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Astronomy (from Greek: ἀστρονομία, literally meaning the 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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SN 1994D (bright spot on the lower left), a type Ia supernova within its host galaxy, NGC 4526
SN 1994D (bright spot on the lower left), a type Ia supernova within its host galaxy, NGC 4526

A supernova (/ˌspərˈnvə/; pl. supernovae /-v/ or supernovas; abbr. SN and SNe) is a powerful and luminous stellar explosion. This transient astronomical event occurs during the last evolutionary stages of a massive star or when a white dwarf is triggered into runaway nuclear fusion. The original object, called the progenitor, either collapses to a neutron star or black hole, or is completely destroyed. The peak optical luminosity of a supernova can be comparable to that of an entire galaxy before fading over several weeks or months.

Supernovae are more energetic than novae. In Latin, nova means "new", referring astronomically to what appears to be a temporary new bright star. Adding the prefix "super-" distinguishes supernovae from ordinary novae, which are far less luminous. The word supernova was coined by Walter Baade and Fritz Zwicky in 1929. (Full article...)

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NGC 2371-2 is a dual lobed planetary nebula located in the constellation Gemini. At 13th magnitude, this nebula is well within the limits of most amateur telescopes.

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Astronomy News

12 October 2021 – Discoveries of exoplanets
NASA astronomers announce the discovery of TIC 257060897b, a Hot Jupiter exoplanet that is 50% larger and 30% less massive than Jupiter. The discovery was made using the Transiting Exoplanet Survey Satellite. (Science Times)

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Astronomical events

All times UT unless otherwise specified.

1 January, 23:00 Moon at perigee
2 January, 18:33 New moon
3 January, 20:56 Peak of Quadrantids meteor shower
4 January, 00:59 Earth at perihelion
7 January, 10:59 Mercury at greatest eastern elongation
9 January, 00:50 Venus at inferior conjunction
14 January, 09:27 Moon at apogee
17 January, 23:48 Full moon
23 January, 10:25 Mercury at inferior conjunction
30 January, 07:09 Moon at perigee



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