. The number of cycles of radiation was chosen to make the length of the defined second correspond as closely as possible to that of the nowobsoleteastronomically determined second ofEphemeris Time(defined as the fraction of the tropical year given above). As the rate of rotation of the Earth...
As oxygen filled the atmosphere,Earth’s ozone layerthickened. Before the presence of an ozone layer, life was restricted to shallow water. Because water shielded harmful radiation, that’s where life existed. Eventually, a thicker ozone layer (O3) enabled life to diversify on land in theProter...
raising its temperature. The heated atmosphere in turn radiates infrared radiation back toward Earth’s surface. (Despite its name, the greenhouse effect is different from the warming in agreenhouse, where panes ofglasstransmitvisible sunlight but hold heat inside the building by trapping warmed air...
In 2020, the laser will celebrate its 60thanniversary. Here Photonics Media presents a timeline of some of the more notable scientific accomplishments related to light amplification by stimulated emission of radiation (laser). Aninteractive version of the laser timelineis also available, as well as ...
In the 1820s, French mathematician and physicist Joseph Fourier proposed that energy reaching the planet as sunlight must be balanced by energy returning to space since heated surfaces emit radiation. But some of that energy, he reasoned, must be held within the atmosphere and not return to spac...
3) push back the phylogenetic age of mosquitoes considerably22 and strongly support the hypothesis that mosquitoes originated in the Triassic (~217 MYA [highest posterior density region, or HPD: 188–250 MYA]), before the major radiations of both dinosaurs and mammals, when the dominant ...
The way the topic of black-body radiation is presented in most of the standard textbooks (i.e., from Rayleigh–Jeans to Max Planck) does not follow the actual historical timeline of the understanding of the black-body radiation problem. Authors believe that a presentation that follows an ...
Timeline: key milestone in cell cultures. Advertisement 2. Live under the microscope The development of biological sciences would not have been possible without one of the greatest inventions—microscopes. In the sixteenth and seventeenth centuries—two countries—the Netherlands and Italy played a cru...
Along with solar radiation levels, it is believed that global warming and cooling is connected to plate tectonic activity. The shifting of the Earth’s plates creates large-scale changes to continental masses, which impacts ocean and atmospheric currents, and triggers volcanic activity that releases...
The five stages of the formation of the universe are the very early universe, the early universe, the Dark Ages and structure emergence, the present, and the future. The history of the universe can be divided into major eras: Radiation, Matter, and Dark Energy.How...