Local Sheet

The Local Sheet in astronomy is a nearby extragalactic region of space where the Milky Way, the members of the Local Group and other galaxies share a similar peculiar velocity.[2] This region lies within a radius of about 7 Mpc (23 Mly),[3] 0.46 Mpc (1.5 Mly) thick,[1] and galaxies beyond that distance show markedly different velocities.[3] The Local Group has only a relatively small peculiar velocity of 66 km⋅s−1 with respect to the Local Sheet. Typical velocity dispersion of galaxies is only 40 km⋅s−1 in the radial direction.[2] Nearly all nearby bright galaxies belong to the Local Sheet.[1] The Local Sheet is part of the Local Volume and is in the Virgo Supercluster (Local Supercluster).[4] The Local Sheet forms a wall of galaxies delineating one boundary of the Local Void.[5]

A significant component of the mean velocity of the galaxies in the Local Sheet appears as the result of the gravitational attraction of the Virgo Cluster of galaxies, resulting in a peculiar motion ~185 km⋅s−1 toward the cluster.[2] A second component is directed away from the center of the Local Void; an expanding region of space spanning an estimated 45 Mpc (150 Mly) that is only sparsely populated with galaxies.[3] This component has a velocity of 259 km⋅s−1.[2] The Local Sheet is inclined 8° from the Local Supercluster (Virgo Supercluster).[4]

The so-called Council of Giants is a ring of twelve large galaxies surrounding the Local Group in the Local Sheet, with a radius of 3.75 Mpc (12.2 Mly).[4] Ten of these are spirals, while the remaining two are ellipticals. The two ellipticals (Maffei 1 and Centaurus A) lie on opposite sides of the Local Group, and their formation may have prompted the development of the Local Group. The Local Sheet's own development outlines a concentration of dark matter in a filament.[1]

Galaxies in the "Council of Giants"[4]
Catalog ID Name Constellation Distance (Mly) Mass *
NGC 253 Sculptor Galaxy Sculptor 11 10.805
PGC 9892 Maffei 1 Cassiopeia 11 10.928
PGC 10217 Maffei 2 Cassiopeia 11 10.493
IC 342   Camelopardalis 11 10.302
NGC 3031 M 81 Ursa Major 12 10.905
NGC 3034 M 82 Ursa Major 11 10.573
NGC 4736 M 94 Canes Venatici 15 10.458
NGC 4826 M 64 Coma Berenices 16 10.496
NGC 5236 M 83 Hydra 16 10.642
NGC 5128 Centaurus A Centaurus 11 11.169
NGC 4945   Centaurus 12 10.528
ESO 97-G13 Circinus Galaxy Circinus 14 10.559

* The mass is given as the logarithm of the mass in solar masses.

Local Sheet
Observation data (Epoch )
Brightest memberLocal Group
Major axis17 Mly (5 Mpc) [1]
Minor axis1.5 Mly (0.5 Mpc) [1]
Mly (0 Mpc)

See also

  • Local Void, the Local Sheet defining the wall of galaxies at one end of the void
  • Leo Chain, a nearby cluster of galaxies opposite to the Local Void from the Local Sheet
  • Supergalactic coordinate system, the coordinate system taking the Local Sheet, the Supergalactic Plane, as its X–Y bases


  1. ^ a b c d e "Milky Way amidst a 'Council of Giants'". Science Daily. 11 March 2014.
  2. ^ a b c d Tully, R. Brent; Shaya, Edward J.; Karachentsev, Igor D.; Courtois, Hélène M.; Kocevski, Dale D.; Rizzi, Luca; Peel, Alan (March 2008). "Our Peculiar Motion Away from the Local Void". The Astrophysical Journal. 676 (1): 184–205. arXiv:0705.4139. Bibcode:2008ApJ...676..184T. doi:10.1086/527428.
  3. ^ a b c Tully, R. Brent (May 2008), "The Local Void is Really Empty", Dark Galaxies and Lost Baryons, Proceedings of the International Astronomical Union, IAU Symposium, 244, pp. 146–151, arXiv:0708.0864, Bibcode:2008IAUS..244..146T, doi:10.1017/S1743921307013932
  4. ^ a b c d McCall, Marshall L. (29 April 2013). "A Council of Giants". Monthly Notices of the Royal Astronomical Society (published 10 March 2014). 440 (1): 405–426. arXiv:1403.3667. Bibcode:2014MNRAS.440..405M. doi:10.1093/mnras/stu199.
  5. ^ Shaya, Ed J.; Tully, R. Brent; (December 2013). "The Formation of the Local Group Planes of Galaxies". Monthly Notices of the Royal Astronomical Society. Oxford University Press. Royal Astronomical Society. 436 (3): 2096–2119. arXiv:1307.4297. Bibcode:2013MNRAS.436.2096S. doi:10.1093/mnras/stt1714.CS1 maint: Uses authors parameter (link)
Circinus Galaxy

The Circinus Galaxy (ESO 97-G13) is a Seyfert galaxy in the constellation of Circinus. It is located 4 degrees below the Galactic plane, and, at a distance of 4.0 Mpc (13 Mly), and is one of the closest galaxies to the Milky Way. The galaxy is undergoing tumultuous changes, as rings of gas are likely being ejected from the galaxy. Its outermost ring is 1400 light-years across while the inner ring is 260 light-years across. Although the Circinus galaxy can be seen using a small telescope, it was not noticed until 1977 because it lies close to the plane of the Milky Way and is obscured by galactic dust. The Circinus Galaxy is a Type II Seyfert galaxy and is one of the closest known active galaxies to the Milky Way, though it is probably slightly farther away than Centaurus A.

Circinus Galaxy produced supernova SN 1996cr, which was identified over a decade after it exploded. This supernova event was first observed during 2001 as a bright, variable object in a Chandra X-ray Observatory image, but it was not confirmed as a supernova until years later.

The Circinus Galaxy is one of twelve large galaxies in the "Council of Giants" surrounding the Local Group in the Local Sheet.

Cosmic Eye

Cosmic Eye is a short film and iOS app, developed by astrophysicist Danail Obreschkow. It shows the largest and smallest known scales of the universe by gradually zooming out from and then back into the face of a young lady called "Louise". According to the developer, the film and app were inspired by the essay Cosmic View (1957) and the short films Cosmic Zoom (1968) and Powers of Ten (1977), but use state-of-the-art know-how and new scientific imaging and computer simulations. Cosmic Eye was developed in 2012 and suddenly become famous in April 2016, when it scored 40 million views in ten days on the Facebook group page of "The Science Scoop". The video has since been viewed more than 200 Million times on Facebook (top-ten counts only) and was featured in major media, such as BBC World News.Cosmic Eye was re-released in 2018 in high-resolution landscape (16:9) format (the first version was portrait shaped).

Cosmic Voyage

Cosmic Voyage is a 1996 short documentary film produced in the IMAX format, directed by Bayley Silleck, produced by Jeffrey Marvin, and narrated by Morgan Freeman. The film was presented by the Smithsonian Institution's National Air and Space Museum,

and played in IMAX theaters worldwide. The film is available in the DVD format.

Craig Chester (astronomer)

Craig Chester is an American astronomer who co-founded the Monterey Institute for Research in Astronomy (MIRA) in the Los Padres National Forest in California along with five other astronomy students from Case Western Reserve University and three non-astronomers. Chester suggested that the Star of Bethlehem was a real historical event, and that Jupiter's "stationary point" during apparent retrograde motion could explain the Star's "stopping" over Bethlehem, He wrote an article which helped inspire The Star of Bethlehem documentary. Chester developed software for satellite communications and ground equipment for the United States military. He was president of MIRA in 2016.

Io (moon)

Io (Jupiter I) is the innermost of the four Galilean moons of the planet Jupiter. It is the fourth-largest moon, has the highest density of all the moons, and has the least amount of water of any known astronomical object in the Solar System. It was discovered in 1610 and was named after the mythological character Io, a priestess of Hera who became one of Zeus' lovers.

With over 400 active volcanoes, Io is the most geologically active object in the Solar System. This extreme geologic activity is the result of tidal heating from friction generated within Io's interior as it is pulled between Jupiter and the other Galilean satellites—Europa, Ganymede and Callisto. Several volcanoes produce plumes of sulfur and sulfur dioxide that climb as high as 500 km (300 mi) above the surface. Io's surface is also dotted with more than 100 mountains that have been uplifted by extensive compression at the base of Io's silicate crust. Some of these peaks are taller than Mount Everest. Unlike most satellites in the outer Solar System, which are mostly composed of water ice, Io is primarily composed of silicate rock surrounding a molten iron or iron-sulfide core. Most of Io's surface is composed of extensive plains coated with sulfur and sulfur-dioxide frost.

Io's volcanism is responsible for many of its unique features. Its volcanic plumes and lava flows produce large surface changes and paint the surface in various subtle shades of yellow, red, white, black, and green, largely due to allotropes and compounds of sulfur. Numerous extensive lava flows, several more than 500 km (300 mi) in length, also mark the surface. The materials produced by this volcanism make up Io's thin, patchy atmosphere and Jupiter's extensive magnetosphere. Io's volcanic ejecta also produce a large plasma torus around Jupiter.

Io played a significant role in the development of astronomy in the 17th and 18th centuries. It was discovered in January 1610 by Galileo Galilei, along with the other Galilean satellites. This discovery furthered the adoption of the Copernican model of the Solar System, the development of Kepler's laws of motion, and the first measurement of the speed of light. From Earth, Io remained just a point of light until the late 19th and early 20th centuries, when it became possible to resolve its large-scale surface features, such as the dark red polar and bright equatorial regions. In 1979, the two Voyager spacecraft revealed Io to be a geologically active world, with numerous volcanic features, large mountains, and a young surface with no obvious impact craters. The Galileo spacecraft performed several close flybys in the 1990s and early 2000s, obtaining data about Io's interior structure and surface composition. These spacecraft also revealed the relationship between Io and Jupiter's magnetosphere and the existence of a belt of high-energy radiation centered on Io's orbit. Io receives about 3,600 rem (36 Sv) of ionizing radiation per day.Further observations have been made by Cassini–Huygens in 2000, New Horizons in 2007, and Juno in 2017 and 2018, as well as from Earth-based telescopes and the Hubble Space Telescope.

Jerry Horan

Jeremiah J. Horan (aka Jerry Horan) (May 1886-April 28, 1937) was an organized crime figure and President of the Building Service Employees International Union from 1927 until his death in 1937. Although praised by newspapers for reducing the level of overt violence and graft which plagued the union under his predecessor, William Quesse, Horan nonetheless still engaged in bribery, extortion, physical intimidation, and other crimes, and permitted George Scalise (his successor) to enter and rise within the organization. Horan established the kickback scheme whereby Scalise would eventually loot the union treasury of millions of dollars in member dues.

Kenosha Elks Club

The Kenosha Elks Club is a historic clubhouse in Kenosha, Wisconsin. Construction began on the building in 1916 and it was formally dedicated on January 20, 1919.

Local Void

The Local Void is a vast, empty region of space, lying adjacent to the Local Group. Discovered by Brent Tully and Rick Fisher in 1987, the Local Void is now known to be composed of three separate sectors, separated by bridges of "wispy filaments". The precise extent of the void is unknown, but it is at least 45 Mpc (150 million light-years) across, and possibly 150 to 300 MPc. The Local Void also appears to have significantly fewer galaxies than expected from standard cosmology.

Location of Earth

Knowledge of the location of Earth has been shaped by 400 years of telescopic observations, and has expanded radically in the last 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 our 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 (over 1000 megaparsecs) the Universe becomes homogeneous meaning that all its parts have on average the same density, composition and structure.Since there is believed to be no "center" or "edge" of the Universe, there is no particular reference point with which to plot the overall location of the Earth in the universe. Because the observable universe is defined as that region of the Universe visible to terrestrial observers, Earth is, because of the constancy of the speed of light, the center of Earth's observable universe. Reference can be made to the Earth's position with respect to specific structures, which exist at various scales. It is still undetermined whether the Universe is infinite. There have been numerous hypotheses that our universe may be only one such example within a higher multiverse; however, no direct evidence of any sort of multiverse has ever been observed, and some have argued that the hypothesis is not falsifiable.

Outline of the Solar System

The following outline is provided as an overview of and topical guide to the Solar System:

Solar System – gravitationally bound system comprising the Sun and the objects that orbit it, either directly or indirectly. Of those objects that orbit the Sun directly, the largest eight are the planets (including Earth), with the remainder being significantly smaller objects, such as dwarf planets and small Solar System bodies. Of the objects that orbit the Sun indirectly, the moons, two are larger than the smallest planet, Mercury.


A planet is an astronomical body orbiting a star or stellar remnant that is massive enough to be rounded by its own gravity, is not massive enough to cause thermonuclear fusion, and has cleared its neighbouring region of planetesimals.The term planet is ancient, with ties to history, astrology, science, mythology, and religion. Five planets in the Solar System are visible to the naked eye. These were regarded by many early cultures as divine, or as emissaries of deities. As scientific knowledge advanced, human perception of the planets changed, incorporating a number of disparate objects. In 2006, the International Astronomical Union (IAU) officially adopted a resolution defining planets within the Solar System. This definition is controversial because it excludes many objects of planetary mass based on where or what they orbit. Although eight of the planetary bodies discovered before 1950 remain "planets" under the modern definition, some celestial bodies, such as Ceres, Pallas, Juno and Vesta (each an object in the solar asteroid belt), and Pluto (the first trans-Neptunian object discovered), that were once considered planets by the scientific community, are no longer viewed as such.

The planets were thought by Ptolemy to orbit Earth in deferent and epicycle motions. Although the idea that the planets orbited the Sun had been suggested many times, it was not until the 17th century that this view was supported by evidence from the first telescopic astronomical observations, performed by Galileo Galilei. About the same time, by careful analysis of pre-telescopic observational data collected by Tycho Brahe, Johannes Kepler found the planets' orbits were elliptical rather than circular. As observational tools improved, astronomers saw that, like Earth, each of the planets rotated around an axis tilted with respect to its orbital pole, and some shared such features as ice caps and seasons. Since the dawn of the Space Age, close observation by space probes has found that Earth and the other planets share characteristics such as volcanism, hurricanes, tectonics, and even hydrology.

Planets are generally divided into two main types: large low-density giant planets, and smaller rocky terrestrials. There are eight planets in the Solar System. In order of increasing distance from the Sun, they are the four terrestrials, Mercury, Venus, Earth, and Mars, then the four giant planets, Jupiter, Saturn, Uranus, and Neptune. Six of the planets are orbited by one or more natural satellites.

Several thousands of planets around other stars ("extrasolar planets" or "exoplanets") have been discovered in the Milky Way. As of 1 April 2019, 4,023 known extrasolar planets in 3,005 planetary systems (including 656 multiple planetary systems), ranging in size from just above the size of the Moon to gas giants about twice as large as Jupiter have been discovered, out of which more than 100 planets are the same size as Earth, nine of which are at the same relative distance from their star as Earth from the Sun, i.e. in the circumstellar habitable zone. On December 20, 2011, the Kepler Space Telescope team reported the discovery of the first Earth-sized extrasolar planets, Kepler-20e and Kepler-20f, orbiting a Sun-like star, Kepler-20. A 2012 study, analyzing gravitational microlensing data, estimates an average of at least 1.6 bound planets for every star in the Milky Way.

Around one in five Sun-like stars is thought to have an Earth-sized planet in its habitable zone.

Sheet Metal Workers' International Association

The Sheet Metal Workers' International Association was a trade union of skilled metal workers who perform architectural sheet metal work, fabricate and install heating and air conditioning work, shipbuilding, appliance construction, heater and boiler construction, precision and specialty parts manufacture, and a variety of other jobs involving sheet metal. On August 11, 2014, it merged with the United Transportation Union (UTU) to form the International Association of Sheet Metal, Air, Rail and Transportation Workers, known by the acronym, SMART.

The Sheet Metal Workers' International Association represented about 150,000 members in 185 local unions in the United States and Canada.

Solar System

The Solar System is the gravitationally bound planetary system of the Sun and the objects that orbit it, either directly or indirectly. Of the objects that orbit the Sun directly, the largest are the eight planets, with the remainder being smaller objects, such as the five dwarf planets and small Solar System bodies. Of the objects that orbit the Sun indirectly—the moons—two are larger than the smallest planet, Mercury.The Solar System formed 4.6 billion years ago from the gravitational collapse of a giant interstellar molecular cloud. The vast majority of the system's mass is in the Sun, with the majority of the remaining mass contained in Jupiter. The four smaller inner planets, Mercury, Venus, Earth and Mars, are terrestrial planets, being primarily composed of rock and metal. The four outer planets are giant planets, being substantially more massive than the terrestrials. The two largest, Jupiter and Saturn, are gas giants, being composed mainly of hydrogen and helium; the two outermost planets, Uranus and Neptune, are ice giants, being composed mostly of substances with relatively high melting points compared with hydrogen and helium, called volatiles, such as water, ammonia and methane. All eight planets have almost circular orbits that lie within a nearly flat disc called the ecliptic.

The Solar System also contains smaller objects. The asteroid belt, which lies between the orbits of Mars and Jupiter, mostly contains objects composed, like the terrestrial planets, of rock and metal. Beyond Neptune's orbit lie the Kuiper belt and scattered disc, which are populations of trans-Neptunian objects composed mostly of ices, and beyond them a newly discovered population of sednoids. Within these populations are several dozen to possibly tens of thousands of objects large enough that they have been rounded by their own gravity. Such objects are categorized as dwarf planets. Identified dwarf planets include the asteroid Ceres and the trans-Neptunian objects Pluto and Eris. In addition to these two regions, various other small-body populations, including comets, centaurs and interplanetary dust clouds, freely travel between regions. Six of the planets, at least four of the dwarf planets, and many of the smaller bodies are orbited by natural satellites, usually termed "moons" after the Moon. Each of the outer planets is encircled by planetary rings of dust and other small objects.

The solar wind, a stream of charged particles flowing outwards from the Sun, creates a bubble-like region in the interstellar medium known as the heliosphere. The heliopause is the point at which pressure from the solar wind is equal to the opposing pressure of the interstellar medium; it extends out to the edge of the scattered disc. The Oort cloud, which is thought to be the source for long-period comets, may also exist at a distance roughly a thousand times further than the heliosphere. The Solar System is located in the Orion Arm, 26,000 light-years from the center of the Milky Way galaxy.

To the End of the Earth

"To the End of the Earth" is a song recorded by Australian singer Jessica Mauboy. The song was digitally released on 17 July 2013, as the lead single from Mauboy's third studio album Beautiful. It was written by Mauboy, Jaden Michaels, Ben Berger and Ryan McMahon, and produced by the latter two. The uptempo dance-pop song received positive reviews from critics, who commended the production. "To the End of the Earth" peaked at number 21 on the ARIA Singles Chart and was certified gold by the Australian Recording Industry Association for selling over 35,000 copies. The track was promoted by performances at the 2013 State of Origin decider, on Sunrise and at Westfield Knox and Westfield Hurstville. The accompanying music video was directed by Emma Tomelty and filmed in Alice Springs. The video received a positive reception from critics, particularly for its presentation.


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