The first USA satellite which detected cosmic X-rays was the third Orbiting Solar Observatory, or OSO-3, launched on March 8, 1967.It was intended primarily to observe the Sun, which it did very well during its 2-year lifetime, but it also detected a flaring episode from the source Sco X-1 and measured the diffuse cosmic X-ray background.; The fourth successful Orbiting Solar …

Australian Aboriginal astronomy is a name given to Aboriginal Australian culture relating to astronomical subjects – such as the Sun and Moon, the stars, planets, and the Milky Way, and their motions on the sky.. Traditional Aboriginal culture and mythology and religion include many components of astronomy, and these traditions have been passed down orally, through …

An azimuth (/ ˈ æ z ə m ə θ / (); from Arabic: اَلسُّمُوت, romanized: as-sumūt, lit. 'the directions') is an angular measurement in a spherical coordinate system.More specifically, it is the horizontal angle from a cardinal direction, most commonly north.. Mathematically, the relative position vector from an observer to a point of interest is projected perpendicularly onto a ...

Infrared astronomy is a sub-discipline of astronomy which specializes in the observation and analysis of astronomical objects using infrared (IR) radiation. The wavelength of infrared light ranges from 0.75 to 300 micrometers, and falls in between visible radiation, which ranges from 380 to 750 nanometers, and submillimeter waves.. Infrared astronomy began in the 1830s, a …

Henrietta Swan Leavitt (/ ˈ l ɛ v ɪ t /; July 4, 1868 – December 12, 1921) was an American astronomer.A graduate of Radcliffe College, she worked at the Harvard College Observatory as a "computer", tasked with examining photographic plates in order to measure and catalog the brightness of stars. This work led her to discover the relation between the luminosity and the …

A minute of arc, arcminute (arcmin), arc minute, or minute arc, denoted by the symbol ′, is a unit of angular measurement equal to 1 / 60 of one degree. Since one degree is 1 / 360 of a turn (or complete rotation), one minute of arc is 1 / 21 600 of a turn. The nautical mile (nmi) was originally defined as the arc length of a minute of latitude on a spherical Earth, so the actual Earth ...

In astronomy, metallicity is the abundance of elements present in an object that are heavier than hydrogen and helium.Most of the normal physical matter in the Universe is either hydrogen or helium, and astronomers use the word "metals" as a convenient short term for "all elements except hydrogen and helium".This word-use is distinct from the conventional chemical or …

SETI@home ("SETI at home") is a project of the Berkeley SETI Research Center to analyze radio signals, searching for signs of extraterrestrial intelligence.Until March 2020, it was run as an Internet-based public volunteer computing project that employed the BOINC software platform. It is hosted by the Space Sciences Laboratory at the University of California, Berkeley, and is …

The Jantar Mantar, Jaipur is a collection of 19 astronomical instruments built by the Rajput king Sawai Jai Singh II, the founder of Jaipur, Rajasthan.The monument was completed in 1734. It features the world's largest stone sundial, and is a UNESCO World Heritage site. It is near City Palace and Hawa Mahal. The instruments allow the observation of astronomical positions with …

Sunset, also known as sundown, is the daily disappearance of the Sun below the horizon due to Earth's rotation.As viewed from everywhere on Earth (except the North and South poles), the equinox Sun sets due west at the moment of both the spring and autumn equinoxes. As viewed from the Northern Hemisphere, the Sun sets to the northwest (or not at all) in the spring and …

Navagraha are nine heavenly bodies and deities that influence human life on Earth according to Hinduism and Hindu astrology. The term is derived from nava (Sanskrit: नव "nine") and graha (Sanskrit: ग्रह "planet, seizing, laying hold of, holding"). Note that the Earth, Uranus, Neptune and Pluto are excluded from the Navagraha,.However, the Sun is part of the Navagraha.

Sofia (/ ˈ s oʊ f i ə, ˈ s ɒ f-, s oʊ ˈ f iː ə / SOH-fee-ə, SOF-; Bulgarian: София, romanized: Sofiya, IPA: ()) is the capital and largest city of Bulgaria.It is situated in the Sofia Valley at the foot of the Vitosha mountain in the western parts of the country. The city is built west of the Iskar river, and has many mineral springs, such as the Sofia Central Mineral Baths.

Messier 81 (also known as NGC 3031 or Bode's Galaxy) is a grand design spiral galaxy about 12 million light-years away in the constellation Ursa Major.It has a D 25 isophotal diameter of 29.44 kiloparsecs (96,000 light-years). Because of its relative proximity to the Milky Way galaxy, large size, and active galactic nucleus (which harbors a 70 million M ☉ supermassive black hole), …

The Declaration of the Rights of Man and of the Citizen (French: Déclaration des droits de l'homme et du citoyen de 1789), set by France's National Constituent Assembly in 1789, is a human civil rights document from the French Revolution. Inspired by Enlightenment philosophers, the Declaration was a core statement of the values of the French Revolution and had a major …