Solar SystemPlanetary system consisting of the Sun and objects orbiting itThe Solar System is the gravitationally bound system of the Sun and the masses that orbit it, most prominently its eight planets, of which Earth is one. The Solar System is an isolated single-star planetary system (not part of a larger star system) within the Milky Way Galaxy.
EarthThird planet from the SunSurface equivalent doserate0.274 μSv/hAbsolute magnitude (H)−3.99AtmosphereSurface pressure101.325 kPa (at sea level)Composition by volume78.08% nitrogen (dry air)20.95% oxygen (dry air)≤1% water vapor (variable)0.9340% argon0.0430% carbon dioxide0.00182% neon0.00052% helium0.00017% methane0.00011% krypton0.00006% hydrogen Source:Earth is the third planet from the Sun and the only astronomical object known to harbor life.
SurfaceA surface, as the term is most generally used, is the outermost or uppermost layer of a physical object. It is the portion or region of the object that can first be observed and with which other objects first interact. The concept of surface has been abstracted and formalized in mathematics, specifically in geometry.
Nuclear fusionReaction that combines atomic nucleiFusion plasma in China's Experimental Advanced Superconducting Tokamak.Nuclear fusion is a reaction in which two or more atomic nuclei combine to form a larger nucleus. The difference in mass between the reactants and products is manifested as either the release or the absorption of energy. This difference in mass arises as a result of the difference in nuclear binding energy between the atomic nuclei before and after the fusion reaction.
StarA star is a luminous spheroid of plasma held together by self-gravity. The nearest star to Earth is the Sun. Many other stars are visible to the naked eye at night; their immense distances from Earth make them appear as fixed points of light. The most prominent stars have been categorised into constellations and asterisms, and many of the brightest stars have proper names.
UltravioletUltraviolet radiation (UV; sometimes called ultraviolet light) is electromagnetic radiation of wavelengths of 100–400 nanometers, shorter than that of visible light, but longer than vacuum ultraviolet and extreme ultraviolet, radiation bands that overlaps UV but shares some properties with soft X-rays. UV radiation is present in sunlight and constitutes about 10% of the total electromagnetic radiation output from the Sun.
InfraredInfrared (IR; sometimes called infrared light) is electromagnetic radiation (EMR) with wavelengths longer than that of visible light but shorter than microwaves. The infrared spectral band begins with the waves that are just longer than those of red light (the longest waves in the visible spectrum), so IR is invisible to the human eye. IR is generally (according to ISO, CIE) understood to include wavelengths from around 780 nm (380 THz) to 1 mm (300 GHz).
Thermal radiationThermal radiation is electromagnetic radiation emitted by the thermal motion of particles in matter. All matter with a temperature greater than absolute zero emits thermal radiation. The emission of energy arises from a combination of electronic, molecular, and lattice oscillations in a material. Kinetic energy is converted to electromagnetism due to charge-acceleration or dipole oscillation.
Plasma (physics)Plasma is a state of matter that results from one of the other three classical states (often, the gaseous one) having undergone an appreciable degree of ionization. It thus consists of a significant portion of charged particles (ions and/or electrons). While rarely encountered on Earth, it is estimated that 99.9% of all ordinary matter in the universe is plasma.
LifeLife is the capacity in matter, formed of one or more units called cells, for processes such as cell signaling, homeostasis, metabolism, cell growth, adaptation, response to stimuli, and reproduction. All life eventually reaches a state of death. Many philosophical definitions of living systems have been proposed, such as self-organizing systems.Sun in cultureThe Sun, as the source of energy and light for life on Earth, has been a central object in culture and religion since prehistory. Ritual solar worship has given rise to solar deities in theistic traditions throughout the world, and solar symbolism is ubiquitous. Apart from its immediate connection to light and warmth, the Sun is also important in timekeeping as the main indicator of the day and the year.
LightLight, visible light, or visible radiation is electromagnetic radiation that can be perceived by the human eye. Visible light spans the visible spectrum and is usually defined as having wavelengths in the range of 400–700 nanometers (nm), corresponding to frequencies of 750–420 terahertz.*As an Amazon Associate I earn from qualifying purchases.