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The heliopause is the final known boundary between the heliosphere and the interstellar space that is filled with material, especially plasma, not from the Earth's own star, the Sun, but from other stars. [46] Even so, just outside the heliosphere (i.e. the "solar bubble") there is a transitional region, as detected by Voyager 1. [47]
The calcium carbonate exoskeleton enhances the amount of light the coccolithophore can uptake, increasing the level of photosynthesis. Finally, the coccoliths protect the phytoplankton from photodamage by UV light from the sun. [28] The coccolithophores are also important in the geological history of Earth.
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 ...
For example, the Great Pyramid of Giza is aligned with the cardinal points, and its descending passage is aligned with the star Thuban in the constellation Draco, which was the pole star at the time. This alignment likely served both symbolic and practical purposes, connecting the Pharaoh's eternal journey with the stars.
Star trails captured during a total lunar eclipse. In astronomy, diurnal motion (from Latin diurnus 'daily', from Latin diēs 'day') is the apparent motion of celestial objects (e.g. the Sun and stars) around Earth, or more precisely around the two celestial poles, over the course of one day.
The poles of astronomical bodies are determined based on their axis of rotation in relation to the celestial poles of the celestial sphere. Astronomical bodies include stars, planets, dwarf planets and small Solar System bodies such as comets and minor planets (e.g., asteroids), as well as natural satellites and minor-planet moons.
This small difference in the Sun's position against the stars causes any particular spot on Earth's surface to catch up with (and stand directly north or south of) the Sun about four minutes later each day than it would if Earth did not orbit; a day on Earth is therefore 24 hours long rather than the approximately 23-hour 56-minute sidereal day ...
The word is often used in reference to the Sun, Earth, and either the Moon or a planet, where the latter is in conjunction or opposition. Solar and lunar eclipses occur at times of syzygy, as do transits and occultations. The term is often applied when the Sun and Moon are in conjunction or in opposition . [4]