The big ears of radio astronomy

2002 ◽  
Vol 10 (2) ◽  
pp. 285-300 ◽  
Author(s):  
FRANCIS GRAHAM - SMITH
Keyword(s):  
Black Holes ◽  
Visible Light ◽  
Radio Astronomy ◽  
International Collaboration ◽  
Extreme Conditions ◽  
Radio Telescopes ◽  
Radio Waves ◽  
Special Value ◽  
The Universe

The special value of radio astronomy lies in the probing of extreme conditions in the universe, including the highest energies and the lowest temperatures. Radio waves can penetrate clouds of gas and dust to reveal objects in the universe and, in particular, in our Galaxy that cannot be seen by visible light. To achieve the highest resolution, radio telescopes in widely separate parts of our globe combine their reception to produce a synthesized image. This is a splendid example of international collaboration. Among the images visualized are pulsars, derived from the remnants of supernovae explosions, and quasar sources powered by black holes.

Radio Waves Tell About the Universe

2005 ◽  
Author(s):  
S.Ya. Braude ◽  
V.M. Kontorovich
Keyword(s):  
Neutron Stars ◽  
Radio Astronomy ◽  
Radio Galaxies ◽  
The Sun ◽  
Radio Radiation ◽  
Radio Telescopes ◽  
Radio Waves ◽  
Evolution Of The Universe ◽  
Space Objects ◽  
The Universe

The book tells about the achievements of modern radio astronomy. Data on radio galaxies, quasars, pulsars, space masers, and other space objects emitting radio waves are presented in a popular form. The ways of evolution of stars, supernovae and radio eruptions of their remains, the formation of white dwarfs and neutron stars, the phenomena in the centers of galaxies and the fusion of galaxies responsible for the formation of radio galaxies and quasars are considered. The radio radiation of the Sun and planets is discussed. A modern view of the evolution of the universe, the origin of the relic radiation left over from the Great Eruption, and its anisotropy is presented. A separate chapter is devoted to the description of radio telescopes.

scholarly journals High Redshift Radio Galaxies

1996 ◽  
Vol 175 ◽  
pp. 571-576
Author(s):  
K. Meisenheimer ◽  
H. Hippelein ◽  
M. Neeser
Keyword(s):  
Radio Emission ◽  
Electromagnetic Waves ◽  
High Redshift ◽  
Radio Galaxies ◽  
Early History ◽  
Radio Telescopes ◽  
Radio Waves ◽  
History Of ◽  
The Universe ◽  
Travel Distances

One hundred years after G. Marconi recorded radio waves over a distance of more than 1000 m, the most sensitive radio telescopes are able to detect the radio emission from light travel distances at least 1.4 × 1023 times greater. The electromagnetic waves from these distant objects are red shifted by Δλ/λ = z > 4. It is not the mere distance of high redshift objects which is fascinating, but rather the fact that one looks back into the early history of the universe by observing them: Objects at a redshift of 4 shined at a time when the universe had reached only about 1/5 of its present age.

The investigation of the Universe by radio astronomy

1961 ◽  
Vol 16 (1) ◽  
pp. 65-68
Keyword(s):  
Wavelength Range ◽  
Radio Astronomy ◽  
Outer Space ◽  
Sunspot Cycle ◽  
Short Wave ◽  
Radio Waves ◽  
Residual Noise ◽  
The Earth ◽  
Long Wave ◽  
The Universe

Although nearly all the major advances in radio astronomy have taken place during the last fifteen years the basic discoveries were made 30 years ago. At that time Jansky realized that the residual noise in his receiving equipment had a daily sidereal variation and must be the result of radio waves reaching the earth from outer space, and Appleton in the U. K. with Breit and Tuve in America through their studies of the ionosphere laid the foundation of the radio echo techniques of radio astronomy. The radio emission from outer space can be received on earth in the wavelength range from a few millimetres to 10 or 20 metres. The short wave end is limited by absorption in the atmosphere and the long wave end by the ionosphere, and this upper limit tends to vary in sympathy with ionospheric conditions throughout the sunspot cycle. These hindrances will soon be overcome when suitable equipment can be carried in earth satellites; then it should be possible to determine the true wavelength range of these extraterrestrial emissions.

scholarly journals Cosmic magnetic field observations with next generation instrumentation

2009 ◽  
Vol 5 (H15) ◽  
pp. 430-431
Author(s):  
Rainer Beck
Keyword(s):  
Magnetic Fields ◽  
Milky Way ◽  
Low Frequency ◽  
Radio Telescopes ◽  
Radio Waves ◽  
Huge Number ◽  
Fundamental Physics ◽  
New Era ◽  
Weak Magnetic Fields ◽  
The Universe

AbstractThe origin of magnetic fields in the Universe is an open problem in astrophysics and fundamental physics. Forthcoming radio telescopes will open a new era in studying cosmic magnetic fields. Low-frequency radio waves will reveal the structure of weak magnetic fields in the outer regions and halos of galaxies and in intracluster media. At higher frequencies, the EVLA and the SKA will map the structure of magnetic fields in galaxies in unprecedented detail. All-sky surveys of Faraday rotation measures (RM) towards a huge number of polarized background sources with the SKA and its pathfinders will allow us to model the structure and strength of the regular magnetic fields in the Milky Way, the interstellar medium of galaxies, in galaxy clusters and the intergalactic medium.

7. The radio sky

2016 ◽  
pp. 77-95
Author(s):  
Geoff Cottrell
Keyword(s):  
Black Holes ◽  
World War Ii ◽  
Neutron Stars ◽  
Radio Telescope ◽  
Radio Astronomy ◽  
Cosmic Radio ◽  
Radio Waves ◽  
World War ◽  
Radar Systems ◽  
Radio Technology

‘The radio sky’ considers radio telescopes that can see much longer wavelengths. Cosmic radio waves were first discovered in 1932 by Karl Jansky, with the first radio telescope built in 1937. Technology for radar systems advanced during World War II and then after the war scientists, such as Bernard Lovell and Martin Ryle, made use of the advances in electronics, radio technology, and digital computers, to found radio astronomy. Single-dish antennas—including the Lovell Telescope at Jodrell Bank Observatory—continue to play important roles. To improve angular resolution two antennas need to be operated as an interferometer. These are described along with the discovery of quasars, supermassive black holes, pulsars, and neutron stars.

Radio-astronomy, Radiometry and Infra-red Techniques

1961 ◽  
Vol 14 (1) ◽  
pp. 14-21 ◽  
Author(s):  
C. M. Cade
Keyword(s):  
Radio Astronomy ◽  
Radiant Energy ◽  
Night Vision ◽  
Radio Waves ◽  
Intensive Study ◽  
Infra Red ◽  
Signal Corps ◽  
Golay Cell ◽  
The Universe ◽  
The U.S

The year 1932 was one which had no great apparent significance for navigators, and yet it saw the commencement of two new lines of research which today, after an interval of more than a quarter-of-a-century, promise important contributions to the safety of navigators both at sea and in the air.The two lines of research were superficially quite unrelated, but fundamentally they relied upon the same principle—the detection of radiant energy emitted by objects solely as a result of their temperature. The first of these small beginnings was the discovery by K. G. Jansky that radio waves could be detected from extra-terrestrial sources: the second was the commencement by the U.S. Signal Corps Engineering Laboratories of an intensive study of infra-red devices with the object of obtaining night vision without illumination of the field of view.From Jansky's discovery has sprung the whole science of radio astronomy, which has revolutionized our ideas about the universe, and brought in its wake, as one practical benefit, the radio sextant. From the work of the U.S. Signal Corps there resulted a number of very useful infra-red components, including the pneumatic detector, better known as the Golay cell.

Black holes in the Universe

2001 ◽  
Vol 171 (3) ◽  
pp. 307 ◽  
Author(s):  
Igor D. Novikov ◽  
Valerii P. Frolov
Keyword(s):  
Black Holes ◽  
The Universe

Beyond the Schwarzschild Metric

2018 ◽  
Author(s):  
David M. Wittman
Keyword(s):  
Black Holes ◽  
General Relativity ◽  
Gravitational Waves ◽  
Test Particle ◽  
Direct Detection ◽  
Relativistic Effects ◽  
Big Bang ◽  
Clusters Of Galaxies ◽  
General Relativistic ◽  
The Universe

General relativity explains much more than the spacetime around static spherical masses.We briefly assess general relativity in the larger context of physical theories, then explore various general relativistic effects that have no Newtonian analog. First, source massmotion gives rise to gravitomagnetic effects on test particles.These effects also depend on the velocity of the test particle, which has substantial implications for orbits around black holes to be further explored in Chapter 20. Second, any changes in the sourcemass ripple outward as gravitational waves, and we tell the century‐long story from the prediction of gravitational waves to their first direct detection in 2015. Third, the deflection of light by galaxies and clusters of galaxies allows us to map the amount and distribution of mass in the universe in astonishing detail. Finally, general relativity enables modeling the universe as a whole, and we explore the resulting Big Bang cosmology.

scholarly journals Black Holes in the Universe

1998 ◽  
Vol 11 (1) ◽  
pp. 28-41
Author(s):  
I.D. Novikov
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Neutron Stars ◽  
Supernova Explosions ◽  
The Universe

Some 30 years ago very few scientists thought that black holes may really exist. Attention focussed on the black hole hypothesis after neutron stars had been discovered. It was rather surprising that astrophysicists immediately ‘welcomed’ black holes. They found their place not only in the remnants of supernova explosions but also in the nuclei of galaxies and quasars.

HEALTH HAZARDS FROM MOBILE TOWER: A REVIEW

2021 ◽  
pp. 78-79
Author(s):  
Avni KP Skandhan ◽  
Skandhan KP ◽  
Prasad BS
Keyword(s):  
Ionizing Radiation ◽  
Ultraviolet Radiation ◽  
Visible Light ◽  
Mobile Phone ◽  
Gamma Rays ◽  
Health Hazards ◽  
X Rays ◽  
Radio Waves ◽  
Fm Radio ◽  
Smart Tv

Our knowledge on X-rays, gamma rays and ultraviolet radiation is ionising . Non-ionising gadget radiation is from Mobile Phone, Laptop, Tablet Smart TV etc. and harmful radiations is from mobile towers . FM radio waves, Microwaves, Visible light are also other forms of non-ionizing radiation.

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