own back yard at Wheaton. Illinois, produced the first maps of sky brightness, at the somewhat shorter wavelength of 1.5 m and later at 70 cm. Taken together, these pioneer observations of Jansky and Reber raised puzzles which were inexplicable by existing theories and indeed are not yet settled, for the sky brightness was several orders of magnitude greater than expected. American physicists for the most part remained oblivious to this particular large‐scale puzzle of nature, and it remained for physicists and astronomers abroad to make most of the advances during the decade which followed World War II. Four groups have been outstanding: the Radiophysics Laboratory of CSIRO in Sydney, Australia; the English radiophysics groups at the Cavendish Laboratory and the University of Manchester; and the astronomers of the Observatory of Leiden, Holland.

ISSN:0031-9228    

DOI:10.1063/1.3057497

出版商:AIP    

年代:1961

数据来源: AIP

摘要:

The history of radio astronomy has been marked by a long series of surprises, many of which have changed the paths of advancement in the science. This has been especially true with the planets, probably the field in which fewest surprises were expected. Now, what kind of radio emission was expected from the planets? Optical studies of the planets have been made, of course, for centuries, and from these we felt that we understood well the physics of the planets. This knowledge suggested that we should expect to observe only thermal radio emission from planets, the Planck radiation due to the planets' nonzero temperature. At radio wavelengths the Planck law becomes the simple Rayleigh‐Jeans approximation in which the brightnessb = 2kT&lgr;2The temperatureTrefers to the level in the outer layers of the planet we are observing with the telescope. This level may be in the atmosphere or it may be at the very surface of the planet itself. From this formula, we expected the spectra of planetary radio emission to follow a&lgr;2law. The observable quantity in radio astronomy is the radio flux density which, for the planets, is the brightness multiplied by the solid angle subtended bSSy the planet in the sky. Obviously, we would also expect this flux density to go as&lgr;2.

ISSN:0031-9228    

DOI:10.1063/1.3057498

出版商:AIP    

年代:1961

数据来源: AIP

摘要:

Cosmic radio radiation is radiation of extraterrestrial origin in the radio‐frequency portion of the electromagnetic spectrum. Such radiation was discovered by Karl Jansky of Bell Telephone Laboratories in 1932 on a wavelength of 14.6 m. While studying the direction of arrival of the atmospheric disturbances which interfere with the transatlantic short‐wave radio communications, Jansky found that in addition to familiar atmospheric static due to local and distant thunderstorms, his directive antenna was picking up persistent strange static noise. From further observations he concluded that the static noise was coming from the general direction of the Milky Way and the maximum noise was from the Constellation of Sagittarius, the central region of the Milky Way. Jansky suggested that this cosmic radio wave might be originating either in the stars or in interstellar space.

ISSN:0031-9228    

DOI:10.1063/1.3057499

出版商:AIP    

年代:1961

数据来源: AIP

摘要:

The question of the existence of intelligent life elsewhere in space has long fascinated people, but, until recently, has been properly left to the science‐fiction writers. This is simply because our technology has not been capable of detecting any reasonable manifestation that might be expected from other civilized communities in space. Lately, however, astrophysical knowledge of the universe and our technology have advanced to a stage where these questions can no longer be ignored by scientists. I would like to describe briefly the astronomical picture connected with the development of life, and to follow this with some anthropomorphic arguments which help us in our search for other abodes of life. Finally, there will be given a brief description of some instruments that one might apply to this problem.

ISSN:0031-9228    

DOI:10.1063/1.3057500

出版商:AIP    

年代:1961

数据来源: AIP

摘要:

During the period September 12–17 a large number of physicists, chemists, and electronic engineers gathered at Pisa to discuss recent advances in radio‐frequency spectroscopy. This meeting was of a truly international character, with participants from many Eastern European universities and research institutes, including those at Warsaw, Leipzig, East Berlin, and Ljubljana, as well as members from all the Western European countries, the United States, and India. The 1960 conference itself was one of a regular annual series organized by the European “Colloque AMPERE (Atonies etMole´culesParEtudesRadio‐Electriques)” which was initiated some years ago mainly due to the enthusiasm of Professor Freymann, and now has its secretariat headquarters, headed by Professor Bene, at the Institute of Physics in Geneva. The entire planning, organization, and control of the present conference, however, were carried out by Professor Gozzini, of the Institute of Physics at Pisa, to whom very considerable praise must be given for the smooth running of such a large international meeting.

ISSN:0031-9228    

DOI:10.1063/1.3057501

出版商:AIP    

年代:1961

数据来源: AIP

摘要:

Both in number and in over-all membership, the Student Sections of the Institute have been growing rapidly. This in itself is not astonishing, but the rate of increase has become extremely impressive even to those of the Institute staff who have been in close touch with the Sections. An approximate tripling has occurred, both in the number of Sections (from 52 to ISO) and in student membership (1500 to 5200), during the past two years.

ISSN:0031-9228    

DOI:10.1063/1.3072790

出版商:AIP    

年代:1961

数据来源: AIP

ISSN:0031-9228    

DOI:10.1063/1.3057503

出版商:AIP    

年代:1961

数据来源: AIP

ISSN:0031-9228    

DOI:10.1063/1.3057505

出版商:AIP    

年代:1961

数据来源: AIP

ISSN:0031-9228    

DOI:10.1063/1.3057507

出版商:AIP    

年代:1961

数据来源: AIP