Solar radiation in the context of "Cloud cover"

A comet is an icy, small Solar System body or interstellar object that warms and begins to release gases when passing close to the Sun, a process called outgassing. This produces an extended, gravitationally unbound atmosphere or coma surrounding the nucleus, and sometimes a tail of gas and dust gas blown out from the coma. These phenomena are due to the effects of solar radiation and the outstreaming solar wind plasma acting upon the nucleus of the comet. Comet nuclei range from a few hundred meters to tens of kilometers across and are composed of loose collections of ice, dust, and small rocky particles. The coma may be up to 15 times Earth's diameter, while the tail may stretch beyond one astronomical unit. If sufficiently close and bright, a comet may be seen from Earth without the aid of a telescope and can subtend an arc of up to 30° (60 Moons) across the sky. Comets have been observed and recorded since ancient times by many cultures and religions.

Comets usually have highly eccentric elliptical orbits, and they have a wide range of orbital periods, ranging from several years to potentially several millions of years. Short-period comets originate in the Kuiper belt or its associated scattered disc, which lie beyond the orbit of Neptune. Long-period comets are thought to originate in the Oort cloud, a spherical cloud of icy bodies extending from outside the Kuiper belt to halfway to the nearest star. Long-period comets are set in motion towards the Sun by gravitational perturbations from passing stars and the galactic tide. Hyperbolic comets may pass once through the inner Solar System before being flung to interstellar space. The appearance of a comet is called an apparition.

In astronomy and planetary science, a magnetosphere is a region of space surrounding an astronomical object, such as a planet or other object, in which charged particles are affected by that object's magnetic field. It is created by a celestial body with an active interior dynamo.

In the space environment close to a planetary body with a dipole magnetic field such as Earth, the field lines resemble a simple magnetic dipole. Farther out, field lines can be significantly distorted by the flow of electrically conducting plasma, as emitted from the Sun (i.e., the solar wind) or a nearby star. Planets having active magnetospheres, like the Earth, are capable of mitigating or blocking the effects of solar radiation or cosmic radiation. Interactions of particles and atmospheres with magnetospheres are studied under the specialized scientific subjects of plasma physics, space physics, and aeronomy.

Earth's climate system is a complex system with five interacting components: the atmosphere (air), the hydrosphere (water), the cryosphere (ice and permafrost), the lithosphere (earth's upper rocky layer) and the biosphere (living things). Climate is the statistical characterization of the climate system. It represents the average weather, typically over a period of 30 years, and is determined by a combination of processes, such as ocean currents and wind patterns. Circulation in the atmosphere and oceans transports heat from the tropical regions to regions that receive less energy from the Sun. Solar radiation is the main driving force for this circulation. The water cycle also moves energy throughout the climate system. In addition, certain chemical elements are constantly moving between the components of the climate system. Two examples for these biochemical cycles are the carbon and nitrogen cycles.

The climate system can change due to internal variability and external forcings. These external forcings can be natural, such as variations in solar intensity and volcanic eruptions, or caused by humans. Accumulation of greenhouse gases in the atmosphere, mainly being emitted by people burning fossil fuels, is causing climate change. Human activity also releases cooling aerosols, but their net effect is far less than that of greenhouse gases. Changes can be amplified by feedback processes in the different climate system components.

Sunlight is the portion of the electromagnetic radiation which is emitted by the Sun (i.e. solar radiation) and received by the Earth, in particular the visible light perceptible to the human eye as well as invisible infrared (typically perceived by humans as warmth) and ultraviolet (which can have physiological effects such as sunburn) lights. However, according to the American Meteorological Society, there are "conflicting conventions as to whether all three [...] are referred to as light, or whether that term should only be applied to the visible portion of the spectrum". Upon reaching the Earth, sunlight is scattered and filtered through the Earth's atmosphere as daylight when the Sun is above the horizon. When direct solar radiation is not blocked by clouds, it is experienced as sunshine, a combination of bright light and radiant heat (atmospheric). When blocked by clouds or reflected off other objects, sunlight is diffused. Sources estimate a global average of between 164 watts to 340 watts per square meter over a 24-hour day; this figure is estimated by NASA to be about a quarter of Earth's average total solar irradiance.

The ultraviolet radiation in sunlight has both positive and negative health effects, as it is both a requisite for vitamin D₃ synthesis and a mutagen.

Diffuse sky radiation, is solar radiation reaching the Earth's surface after having been scattered from the direct solar beam by molecules or particulates in the atmosphere. It is also called sky radiation, the determinative process for changing the colors of the sky. It is normally measured on a horizontal surface, thus frequently termed diffuse horizontal irradiance (DHI), often in the unit of watts per square meter (W/m). Approximately 23% of direct incident radiation of total sunlight is removed from the direct solar beam by scattering into the atmosphere; of this amount (of incident radiation) about two-thirds ultimately reaches the earth as photon diffused skylight radiation.

The dominant radiative scattering processes in the atmosphere are Rayleigh scattering and Mie scattering; they are elastic, meaning that a photon of light can be deviated from its path without being absorbed and without changing wavelength.

A comet tail is a projection of material from a comet that often becomes visible when illuminated by the Sun, while the comet passes through the inner Solar System. As a comet approaches the Sun, solar radiation causes the volatile materials within the comet to vaporize and stream out of the comet nucleus, carrying dust away with them.

Blown by the solar wind, these materials typically form two separate tails that extend outwards from the comet's orbit: the dust tail, composed of comet dust, and the gas or ion tail, composed of ionized gases. They become visible through different mechanisms: the dust tail reflects sunlight directly, while the gas tail glows because of the ionization.

A sea breeze or onshore breeze is a wind that blows in the afternoon from a large body of water toward or onto a landmass. By contrast, a land breeze or offshore breeze is a wind that blows in the night from a landmass toward or onto a large body of water. Sea breezes and land breezes are both important factors in coastal regions' prevailing winds.

Sea breeze and land breeze develop due to differences in air pressure created by the differing heat capacities of water and dry land. As such, sea breezes and land breezes are more localised than prevailing winds. Since land heats up much faster than water under solar radiation, a sea breeze is a common occurrence along coasts after sunrise. On the other hand, dry land also cools faster than water without solar radiation, so the wind instead flows from the land towards the sea when the sea breeze dissipates after sunset.

Numerical weather prediction (NWP) uses mathematical models of the atmosphere and oceans to predict the weather based on current weather conditions. Though first attempted in the 1920s, it was not until the advent of computer simulation in the 1950s that numerical weather predictions produced realistic results. A number of global and regional forecast models are run in different countries worldwide, using current weather observations relayed from radiosondes, weather satellites and other observing systems as inputs.

Mathematical models based on the same physical principles can be used to generate either short-term weather forecasts or longer-term climate predictions; the latter are widely applied for understanding and projecting climate change. The improvements made to regional models have allowed significant improvements in tropical cyclone track and air quality forecasts; however, atmospheric models perform poorly at handling processes that occur in a relatively constricted area, such as wildfires.

Spacecraft charging is a physical phenomenon where spacecraft accumulate electrical charge while operating in space environments. This effect occurs due to interactions between the spacecraft and the surrounding plasma environment, solar radiation, and cosmic rays.