A galaxy is a system of stars, stellar remnants, interstellar gas, dust, dark matter, bound together by gravity. The word is derived from the Greek galaxias (γαλαξίας), literally 'milky', a reference to the Milky Way galaxy that contains the Solar System. Galaxies, averaging an estimated 100 million stars, range in size from dwarfs with less than a hundred million stars, to the largest galaxies known – supergiants with one hundred trillion stars, each orbiting its galaxy's center of mass. Most of the mass in a typical galaxy is in the form of dark matter, with only a few percent of that mass visible in the form of stars and nebulae. Supermassive black holes are a common feature at the centres of galaxies.
The following is a timeline of galaxies, clusters of galaxies, and large-scale structure of the universe.
The Andromeda Galaxy, also known as Messier 31, M31, or NGC 224 and originally the Andromeda Nebula, is a barred spiral galaxy with the diameter of about 46.56 kiloparsecs approximately 765 kpc from Earth and the nearest large galaxy to the Milky Way. The galaxy's name stems from the area of Earth's sky in which it appears, the constellation of Andromeda, which itself is named after the princess who was the wife of Perseus in Greek mythology.
Sanquhar is a village on the River Nith in Dumfries and Galloway, Scotland, north of Thornhill and west of Moffat. It is a former Royal Burgh.
Andromeda is one of the 48 constellations listed by the 2nd-century Greco-Roman astronomer Ptolemy, and one of the 88 modern constellations. Located in the northern celestial hemisphere, it is named for Andromeda, daughter of Cassiopeia, in the Greek myth, who was chained to a rock to be eaten by the sea monster Cetus. Andromeda is most prominent during autumn evenings in the Northern Hemisphere, along with several other constellations named for characters in the Perseus myth. Because of its northern declination, Andromeda is visible only north of 40° south latitude; for observers farther south, it lies below the horizon. It is one of the largest constellations, with an area of 722 square degrees. This is over 1,400 times the size of the full moon, 55% of the size of the largest constellation, Hydra, and over 10 times the size of the smallest constellation, Crux.
Dumfriesshire or the County of Dumfries or Shire of Dumfries is a historic county and registration county in southern Scotland. The Dumfries lieutenancy area covers a similar area to the historic county.
Charles Alexander Jencks was an American cultural theorist, landscape designer, architectural historian, and co-founder of the Maggie’s Cancer Care Centres. He published over thirty books and became famous in the 1980s as a theorist of Postmodernism. Jencks devoted time to landform architecture, especially in Scotland. These landscapes include the Garden of Cosmic Speculation and earthworks at Jupiter Artland outside Edinburgh. His continuing project Crawick Multiverse, commissioned by the Duke of Buccleuch, opened in 2015 near Sanquhar.
Intergalactic travel is the hypothetical crewed or uncrewed travel between galaxies. Due to the enormous distances between the Milky Way and even its closest neighbors—tens of thousands to millions of light-years—any such venture would be far more technologically and financially demanding than even interstellar travel. Intergalactic distances are roughly a hundred-thousandfold greater than their interstellar counterparts.
The Milky Way is the galaxy that includes the Solar System, with the name describing the galaxy's appearance from Earth: a hazy band of light seen in the night sky formed from stars that cannot be individually distinguished by the naked eye. The term Milky Way is a translation of the Latin via lactea, from the Greek γαλακτικὸς κύκλος, meaning "milky circle". From Earth, the Milky Way appears as a band because its disk-shaped structure is viewed from within. Galileo Galilei first resolved the band of light into individual stars with his telescope in 1610. Until the early 1920s, most astronomers thought that the Milky Way contained all the stars in the Universe. Following the 1920 Great Debate between the astronomers Harlow Shapley and Heber Doust Curtis, observations by Edwin Hubble showed that the Milky Way is just one of many galaxies.
NGC 4565 is an edge-on spiral galaxy about 30 to 50 million light-years away in the constellation Coma Berenices. It lies close to the North Galactic Pole and has a visual magnitude of approximately 10. It is known as the Needle Galaxy for its narrow profile. First recorded in 1785 by William Herschel, it is a prominent example of an edge-on spiral galaxy.
Dunragit is a village on the A75, between Stranraer and Glenluce in Dumfries and Galloway, south-west Scotland. Dunragit is within the parish of Old Luce, in the traditional county of Wigtownshire. The modern village grew up around the west gate of Dunragit House, an 18th-century country house, though there is evidence of Neolithic settlement in the area.
Knowledge of the location of Earth has been shaped by 400 years of telescopic observations, and has expanded radically since the start of the 20th century. Initially, Earth was believed to be the center of the Universe, which consisted only of those planets visible with the naked eye and an outlying sphere of fixed stars. After the acceptance of the heliocentric model in the 17th century, observations by William Herschel and others showed that the Sun lay within a vast, disc-shaped galaxy of stars. By the 20th century, observations of spiral nebulae revealed that the Milky Way galaxy was one of billions in an expanding universe, grouped into clusters and superclusters. By the end of the 20th century, the overall structure of the visible universe was becoming clearer, with superclusters forming into a vast web of filaments and voids. Superclusters, filaments and voids are the largest coherent structures in the Universe that we can observe. At still larger scales the Universe becomes homogeneous, meaning that all its parts have on average the same density, composition and structure.
The Garden of Cosmic Speculation is a 30 acre sculpture garden created by landscape architect and theorist Charles Jencks at his home, Portrack House, in Dumfriesshire, Scotland. Like much of Jencks' work, the garden is inspired by modern cosmology.
An intergalactic star, also known as an intracluster star or a rogue star, is a star not gravitationally bound to any galaxy. Although a source of much discussion in the scientific community during the late 1990s, intergalactic stars are now generally thought to have originated in galaxies, like other stars, before being expelled as the result of either galaxies colliding or of a multiple-star system traveling too close to a supermassive black hole, which are found at the center of many galaxies.
Northumberlandia is a huge land sculpture in the shape of a reclining female figure, which was completed in 2012, near Cramlington, Northumberland, northern England.
The center of the Universe is a concept that lacks a coherent definition in modern astronomy; according to standard cosmological theories on the shape of the universe, it has no center.
The Star of Caledonia, also called the Gretna Landmark, is a planned sculpture designed by Cecil Balmond, Charles Jencks and Andy Goldsworthy. It is to be located near Gretna, Dumfries and Galloway, Scotland, close to the England-Scotland border. The sculpture was approved on 27 February 2013. The project is being promoted by the Gretna Landmark Trust.
Midpark Hospital is a modern acute mental health unit located in Dumfries. The hospital is managed by NHS Dumfries and Galloway.
Holm House and the Crawick Glen were originally part of a small estate in the parishes of Kirkconnel and Sanquhar and lay less than a 1 mile (1.6 km) upstream from the small village of Crawick that itself stands close to the A76 near Sanquhar in Dumfries and Galloway, south-west Scotland.
