Related topics: galaxies · planets · universe

Milky Way's black hole was 'birth cry' of radio astronomy

The first image of the supermassive black hole at the center of our Milky Way galaxy brings radio astronomy back to its celestial birthplace. The Event Horizon Telescope (EHT), a worldwide collection of millimeter-wave radio ...

A space telescope could reveal a black hole's photon ring

Despite decades of study, black holes are still among the most powerful and mysterious celestial objects ever studied. Because of the extreme gravitational forces involved, nothing can escape the surface of a black hole (including ...

Future of Earth's defense is ground-based planetary radar

Powerful radar systems have played a major role in the study of planets, moons, asteroids, and other objects in our Solar System for several decades, and now have a "unique role" to play in planetary defense—"providing ...

A new spin on the blue stellar sequence

Some humans try to look younger than they really are—stars do, too. This is reported by an international team of astronomers in a paper just published in Nature Astronomy.

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Astronomy

Astronomy (from the Greek words astron (ἄστρον), "star", and nomos (νόμος), "law") is the scientific study of celestial objects (such as stars, planets, comets, and galaxies) and phenomena that originate outside the Earth's atmosphere (such as the cosmic background radiation). It is concerned with the evolution, physics, chemistry, meteorology, and motion of celestial objects, as well as the formation and development of the universe.

Astronomy is one of the oldest sciences. Astronomers of early civilizations performed methodical observations of the night sky, and astronomical artifacts have been found from much earlier periods. However, the invention of the telescope was required before astronomy was able to develop into a modern science. Historically, astronomy has included disciplines as diverse as astrometry, celestial navigation, observational astronomy, the making of calendars, and even astrology, but professional astronomy is nowadays often considered to be synonymous with astrophysics.

Since the 20th century, the field of professional astronomy split into observational and theoretical branches. Observational astronomy is focused on acquiring and analyzing data, mainly using basic principles of physics. Theoretical astronomy is oriented towards the development of computer or analytical models to describe astronomical objects and phenomena. The two fields complement each other, with theoretical astronomy seeking to explain the observational results, and observations being used to confirm theoretical results.

Amateur astronomers have contributed to many important astronomical discoveries, and astronomy is one of the few sciences where amateurs can still play an active role, especially in the discovery and observation of transient phenomena.

Old or even ancient astronomy is not to be confused with astrology, the belief system which claims that human affairs are correlated with the positions of celestial objects. Although the two fields share a common origin and a part of their methods (namely, the use of ephemerides), they are distinct.

2009 has been declared by the UN to be the International Year of Astronomy 2009 (IYA2009). The focus is on enhancing the public’s understanding and engagement with astronomy.

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