38 relations: Accretion (astrophysics), Andromeda (constellation), Andromeda Galaxy, Annual Review of Astronomy and Astrophysics, Astrophysics (journal), Atlas of Peculiar Galaxies, Brady Haran, Constellation, Effective radius, Elliptical galaxy, Galactic tide, Galaxy formation and evolution, Gravitational microlensing, Guillaume Le Gentil, Hubble Space Telescope, Kilometre, Lenticular galaxy, Light-year, List of Andromeda's satellite galaxies, List of galaxies, Messier object, Monthly Notices of the Royal Astronomical Society, New General Catalogue, Orders of magnitude (length), Parsec, Planetary nebula, Principal Galaxies Catalogue, Sagittarius A*, Satellite galaxy, Second, Spiral galaxy, Star formation, Supermassive black hole, Surface brightness fluctuation, The Astronomical Journal, The Astrophysical Journal, Tip of the red-giant branch, Uppsala General Catalogue.
In astrophysics, accretion is the accumulation of particles into a massive object by gravitationally attracting more matter, typically gaseous matter, in an accretion disk.
Andromeda is one of the 48 constellations listed by the 2nd-century Greco-Roman astronomer Ptolemy and remains one of the 88 modern constellations.
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.
The Annual Review of Astronomy and Astrophysics is an annual peer reviewed scientific journal published by Annual Reviews.
Astrophysics is a peer-reviewed scientific journal of astrophysics published by Springer.
The Atlas of Peculiar Galaxies is a catalog of peculiar galaxies produced by Halton Arp in 1966.
Brady John Haran (born 18 June 1976) is an Australian-born British independent filmmaker and video journalist who is known for his educational videos and documentary films produced for BBC News and his YouTube channels, the most notable being Periodic Videos and Numberphile.
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.
The effective radius (R_e) of a galaxy is the radius at which half of the total light of the system is emitted.
An elliptical galaxy is a type of galaxy having an approximately ellipsoidal shape and a smooth, nearly featureless image.
A galactic tide is a tidal force experienced by objects subject to the gravitational field of a galaxy such as the Milky Way.
The study of galaxy formation and evolution is concerned with the processes that formed a heterogeneous universe from a homogeneous beginning, the formation of the first galaxies, the way galaxies change over time, and the processes that have generated the variety of structures observed in nearby galaxies.
Gravitational microlensing is an astronomical phenomenon due to the gravitational lens effect.
Guillaume Joseph Hyacinthe Jean-Baptiste Le Gentil de la Galaisière (Coutances, 12 September 1725 – Paris, 22 October 1792) was a French astronomer.
The Hubble Space Telescope (HST) is a space telescope that was launched into low Earth orbit in 1990 and remains in operation.
The kilometre (International spelling as used by the International Bureau of Weights and Measures; SI symbol: km; or) or kilometer (American spelling) is a unit of length in the metric system, equal to one thousand metres (kilo- being the SI prefix for). It is now the measurement unit used officially for expressing distances between geographical places on land in most of the world; notable exceptions are the United States and the road network of the United Kingdom where the statute mile is the official unit used.
A lenticular galaxy (denoted S0) is a type of galaxy intermediate between an elliptical (denoted E) and a spiral galaxy in galaxy morphological classification schemes.
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 Andromeda Galaxy (M31) has satellite galaxies just like the Milky Way.
The following is a list of notable galaxies.
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.
Monthly Notices of the Royal Astronomical Society (MNRAS) is a peer-reviewed scientific journal covering research in astronomy and astrophysics.
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.
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.
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.
A planetary nebula, abbreviated as PN or plural PNe, is a type of emission nebula consisting of an expanding, glowing shell of ionized gas ejected from red giant stars late in their lives.
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.
Sagittarius A* (pronounced "Sagittarius A-star", standard abbreviation Sgr A*) is a bright and very compact astronomical radio source at the center of the Milky Way, near the border of the constellations Sagittarius and Scorpius.
A satellite galaxy is a smaller companion galaxy that travels on bound orbits within the gravitational potential of a more massive and luminous host galaxy (also known as the primary galaxy).
The second is the SI base unit of time, commonly understood and historically defined as 1/86,400 of a day – this factor derived from the division of the day first into 24 hours, then to 60 minutes and finally to 60 seconds each.
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.
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 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.
Surface brightness fluctuation (SBF) is a secondary distance indicator used to estimate distances to galaxies.
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.
Tip of the red-giant branch (TRGB) is a primary distance indicator used in astronomy.
The Uppsala General Catalogue of Galaxies (UGC) is a catalogue of 12,921 galaxies visible from the northern hemisphere.
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.
2MASX J00424182+4051546, APG 168, Ark 12, Arp 168, Dwarf Elliptical Galaxy M32, Dwarf elliptical galaxy M32, Elliptical Galaxy M32, IRAS 00399+4035, K79 1B, LEDA 2555, MCG+07-02-015, Messier Object 32, NGC 221, NGC221, PGC 2555, RX J0042.6+4052, UGC 452, Z 0039.9+4036, Z 535-16.