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114-614: Celestia is available for AmigaOS 4 , Linux , macOS , Microsoft Windows , Xbox , iOS , and Android . It is free and open source software released under the GNU General Public License . Celestia's development stopped in 2013, with the final release in 2011. Since then, some of its development team went to work on celestia.Sci, a cosmological visualizer featuring more realistic rendering of galaxies and planets, gravitational lensing, and many other scientifically accurate enhancements, but there have been no updates on

228-540: A circumstellar disk , and then the planets grow out of that disk with the Sun. A nebula contains gas, ice grains, and dust (including primordial nuclides ). According to nebular theory , planetesimals formed by accretion , with the primordial Earth being estimated as likely taking anywhere from 70 to 100 million years to form. Estimates of the age of the Moon range from 4.5 Ga to significantly younger. A leading hypothesis

342-633: A 68020 or better and at least 4 MB fast RAM. In 2001 Amiga Inc. signed a contract with Hyperion Entertainment to develop the PowerPC native AmigaOS 4 from their previous AmigaOS 3.1 release. Unlike the previous versions which were based on the Motorola 68k central processor, OS4 runs only on PowerPC computer systems. Amiga, Inc.'s (current Amiga trademark owners) distribution policies for AmigaOS 4.0 and any later versions required that OS4 must be bundled with all new third-party hardware "Amigas", with

456-492: A common barycenter every 27.32 days relative to the background stars. When combined with the Earth–Moon system's common orbit around the Sun, the period of the synodic month , from new moon to new moon, is 29.53 days. Viewed from the celestial north pole , the motion of Earth, the Moon, and their axial rotations are all counterclockwise . Viewed from a vantage point above the Sun and Earth's north poles, Earth orbits in

570-548: A counterclockwise direction about the Sun. The orbital and axial planes are not precisely aligned: Earth's axis is tilted some 23.44 degrees from the perpendicular to the Earth–Sun plane (the ecliptic ), and the Earth-Moon plane is tilted up to ±5.1 degrees against the Earth–Sun plane. Without this tilt, there would be an eclipse every two weeks, alternating between lunar eclipses and solar eclipses . The Hill sphere , or

684-463: A few hundred systems of multiple stars. Most binary star systems cannot be simulated with 100% accuracy because adequate orbital information is not yet available. Celestia does not include any stars that are more than a few thousand light-years from the Sun because the parallaxes of more distant stars are too small to be accurately measured by the Hipparcos astrometric satellite. However, with

798-420: A full rotation about its axis so that the Sun returns to the meridian . The orbital speed of Earth averages about 29.78 km/s (107,200 km/h; 66,600 mph), which is fast enough to travel a distance equal to Earth's diameter, about 12,742 km (7,918 mi), in seven minutes, and the distance from Earth to the Moon, 384,400 km (238,900 mi), in about 3.5 hours. The Moon and Earth orbit

912-421: A globe-spanning mid-ocean ridge system. At Earth's polar regions , the ocean surface is covered by seasonally variable amounts of sea ice that often connects with polar land, permafrost and ice sheets , forming polar ice caps . Earth's land covers 29.2%, or 149 million km (58 million sq mi) of Earth's surface. The land surface includes many islands around the globe, but most of

1026-560: A heavily modified version of Celestia in 2016, called VTS Timeloop, and it has since been used by multiple space agencies, including ESA and CNES themselves. Celestia was used in the media by the CBS television show NCIS (Season 4, Episode 22: " In the Dark "). Character Timothy McGee explains what Celestia is and how an add-on can allow the user to store a diary within the program, as well. Textures designed by Celestia graphic artists were used in

1140-518: A settlement agreement where Hyperion is granted an exclusive right to AmigaOS 3.1 and market AmigaOS 4 and subsequent versions of AmigaOS (including AmigaOS 5 without limitation). Hyperion has assured the Amiga community that it will continue the development and the distribution of AmigaOS 4.x (and beyond), as it has done since November 2001. AmigaOS 4 can be divided into two parts: the Workbench and

1254-516: A third party bootloader, known as the "Moana", was released by Acube on torrent sites; it allows installation of the Sam440ep version of OS4 to Mac Mini G4s . However this is both unofficial and unsupported as of today, and very incomplete, especially regarding drivers. During the judicial procedure (between Hyperion and Amiga, Inc.), OS4 was still being developed and distributed. On 30 September 2009, Hyperion Entertainment and Amiga, Inc. reached

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1368-446: A ton of more enhancements. In 2019, Celestia Forum member FarGetaNik created an addon pack called Project Echoes, featuring higher-quality renderings that replace all vanilla textures. Celestia 1.7.0 appears to use Project Echoes as inspiration for its textures. NASA and ESA have used Celestia in their educational and outreach programs, as well as for interfacing to trajectory analysis software. The French Space Agency (CNES) created

1482-483: A vastly improved file system API and many other features. Prominent features compared to other operating systems or previous versions of AmigaOS: Released for Amigas equipped with third party PPC add-on boards: Released for AmigaOne motherboards: Released for Pegasos systems: Released for Sam440 systems: For the AmigaOS 4.2, Hyperion Entertainment planned the following updates: Earth Earth

1596-456: Is a spheroid . The irregular surface of the Earth causes low Earth orbit satellites to appear to be in the wrong places in the sky when watched from the surface, even when the Earth's oblateness is specified, as Celestia does not simulate 3D surfaces. Many types of astronomical objects are not included with Celestia. Variable stars , supernovae , black holes , and nebulae are missing from

1710-456: Is a chemically distinct silicate solid crust, which is underlain by a highly viscous solid mantle. The crust is separated from the mantle by the Mohorovičić discontinuity . The thickness of the crust varies from about 6 kilometres (3.7 mi) under the oceans to 30–50 km (19–31 mi) for the continents. The crust and the cold, rigid, top of the upper mantle are collectively known as

1824-474: Is an optional function. The time simulated by Celestia can be set to any time 2 billion years forward or backward from the present, although planetary orbits are only accurate within a few thousand years of the present day, and date arithmetic overflows at the year 5,874,774. Celestia simulates the appearance of atmospheres on planets and moons, planetshine on orbiting satellites, and miscellaneous planetary details such as sunrise and sunset. Information about

1938-483: Is approximately 9.8 m/s (32 ft/s ). Local differences in topography, geology, and deeper tectonic structure cause local and broad regional differences in Earth's gravitational field, known as gravity anomalies . The main part of Earth's magnetic field is generated in the core, the site of a dynamo process that converts the kinetic energy of thermally and compositionally driven convection into electrical and magnetic field energy. The field extends outwards from

2052-435: Is at least somewhat humid and covered by vegetation , while large sheets of ice at Earth's polar deserts retain more water than Earth's groundwater , lakes, rivers and atmospheric water combined. Earth's crust consists of slowly moving tectonic plates , which interact to produce mountain ranges, volcanoes , and earthquakes. Earth has a liquid outer core that generates a magnetosphere capable of deflecting most of

2166-601: Is because irregularly shaped objects do not cast shadows in the current version of Celestia, although this is planned for future versions. Additionally, moons smaller than 0.5% of their parent objects' size do not cast shadows at all, as the original development team decided that they would be too small to be relevant. However, the new development team has considered removing this hard-coded limit. Most real-world spacecraft such as Voyager 2 are not available in Celestia but are provided as add-ons by users. Additionally, most of

2280-529: Is contained in 3.45 billion-year-old Australian rocks showing fossils of microorganisms . During the Neoproterozoic , 1000 to 539 Ma , much of Earth might have been covered in ice. This hypothesis has been termed " Snowball Earth ", and it is of particular interest because it preceded the Cambrian explosion , when multicellular life forms significantly increased in complexity. Following

2394-457: Is farthest out from its center of mass at its equatorial bulge, the summit of the volcano Chimborazo in Ecuador (6,384.4 km or 3,967.1 mi) is its farthest point out. Parallel to the rigid land topography the ocean exhibits a more dynamic topography . To measure the local variation of Earth's topography, geodesy employs an idealized Earth producing a geoid shape. Such a shape

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2508-516: Is gained if the ocean is idealized, covering Earth completely and without any perturbations such as tides and winds. The result is a smooth but irregular geoid surface, providing a mean sea level (MSL) as a reference level for topographic measurements. Earth's surface is the boundary between the atmosphere, and the solid Earth and oceans. Defined in this way, it has an area of about 510 million km (197 million sq mi). Earth can be divided into two hemispheres : by latitude into

2622-509: Is mainly based on AmigaOS 3.1 source code developed by Commodore , and partially on version 3.9 developed by Haage & Partner . "The Final Update" (for OS version 4.0) was released on 24 December 2006 (originally released in April 2004) after five years of development by the Belgian company Hyperion Entertainment under license from Amiga, Inc. for AmigaOne registered users. During

2736-513: Is now slightly longer than it was during the 19th century due to tidal deceleration , each day varies between 0 and 2 ms longer than the mean solar day. Earth's rotation period relative to the fixed stars , called its stellar day by the International Earth Rotation and Reference Systems Service (IERS), is 86,164.0989 seconds of mean solar time ( UT1 ), or 23 56 4.0989 . Earth's rotation period relative to

2850-622: Is rare, though the alternative spelling Gaia has become common due to the Gaia hypothesis , in which case its pronunciation is / ˈ ɡ aɪ . ə / rather than the more classical English / ˈ ɡ eɪ . ə / . There are a number of adjectives for the planet Earth. The word "earthly" is derived from "Earth". From the Latin Terra comes terran / ˈ t ɛr ə n / , terrestrial / t ə ˈ r ɛ s t r i ə l / , and (via French) terrene / t ə ˈ r iː n / , and from

2964-525: Is relatively limited. Celestia can be extended with new objects, and has support for third-party, user-created add-ons available for installation, both fictional and realistic. Add-ons are commonly made up of plain text files, textures, and occasionally 3D models. Celestia also uses the custom CEL scripting language, and improved CELX scripts written in the Lua programming language , which can execute many different commands. The default setting for Celestia's Earth

3078-487: Is that it was formed by accretion from material loosed from Earth after a Mars -sized object with about 10% of Earth's mass, named Theia , collided with Earth. It hit Earth with a glancing blow and some of its mass merged with Earth. Between approximately 4.1 and 3.8 Ga , numerous asteroid impacts during the Late Heavy Bombardment caused significant changes to the greater surface environment of

3192-453: Is the basis for the astronomical unit (AU) and is equal to roughly 8.3 light minutes or 380 times Earth's distance to the Moon . Earth orbits the Sun every 365.2564 mean solar days , or one sidereal year . With an apparent movement of the Sun in Earth's sky at a rate of about 1°/day eastward, which is one apparent Sun or Moon diameter every 12 hours. Due to this motion, on average it takes 24 hours—a solar day—for Earth to complete

3306-589: Is the third planet from the Sun and the only astronomical object known to harbor life . This is enabled by Earth being an ocean world , the only one in the Solar System sustaining liquid surface water . Almost all of Earth's water is contained in its global ocean, covering 70.8% of Earth's crust . The remaining 29.2% of Earth's crust is land, most of which is located in the form of continental landmasses within Earth's land hemisphere . Most of Earth's land

3420-457: Is tied to that of the Sun. Over the next 1.1 billion years , solar luminosity will increase by 10%, and over the next 3.5 billion years by 40%. Earth's increasing surface temperature will accelerate the inorganic carbon cycle , possibly reducing CO 2 concentration to levels lethally low for current plants ( 10  ppm for C4 photosynthesis ) in approximately 100–900 million years . A lack of vegetation would result in

3534-771: The Chelyabinsk meteor ). Numerous scripts are available. These include simple tours, reconstructions of complex space missions such as Cassini–Huygens and Deep Impact , and scripts showing useful information, like size comparisons, or particular events such as multiple simultaneous eclipses of Jupiter's moons or the evolution of a star. Fictional universes can be depicted, with planetary systems and 3D models—films such as 2001: A Space Odyssey , Star Trek and Star Wars , and TV shows including Stargate SG-1 and Babylon 5 . Add-ons illustrating less well-known internet fiction, like Orion's Arm , or role-playing games , like 2300 AD , and personal works by members of

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3648-782: The Hipparcos Catalogue (HIP) of 118,322 stars and a compiled catalogue of galaxies, while version 1.7.0 includes stars from the Tycho-2 Catalogue alongside the Hipparcos stars, with some data from Gaia , increasing the star count to over 2 million. Celestia uses the VSOP87 theory of planetary orbits to provide a solar and lunar eclipse finder and to display the orbital paths of planets (including extrasolar planets ), dwarf planets , moons , asteroids , comets , artificial satellites , and spacecraft . Using

3762-510: The Julian calendar and cannot go back or forward more than 2 billion years, and the default time-setting system cannot go further than the years -9999 or 9999. Well over 80  GB of extensions are available in addition to the base program, produced by an active user community. Higher resolution surface textures are available for most Solar System bodies, including Virtual Textures with coverage up to 65536 pixels wide (0.625 km/pixel at

3876-576: The Kickstart . The Workbench is the GUI of OS4, a graphical interface file manager and application launcher for the Operating System. It also includes some general purpose tools and utility programs such as a Notepad for typing text, MultiView for viewing images and Amigaguide documents, Unarc for unpacking Archives, a PDF reader, a number of small preferences programs for changing settings of

3990-583: The Milky Way and orbits about 28,000  light-years from its center. It is about 20 light-years above the galactic plane in the Orion Arm . The axial tilt of Earth is approximately 23.439281° with the axis of its orbit plane, always pointing towards the Celestial Poles . Due to Earth's axial tilt, the amount of sunlight reaching any given point on the surface varies over the course of

4104-759: The Pacific , North American , Eurasian , African , Antarctic , Indo-Australian , and South American . Other notable plates include the Arabian Plate , the Caribbean Plate , the Nazca Plate off the west coast of South America and the Scotia Plate in the southern Atlantic Ocean. The Australian Plate fused with the Indian Plate between 50 and 55 Ma . The fastest-moving plates are

4218-419: The asthenosphere , the solid but less-viscous part of the upper mantle that can flow and move along with the plates. As the tectonic plates migrate, oceanic crust is subducted under the leading edges of the plates at convergent boundaries. At the same time, the upwelling of mantle material at divergent boundaries creates mid-ocean ridges. The combination of these processes recycles the oceanic crust back into

4332-415: The celestial equator , this is equivalent to an apparent diameter of the Sun or the Moon every two minutes; from Earth's surface, the apparent sizes of the Sun and the Moon are approximately the same. Earth orbits the Sun, making Earth the third-closest planet to the Sun and part of the inner Solar System . Earth's average orbital distance is about 150 million km (93 million mi), which

4446-410: The equatorial region receiving more sunlight than the polar regions) drive atmospheric and ocean currents , producing a global climate system with different climate regions , and a range of weather phenomena such as precipitation , allowing components such as nitrogen to cycle . Earth is rounded into an ellipsoid with a circumference of about 40,000 km. It is the densest planet in

4560-408: The ocean floor form the top of Earth's crust , which together with parts of the upper mantle form Earth's lithosphere . Earth's crust may be divided into oceanic and continental crust. Beneath the ocean-floor sediments, the oceanic crust is predominantly basaltic , while the continental crust may include lower density materials such as granite , sediments and metamorphic rocks. Nearly 75% of

4674-430: The precessing or moving mean March equinox (when the Sun is at 90° on the equator), is 86,164.0905 seconds of mean solar time (UT1) (23 56 4.0905 ) . Thus the sidereal day is shorter than the stellar day by about 8.4 ms. Apart from meteors within the atmosphere and low-orbiting satellites, the main apparent motion of celestial bodies in Earth's sky is to the west at a rate of 15°/h = 15'/min. For bodies near

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4788-474: The sphere of gravitational influence , of Earth is about 1.5 million km (930,000 mi) in radius. This is the maximum distance at which Earth's gravitational influence is stronger than that of the more distant Sun and planets. Objects must orbit Earth within this radius, or they can become unbound by the gravitational perturbation of the Sun. Earth, along with the Solar System, is situated in

4902-464: The "last ice age", covered large parts of the continents, to the middle latitudes, in ice and ended about 11,700 years ago. Chemical reactions led to the first self-replicating molecules about four billion years ago. A half billion years later, the last common ancestor of all current life arose. The evolution of photosynthesis allowed the Sun's energy to be harvested directly by life forms. The resultant molecular oxygen ( O 2 ) accumulated in

5016-463: The 1.7.0 render limit experience floating point errors, meaning their position is inaccurate. Finally, Celestia does not consider the wobbling of some stars induced by their planets, unless said wobbling is very noticeable. Wavelength filtering is not implemented in Celestia's engine. The actual rendering tries to match human vision at the observer's position as accurately as possible. This means false-color maps and multi-color nebulae are not part of

5130-484: The Cambrian explosion, 535 Ma , there have been at least five major mass extinctions and many minor ones. Apart from the proposed current Holocene extinction event, the most recent was 66 Ma , when an asteroid impact triggered the extinction of non-avian dinosaurs and other large reptiles, but largely spared small animals such as insects, mammals , lizards and birds. Mammalian life has diversified over

5244-410: The Celestia community depicting fictional planetary systems with inhabited worlds, spacecraft, cities, and special effects can also be added. Educational add-ons can also be implemented in different languages. These activities provide approximately 40 hours of space journeys and astronomical lessons to include extensive tours of the Celestia universe, the complete life cycle of stars, the Solar System,

5358-637: The Earth can be drawn by the program. Add-ons also include other objects such as red and blue supergiants, red and brown dwarfs, neutron stars, spinning pulsars, rotating black holes with accretion disks, protostars, Wolf-Rayet stars, star nursery nebulae, supernova remnants, planetary nebulae, galactic redshifts, geological planetary displays (e.g. 3D interiors, topographic and bathymetric maps, paleogeography ), planetary aurorae , rotating magnetic fields, animated solar prominences , 3D craters and mountains, and historic collision events (Either spacecraft such as Deep Impact and DART , or meteoric impacts such as

5472-749: The Earth's equator), with selected coverage at higher resolutions. This allows closer views of well-mapped objects that have high-resolution VTs available for download. 3D models of historical and existing spacecraft are available flying in reasonably accurate trajectories, such as Sputnik 1 , Voyager 2 , the Hubble Space Telescope , and the International Space Station , as are extended data plots for stars (2 million with correct spatial coordinates), DSOs (nebulae, galaxies, open clusters , etc.), as well as catalogs of asteroids and comets, and more than 96,000 locations on

5586-654: The Earth. Terra is also the name of the planet in some Romance languages , languages that evolved from Latin , like Italian and Portuguese , while in other Romance languages the word gave rise to names with slightly altered spellings, like the Spanish Tierra and the French Terre . The Latinate form Gæa or Gaea ( English: / ˈ dʒ iː . ə / ) of the Greek poetic name Gaia ( Γαῖα ; Ancient Greek : [ɡâi̯.a] or [ɡâj.ja] )

5700-599: The GUI and OS, among other programs. The Kickstart contains many of the core components of the OS. Prior to version 4 of AmigaOS the Kickstart had been released mostly on a ROM (hardware included with the computer). In OS4 the Kickstart is instead stored on the hard disk. It consists mainly of: There have been many different versions of the AmigaOS operating system (OS) during its three decades of history. The first AmigaOS

5814-533: The Latin Tellus comes tellurian / t ɛ ˈ l ʊər i ə n / and telluric . The oldest material found in the Solar System is dated to 4.5682 +0.0002 −0.0004 Ga (billion years) ago. By 4.54 ± 0.04 Ga the primordial Earth had formed. The bodies in the Solar System formed and evolved with the Sun. In theory, a solar nebula partitions a volume out of a molecular cloud by gravitational collapse, which begins to spin and flatten into

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5928-426: The Moon and, by inference, to that of Earth. Earth's atmosphere and oceans were formed by volcanic activity and outgassing . Water vapor from these sources condensed into the oceans, augmented by water and ice from asteroids, protoplanets , and comets . Sufficient water to fill the oceans may have been on Earth since it formed. In this model, atmospheric greenhouse gases kept the oceans from freezing when

6042-416: The Solar System . Of the four rocky planets , it is the largest and most massive. Earth is about eight light-minutes away from the Sun and orbits it , taking a year (about 365.25 days) to complete one revolution. Earth rotates around its own axis in slightly less than a day (in about 23 hours and 56 minutes). Earth's axis of rotation is tilted with respect to the perpendicular to its orbital plane around

6156-458: The Solar System's planetary-sized objects, Earth is the object with the highest density . Earth's mass is approximately 5.97 × 10   kg ( 5.970  Yg ). It is composed mostly of iron (32.1% by mass ), oxygen (30.1%), silicon (15.1%), magnesium (13.9%), sulfur (2.9%), nickel (1.8%), calcium (1.5%), and aluminium (1.4%), with the remaining 1.2% consisting of trace amounts of other elements. Due to gravitational separation ,

6270-676: The Solar System, formed 4.5 billion years ago from gas and dust in the early Solar System . During the first billion years of Earth's history , the ocean formed and then life developed within it. Life spread globally and has been altering Earth's atmosphere and surface, leading to the Great Oxidation Event two billion years ago. Humans emerged 300,000 years ago in Africa and have spread across every continent on Earth. Humans depend on Earth's biosphere and natural resources for their survival, but have increasingly impacted

6384-403: The Sun when the star reaches its maximum radius, otherwise, with tidal effects, it may enter the Sun's atmosphere and be vaporized. Earth has a rounded shape , through hydrostatic equilibrium , with an average diameter of 12,742 kilometres (7,918 mi), making it the fifth largest planetary sized and largest terrestrial object of the Solar System . Due to Earth's rotation it has

6498-465: The Sun, producing seasons . Earth is orbited by one permanent natural satellite , the Moon , which orbits Earth at 384,400 km (1.28 light seconds) and is roughly a quarter as wide as Earth. The Moon's gravity helps stabilize Earth's axis, causes tides and gradually slows Earth's rotation . Tidal locking has made the Moon always face Earth with the same side. Earth, like most other bodies in

6612-541: The addition of Gaia data in 1.7.0, stars as far away as the Galactic Center are included. In addition, objects in star systems are only drawn to a distance of one light-year from their parent stars, any further and they will simply not be rendered at all. Similarly, there is a render limit for stars at 10 million light-years in versions 1.6.3 and under, increased to 1 billion light-years in 1.7.0. Any stars beyond that limit are not rendered, and stars that are close to

6726-425: The atmosphere and due to interaction with ultraviolet solar radiation, formed a protective ozone layer ( O 3 ) in the upper atmosphere. The incorporation of smaller cells within larger ones resulted in the development of complex cells called eukaryotes . True multicellular organisms formed as cells within colonies became increasingly specialized. Aided by the absorption of harmful ultraviolet radiation by

6840-426: The atmosphere, particularly carbon dioxide (CO 2 ), creates the conditions for both liquid surface water and water vapor to persist via the capturing of energy from the Sun's light . This process maintains the current average surface temperature of 14.76 °C (58.57 °F), at which water is liquid under normal atmospheric pressure. Differences in the amount of captured energy between geographic regions (as with

6954-534: The bugfix releases 1.6.2 and 1.6.3, which were released in 2020 and 2023 respectively. Celestia was ported to mobile devices in 2020, and it continues to receive updates and experimental beta versions. Celestia is available for download from its main website, celestiaproject.space, but it can be obtained from a large multitude of free software websites as well. Between 2001 and May 2017, the former central distribution site SourceForge counted approximately 12 million downloads. Celestia versions 1.6.3 and under display

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7068-450: The center, the temperature may be up to 6,000 °C (10,830 °F), and the pressure could reach 360  GPa (52 million  psi ). Because much of the heat is provided by radioactive decay, scientists postulate that early in Earth's history, before isotopes with short half-lives were depleted, Earth's heat production was much higher. At approximately 3  Gyr , twice the present-day heat would have been produced, increasing

7182-454: The continental crust , particularly during the early stages of Earth's history. New continental crust forms as a result of plate tectonics , a process ultimately driven by the continuous loss of heat from Earth's interior. Over the period of hundreds of millions of years, tectonic forces have caused areas of continental crust to group together to form supercontinents that have subsequently broken apart. At approximately 750 Ma , one of

7296-616: The continental surfaces are covered by sedimentary rocks, although they form about 5% of the mass of the crust. Earth's surface topography comprises both the topography of the ocean surface , and the shape of Earth's land surface. The submarine terrain of the ocean floor has an average bathymetric depth of 4 km, and is as varied as the terrain above sea level. Earth's surface is continually being shaped by internal plate tectonic processes including earthquakes and volcanism ; by weathering and erosion driven by ice, water, wind and temperature; and by biological processes including

7410-419: The core are chaotic; the magnetic poles drift and periodically change alignment. This causes secular variation of the main field and field reversals at irregular intervals averaging a few times every million years. The most recent reversal occurred approximately 700,000 years ago. The extent of Earth's magnetic field in space defines the magnetosphere . Ions and electrons of the solar wind are deflected by

7524-527: The core is primarily composed of the denser elements: iron (88.8%), with smaller amounts of nickel (5.8%), sulfur (4.5%), and less than 1% trace elements. The most common rock constituents of the crust are oxides . Over 99% of the crust is composed of various oxides of eleven elements, principally oxides containing silicon (the silicate minerals ), aluminium, iron, calcium, magnesium, potassium, or sodium. The major heat-producing isotopes within Earth are potassium-40 , uranium-238 , and thorium-232 . At

7638-463: The core, through the mantle, and up to Earth's surface, where it is, approximately, a dipole . The poles of the dipole are located close to Earth's geographic poles. At the equator of the magnetic field, the magnetic-field strength at the surface is 3.05 × 10 T , with a magnetic dipole moment of 7.79 × 10 Am at epoch 2000, decreasing nearly 6% per century (although it still remains stronger than its long time average). The convection movements in

7752-539: The days shorter. Above the Arctic Circle and below the Antarctic Circle there is no daylight at all for part of the year, causing a polar night , and this night extends for several months at the poles themselves. These same latitudes also experience a midnight sun , where the sun remains visible all day. By astronomical convention, the four seasons can be determined by the solstices—the points in

7866-441: The destructive solar winds and cosmic radiation . Earth has a dynamic atmosphere , which sustains Earth's surface conditions and protects it from most meteoroids and UV-light at entry . It has a composition of primarily nitrogen and oxygen . Water vapor is widely present in the atmosphere, forming clouds that cover most of the planet. The water vapor acts as a greenhouse gas and, together with other greenhouse gases in

7980-611: The earliest known supercontinents, Rodinia , began to break apart. The continents later recombined to form Pannotia at 600–540 Ma , then finally Pangaea , which also began to break apart at 180 Ma . The most recent pattern of ice ages began about 40 Ma , and then intensified during the Pleistocene about 3 Ma . High- and middle-latitude regions have since undergone repeated cycles of glaciation and thaw, repeating about every 21,000, 41,000 and 100,000 years. The Last Glacial Period , colloquially called

8094-544: The equally large area of land under permafrost ) or deserts (33%). The pedosphere is the outermost layer of Earth's land surface and is composed of soil and subject to soil formation processes. Soil is crucial for land to be arable. Earth's total arable land is 10.7% of the land surface, with 1.3% being permanent cropland. Earth has an estimated 16.7 million km (6.4 million sq mi) of cropland and 33.5 million km (12.9 million sq mi) of pastureland. The land surface and

8208-546: The first time, a standardised "look and feel" was added. This was done by creating the Amiga Style Guide , and including libraries and software which assisted developers in making conformant software. Technologies included the GUI element creation library gadtools , the software installation scripting language Installer , and the AmigaGuide hypertext help system. After the demise of Commodore International ,

8322-685: The five years of development, purchasers of AmigaOne machines could download pre-release versions of AmigaOS 4.0 from Hyperion's repository as long as these were made available. On 20 December 2006, Amiga, Inc. terminated the contract with Hyperion Entertainment to produce or sell AmigaOS 4. Nevertheless, AmigaOS 4.0 was released commercially for Amigas with PowerUP accelerator cards in November 2007 (having been available only to developers and beta-testers until then). The Italian computer company ACube Systems has announced Sam440ep and Sam440ep-flex motherboards, which are AmigaOS 4 compatible. Also,

8436-638: The growth and decomposition of biomass into soil . Earth's mechanically rigid outer layer of Earth's crust and upper mantle , the lithosphere , is divided into tectonic plates . These plates are rigid segments that move relative to each other at one of three boundaries types: at convergent boundaries , two plates come together; at divergent boundaries , two plates are pulled apart; and at transform boundaries , two plates slide past one another laterally. Along these plate boundaries, earthquakes, volcanic activity , mountain-building , and oceanic trench formation can occur. The tectonic plates ride on top of

8550-404: The heat in Earth is lost through plate tectonics, by mantle upwelling associated with mid-ocean ridges . The final major mode of heat loss is through conduction through the lithosphere, the majority of which occurs under the oceans. The gravity of Earth is the acceleration that is imparted to objects due to the distribution of mass within Earth. Near Earth's surface, gravitational acceleration

8664-675: The human space program, the Search for Extraterrestrial Intelligence (SETI), and depictions of astronomical events such as the formation of the Moon billions of years ago, and the possible terraforming of Mars in the future. In mid 2016, a large addon pack project called Celestia Origin was created, which replaces all vanilla textures and graphics with higher-quality renderings, adds more minor objects such as TNOs and asteroids, while also adding more extrasolar planets with custom textures, more nebulae with full 3D and accurate models, more stars and galaxies, more star clusters , more spacecraft, and

8778-598: The installed catalogues, the names of celestial objects can be displayed, including artificial satellites. The names and locations of Earth features such as continents, mountains, seas, oceans, and cities can also be displayed. Surface features on other celestial objects such as craters, basins and canyons can be shown as well. Celestia allows users to navigate at different speeds, and allow users to orbit stars, planets, moons, and other space objects, track space objects such as spacecraft, asteroids, and comets as they fly by, or travel to and/or fly through galaxies. Light time delay

8892-406: The land surface is taken by the four continental landmasses , which are (in descending order): Africa-Eurasia , America (landmass) , Antarctica , and Australia (landmass) . These landmasses are further broken down and grouped into the continents . The terrain of the land surface varies greatly and consists of mountains, deserts , plains , plateaus , and other landforms . The elevation of

9006-513: The land surface varies from a low point of −418 m (−1,371 ft) at the Dead Sea , to a maximum altitude of 8,848 m (29,029 ft) at the top of Mount Everest . The mean height of land above sea level is about 797 m (2,615 ft). Land can be covered by surface water , snow, ice, artificial structures or vegetation. Most of Earth's land hosts vegetation, but considerable amounts of land are ice sheets (10%, not including

9120-476: The later owners of the Amiga trademark granted a license to a German company called Haage & Partner to update the Amiga's operating system. Along with this update came a change in the way people referred to the Amiga's operating system. Rather than specifying "Kickstart" or "Workbench", the updates were most often referred to as simply "AmigaOS". Whereas all previous OS releases ran on vanilla Amiga 500 with 68000 and 512 kB RAM, release 3.5 onwards required

9234-399: The lithosphere, which is divided into independently moving tectonic plates. Beneath the lithosphere is the asthenosphere , a relatively low-viscosity layer on which the lithosphere rides. Important changes in crystal structure within the mantle occur at 410 and 660 km (250 and 410 mi) below the surface, spanning a transition zone that separates the upper and lower mantle. Beneath

9348-410: The loss of oxygen in the atmosphere, making current animal life impossible. Due to the increased luminosity, Earth's mean temperature may reach 100 °C (212 °F) in 1.5 billion years, and all ocean water will evaporate and be lost to space, which may trigger a runaway greenhouse effect , within an estimated 1.6 to 3 billion years. Even if the Sun were stable, a fraction of the water in

9462-456: The lowercase when it is preceded by "the", such as "the atmosphere of the earth". It almost always appears in lowercase in colloquial expressions such as "what on earth are you doing?" The name Terra / ˈ t ɛr ə / occasionally is used in scientific writing and especially in science fiction to distinguish humanity's inhabited planet from others, while in poetry Tellus / ˈ t ɛ l ə s / has been used to denote personification of

9576-497: The magnetosphere. During magnetic storms and substorms , charged particles can be deflected from the outer magnetosphere and especially the magnetotail, directed along field lines into Earth's ionosphere , where atmospheric atoms can be excited and ionized, causing an aurora . Earth's rotation period relative to the Sun—its mean solar day—is 86,400 seconds of mean solar time ( 86,400.0025 SI seconds ). Because Earth's solar day

9690-409: The magnetosphere; solar wind pressure compresses the day-side of the magnetosphere, to about 10 Earth radii, and extends the night-side magnetosphere into a long tail. Because the velocity of the solar wind is greater than the speed at which waves propagate through the solar wind, a supersonic bow shock precedes the day-side magnetosphere within the solar wind. Charged particles are contained within

9804-483: The magnetosphere; the plasmasphere is defined by low-energy particles that essentially follow magnetic field lines as Earth rotates. The ring current is defined by medium-energy particles that drift relative to the geomagnetic field, but with paths that are still dominated by the magnetic field, and the Van Allen radiation belts are formed by high-energy particles whose motion is essentially random, but contained in

9918-417: The mantle, an extremely low viscosity liquid outer core lies above a solid inner core . Earth's inner core may be rotating at a slightly higher angular velocity than the remainder of the planet, advancing by 0.1–0.5° per year, although both somewhat higher and much lower rates have also been proposed. The radius of the inner core is about one-fifth of that of Earth. The density increases with depth. Among

10032-612: The mantle. Due to this recycling, most of the ocean floor is less than 100 Ma old. The oldest oceanic crust is located in the Western Pacific and is estimated to be 200 Ma old. By comparison, the oldest dated continental crust is 4,030 Ma , although zircons have been found preserved as clasts within Eoarchean sedimentary rocks that give ages up to 4,400 Ma , indicating that at least some continental crust existed at that time. The seven major plates are

10146-548: The modern oceans will descend to the mantle , due to reduced steam venting from mid-ocean ridges. The Sun will evolve to become a red giant in about 5 billion years . Models predict that the Sun will expand to roughly 1  AU (150 million km; 93 million mi), about 250 times its present radius. Earth's fate is less clear. As a red giant, the Sun will lose roughly 30% of its mass, so, without tidal effects, Earth will move to an orbit 1.7 AU (250 million km; 160 million mi) from

10260-399: The mother of Thor . Historically, "Earth" has been written in lowercase. Beginning with the use of Early Middle English , its definite sense as "the globe" was expressed as "the earth". By the era of Early Modern English , capitalization of nouns began to prevail , and the earth was also written the Earth , particularly when referenced along with other heavenly bodies. More recently,

10374-548: The movie The Day After Tomorrow and the 2008 miniseries The Andromeda Strain . Celestia has also appeared on the Science Channel's Through the Wormhole . Eurogamer 's Jim Rossignol named Celestia among a top 20 list of Summer of PC Freeware games in 2006. AmigaOS 4 AmigaOS 4 (abbreviated as OS4 or AOS4 ) is a line of Amiga operating systems which runs on PowerPC microprocessors. It

10488-424: The name is sometimes simply given as Earth , by analogy with the names of the other planets , though "earth" and forms with "the earth" remain common. House styles now vary: Oxford spelling recognizes the lowercase form as the more common, with the capitalized form an acceptable variant. Another convention capitalizes "Earth" when appearing as a name, such as a description of the "Earth's atmosphere", but employs

10602-456: The name of their original disks to preserve original custom. Workbench 2.0 improvements introduced a lot of major advances to the GUI of Amiga operating system. The blue and orange colour scheme was replaced with a grey and light blue with 3D aspect in the border of the windows. The Workbench was no longer tied to the 640×256 (PAL) or 640×200 (NTSC) display modes, and much of the system was improved with an eye to making future expansion easier. For

10716-425: The newly forming Sun had only 70% of its current luminosity . By 3.5 Ga , Earth's magnetic field was established, which helped prevent the atmosphere from being stripped away by the solar wind . As the molten outer layer of Earth cooled it formed the first solid crust , which is thought to have been mafic in composition. The first continental crust , which was more felsic in composition, formed by

10830-441: The objects that Celestia draws can also be displayed, such as temperature, distance from observer, radius, rotational period, luminosity, and more. The user can change Celestia's field of view, and the window can be split into multiple different panes, meaning that several objects can be displayed on the screen at once. Screenshots and movies can be captured in classic or HD resolutions. Celestia's support for gamepads and joysticks

10944-593: The ocean may have covered Earth completely. The world ocean is commonly divided into the Pacific Ocean, Atlantic Ocean, Indian Ocean, Antarctic or Southern Ocean , and Arctic Ocean, from largest to smallest. The ocean covers Earth's oceanic crust , with the shelf seas covering the shelves of the continental crust to a lesser extent. The oceanic crust forms large oceanic basins with features like abyssal plains , seamounts , submarine volcanoes , oceanic trenches , submarine canyons , oceanic plateaus , and

11058-670: The oceanic plates, with the Cocos Plate advancing at a rate of 75 mm/a (3.0 in/year) and the Pacific Plate moving 52–69 mm/a (2.0–2.7 in/year). At the other extreme, the slowest-moving plate is the South American Plate, progressing at a typical rate of 10.6 mm/a (0.42 in/year). Earth's interior, like that of the other terrestrial planets, is divided into layers by their chemical or physical ( rheological ) properties. The outer layer

11172-484: The official distribution, but many are available as add-ons. Camera artifacts such as lens flare and glare are not rendered. Celestia also does not simulate gravity . For example, a near-Earth object approaching the Earth will not be deflected by the Earth's gravity unless the person who defined the NEO's trajectory for Celestia included that effect. Some moons do not cast shadows on their planet during eclipses . This

11286-599: The orbit of maximum axial tilt toward or away from the Sun—and the equinoxes , when Earth's rotational axis is aligned with its orbital axis. In the Northern Hemisphere, winter solstice currently occurs around 21 December; summer solstice is near 21 June, spring equinox is around 20 March and autumnal equinox is about 22 or 23 September. In the Southern Hemisphere, the situation is reversed, with

11400-649: The ozone layer, life colonized Earth's surface. Among the earliest fossil evidence for life is microbial mat fossils found in 3.48 billion-year-old sandstone in Western Australia , biogenic graphite found in 3.7 billion-year-old metasedimentary rocks in Western Greenland , and remains of biotic material found in 4.1 billion-year-old rocks in Western Australia. The earliest direct evidence of life on Earth

11514-474: The partial melting of this mafic crust. The presence of grains of the mineral zircon of Hadean age in Eoarchean sedimentary rocks suggests that at least some felsic crust existed as early as 4.4 Ga , only 140  Ma after Earth's formation. There are two main models of how this initial small volume of continental crust evolved to reach its current abundance: (1) a relatively steady growth up to

11628-501: The past 66 Mys , and several million years ago, an African ape species gained the ability to stand upright. This facilitated tool use and encouraged communication that provided the nutrition and stimulation needed for a larger brain, which led to the evolution of humans . The development of agriculture , and then civilization , led to humans having an influence on Earth and the nature and quantity of other life forms that continues to this day. Earth's expected long-term future

11742-478: The planet's environment . Humanity's current impact on Earth's climate and biosphere is unsustainable , threatening the livelihood of humans and many other forms of life, and causing widespread extinctions . The Modern English word Earth developed, via Middle English , from an Old English noun most often spelled eorðe . It has cognates in every Germanic language , and their ancestral root has been reconstructed as * erþō . In its earliest attestation,

11856-421: The polar Northern and Southern hemispheres; or by longitude into the continental Eastern and Western hemispheres. Most of Earth's surface is ocean water: 70.8% or 361 million km (139 million sq mi). This vast pool of salty water is often called the world ocean , and makes Earth with its dynamic hydrosphere a water world or ocean world . Indeed, in Earth's early history

11970-495: The present day, which is supported by the radiometric dating of continental crust globally and (2) an initial rapid growth in the volume of continental crust during the Archean , forming the bulk of the continental crust that now exists, which is supported by isotopic evidence from hafnium in zircons and neodymium in sedimentary rocks. The two models and the data that support them can be reconciled by large-scale recycling of

12084-413: The progress of the program since 2020. The original creator of Celestia, Chris Laurel, created Fifth Star Labs shortly after Celestia's development stopped, and began working on an iOS-only planetarium app called Sky Guide. In late 2016, the official Celestia forums were restored, and development restarted under a new development team. As of 2018, beta testing builds of version 1.7.0 are available, as well as

12198-493: The rates of mantle convection and plate tectonics, and allowing the production of uncommon igneous rocks such as komatiites that are rarely formed today. The mean heat loss from Earth is 87 mW m , for a global heat loss of 4.42 × 10  W . A portion of the core's thermal energy is transported toward the crust by mantle plumes , a form of convection consisting of upwellings of higher-temperature rock. These plumes can produce hotspots and flood basalts . More of

12312-522: The shape of an ellipsoid , bulging at its Equator ; its diameter is 43 kilometres (27 mi) longer there than at its poles . Earth's shape also has local topographic variations; the largest local variations, like the Mariana Trench (10,925 metres or 35,843 feet below local sea level), shortens Earth's average radius by 0.17% and Mount Everest (8,848 metres or 29,029 feet above local sea level) lengthens it by 0.14%. Since Earth's surface

12426-610: The sole exception of Amigas with Phase5 PowerPC accelerator boards, for which OS4 is sold separately. This requirement was overturned in the agreement reached between Amiga, Inc. and Hyperion in the settlement of a lawsuit over the ownership of AmigaOS 4. In 2014 Hyperion introduced AmigaOS 4.1 Final Edition incorporating all previous downloadable updates and some new features like unified graphics library with RTG support and support for more than 2 GB RAM. In May 2012 Hyperion announced that they were working on AmigaOS 4.2. It would introduce hardware accelerated 3D support, multi-core support,

12540-548: The spacecraft included with Celestia 1.6.3 use outdated or low-quality models, such as the stock Mir model which is very basic and barely detailed, and the stock ISS model which hasn't had an update since around 2007, meaning it is missing a lot of modules that have been added to the ISS since then. However, there are many add-ons that replace these models with higher-quality and more up-to-date ones. Fortunately, version 1.7.0 will include better models upon its final release. Celestia uses

12654-455: The standard distribution. Many of these are available as add-ons. Although objects that form part of a planetary system move, and stars rotate about their axes and orbit each other in multiple star systems, stellar proper motion is not simulated, and galaxies are at fixed locations. As a result, the constellations in Celestia do not gradually change shape as they do in the real world. In addition, Celestia's binary star catalogs only describe

12768-461: The word eorðe was used to translate the many senses of Latin terra and Greek γῆ gē : the ground, its soil , dry land, the human world, the surface of the world (including the sea), and the globe itself. As with Roman Terra /Tellūs and Greek Gaia , Earth may have been a personified goddess in Germanic paganism : late Norse mythology included Jörð ("Earth"), a giantess often given as

12882-620: The year. This causes the seasonal change in climate, with summer in the Northern Hemisphere occurring when the Tropic of Cancer is facing the Sun, and in the Southern Hemisphere when the Tropic of Capricorn faces the Sun. In each instance, winter occurs simultaneously in the opposite hemisphere. During the summer, the day lasts longer, and the Sun climbs higher in the sky. In winter, the climate becomes cooler and

12996-408: Was introduced in 1985 and developed by Commodore International . It was nicknamed Workbench from the name of its Graphical user interface (GUI), due to an error of Commodore Marketing and Sales Department, which labeled the OS disk just with the name "Workbench Disk" and not with the correct name "AmigaOS Disk (Workbench)". The first versions of AmigaOS (1.0 and up to 1.3) are here indicated with

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