Angel and demon - Celestial Beings, Spirits, & Mythology | Britannica
2024年11月21日 · Celestial and noncelestial forms: relationships of beliefs in angels and demons to views of the cosmos
Astronomy - Ancient, Celestial, Observations | Britannica
2024年11月17日 · Astronomy - Ancient, Celestial, Observations: Astronomy was the first natural science to reach a high level of sophistication and predictive ability, which it achieved already in the second half of the 1st millennium bce.
Astronomy | Definition, History, Discoveries, & Facts | Britannica
2024年11月17日 · Astronomy, science that encompasses the study of all extraterrestrial objects and phenomena. Since the late 19th century, astronomy has expanded to include astrophysics, the application of physical and chemical knowledge to an …
Celestial sphere | Night Sky, Celestial Bodies & Constellations ...
Celestial sphere, the apparent surface of the heavens, on which the stars seem to be fixed. For the purpose of establishing coordinate systems to mark the positions of heavenly bodies, it can be considered a real sphere at an infinite distance from the Earth.
Armillary sphere | Navigation, Celestial, Celestial Sphere | Britannica
Armillary sphere, early astronomical device for representing the great circles of the heavens, including in the most elaborate instruments the horizon, meridian, Equator, tropics, polar circles, and an ecliptic hoop. The sphere is a skeleton celestial globe, with circles divided into degrees for
Angel and demon - Varieties, Religions, World | Britannica
2024年11月21日 · In the Western religions, which are monotheistic and view the cosmos as a tripartite universe, angels and demons are generally conceived as celestial or atmospheric spirits.
Astronomy - Solar System, Planets, Stars | Britannica
2024年11月17日 · Astronomy - Solar System, Planets, Stars: The solar system took shape 4.57 billion years ago, when it condensed within a large cloud of gas and dust. Gravitational attraction holds the planets in their elliptical orbits around the Sun.
Equinox | Definition, Dates, & Facts | Britannica
equinox, either of the two moments in the year when the Sun is exactly above the Equator and day and night are of equal length; also, either of the two points in the sky where the ecliptic (the Sun’s annual pathway) and the celestial equator intersect.
Celestial navigation | Astronomy, Sextant, Stars | Britannica
Celestial navigation, use of the observed positions of celestial bodies to determine a navigator’s position. At any moment some celestial body is at the zenith of any particular location on the Earth’s surface.
Zenith | Celestial Point, Celestial Sphere & Celestial Coordinates ...
Zenith, point on the celestial sphere directly above an observer on the Earth. The point 180° opposite the zenith, directly underfoot, is the nadir. Astronomical zenith is defined by gravity; i.e., by sighting up a plumb line.