Astronomy (from Ancient Greek ἀστρονομία (astronomía) 'science that studies the laws of the stars') is a natural science that studies celestial objects and phenomena. It uses mathematics, physics, and chemistry in order to explain their origin and evolution. Objects of interest include planets, moons, stars, nebulae, galaxies, 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 Babylonians, Greeks, Indians, Egyptians, 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. Nowadays, professional astronomy is often said to be the same as astrophysics.

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...)

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Earthrise Taken from Apollo 8 by William Anders

Apollo 8 (December 21–27, 1968) was the first crewed spacecraft to leave low Earth orbit and the first human spaceflight to reach the Moon. The crew orbited the Moon ten times without landing, and then departed safely back to Earth. These three astronauts—Frank Borman, James Lovell, and William Anders—were the first humans to personally witness and photograph the far side of the Moon and an Earthrise.

Apollo 8 launched on December 21, 1968, and was the second crewed spaceflight mission flown in the United States Apollo space program after Apollo 7, which stayed in Earth orbit. Apollo 8 was the third flight and the first crewed launch of the Saturn V rocket, and was the first human spaceflight from the Kennedy Space Center, located adjacent to Cape Kennedy Air Force Station in Florida. (Full article...)

• ... that Abell 2142, a galaxy cluster, is one of the most massive objects in the universe?
• ... that a jet from one of the component stars of Z Canis Majoris is over 11 light-years long?
• ... that Messier 58 is one of the brightest galaxies in the Virgo Cluster and is 1 of 4 barred spiral galaxies included in Charles Messier's catalog?
• ... that the asteroid 2014 AA entered Earth's atmosphere on the early morning of January 2, 2014, less than a day after it was discovered?
• ... that ATIC, a balloon-borne detector flying over Antarctica, recently found excess cosmic ray electrons that might provide evidence for dark matter consisting of Kaluza-Klein particles?
• .... that the Sun fuses about 620 million metric tons of hydrogen per seconds due to Gravity?

• ... that Mariner 1, the United States' first interplanetary probe, was lost in 1962 due to the miscoding of a single character in its software?
• ... that The City in the Middle of the Night, a 2019 climate-fiction novel by Charlie Jane Anders, is set on a tidally locked planet?
• ... that Nandivada Rathnasree, who ran Delhi's planetarium, proposed that astronomers could be taught using India's stone-built observatories?
• ... that NGC 4848, a spiral galaxy, lost most of its hydrogen gas as it passed through the Coma Cluster due to ram pressure?
• ... that the producers of The Jet Propelled Couch hired "Miss Color TV", Vampira, and several Miss Americas to portray attractive creatures inhabiting an imaginary planet?
• ... that pushbacks of migrants in the Aegean Sea have been described as "a human rights violation that encapsulates a will to eliminate a person's presence on the face of the planet"?

WikiProject Astronomy	WikiProject Solar System
WikiProject Cosmology	WikiProject Spaceflight

A coronal mass ejection (CME) is a significant release of plasma and accompanying magnetic field from the solar corona. They often follow solar flares and are normally present during a solar prominence eruption. Coronal mass ejections release large quantities of matter and electromagnetic radiation into space above the Sun's surface, either near the corona, or farther into the planetary system, or beyond (interplanetary CME).

9 August 2022 – Discoveries of exoplanets

Radio astronomers have discovered a newborn, Jupiter-size exoplanet orbiting the star AS 209, using the Atacama Large Millimeter Array telescope in Chile. (Space.com)

• 7 December 1972 – The “Blue Marble” photograph is taken by the Apollo 17 crew
• 8 December 1992 – Galileo completes the second Earth flyby
• 14 December 1962 – Mariner 2 becomes the first space probe to perform a flyby of a planet, when it passes within 35,000 kilometers of Venus
• 17 December 1917 – “2001: A Space Odyssey” science fiction author Arthur C. Clarke is born
• 19 December 2013 – Gaia is launched for the mission to study billions of stars in the Milky Way
• 21 December 1968 – Apollo 8, is launched with the first crewed spacecraft to leave Earth orbit, reach the Moon, orbit it, and return safely to Earth
• 27 December 1571 – Astronomer, mathematician, and astrologer Johannes Kepler is born