Portal:Astronomy
The Astronomy Portal
Introduction![]() Astronomy is a natural science that studies celestial objects and the phenomena that occur in the cosmos. It uses mathematics, physics, and chemistry in order to explain their origin and their overall evolution. Objects of interest include planets, moons, stars, nebulae, galaxies, meteoroids, asteroids, and comets. Relevant phenomena include supernova explosions, gamma ray bursts, quasars, blazars, pulsars, and cosmic microwave background radiation. More generally, astronomy studies everything that originates beyond Earth's atmosphere. Cosmology is a branch of astronomy that studies the universe as a whole. Astronomy is one of the oldest natural sciences. The early civilizations in recorded history made methodical observations of the night sky. These include the Egyptians, Babylonians, Greeks, Indians, Chinese, Maya, and many ancient indigenous peoples of the Americas. In the past, astronomy included disciplines as diverse as astrometry, celestial navigation, observational astronomy, and the making of calendars. Professional astronomy is split into observational and theoretical branches. Observational astronomy is focused on acquiring data from observations of astronomical objects. This data is then analyzed using basic principles of physics. Theoretical astronomy is oriented toward the development of computer or analytical models to describe astronomical objects and phenomena. These two fields complement each other. Theoretical astronomy seeks to explain observational results and observations are used to confirm theoretical results. Astronomy is one of the few sciences in which amateurs play an active role. This is especially true for the discovery and observation of transient events. Amateur astronomers have helped with many important discoveries, such as finding new comets. (Full article...) General images -The following are images from various astronomy-related articles on Wikipedia.
This is a Featured article, which represents some of the best content on English Wikipedia.
Enceladus is the sixth-largest moon of Saturn and the 19th-largest in the Solar System. It is about 500 kilometers (310 miles) in diameter, about a tenth of that of Saturn's largest moon, Titan. It is mostly covered by fresh, clean ice, making it one of the most reflective bodies of the Solar System. Consequently, its surface temperature at noon reaches only −198 °C (75.1 K; −324.4 °F), far colder than a light-absorbing body would be. Despite its small size, Enceladus has a wide variety of surface features, ranging from old, heavily cratered regions to young, tectonically deformed terrain. Enceladus was discovered on August 28, 1789, by William Herschel, but little was known about it until the two Voyager spacecrafts, Voyager 1 and Voyager 2, flew by Saturn in 1980 and 1981. In 2005, the spacecraft Cassini started multiple close flybys of Enceladus, revealing its surface and environment in greater detail. In particular, Cassini discovered water-rich plumes venting from the south polar region. Cryovolcanoes near the south pole shoot geyser-like jets of water vapor, molecular hydrogen, other volatiles, and solid material, including sodium chloride crystals and ice particles, into space, totaling about 200 kilograms (440 pounds) per second. More than 100 geysers have been identified. Some of the water vapor falls back as "snow"; the rest escapes and supplies most of the material making up Saturn's E ring. According to NASA scientists, the plumes are similar in composition to comets. In 2014, NASA reported that Cassini had found evidence for a large south polar subsurface ocean of liquid water with a thickness of around 10 km (6 mi). The existence of Enceladus' subsurface ocean has since been mathematically modelled and replicated. (Full article...)Did you know -
More Did you know (auto generated)![]()
WikiProjectsSelected image -![]() The five Moons of Pluto include Pluto's small satellite Hydra. Image is an artist's concept of the surface of Pluto, Hydra (center), Charon (right) and Nix (bright dot on left). Astronomy News
September anniversaries
Space-related PortalsAstronomical eventsAll times UT unless otherwise specified. Portal:Astronomy/Events/September 2024 TopicsSubcategoriesSelect [►] to view subcategories
Things you can do
Wikibooks![]() These books may be in various stages of development. See also the related Science and Mathematics bookshelves.
WikijuniorAssociated WikimediaThe following Wikimedia Foundation sister projects provide more on this subject:
Discover Wikipedia using portals Shortcuts to this page: Astronomy portal • P:ASTRO Purge server cache |