60 relations: Active galactic nucleus, Alpha Ursae Majoris, Amateur astronomy, Andromeda Galaxy, Aperture, Astronomer, Binoculars, Cambridge University Press, Central Bureau for Astronomical Telegrams, Charles Messier, Constellation, Cosmic dust, Earth, Galaxies in fiction, Galaxy group, Helium, Hydrogen, IAU Circular, Interacting galaxy, Interstellar medium, Johann Elert Bode, Light-year, List of galaxies, List of Messier objects, Local Group, Low-ionization nuclear emission-line region, M81 Group, Messier 82, Messier object, Micrometre, Milky Way, Minute and second of arc, Morphological Catalogue of Galaxies, Nature (journal), New General Catalogue, NGC 3077, Nova, Orders of magnitude (length), Parsec, Pierre Méchain, Polycyclic aromatic hydrocarbon, Principal Galaxies Catalogue, SN 1993J, Spain, Spectral line, Spiral galaxy, Spitzer Space Telescope, Star formation, Starburst galaxy, Stellar classification, ..., Supermassive black hole, Supernova, Telescope, The Astronomical Journal, The Astrophysical Journal, Triangulum Galaxy, Type II supernova, Uppsala General Catalogue, Ursa Major, Virgo Supercluster. Expand index (10 more) » « Shrink index
An active galactic nucleus (AGN) is a compact region at the center of a galaxy that has a much higher than normal luminosity over at least some portion—and possibly all—of the electromagnetic spectrum, with characteristics indicating that the excess luminosity is not produced by stars.
Alpha Ursae Majoris (α Ursae Majoris, abbreviated Alpha UMa, α UMa), also named Dubhe, is (despite being designated 'alpha') the second-brightest star in the constellation of Ursa Major.
Amateur astronomy is a hobby whose participants enjoy observing or imaging celestial objects in the sky using the unaided eye, binoculars, or telescopes.
The Andromeda Galaxy, also known as Messier 31, M31, or NGC 224, is a spiral galaxy approximately 780 kiloparsecs (2.5 million light-years) from Earth, and the nearest major galaxy to the Milky Way.
In optics, an aperture is a hole or an opening through which light travels.
An astronomer is a scientist in the field of astronomy who concentrates their studies on a specific question or field outside the scope of Earth.
Binoculars or field glasses are two telescopes mounted side-by-side and aligned to point in the same direction, allowing the viewer to use both eyes (binocular vision) when viewing distant objects.
Cambridge University Press (CUP) is the publishing business of the University of Cambridge.
The Central Bureau for Astronomical Telegrams (CBAT) is the official international clearing house for information relating to transient astronomical events.
Charles Messier (26 June 1730 – 12 April 1817) was a French astronomer most notable for publishing an astronomical catalogue consisting of nebulae and star clusters that came to be known as the 110 "Messier objects".
Christmas is an annual festival commemorating the birth of Jesus Christ,Martindale, Cyril Charles.
The Christmas season, also called the festive season, or the holiday season (mainly in the U.S. and Canada; often simply called the holidays),, is an annually recurring period recognized in many Western and Western-influenced countries that is generally considered to run from late November to early January.
Christmas Eve is the evening or entire day before Christmas Day, the festival commemorating the birth of Jesus.
Christmas traditions vary from country to country.
A constellation is a group of stars that are considered to form imaginary outlines or meaningful patterns on the celestial sphere, typically representing animals, mythological people or gods, mythological creatures, or manufactured devices.
Cosmic dust, also called extraterrestrial dust or space dust, is dust which exists in outer space, as well as all over planet Earth.
Earth is the third planet from the Sun and the only astronomical object known to harbor life.
Galaxies other than the Milky Way are popular settings for creators of science fiction, particularly those working with broad-scale space opera settings.
A galaxy group or group of galaxies (GrG) is an aggregation of galaxies comprising about 50 or fewer gravitationally bound members, each at least as luminous as the Milky Way (about 1010 times the luminosity of the Sun); collections of galaxies larger than groups that are first-order clustering are called galaxy clusters.
Helium (from lit) is a chemical element with symbol He and atomic number 2.
Hydrogen is a chemical element with symbol H and atomic number 1.
The International Astronomical Union Circulars (IAUCs) are notices that give information about astronomical phenomena.
Interacting galaxies (colliding galaxies) are galaxies whose gravitational fields result in a disturbance of one another.
In astronomy, the interstellar medium (ISM) is the matter and radiation that exists in the space between the star systems in a galaxy.
Johann Elert Bode (19 January 1747 – 23 November 1826) was a German astronomer known for his reformulation and popularisation of the Titius–Bode law.
The light-year is a unit of length used to express astronomical distances and measures about 9.5 trillion kilometres or 5.9 trillion miles.
The following is a list of notable galaxies.
The Messier objects are a set of 110 astronomical objects catalogued by the French astronomer Charles Messier in his "Catalogue des Nébuleuses et des Amas d'Étoiles" ("Catalogue of Nebulae and Star Clusters").
The Local Group is the galaxy group that includes the Milky Way.
A low-ionization nuclear emission-line region (LINER) is a type of galactic nucleus that is defined by its spectral line emission.
The M81 Group is a galaxy group in the constellations Ursa Major and Camelopardalis that includes the galaxies Messier 81 and Messier 82, as well as several other galaxies with high apparent brightnesses.
Messier 82 (also known as NGC 3034, Cigar Galaxy or M82) is a starburst galaxy approximately 12 million light-years away in the constellation Ursa Major.
The Messier objects are a set of 110 astronomical objects, of which 103 were included in lists published by French astronomer Charles Messier in 1771 and 1781.
The micrometre (International spelling as used by the International Bureau of Weights and Measures; SI symbol: μm) or micrometer (American spelling), also commonly known as a micron, is an SI derived unit of length equaling (SI standard prefix "micro-".
The Milky Way is the galaxy that contains our Solar System.
A minute of arc, arcminute (arcmin), arc minute, or minute arc is a unit of angular measurement equal to of one degree.
The Morphological Catalogue of Galaxies (MCG) or Morfologiceskij Katalog Galaktik, is a Russian catalogue of 30,642 galaxies compiled by Boris Vorontsov-Velyaminov and V. P. Arkhipova.
Nature is a British multidisciplinary scientific journal, first published on 4 November 1869.
The New General Catalogue of Nebulae and Clusters of Stars (abbreviated as NGC) is a catalogue of deep-sky objects compiled by John Louis Emil Dreyer in 1888.
NGC 3077 is a small galaxy, a member of the M81 Group, which is located in the northern constellation Ursa Major.
New Year is the time or day at which a new calendar year begins and the calendar's year count increments by one.
New Year's Day, also called simply New Year's or New Year, is observed on January 1, the first day of the year on the modern Gregorian calendar as well as the Julian calendar.
In the Gregorian calendar, New Year's Eve (also known as Old Year's Day or Saint Sylvester's Day in many countries), the last day of the year, is on 31 December which is the seventh day of Christmastide.
A nova (plural novae or novas) or classical nova (CN, plural CNe) is a transient astronomical event that causes the sudden appearance of a bright, apparently "new" star, that slowly fades over several weeks or many months.
The following are examples of orders of magnitude for different lengths.
The parsec (symbol: pc) is a unit of length used to measure large distances to astronomical objects outside the Solar System.
Pierre François André Méchain (16 August 1744 – 20 September 1804) was a French astronomer and surveyor who, with Charles Messier, was a major contributor to the early study of deep sky objects and comets.
Polycyclic aromatic hydrocarbons (PAHs, also polyaromatic hydrocarbons or polynuclear aromatic hydrocarbons) are hydrocarbons—organic compounds containing only carbon and hydrogen—that are composed of multiple aromatic rings (organic rings in which the electrons are delocalized).
The Catalogue of Principal Galaxies (PGC) is an astronomical catalog published in 1989 that lists B1950 and J2000 equatorial coordinates and cross-identifications for 73,197 galaxies.
SN 1993J is a supernova observed in the galaxy M81.
Spain (España), officially the Kingdom of Spain (Reino de España), is a sovereign state mostly located on the Iberian Peninsula in Europe.
A spectral line is a dark or bright line in an otherwise uniform and continuous spectrum, resulting from emission or absorption of light in a narrow frequency range, compared with the nearby frequencies.
Spiral galaxies form a class of galaxy originally described by Edwin Hubble in his 1936 work The Realm of the Nebulae(pp. 124–151) and, as such, form part of the Hubble sequence.
The Spitzer Space Telescope (SST), formerly the Space Infrared Telescope Facility (SIRTF), is an infrared space telescope launched in 2003 and still operating as of 2018.
Star formation is the process by which dense regions within molecular clouds in interstellar space, sometimes referred to as "stellar nurseries" or "star-forming regions", collapse and form stars.
A starburst galaxy is a galaxy undergoing an exceptionally high rate of star formation, as compared to the long-term average rate of star formation in the galaxy or the star formation rate observed in most other galaxies.
In astronomy, stellar classification is the classification of stars based on their spectral characteristics.
A supermassive black hole (SMBH or SBH) is the largest type of black hole, on the order of hundreds of thousands to billions of solar masses, and is found in the centre of almost all currently known massive galaxies.
A supernova (plural: supernovae or supernovas, abbreviations: SN and SNe) is a transient astronomical event that occurs during the last stellar evolutionary stages of a star's life, either a massive star or a white dwarf, whose destruction is marked by one final, titanic explosion.
A telescope is an optical instrument that aids in the observation of remote objects by collecting electromagnetic radiation (such as visible light).
The Astronomical Journal (often abbreviated AJ in scientific papers and references) is a peer-reviewed monthly scientific journal owned by the American Astronomical Society and currently published by IOP Publishing.
The Astrophysical Journal, often abbreviated ApJ (pronounced "ap jay") in references and speech, is a peer-reviewed scientific journal of astrophysics and astronomy, established in 1895 by American astronomers George Ellery Hale and James Edward Keeler.
The Triangulum Galaxy is a spiral galaxy approximately 3 million light-years (ly) from Earth in the constellation Triangulum.
A Type II supernova (plural: supernovae or supernovas) results from the rapid collapse and violent explosion of a massive star.
The Uppsala General Catalogue of Galaxies (UGC) is a catalogue of 12,921 galaxies visible from the northern hemisphere.
Ursa Major (also known as the Great Bear) is a constellation in the northern sky, whose associated mythology likely dates back into prehistory.
The Virgo Supercluster (Virgo SC) or the Local Supercluster (LSC or LS) is a mass concentration of galaxies containing the Virgo Cluster and Local Group, which in turn contains the Milky Way and Andromeda galaxies.
2018 has been designated as the third International Year of the Reef by the International Coral Reef Initiative.
2019 (MMXIX) will be a common year starting on Tuesday of the Gregorian calendar, the 2019th year of the Common Era (CE) and Anno Domini (AD) designations, the 19th year of the 3rd millennium, the 19th year of the 21st century, and the 10th and last year of the 2010s decade.