At first, the expansion is slowed down by gravitation due to the radiation and matter content of the universe.

The cosmic microwave background is radiation left over from decoupling after the epoch of recombination when neutral atoms first formed.

The first radiation of the diatoms ( generally siliceous, rather than calcareous ) in the oceans occurred during the Cretaceous ; freshwater diatoms did not appear until the Miocene.

The Devonian period experienced the first significant adaptive radiation of terrestrial life.

Besides being the first U. S. satellite, it is known for discovering the Van Allen radiation belt.

Fick's first law is also important in radiation transfer equations.

He designed the first instruments used in satellites to measure cosmic radiation and ozone, and in 1951 or 1952 designed the MOUSE (" Minimal Orbital Unmanned Satellite, Earth "), a proposed satellite that would contain Geiger counters for measuring cosmic rays, photo cells for scanning the Earth, telemetry electronics for sending data back to Earth, a magnetic data storage device, and rudimentary solar energy cells.

The existence of infrared radiation was first discovered in 1800 by astronomer William Herschel.

In 1917, Albert Einstein established the theoretical foundations for the laser and the maser in the paper Zur Quantentheorie der Strahlung ( On the Quantum Theory of Radiation ); via a re-derivation of Max Planck ’ s law of radiation, conceptually based upon probability coefficients ( Einstein coefficients ) for the absorption, spontaneous emission, and stimulated emission of electromagnetic radiation ; in 1928, Rudolf W. Ladenburg confirmed the existences of the phenomena of stimulated emission and negative absorption ; in 1939, Valentin A. Fabrikant predicted the use of stimulated emission to amplify “ short ” waves ; in 1947, Willis E. Lamb and R. C. Retherford found apparent stimulated emission in hydrogen spectra and effected the first demonstration of stimulated emission ; in 1950, Alfred Kastler ( Nobel Prize for Physics 1966 ) proposed the method of optical pumping, experimentally confirmed, two years later, by Brossel, Kastler, and Winter.

In 1953, Charles Hard Townes and graduate students James P. Gordon and Herbert J. Zeiger produced the first microwave amplifier, a device operating on similar principles to the laser, but amplifying microwave radiation rather than infrared or visible radiation.

When the first scientific satellites were launched in the first half of 1958 — Explorers 1 and 3 by the US, Sputnik 3 by the Soviet Union — they observed an intense ( and unexpected ) radiation belt around Earth, held by its magnetic field.

In this early work, TTAPS carried out the first estimates of the total smoke and dust emissions that would result from a major nuclear exchange, and determined quantitatively the subsequent effects on the atmospheric radiation balance and temperature structure.

However, when confronted with totally unexpected phenomena, such as the first evidence for invisible radiation, experimental scientists often use the same approach as historical scientists: construct a set of hypotheses about the causes and then look for a " smoking gun ".

‪ File: Roentgen2. jpg ‬‬| Wilhelm Röntgen ( 1845-1923 ): produced and detected electromagnetic radiation in a wavelength range of X-rays or Röntgen rays in 1895, for which he earned the first Nobel Prize in Physics in 1901, namesake of element 111, Roentgenium ‬‬‬‬

File: Ernest Rutherford 1908. jpg | Ernest Rutherford ( 1871-1937 ): considered " Father of Nuclear Physics ", showed how the atomic nucleus has a positive charge, first to change one element into another by an artificial nuclear reaction, differentiated and named alpha and beta radiation, awarded Nobel Prize for Chemistry in 1908

Polonium solutions are first colored in pink by the Po < sup > 2 +</ sup > ions, but then rapidly become yellow because alpha radiation from polonium ionizes the solvent and converts Po < sup > 2 +</ sup > into Po < sup > 4 +</ sup >.

Work by Gordon Brownell, Charles Burnham and their associates at the Massachusetts General Hospital beginning in the 1950s contributed significantly to the development of PET technology and included the first demonstration of annihilation radiation for medical imaging.

Warren Maltzman, of the Waksman Institute of Rutgers University first demonstrated that TP53 was responsive to DNA damage in the form of ultraviolet radiation.

At around the same time, the atomic theory and the corpuscular theory of light ( as updated by Einstein ) first came to be widely accepted as scientific fact ; these latter theories can be viewed as quantum theories of matter and electromagnetic radiation, respectively.

The first formulation of a quantum theory describing radiation and matter interaction is due to British scientist Paul Dirac, who, during the 1920s, was first able to compute the coefficient of spontaneous emission of an atom.

This result suggests a very high temperature at the solid surface of the planet, although there is the possibility that the observed radiation may be a combination of both thermal and non-thermal components and that the observed spectrum is that of a black body merely by coincidence.

Mars has been observed twice at about 3-cm wave length, and the intensity of the observed radiation is in reasonable agreement with the thermal radiation which might be predicted on the basis of the known temperature of Mars.

Steady radiation which was presumably of thermal origin was observed from Venus at 3.15 and 9.4 cm, and from Mars and Jupiter at 3.15 cm in 1956 ( Mayer, McCullough, and Sloanaker, 1958, A, B, C ), and from Saturn at 3.75 cm in 1957 ( Drake and Ewen, 1958 ).

The apparent black-body disk temperature is the temperature which must be assumed for the black body in order that the intensity of its radiation should equal that of the observed radiation.

In fact, any increase or decrease in radiation intensity that is observed to the same extent at all pixels chosen for correction is eliminated by the correction algorithm.

At these very high vacuums the effect of photon radiation pressure on the vanes can be observed in very sensitive apparatus ( see Nichols radiometer ) but this is insufficient to cause rotation.

However, it remains difficult to find a solution to the coronal heating problem as these structures are being observed remotely, where many ambiguities are present ( i. e. radiation contributions along the LOS ).

Rapidly moving electrons are most sharply accelerated when they encounter a region of force, so they are responsible for producing much of the highest frequency electromagnetic radiation observed in nature.

In 1900, Max Planck developed a new theory of black-body radiation that explained the observed spectrum.

More than half of the cosmic radiation observed from the Earth's surface consists of muons.

In astrophysics, gravitational redshift or Einstein shift is the process by which electromagnetic radiation originating from a source that is in gravitational field is reduced in frequency, or redshifted, when observed in a region of a weaker gravitational field.

In a key experiment he used a prism to isolate ultraviolet radiation from sunlight and observed blue light emitted by an ethanol solution of quinine exposed by it.

To separate and analyze them, the fluorescent radiation is passed through an Emission monochromator, and observed selectively by a detector.

In 1944, Hendrik van de Hulst predicted microwave radiation at a wavelength of 21 cm resulting from interstellar atomic hydrogen gas ; this radiation was observed in 1951.

One of these used no filters and observed all incoming radiation, both solar and thermal.

In 1932 Chadwick realized that radiation that had been observed by Walther Bothe, Herbert L. Becker, Irène and Frédéric Joliot-Curie was actually due to a neutral particle of about the same mass as the proton, that he called the neutron ( following a suggestion about the need for such a particle, by Rutherford ).

Thus the observed radiation density ( the sky brightness of extragalactic background light ) can be independent of finiteness of the Universe.

The original concept relied only on radiation from the Sun – for example in Arthur C. Clarke's 1965 story " Sunjammer ".

The astronomical phenomena included quasars ( 1963 ), the 3-kelvin microwave background radiation ( 1965 ), pulsars ( 1967 ), and the discovery of the first black hole candidates ( 1971 ).

* 1965 — Arno Penzias and Robert Wilson, astronomers at Bell Labs discover the 2. 7 K microwave background radiation, which earns them the 1978 Nobel Prize in Physics.

For most cosmologists, the refutation of the steady-state theory came with the discovery of the cosmic microwave background radiation in 1965, which was predicted by the Big Bang theory.

Since the discovery of the Cosmic microwave background radiation ( CMB ) by Penzias and Robert Wilson in 1965, most cosmologists concluded that observations were best explained by the big bang model.

The gray was defined in 1975 in honour of Louis Harold Gray ( 1905 – 1965 ) who, in 1940, first proposed a similar concept, " that amount of neutron radiation which produces an increment of energy in unit volume of tissue equal to the increment of energy produced in unit volume of water by one röntgen of radiation ".

The fallout radiation advice in Protect and Survive was based on 1960s fallout shelter experiments summarized by Daniel T. Jones of the Home Office Scientific Advisory Branch in his report, The Protection Against Fallout Radiation Afforded by Core Shelters in a Typical British House which was published in Protective Structures for Civilian Populations, Proceedings of the Symposium held at Washington, D. C., April 19 – 23, 1965, by the Subcommittee on Protective Structures, Advisory Committee on Civil Defense, U. S. National Academy of Sciences, National Research Council.

Ralph Alpher and Robert Herman made a scientific prediction in 1948 that we should still be able to observe these red-shifted photons today as an ambient cosmic microwave background radiation ( CMBR ) pervading all space with a temperature of about five Kelvin ( when the CMBR was actually first detected in 1965, its temperature was found to be three Kelvin ).

In 1965, the Mariner 4 probe discovered that Mars had no global magnetic field that would protect the planet from potentially life-threatening cosmic radiation and solar radiation ; observations made in the late 1990s by the Mars Global Surveyor confirmed this discovery.

* 1965 – Arno Penzias, Robert Wilson: Cosmic microwave background radiation, evidence of the Big Bang

In 1965 while using this antenna, Penzias and Wilson discovered the microwave background radiation that permeates the universe.

Bell Labs ' Horn Antenna in Crawford Hill, NJ-In 1965 while using the Horn Antenna, Penzias and Wilson stumbled on the microwave background radiation that permeates the universe.

In order to facilitate his plan to use her as a surrogate candidate in 1966, Mrs. Wallace cooperated with a campaign of dissimulation and misdirection as she began radiation therapy in December 1965.

The discovery of microwave cosmic background radiation announced in 1965 finally brought an effective end to the remaining scientific uncertainty over the expanding Universe.

Probably the most photographed and well-known example is the 15 meter ( 50 foot ) long Holmdel Horn Antenna at Bell Labs in Holmdel, New Jersey, with which Arno Penzias and Robert Wilson discovered cosmic microwave background radiation in 1965, for which they won the 1978 Nobel Prize in Physics.

* Samuel C. Lind ( 1879 – 1965 ), American radiation chemist

* 1965: Arno Penzias and Robert Wilson discover the cosmic microwave background radiation,

* 1965: Arno Penzias and Robert Wilson discover the cosmic microwave background radiation,