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  2. Sun - Wikipedia

    en.wikipedia.org/wiki/Sun

    The core is the only region of the Sun that produces an appreciable amount of thermal energy through fusion; 99% of the Sun's power is generated in the innermost 24% of its radius, and almost no fusion occurs beyond 30% of the radius. The rest of the Sun is heated by this energy as it is transferred outward through many successive layers ...

  3. Tachocline - Wikipedia

    en.wikipedia.org/wiki/Tachocline

    The tachocline is the transition region of stars of more than 0.3 solar masses, between the radiative interior and the differentially rotating outer convective zone. This causes the region to have a very large shear as the rotation rate changes very rapidly. The convective exterior rotates as a normal fluid with differential rotation with the ...

  4. Geographical zone - Wikipedia

    en.wikipedia.org/wiki/Geographical_zone

    The frigid zones are the coldest regions of Earth and are generally covered in ice and snow. It receives slanting rays of the Sun, as this region lies farthest from the equator. Summer in this region lasts for about 2 to 3 months, and there is almost 24-hour sunlight during summer.

  5. Solar System - Wikipedia

    en.wikipedia.org/wiki/Solar_System

    Thus, the Sun occupies 0.00001% (1 part in 10 7) of the volume of a sphere with a radius the size of Earth's orbit, whereas Earth's volume is roughly 1 millionth (10 −6) that of the Sun. Jupiter, the largest planet, is 5.2 AU from the Sun and has a radius of 71,000 km (0.00047 AU; 44,000 mi), whereas the most distant planet, Neptune, is 30 AU ...

  6. Umbra, penumbra and antumbra - Wikipedia

    en.wikipedia.org/wiki/Umbra,_penumbra_and_antumbra

    The antumbra (from the Latin ante "before" and umbra "shadow") is the region from which the occluding body appears entirely within the disc of the light source. An observer in this region experiences an annular eclipse, in which a bright ring is visible around the eclipsing body. If the observer moves closer to the light source, the apparent ...

  7. Tropics - Wikipedia

    en.wikipedia.org/wiki/Tropics

    Many tropical areas have both a dry and a wet season. The wet season, rainy season or green season is the time of year, ranging from one or more months when most of the average annual rainfall in a region falls. [9] Areas with wet seasons are disseminated across portions of the tropics and subtropics, some even in temperate regions. [10]

  8. Solar plage - Wikipedia

    en.wikipedia.org/wiki/Solar_plage

    A plage / p l eɪ dʒ / is a bright region in the Sun's chromosphere, typically found in and around active regions. Historically, they have been referred to as bright flocculi, in contrast to dark flocculi, and as chromospheric faculae, in contrast to photospheric faculae. [1]

  9. Ionosphere - Wikipedia

    en.wikipedia.org/wiki/Ionosphere

    The more magnetically active the Sun is, the more sunspot active regions there are on the Sun at any one time. Sunspot active regions are the source of increased coronal heating and accompanying increases in EUV and X-ray irradiance, particularly during episodic magnetic eruptions that include solar flares that increase ionization on the sunlit ...