Astronomy

Relevant phenomena include supernova explosions, gamma ray bursts, quasars, blazars, pulsars, and cosmic microwave background radiation.

In addition to their ceremonial uses, these observatories could be employed to determine the seasons, an important factor in knowing when to plant crops and in understanding the length of the year.

From these observations, early ideas about the motions of the planets were formed, and the nature of the Sun, Moon and the Earth in the Universe were explored philosophically.

Mesopotamia is worldwide the place of the earliest known astronomer and poet by name: Enheduanna, Akkadian high priestess to the lunar deity Nanna/Sin and princess, daughter of Sargon the Great (c. 2334 – c. 2279 BCE).

[18] In the 2nd century BC, Hipparchus discovered precession, calculated the size and distance of the Moon and invented the earliest known astronomical devices such as the astrolabe.

[20] The Antikythera mechanism (c. 150–80 BC) was an early analog computer designed to calculate the location of the Sun, Moon, and planets for a given date.

Iranian scholar Al-Biruni observed that, contrary to Ptolemy, the Sun's apogee (highest point in the heavens) was mobile, not fixed.

[32] In Post-classical West Africa, Astronomers studied the movement of stars and relation to seasons, crafting charts of the heavens as well as precise diagrams of orbits of the other planets based on complex mathematical calculations.

[33][34] Europeans had previously believed that there had been no astronomical observation in sub-Saharan Africa during the pre-colonial Middle Ages, but modern discoveries show otherwise.

[35][36][37][38] For over six centuries (from the recovery of ancient learning during the late Middle Ages into the Enlightenment), the Roman Catholic Church gave more financial and social support to the study of astronomy than probably all other institutions.

[40] Georg von Peuerbach (1423–1461) and Regiomontanus (1436–1476) helped make astronomical progress instrumental to Copernicus's development of the heliocentric model decades later.

[44] During the 18–19th centuries, the study of the three-body problem by Leonhard Euler, Alexis Claude Clairaut, and Jean le Rond d'Alembert led to more accurate predictions about the motions of the Moon and planets.

This work was further refined by Joseph-Louis Lagrange and Pierre Simon Laplace, allowing the masses of the planets and moons to be estimated from their perturbations.

[48] Theoretical astronomy led to speculations on the existence of objects such as black holes and neutron stars, which have been used to explain such observed phenomena as quasars, pulsars, blazars, and radio galaxies.

In the early 1900s the model of the Big Bang theory was formulated, heavily evidenced by cosmic microwave background radiation, Hubble's law, and the cosmological abundances of elements.

[8][53] A wide variety of other objects are observable at radio wavelengths, including supernovae, interstellar gas, pulsars, and active galactic nuclei.

Observations from the Wide-field Infrared Survey Explorer (WISE) have been particularly effective at unveiling numerous galactic protostars and their host star clusters.

Other objects commonly observed in ultraviolet light include planetary nebulae, supernova remnants, and active galactic nuclei.

These steady gamma-ray emitters include pulsars, neutron stars, and black hole candidates such as active galactic nuclei.

Measurements of the radial velocity and proper motion of stars allow astronomers to plot the movement of these systems through the Milky Way galaxy.

[73] Astrophysics is the branch of astronomy that employs the principles of physics and chemistry "to ascertain the nature of the astronomical objects, rather than their positions or motions in space".

[80] Astrobiology makes use of molecular biology, biophysics, biochemistry, chemistry, astronomy, physical cosmology, exoplanetology and geology to investigate the possibility of life on other worlds and help recognize biospheres that might be different from that on Earth.

Observations of the large-scale structure of the Universe, a branch known as physical cosmology, have provided a deep understanding of the formation and evolution of the cosmos.

Fundamental to modern cosmology is the well-accepted theory of the Big Bang, wherein our Universe began at a single point in time, and thereafter expanded over the course of 13.8 billion years[86] to its present condition.

[97] As the more massive stars appear, they transform the cloud into an H II region (ionized atomic hydrogen) of glowing gas and plasma.

The resulting red giant formed by the expanding outer layers enjoys a brief life span, before the helium fuel in the core is in turn consumed.

[104] Closely orbiting binary stars can follow more complex evolutionary paths, such as mass transfer onto a white dwarf companion that can potentially cause a supernova.

The radiation pressure of the solar wind then expelled most of the unaccreted matter, and only those planets with sufficient mass retained their gaseous atmosphere.

The planets continued to sweep up, or eject, the remaining matter during a period of intense bombardment, evidenced by the many impact craters on the Moon.

[132] Likewise, questions remain about the formation of the first galaxies,[133] the origin of supermassive black holes,[134] the source of ultra-high-energy cosmic rays,[135] and more.

The Paranal Observatory of European Southern Observatory shooting a laser guide star to the Galactic Center
The Nebra sky disc ( c. 1800–1600 BCE ), found near a possibly astronomical complex , most likely depicting the Sun or full Moon, the Moon as a crescent, the Pleiades and the summer and winter solstices as strips of gold on the side of the disc, [ 9 ] [ 10 ] with the top representing the horizon [ 11 ] and north .
A Babylonian planisphere (7th century BCE). Babylonian astronomy made early advances in astronomy. Its use of sexagesimals (e.g. 12, 24, 60, 360) is still being used today through having been broadly adopted for timekeeping and astrometry . [ 13 ]
Portrait of Alfraganus in the Compilatio astronomica , 1493. Islamic astronomers began just before the 9th century to collect and translate Indian , Persian and Greek astronomical texts, adding their own astronomy and enabling later, particularly European astronomy to build on. [ 23 ]
The first sketches of the Moon's topography, from Galileo 's ground-breaking Sidereus Nuncius (1610), publishing his findings from the first telescopic astronomical observations.
The earliest known photograph of the Great Andromeda "Nebula" , by Isaac Roberts from 29 December 1888. With the calculation of its distance in 1923 intergalactic space was proven, allowing the calculation of the age and expanse of the Universe .
First ever direct image of a ( supermassive ) black hole , taken 2019 in radio wavelength , located at the core of Messier 87 .
Overview of types of observational astronomy by observed wavelengths and their observability
The Very Large Array in New Mexico , an example of a radio telescope
ALMA Observatory is one of the highest observatory sites on Earth. Atacama, Chile. [ 54 ]
The Subaru Telescope (left) and Keck Observatory (center) on Mauna Kea , both examples of an observatory that operates at near-infrared and visible wavelengths. The NASA Infrared Telescope Facility (right) is an example of a telescope that operates only at near-infrared wavelengths.
X-ray jet made from a supermassive black hole found by NASA's Chandra X-ray Observatory, made visible by light from the early Universe
Star cluster Pismis 24 with a nebula
Astrophysics applies physics and chemistry to understand the measurements made by astronomy. Representation of the Observable Universe that includes images from Hubble and other telescopes .
Hubble Extreme Deep Field
This image shows several blue, loop-shaped objects that are multiple images of the same galaxy, duplicated by the gravitational lens effect of the cluster of yellow galaxies near the middle of the photograph. The lens is produced by the cluster's gravitational field that bends light to magnify and distort the image of a more distant object.
A diagram of the Sun's location in the Milky Way, the angles represent longitudes in the galactic coordinate system
Mz 3 , often referred to as the Ant planetary nebula. Ejecting gas from the dying central star shows symmetrical patterns unlike the chaotic patterns of ordinary explosions.
An ultraviolet image of the Sun's active photosphere as viewed by the NASA's TRACE space telescope.
Solar observatory Lomnický štít ( Slovakia ) built in 1962
The black spot at the top is a dust devil climbing a crater wall on Mars . This moving, swirling column of Martian atmosphere (comparable to a terrestrial tornado ) created the long, dark streak.
Amateur astronomers can build their own equipment, and hold star parties and gatherings, such as Stellafane .
The Sun, the planets, their moons, and several trans-Neptunian objects The Sun Mercury Venus The Moon Earth Mars Phobos and Deimos Ceres The main asteroid belt Jupiter Moons of Jupiter Rings of Jupiter Saturn Moons of Saturn Rings of Saturn Uranus Moons of Uranus Rings of Uranus Neptune Moons of Neptune Rings of Neptune Pluto Moons of Pluto Haumea Moons of Haumea Makemake S/2015 (136472) 1 The Kuiper Belt Eris Dysnomia The Scattered Disc The Hills Cloud The Oort Cloud