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  Aplanet is a large,roundedastronomical body that is generally required to be inorbit around astar,stellar remnant, orbrown dwarf, and is not one itself. TheSolar System has eight planets by the most restrictive definition of the term: theterrestrial planetsMercury,Venus,Earth, andMars, and thegiant planetsJupiter,Saturn,Uranus, andNeptune. The best available theory of planet formation is thenebular hypothesis, which posits that aninterstellar cloud collapses out of anebula to create a youngprotostar orbited by aprotoplanetary disk. Planets grow in this disk by the gradual accumulation of material driven bygravity, a process calledaccretion.
  
  The wordplanet comes from the Greekπλανήται (planḗtai)'wanderers'. Inantiquity, this word referred to theSun,Moon, and five points of light visible to the naked eye that moved across the background of the stars—namely, Mercury, Venus, Mars, Jupiter, and Saturn. Planets have historically had religious associations:multiple cultures identified celestial bodies with gods, and these connections with mythology andfolklore persist in the schemes for naming newly discovered Solar System bodies. Earth itself was recognized as a planet whenheliocentrism supplantedgeocentrism during the 16th and 17th centuries. (Full article...)
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  There are 167Sites of Special Scientific Interest (SSSIs) in Cornwall (including theIsles of Scilly).Cornwall, in the south-west of England, UK, has a population of 583,289 (2024) across an area of 3,545 km² (875,988.6 acres), making it one of the least densely populated counties within England. The north coast of Cornwall falls on theCeltic Sea in the Atlantic Ocean, which also surrounds the Isles of Scilly, the south coast falls on theEnglish Channel and the county is bounded by theRiver Tamar, forming the border withDevon, to the east. Cornish geology consists mainly of rocks from theDevonian andCarboniferous geological periods. Granite forms a large part of these, with mineralisations of tin, copper, lead andarsenic having beenmined in the area. This gives rise to many distinct habitats, with strong marine influences, includingsand dunes, rockyreefs,stacks andheadlands as well asheathland,moorland and unusual river profiles.
  
  In England the body responsible for designatingSSSIs isNatural England, which chooses a site "because of itsflora,fauna, or geological or physiographical features". Natural England took over the role of designating and managing SSSIs fromEnglish Nature in October 2006 when it was formed from the amalgamation of English Nature, parts of theCountryside Agency and theRural Development Service. Natural England, like its predecessor, uses the1974–96 county system and as such the same approach is followed here, rather than adopting the currentlocal government orceremonial county boundaries. (Full article...)
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  Earth is the thirdplanet from theSun and the onlyastronomical object known toharbor life. This is enabled by Earth being anocean world, the only one in theSolar System sustaining liquidsurface water. Almost all of Earth's water is contained in its global ocean, covering70.8% ofEarth's crust. The remaining 29.2% of Earth's crust is land, most of which is located in the form ofcontinentallandmasses within Earth'sland hemisphere. Most of Earth's land is at least somewhathumid and covered by vegetation, while largeice sheets at Earth'spolar deserts retain more water than Earth'sgroundwater, lakes, rivers, andatmospheric water combined. Earth's crust consists of slowly movingtectonic plates, which interact to produce mountain ranges,volcanoes, and earthquakes.Earth has a liquid outer core that generates amagnetosphere capable of deflecting most of the destructivesolar winds andcosmic radiation.
  
  Earth hasa dynamic atmosphere, which sustains Earth's surface conditions and protects it from mostmeteoroids andUV-light at entry. It is composed primarily ofnitrogen andoxygen.Water vapor is widely present in the atmosphere,forming clouds that cover most of the planet. The water vapor acts as agreenhouse gas and, together with other greenhouse gases in the atmosphere, particularlycarbon dioxide (CO₂), creates the conditions for both liquid surface water and water vapor to persist via the capturing ofenergy 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 theequatorial region receiving more sunlight than the polar regions) driveatmospheric andocean currents, producing a globalclimate system with differentclimate regions, and a range of weather phenomena such asprecipitation, allowing components such ascarbon andnitrogen tocycle. (Full article...)
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  In avolcanic eruption,lava,volcanic bombs,ash, and various gases are expelled from avolcanic vent andfissure. While many eruptions only pose dangers to the immediately surrounding area,Earth's largest eruptions can have a major regional or even global impact, with some affecting the climate and contributing tomass extinctions. Volcanic eruptions can generally be characterized as eitherexplosive eruptions, sudden ejections of rock and ash, oreffusive eruptions, relatively gentle outpourings of lava. A separate list is given below for each type.
  
  There have probably been many such eruptions duringEarth's history beyond those shown in these lists. Howevererosion andplate tectonics have taken their toll, and many eruptions have not left enough evidence for geologists to establish their size. Even for the eruptions listed here, estimates of the volume erupted can be subject to considerable uncertainty. (Full article...)
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  TheQayen earthquake, also known as theArdekul orQaen earthquake, struck northernIran'sKhorasan Province in the vicinity ofQaen on May 10, 1997, at 07:57UTC (12:57 local time). The largest in the area since 1990, the earthquake registered 7.3 on themoment magnitude scale and was centered approximately 270 kilometers (170 mi) south ofMashhad on the village of Ardekul. The third earthquake that year to cause severe damage, it devastated the Birjand–Qayen region, killing 1,567 and injuring more than 2,300. The earthquake—which left 50,000 homeless and damaged or destroyed over 15,000 homes—was described as the deadliest of 1997 by theUnited States Geological Survey. Some 155 aftershocks caused further destruction and drove away survivors. The earthquake was later discovered to have been caused by a rupture along afault that runs underneath the Iran–Afghanistan border.
  
  Damage was eventually estimated at $100 million, and many countriesresponded to the emergency with donations of blankets, tents, clothing, and food. Rescue teams were also dispatched to assist local volunteers infinding survivors trapped under the debris. The destruction around the earthquake'sepicenter was, in places, almost total; this has been attributed to poor construction practices in rural areas, and imparted momentum to a growing movement for changes inbuilding codes forearthquake-safe buildings. With 1 in 3,000 deaths in Iran attributable to earthquakes, a USgeophysicist has suggested that a country-wide rebuilding program would be needed to address the ongoing public safety concerns. (Full article...)
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  Photograph of theeruption column, May 18, 1980, taken byAustin Post

  
  In March 1980, a series ofvolcanic explosions andpyroclastic flows began atMount St. Helens inSkamania County, Washington, United States. A series ofphreatic blasts occurred from the summit and escalated for nearly two months until a major explosive eruption took place on May 18, 1980, at 8:32 a.m. The eruption, which had avolcanic explosivity index of 5, was the first to occur in thecontiguous United States since the much smaller 1915 eruption ofLassen Peak in California. It has often been considered the most disastrous volcanic eruption in U.S. history.
  
  The eruption was preceded by a series of earthquakes and steam-venting episodes caused by an injection ofmagma at shallow depth below thevolcano that created a large bulge and a fracture system on the mountain's north slope. An earthquake at 8:32:11 amPDT (UTC−7) on May 18, 1980, caused the entire weakened north face to slide away, asector collapse which was the largestsubaerial landslide in recorded history. This allowed the partly molten rock, rich in high-pressure gas and steam, to suddenly explode northward towardSpirit Lake in a hot mix oflava and pulverized older rock, overtaking the landslide. Aneruption column rose 80,000 feet (24 km; 15 mi) into the atmosphere and deposited ash in eleven U.S. states and various Canadian provinces. At the same time, snow, ice, and several entireglaciers on the volcano melted, forming a series of largelahars (volcanicmudslides) that reached as far as theColumbia River, nearly 50 miles (80 km; 260,000 ft) to the southwest. Less severe outbursts continued into the next day, only to be followed by other large, but not as destructive, eruptions later that year. The thermal energy released during the eruption was equal to 26 megatons ofTNT. (Full article...)
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  Radiocarbon dating (also referred to ascarbon dating orcarbon-14 dating) is a method fordetermining the age of an object containingorganic material by using the properties ofradiocarbon, aradioactiveisotope of carbon.
  
  The method was developed in the late 1940s at theUniversity of Chicago byWillard Libby. It is based on the fact that radiocarbon (¹⁴
  C) is constantly being created in theEarth's atmosphere by the interaction ofcosmic rays with atmosphericnitrogen. The resulting¹⁴
  C combines with atmosphericoxygen to form radioactivecarbon dioxide, which is incorporated into plants byphotosynthesis; animals then acquire¹⁴
  C by eating the plants. When the animal or plant dies, it stops exchanging carbon with its environment, and thereafter the amount of¹⁴
  C it contains begins to decrease as the¹⁴
  C undergoesradioactive decay. Measuring the amount of¹⁴
  C in a sample from a dead plant or animal, such as a piece of wood or a fragment of bone, provides information that can be used to calculate when the animal or plant died. The older a sample is, the less¹⁴
  C there is to be detected. Thehalf-life of¹⁴
  C (the period of time after which half of a given sample will have decayed) is about 5,730 years, so the oldest dates that can be reliably measured by this process date to approximately 50,000 years ago, although special preparation methods occasionally make an accurate analysis of older samples possible. Libby received theNobel Prize in Chemistry for his work in 1960. (Full article...)
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  TheLassen volcanic area presents ageological record ofsedimentation andvolcanic activity in and aroundLassen Volcanic National Park inNorthern California, U.S. The park is located in the southernmost part of theCascade Mountain Range in thePacific Northwest region of the United States. Pacific Oceanictectonic plates have plunged below theNorth American Plate in this part of North America for hundreds of millions of years. Heat and molten rock from thesesubducting plates has fed scores of volcanoes inCalifornia,Oregon,Washington andBritish Columbia over at least the past 30 million years, including these in the Lassen volcanic areas.
  
  Between 3 and 4 million years ago, volcanic-derived mud flows calledlahars streamed down several major mountains that included nearby but now extinctMount Yana andMount Maidu to become the Tuscan Formation.Basaltic and laterandesitic todacitic flows oflava covered increasingly larger areas of this formation to eventually form thelava plateau upon which the park is situated. About 600,000 years ago,Mount Tehama started to rise as astratovolcano in the southwestern corner of the park, eventually reaching an estimated 11,000 ft (3,400 m) in height. (Full article...)
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  The2002 Bou'in-Zahra earthquake (also known as the2002 Avaj earthquake or the2002 Changureh earthquake) occurred on 22 June 2002. Theepicenter was near the city ofBou'in-Zahra inQazvin province, a region of northwesternIran which is crossed by several majorfaults that is known for destructive earthquakes. The shock measured 6.5 on theM_wc scale, had a maximumMercalli intensity of VIII (Severe), and was followed by more than 20aftershocks. At least 261 people were killed and 1,500 more were injured.
  
  According to the International Institute of Earthquake Engineering and Seismology (IIEES), the earthquake was felt as far away as the capital city ofTehran, approximately 290 kilometres (180 mi) east of the epicenter, although no damage was reported there. Most houses in the region were single-storymasonry buildings, and virtually all of these collapsed. The public became angry due to the slow official response to victims who needed supplies. Residents of the town ofAvaj resorted to throwing stones at the car of a government minister. (Full article...)
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  Anearthquake occurred on November 27, 2005, at 13:52IRST (10:22UTC) on the sparsely populatedQeshm Island offSouthern Iran, killing 13 people and devastating 13 villages. It was Iran's second major earthquake of 2005, following the one atZarand in February. Theepicenter was about 1,500 kilometers (930 mi) south ofTehran, close to Iran's southern borders. Initial measurements showed that the earthquake registered about 6.0 on themoment magnitude scale, although that was reduced to 5.8 after further analysis. More than 400 minoraftershocks followed the main quake, 36 of which were greater than magnitude 2.5. The earthquake occurred in a remote area during the middle of the day, limiting the number of fatalities. Iranian relief efforts were effective and largely adequate, leading the country to decline offers of support from other nations andUNICEF.
  
  Qeshm Island is part of the Simply Folded Belt, the most seismically active part of theZagros fold and thrust belt. Similar to most earthquakes in the area, the 2005 event resulted fromreverse slip faulting. Since it lies in such a seismically active area, there is a high risk of destructive earthquakes in Iran; 1 in 3,000 deaths are attributable to earthquakes. One geophysicist has cited the lack of strict building codes as a serious concern. (Full article...)

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  Earth is the thirdplanet from theSun and the onlyastronomical object known toharbor life. This is enabled by Earth being anocean world, the only one in theSolar System sustaining liquidsurface water. Almost all of Earth's water is contained in its global ocean, covering70.8% ofEarth's crust. The remaining 29.2% of Earth's crust is land, most of which is located in the form ofcontinentallandmasses within Earth'sland hemisphere. Most of Earth's land is at least somewhathumid and covered by vegetation, while largeice sheets at Earth'spolar deserts retain more water than Earth'sgroundwater, lakes, rivers, andatmospheric water combined. Earth's crust consists of slowly movingtectonic plates, which interact to produce mountain ranges,volcanoes, and earthquakes.Earth has a liquid outer core that generates amagnetosphere capable of deflecting most of the destructivesolar winds andcosmic radiation. (Full article...)
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  Aerial photo from the south, with Mount Everest rising above the ridge connectingNuptse andLhotse

  
  Mount Everest (known locally asSagarmāthā inNepal andQomolangma inTibet) is Earth's highest mountain abovesea level. It lies in theMahalangur Himal sub-range of theHimalayas and marks part of theChina–Nepal border at its summit. Its height was most recently measured in 2020 by Chinese and Nepali authorities as 8,848.86 m (29,031 ft8+1⁄2 in). (Full article...)
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  Refined rare-earth oxides are heavy, gritty powders usually brown or black, but can be lighter colors as shown here.

  
  Back row:gadolinium · praseodymium · cerium
  Middle row:samarium · lanthanum
  
  Front:neodymium

  
  Therare-earth elements (REE), also calledrare-earth metals, orrare earths, are a set of 17 nearly indistinguishable lustrous silvery-white softheavy metals. The 15lanthanides (or lanthanoids), along withscandium andyttrium, are usually included as rare earths. Compounds containing rare-earths have diverse applications in electrical and electronic components,lasers, glass, magnetic materials, and industrial processes. Rare-earths are to be distinguished fromcritical minerals, which are materials of strategic or economic importance that are defined differently by different countries, andrare-earth minerals, which areminerals that contain one or more rare-earth elements as major metal constituents. (Full article...)
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  Acontinent is any of several large terrestrial geographical regions. Continents are generally identified byconvention rather than any strict criteria. A continent could be a single largelandmass, a landmass and nearby islands either on or beyond itscontinental shelf, or a part of a larger landmass, as in the case of Asia and Europe withinEurasia. Due to these varying definitions, the number of continents varies, up to seven or as few as four. MostEnglish-speaking countries recognize seven continents. In order from largest to smallest in area, these seven areAsia,Africa,North America,South America,Antarctica,Europe, andAustralia (or sometimesOceania orAustralasia). Different variations with fewer continents merge some of these regions; examples of this are merging Asia and Europe intoEurasia, North America and South America into theAmericas (or simply America), and Africa, Asia, and Europe intoAfro-Eurasia. (Full article...)
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  Imaging fromNASA's Shuttle Radar Topography MissionSTS-99 reveals part of the diameter ring of the crater in the form of a shallow circular trough. Numerouscenotes (sinkholes) cluster around the trough marking the inner crater rim.

  
  TheChicxulub crater is animpact crater buried underneath theYucatán Peninsula in Mexico. Its center is offshore, but the crater is named after the onshore community ofChicxulub Pueblo (not the larger coastal town ofChicxulub Puerto). It was formed slightly over 66million years ago when anasteroid, about ten kilometers (six miles) in diameter, struckEarth. The crater is estimated to be 200 kilometers (120 miles) in diameter and 30 kilometers (19 miles) in depth. It is one of thelargest impact structures on Earth, alongside the much olderSudbury andVredefort impact structures, and the only one whosepeak ring is intact and directly accessible for scientific research. (Full article...)
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  Darwin,c. 1854, when he was preparingOn the Origin of Species

  
  Charles Robert Darwin (/ˈdɑːrwɪn/DAR-win; 12 February 1809 – 19 April 1882) was an Englishnaturalist,geologist, andbiologist, widely known for his contributions toevolutionary biology. His proposition that allspecies of life have descended from acommon ancestor is now generally accepted and considered a fundamental scientific concept. In a joint presentation withAlfred Russel Wallace, he introduced his scientific theory that thisbranching pattern ofevolution resulted from a process he callednatural selection, in which thestruggle for existence has a similar effect to the artificial selection involved inselective breeding. Darwin has been described as one of the most influential figures inhuman history and was honoured byburial in Westminster Abbey. (Full article...)
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  Bathymetry of the Gulf of Mexico

  
  TheGulf of Mexico (Spanish:Golfo de México) is anoceanic basin and amarginal sea of the Atlantic Ocean, mostly surrounded by the North American continent. It is bounded on the northeast, north, and northwest by theGulf Coast of the United States; on the southwest and south by theMexican states ofTamaulipas,Veracruz,Tabasco,Campeche,Yucatán, andQuintana Roo; and on the southeast byCuba. (Full article...)
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  Gold is achemical element; it haschemical symbolAu (fromLatinaurum) andatomic number 79. In its pure form, it is abright-metallic-yellow, dense, soft,malleable, andductilemetal. Chemically, gold is atransition metal, agroup 11 element, and one of thenoble metals. It is one of the leastreactive chemical elements, being the second lowest in thereactivity series, with onlyplatinum ranked as less reactive. Gold is solid understandard conditions. (Full article...)
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  Changes insurface air temperature over the past 50 years. TheArctic has warmed the most, and temperatures on land have generally increased more thansea surface temperatures.

  
  Present-dayclimate change includes bothglobal warming—the ongoing increase inglobal average temperature—and its wider effects on Earth'sclimate system.Climate change in a broader sense also includes previous long-term changes to Earth'sclimate. The current rise in global temperatures isdriven by human activities, especiallyfossil fuel (coal,oil andnatural gas) burning since theIndustrial Revolution. Fossil fuel use,deforestation, and someagricultural and industrial practices releasegreenhouse gases. These gasesabsorb some of the heat that the Earthradiates after it warms from sunlight, warming the lower atmosphere.Carbon dioxide, the primary gas driving global warming,has increased in concentration by about 50% since thepre-industrial era to levels not seen for millions of years. (Full article...)
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  Lower and upper fault plain along the West Valley Fault in Carmona, Cavite

  
  TheMarikina Valley fault system, also known as theValley fault system (VFS), is a dominantlyright-lateralstrike-slip fault system inLuzon, Philippines. It extends fromDoña Remedios Trinidad,Bulacan in the north, running through theprovinces ofRizal, theMetro Manilacities ofQuezon,Marikina,Pasig,Taguig andMuntinlupa, and the provinces ofCavite andLaguna, before ending inCanlubang in the south. (Full article...)

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