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6,300 | In Vulgar Latin and the Romance languages, merged with . During the Classical Latin period this form of speaking was deliberately avoided by well-educated speakers. | https://en.wikipedia.org/wiki?curid=17730 |
6,301 | Syllables in Latin are signified by the presence of diphthongs and vowels. The number of syllables is the same as the number of vowel sounds. | https://en.wikipedia.org/wiki?curid=17730 |
6,302 | Further, if a consonant separates two vowels, it will go into the syllable of the second vowel. When there are two consonants between vowels, the last consonant will go with the second vowel. An exception occurs when a phonetic stop and liquid come together. In this situation, they are thought to be a single consonant,... | https://en.wikipedia.org/wiki?curid=17730 |
6,303 | Syllables in Latin are considered either long or short. Within a word, a syllable may either be long by nature or long by position. A syllable is long by nature if it has a diphthong or a long vowel. On the other hand, a syllable is long by position if the vowel is followed by more than one consonant. | https://en.wikipedia.org/wiki?curid=17730 |
6,304 | Latin was written in the Latin alphabet, derived from the Etruscan alphabet, which was in turn drawn from the Greek alphabet and ultimately the Phoenician alphabet. This alphabet has continued to be used over the centuries as the script for the Romance, Celtic, Germanic, Baltic, Finnic and many Slavic languages (Polish... | https://en.wikipedia.org/wiki?curid=17730 |
6,305 | The number of letters in the Latin alphabet has varied. When it was first derived from the Etruscan alphabet, it contained only 21 letters. Later, "G" was added to represent , which had previously been spelled "C", and "Z" ceased to be included in the alphabet, as the language then had no voiced alveolar fricative. The... | https://en.wikipedia.org/wiki?curid=17730 |
6,306 | "W" was created in the 11th century from "VV". It represented in Germanic languages, not Latin, which still uses "V" for the purpose. "J" was distinguished from the original "I" only during the late Middle Ages, as was the letter "U" from "V". Although some Latin dictionaries use "J", it is rarely used for Latin text, ... | https://en.wikipedia.org/wiki?curid=17730 |
6,307 | Classical Latin did not contain sentence punctuation, letter case, or interword spacing, but apices were sometimes used to distinguish length in vowels and the interpunct was used at times to separate words. The first line of Catullus 3, originally written as | https://en.wikipedia.org/wiki?curid=17730 |
6,308 | The Roman cursive script is commonly found on the many wax tablets excavated at sites such as forts, an especially extensive set having been discovered at Vindolanda on Hadrian's Wall in Britain. Most notable is the fact that while most of the Vindolanda tablets show spaces between words, spaces were avoided in monumen... | https://en.wikipedia.org/wiki?curid=17730 |
6,309 | Latin is a synthetic, fusional language in the terminology of linguistic typology. In more traditional terminology, it is an inflected language, but typologists are apt to say "inflecting". Words include an objective semantic element and markers specifying the grammatical use of the word. The fusion of root meaning and... | https://en.wikipedia.org/wiki?curid=17730 |
6,310 | The grammatical function can be changed by changing the markers: the word is "inflected" to express different grammatical functions, but the semantic element usually does not change. (Inflection uses affixing and infixing. Affixing is prefixing and suffixing. Latin inflections are never prefixed.) | https://en.wikipedia.org/wiki?curid=17730 |
6,311 | For example, , "he (or she or it) will love", is formed from the same stem, , to which a future tense marker, , is suffixed, and a third person singular marker, , is suffixed. There is an inherent ambiguity: may denote more than one grammatical category: masculine, feminine, or neuter gender. A major task in understand... | https://en.wikipedia.org/wiki?curid=17730 |
6,312 | The inflections express gender, number, and case in adjectives, nouns, and pronouns, a process called "declension". Markers are also attached to fixed stems of verbs, to denote person, number, tense, voice, mood, and aspect, a process called "conjugation". Some words are uninflected and undergo neither process, such as... | https://en.wikipedia.org/wiki?curid=17730 |
6,313 | A regular Latin noun belongs to one of five main declensions, a group of nouns with similar inflected forms. The declensions are identified by the genitive singular form of the noun. | https://en.wikipedia.org/wiki?curid=17730 |
6,314 | There are seven Latin noun cases, which also apply to adjectives and pronouns and mark a noun's syntactic role in the sentence by means of inflections. Thus, word order is not as important in Latin as it is in English, which is less inflected. The general structure and word order of a Latin sentence can therefore vary.... | https://en.wikipedia.org/wiki?curid=17730 |
6,315 | Latin lacks both definite and indefinite articles so can mean either "the boy is running" or "a boy is running". | https://en.wikipedia.org/wiki?curid=17730 |
6,316 | There are two types of regular Latin adjectives: first- and second-declension and third-declension. They are so-called because their forms are similar or identical to first- and second-declension and third-declension nouns, respectively. Latin adjectives also have comparative and superlative forms. There are also a num... | https://en.wikipedia.org/wiki?curid=17730 |
6,317 | First- and second-declension adjectives are declined like first-declension nouns for the feminine forms and like second-declension nouns for the masculine and neuter forms. For example, for (dead), is declined like a regular first-declension noun (such as (girl)), is declined like a regular second-declension masculine ... | https://en.wikipedia.org/wiki?curid=17730 |
6,318 | Third-declension adjectives are mostly declined like normal third-declension nouns, with a few exceptions. In the plural nominative neuter, for example, the ending is "-ia" ( (all, everything)), and for third-declension nouns, the plural nominative neuter ending is "-a" or "-ia" ( (heads), (animals)) They can have one,... | https://en.wikipedia.org/wiki?curid=17730 |
6,319 | Latin participles, like English participles, are formed from a verb. There are a few main types of participles: Present Active Participles, Perfect Passive Participles, Future Active Participles, and Future Passive Participles. | https://en.wikipedia.org/wiki?curid=17730 |
6,320 | Latin sometimes uses prepositions, depending on the type of prepositional phrase being used. Most prepositions are followed by a noun in either the accusative or ablative case: "apud puerum" (with the boy), with "puerum" being the accusative form of "puer", boy, and "sine puero" (without the boy), "puero" being the abl... | https://en.wikipedia.org/wiki?curid=17730 |
6,321 | A regular verb in Latin belongs to one of four main conjugations. A conjugation is "a class of verbs with similar inflected forms." The conjugations are identified by the last letter of the verb's present stem. The present stem can be found by omitting the -"re" (-"rī" in deponent verbs) ending from the present infinit... | https://en.wikipedia.org/wiki?curid=17730 |
6,322 | Irregular verbs are verbs that do not follow the regular conjugations in the formation of the inflected form. Irregular verbs in Latin are "esse", "to be"; "velle", "to want"; "ferre", "to carry"; "edere", "to eat"; "dare", "to give"; "ire", "to go"; "posse", "to be able"; "fieri", "to happen"; and their compounds. | https://en.wikipedia.org/wiki?curid=17730 |
6,323 | There are six general tenses in Latin (present, imperfect, future, perfect, pluperfect and future perfect), three moods (indicative, imperative and subjunctive, in addition to the infinitive, participle, gerund, gerundive and supine), three persons (first, second and third), two numbers (singular and plural), two voice... | https://en.wikipedia.org/wiki?curid=17730 |
6,324 | The six tenses of Latin are divided into two tense systems: the present system, which is made up of the present, imperfect and future tenses, and the perfect system, which is made up of the perfect, pluperfect and future perfect tenses. Each tense has a set of endings corresponding to the person, number, and voice of t... | https://en.wikipedia.org/wiki?curid=17730 |
6,325 | The table below displays the common inflected endings for the indicative mood in the active voice in all six tenses. For the future tense, the first listed endings are for the first and second conjugations, and the second listed endings are for the third and fourth conjugations: | https://en.wikipedia.org/wiki?curid=17730 |
6,326 | Some Latin verbs are deponent, causing their forms to be in the passive voice but retain an active meaning: "hortor, hortārī, hortātus sum" (to urge). | https://en.wikipedia.org/wiki?curid=17730 |
6,327 | As Latin is an Italic language, most of its vocabulary is likewise Italic, ultimately from the ancestral Proto-Indo-European language. However, because of close cultural interaction, the Romans not only adapted the Etruscan alphabet to form the Latin alphabet but also borrowed some Etruscan words into their language, i... | https://en.wikipedia.org/wiki?curid=17730 |
6,328 | After the Fall of Tarentum (272 BC), the Romans began Hellenising, or adopting features of Greek culture, including the borrowing of Greek words, such as (vaulted roof), (symbol), and (bath). This Hellenisation led to the addition of "Y" and "Z" to the alphabet to represent Greek sounds. Subsequently, the Romans transp... | https://en.wikipedia.org/wiki?curid=17730 |
6,329 | Because of the Roman Empire's expansion and subsequent trade with outlying European tribes, the Romans borrowed some northern and central European words, such as (beaver), of Germanic origin, and (breeches), of Celtic origin. The specific dialects of Latin across Latin-speaking regions of the former Roman Empire after ... | https://en.wikipedia.org/wiki?curid=17730 |
6,330 | During and after the adoption of Christianity into Roman society, Christian vocabulary became a part of the language, either from Greek or Hebrew borrowings or as Latin neologisms. Continuing into the Middle Ages, Latin incorporated many more words from surrounding languages, including Old English and other Germanic la... | https://en.wikipedia.org/wiki?curid=17730 |
6,331 | Over the ages, Latin-speaking populations produced new adjectives, nouns, and verbs by affixing or compounding meaningful segments. For example, the compound adjective, , "all-powerful," was produced from the adjectives , "all", and , "powerful", by dropping the final "s" of and concatenating. Often, the concatenation ... | https://en.wikipedia.org/wiki?curid=17730 |
6,332 | The phrases are mentioned with accents to show where stress is placed. In Latin, words are normally stressed either on the second-to-last (penultimate) syllable, called in Latin or , or on the third-to-last syllable, called in Latin or . In the following notation, accented short vowels have an acute diacritic, accented... | https://en.wikipedia.org/wiki?curid=17730 |
6,333 | In ancient times, numbers in Latin were written only with letters. Today, the numbers can be written with the Arabic numbers as well as with Roman numerals. The numbers 1, 2 and 3 and every whole hundred from 200 to 900 are declined as nouns and adjectives, with some differences. | https://en.wikipedia.org/wiki?curid=17730 |
6,334 | The numbers from 4 to 100 do not change their endings. As in modern descendants such as Spanish, the gender for naming a number in isolation is masculine, so that "1, 2, 3" is counted as . | https://en.wikipedia.org/wiki?curid=17730 |
6,335 | The same text may be marked for all long vowels (before any possible elisions at word boundary) with apices over vowel letters, including customarily before "nf" and "ns" where a long vowel is automatically produced: | https://en.wikipedia.org/wiki?curid=17730 |
6,336 | Mars is the fourth planet from the Sun and the second-smallest planet in the Solar System, only being larger than Mercury. In the English language, Mars is named for the Roman god of war. Mars is a terrestrial planet with a thin atmosphere (less than 1% that of Earth's), and has a crust primarily composed of elements s... | https://en.wikipedia.org/wiki?curid=14640471 |
6,337 | Some of the most notable surface features on Mars include Olympus Mons, the largest volcano and highest known mountain in the Solar System and Valles Marineris, one of the largest canyons in the Solar System. The Borealis basin in the Northern Hemisphere covers approximately 40% of the planet and may be a large impact ... | https://en.wikipedia.org/wiki?curid=14640471 |
6,338 | Mars has been explored by several uncrewed spacecraft, beginning with "Mariner 4" in 1965. NASA's "Viking 1" lander transmitted in 1976 the first images from the Martian surface. Two countries have successfully deployed rovers on Mars, the United States first doing so with "Sojourner" in 1997 and China with "Zhurong" i... | https://en.wikipedia.org/wiki?curid=14640471 |
6,339 | Mars can be viewed from Earth with the naked eye, as can its reddish coloring. This appearance, due to the iron oxide prevalent on its surface, has led to Mars often being called the Red Planet. It is among the brightest objects in Earth's sky, with an apparent magnitude that reaches −2.94, comparable to that of Jupite... | https://en.wikipedia.org/wiki?curid=14640471 |
6,340 | The history of observations of Mars is marked by the oppositions of Mars when the planet is closest to Earth and hence is most easily visible, which occur every couple of years. Even more notable are the perihelic oppositions of Mars, which are distinguished because Mars is close to perihelion, making it even closer to... | https://en.wikipedia.org/wiki?curid=14640471 |
6,341 | The ancient Sumerians named Mars Nergal, the god of war and plague. During Sumerian times, Nergal was a minor deity of little significance, but, during later times, his main cult center was the city of Nineveh. In Mesopotamian texts, Mars is referred to as the "star of judgement of the fate of the dead." The existence ... | https://en.wikipedia.org/wiki?curid=14640471 |
6,342 | In the fourth century BCE, Aristotle noted that Mars disappeared behind the Moon during an occultation, indicating that the planet was farther away. Ptolemy, a Greek living in Alexandria, attempted to address the problem of the orbital motion of Mars. Ptolemy's model and his collective work on astronomy was presented i... | https://en.wikipedia.org/wiki?curid=14640471 |
6,343 | During the seventeenth century A.D., Tycho Brahe measured the diurnal parallax of Mars that Johannes Kepler used to make a preliminary calculation of the relative distance to the planet. From Brahe's observations of Mars, Kepler deduced that the planet orbited the Sun not in a circle, but in an ellipse. Moreover, Keple... | https://en.wikipedia.org/wiki?curid=14640471 |
6,344 | By the 19th century, the resolution of telescopes reached a level sufficient for surface features to be identified. On 5 September 1877, a perihelic opposition of Mars occurred. The Italian astronomer Giovanni Schiaparelli used a telescope in Milan to help produce the first detailed map of Mars. These maps notably cont... | https://en.wikipedia.org/wiki?curid=14640471 |
6,345 | Influenced by the observations, the orientalist Percival Lowell founded an observatory which had 30- and 45-centimetre (12- and 18-in) telescopes. The observatory was used for the exploration of Mars during the last good opportunity in 1894 and the following less favorable oppositions. He published several books on Mar... | https://en.wikipedia.org/wiki?curid=14640471 |
6,346 | The seasonal changes (consisting of the diminishing of the polar caps and the dark areas formed during Martian summer) in combination with the canals led to speculation about life on Mars, and it was a long-held belief that Mars contained vast seas and vegetation. As bigger telescopes were used, fewer long, straight "c... | https://en.wikipedia.org/wiki?curid=14640471 |
6,347 | Mars is approximately half the diameter of Earth, with a surface area only slightly less than the total area of Earth's dry land. Mars is less dense than Earth, having about 15% of Earth's volume and 11% of Earth's mass, resulting in about 38% of Earth's surface gravity. The red-orange appearance of the Martian surface... | https://en.wikipedia.org/wiki?curid=14640471 |
6,348 | Like Earth, Mars has differentiated into a dense metallic core overlaid by less dense materials. Current models of its interior imply a core consisting primarily of iron and nickel with about 16–17% sulfur. This iron(II) sulfide core is thought to be twice as rich in lighter elements as Earth's. The core is surrounded ... | https://en.wikipedia.org/wiki?curid=14640471 |
6,349 | Mars is seismically active. InSight has detected and recorded over 450 marsquakes and related events in 2019. In 2021 it was reported that based on eleven low-frequency Marsquakes detected by the "InSight" lander the core of Mars is indeed liquid and has a radius of about and a temperature around 1900–2000 K. The Marti... | https://en.wikipedia.org/wiki?curid=14640471 |
6,350 | The core of Mars is overlaid by the rocky mantle, which, however, does not seem to have a layer analogous to the Earth's lower mantle. The Martian mantle appears to be solid down to the depth of about 500 km, where the low-velocity zone (partially melted asthenosphere) begins. Below the asthenosphere the velocity of se... | https://en.wikipedia.org/wiki?curid=14640471 |
6,351 | Mars is a terrestrial planet with a surface that consists of minerals containing silicon and oxygen, metals, and other elements that typically make up rock. The Martian surface is primarily composed of tholeiitic basalt, although parts are more silica-rich than typical basalt and may be similar to andesitic rocks on Ea... | https://en.wikipedia.org/wiki?curid=14640471 |
6,352 | Although Mars has no evidence of a structured global magnetic field, observations show that parts of the planet's crust have been magnetized, suggesting that alternating polarity reversals of its dipole field have occurred in the past. This paleomagnetism of magnetically susceptible minerals is similar to the alternati... | https://en.wikipedia.org/wiki?curid=14640471 |
6,353 | Scientists have theorized that during the Solar System's formation Mars was created as the result of a random process of run-away accretion of material from the protoplanetary disk that orbited the Sun. Mars has many distinctive chemical features caused by its position in the Solar System. Elements with comparatively l... | https://en.wikipedia.org/wiki?curid=14640471 |
6,354 | After the formation of the planets, all were subjected to the so-called "Late Heavy Bombardment". About 60% of the surface of Mars shows a record of impacts from that era, whereas much of the remaining surface is probably underlain by immense impact basins caused by those events. There is evidence of an enormous impact... | https://en.wikipedia.org/wiki?curid=14640471 |
6,355 | The geological history of Mars can be split into many periods, but the following are the three primary periods: | https://en.wikipedia.org/wiki?curid=14640471 |
6,356 | Geological activity is still taking place on Mars. The Athabasca Valles is home to sheet-like lava flows created about 200 mya. Water flows in the grabens called the Cerberus Fossae occurred less than 20 Mya, indicating equally recent volcanic intrusions. The "Mars Reconnaissance Orbiter" has captured images of avalanc... | https://en.wikipedia.org/wiki?curid=14640471 |
6,357 | The "Phoenix" lander returned data showing Martian soil to be slightly alkaline and containing elements such as magnesium, sodium, potassium and chlorine. These nutrients are found in soils on Earth. They are necessary for growth of plants. Experiments performed by the lander showed that the Martian soil has a basic pH... | https://en.wikipedia.org/wiki?curid=14640471 |
6,358 | Streaks are common across Mars and new ones appear frequently on steep slopes of craters, troughs, and valleys. The streaks are dark at first and get lighter with age. The streaks can start in a tiny area, then spread out for hundreds of metres. They have been seen to follow the edges of boulders and other obstacles in... | https://en.wikipedia.org/wiki?curid=14640471 |
6,359 | Water in its liquid form cannot exist on the surface of Mars due to low atmospheric pressure, which is less than 1% that of Earth's, except at the lowest elevations for short periods. The two polar ice caps appear to be made largely of water. The volume of water ice in the south polar ice cap, if melted, would be enoug... | https://en.wikipedia.org/wiki?curid=14640471 |
6,360 | Landforms visible on Mars strongly suggest that liquid water has existed on the planet's surface. Huge linear swathes of scoured ground, known as outflow channels, cut across the surface in about 25 places. These are thought to be a record of erosion caused by the catastrophic release of water from subsurface aquifers,... | https://en.wikipedia.org/wiki?curid=14640471 |
6,361 | Along crater and canyon walls, there are thousands of features that appear similar to terrestrial gullies. The gullies tend to be in the highlands of the Southern Hemisphere and to face the Equator; all are poleward of 30° latitude. A number of authors have suggested that their formation process involves liquid water, ... | https://en.wikipedia.org/wiki?curid=14640471 |
6,362 | In 2004, "Opportunity" detected the mineral jarosite. This forms only in the presence of acidic water, showing that water once existed on Mars. The "Spirit" rover found concentrated deposits of silica in 2007 that indicated wet conditions in the past, and in December 2011, the mineral gypsum, which also forms in the pr... | https://en.wikipedia.org/wiki?curid=14640471 |
6,363 | On 18 March 2013, NASA reported evidence from instruments on the "Curiosity" rover of mineral hydration, likely hydrated calcium sulfate, in several rock samples including the broken fragments of "Tintina" rock and "Sutton Inlier" rock as well as in veins and nodules in other rocks like "Knorr" rock and "Wernicke" rock... | https://en.wikipedia.org/wiki?curid=14640471 |
6,364 | Researchers suspect much of the low northern plains of the planet were covered with an ocean hundreds of meters deep, though this theory remains controversial. In March 2015, scientists stated that such an ocean might have been the size of Earth's Arctic Ocean. This finding was derived from the ratio of water to deuter... | https://en.wikipedia.org/wiki?curid=14640471 |
6,365 | In November 2016, NASA reported finding a large amount of underground ice in the Utopia Planitia region. The volume of water detected has been estimated to be equivalent to the volume of water in Lake Superior. During observations from 2018 through 2021, the ExoMars Trace Gas Orbiter spotted indications of water, proba... | https://en.wikipedia.org/wiki?curid=14640471 |
6,366 | Mars has two permanent polar ice caps. During a pole's winter, it lies in continuous darkness, chilling the surface and causing the deposition of 25–30% of the atmosphere into slabs of CO ice (dry ice). When the poles are again exposed to sunlight, the frozen CO sublimes. These seasonal actions transport large amounts ... | https://en.wikipedia.org/wiki?curid=14640471 |
6,367 | The caps at both poles consist primarily (70%) of water ice. Frozen carbon dioxide accumulates as a comparatively thin layer about one metre thick on the north cap in the northern winter only, whereas the south cap has a permanent dry ice cover about eight metres thick. This permanent dry ice cover at the south pole is... | https://en.wikipedia.org/wiki?curid=14640471 |
6,368 | The seasonal frosting of areas near the southern ice cap results in the formation of transparent 1-metre-thick slabs of dry ice above the ground. With the arrival of spring, sunlight warms the subsurface and pressure from subliming CO builds up under a slab, elevating and ultimately rupturing it. This leads to geyser-l... | https://en.wikipedia.org/wiki?curid=14640471 |
6,369 | Although better remembered for mapping the Moon, Johann Heinrich Mädler and Wilhelm Beer were the first areographers. They began by establishing that most of Mars's surface features were permanent and by more precisely determining the planet's rotation period. In 1840, Mädler combined ten years of observations and drew... | https://en.wikipedia.org/wiki?curid=14640471 |
6,370 | Features on Mars are named from a variety of sources. Albedo features are named for classical mythology. Craters larger than roughly 50 km are named for deceased scientists and writers and others who have contributed to the study of Mars. Smaller craters are named for towns and villages of the world with populations of... | https://en.wikipedia.org/wiki?curid=14640471 |
6,371 | Large albedo features retain many of the older names but are often updated to reflect new knowledge of the nature of the features. For example, "Nix Olympica" (the snows of Olympus) has become "Olympus Mons" (Mount Olympus). The surface of Mars as seen from Earth is divided into two kinds of areas, with differing albed... | https://en.wikipedia.org/wiki?curid=14640471 |
6,372 | Mars's equator is defined by its rotation, but the location of its Prime Meridian was specified, as was Earth's (at Greenwich), by choice of an arbitrary point; Mädler and Beer selected a line for their first maps of Mars in 1830. After the spacecraft "Mariner 9" provided extensive imagery of Mars in 1972, a small crat... | https://en.wikipedia.org/wiki?curid=14640471 |
6,373 | Because Mars has no oceans and hence no "sea level", a zero-elevation surface had to be selected as a reference level; this is called the "areoid" of Mars, analogous to the terrestrial geoid. Zero altitude was defined by the height at which there is of atmospheric pressure. This pressure corresponds to the triple point... | https://en.wikipedia.org/wiki?curid=14640471 |
6,374 | For mapping purposes, the United States Geological Survey divides the surface of Mars into thirty cartographic quadrangles, each named for a classical albedo feature it contains. | https://en.wikipedia.org/wiki?curid=14640471 |
6,375 | The shield volcano Olympus Mons ("Mount Olympus") is an extinct volcano in the vast upland region Tharsis, which contains several other large volcanoes. The edifice is over wide. Because the mountain is so large, with complex structure at its edges, allocating a height to it is difficult. Its local relief, from the foo... | https://en.wikipedia.org/wiki?curid=14640471 |
6,376 | The dichotomy of Martian topography is striking: northern plains flattened by lava flows contrast with the southern highlands, pitted and cratered by ancient impacts. It is possible that, four billion years ago, the Northern Hemisphere of Mars was struck by an object one-tenth to two-thirds the size of Earth's Moon. If... | https://en.wikipedia.org/wiki?curid=14640471 |
6,377 | Mars is scarred by a number of impact craters: a total of 43,000 craters with a diameter of or greater have been found. The largest exposed crater is Hellas, which is wide and deep, and is a light albedo feature clearly visible from Earth. There are other notable impact features, such as Argyre, which is around in diam... | https://en.wikipedia.org/wiki?curid=14640471 |
6,378 | The large canyon, Valles Marineris (Latin for "Mariner Valleys", also known as Agathodaemon in the old canal maps), has a length of and a depth of up to . The length of Valles Marineris is equivalent to the length of Europe and extends across one-fifth the circumference of Mars. By comparison, the Grand Canyon on Earth... | https://en.wikipedia.org/wiki?curid=14640471 |
6,379 | Images from the Thermal Emission Imaging System (THEMIS) aboard NASA's Mars Odyssey orbiter have revealed seven possible cave entrances on the flanks of the volcano Arsia Mons. The caves, named after loved ones of their discoverers, are collectively known as the "seven sisters". Cave entrances measure from wide and the... | https://en.wikipedia.org/wiki?curid=14640471 |
6,380 | Mars lost its magnetosphere 4 billion years ago, possibly because of numerous asteroid strikes, so the solar wind interacts directly with the Martian ionosphere, lowering the atmospheric density by stripping away atoms from the outer layer. Both "Mars Global Surveyor" and "Mars Express" have detected ionised atmospheri... | https://en.wikipedia.org/wiki?curid=14640471 |
6,381 | The atmosphere of Mars consists of about 96% carbon dioxide, 1.93% argon and 1.89% nitrogen along with traces of oxygen and water. The atmosphere is quite dusty, containing particulates about 1.5 µm in diameter which give the Martian sky a tawny color when seen from the surface. It may take on a pink hue due to iron ox... | https://en.wikipedia.org/wiki?curid=14640471 |
6,382 | Compared to Earth, its higher concentration of atmospheric CO and lower surface pressure may be why sound is attenuated more on Mars, where natural sources are rare apart from the wind. Using acoustic recordings collected by the "Perseverance" rover, researchers concluded that the speed of sound there is approximately ... | https://en.wikipedia.org/wiki?curid=14640471 |
6,383 | Auroras have been detected on Mars. Because Mars lacks a global magnetic field, the types and distribution of auroras there differ from those on Earth; rather than being mostly restricted to polar regions, a Martian aurora can encompass the planet. In September 2017, NASA reported radiation levels on the surface of the... | https://en.wikipedia.org/wiki?curid=14640471 |
6,384 | Of all the planets in the Solar System, the seasons of Mars are the most Earth-like, due to the similar tilts of the two planets' rotational axes. The lengths of the Martian seasons are about twice those of Earth's because Mars's greater distance from the Sun leads to the Martian year being about two Earth years long. ... | https://en.wikipedia.org/wiki?curid=14640471 |
6,385 | If Mars had an Earth-like orbit, its seasons would be similar to Earth's because its axial tilt is similar to Earth's. The comparatively large eccentricity of the Martian orbit has a significant effect. Mars is near perihelion when it is summer in the Southern Hemisphere and winter in the north, and near aphelion when ... | https://en.wikipedia.org/wiki?curid=14640471 |
6,386 | Mars has the largest dust storms in the Solar System, reaching speeds of over . These can vary from a storm over a small area, to gigantic storms that cover the entire planet. They tend to occur when Mars is closest to the Sun, and have been shown to increase the global temperature. | https://en.wikipedia.org/wiki?curid=14640471 |
6,387 | Mars's average distance from the Sun is roughly , and its orbital period is 687 (Earth) days. The solar day (or sol) on Mars is only slightly longer than an Earth day: 24 hours, 39 minutes, and 35.244 seconds. A Martian year is equal to 1.8809 Earth years, or 1 year, 320 days, and 18.2 hours. | https://en.wikipedia.org/wiki?curid=14640471 |
6,388 | The axial tilt of Mars is 25.19° relative to its orbital plane, which is similar to the axial tilt of Earth. As a result, Mars has seasons like Earth, though on Mars they are nearly twice as long because its orbital period is that much longer. In the present day epoch, the orientation of the north pole of Mars is close... | https://en.wikipedia.org/wiki?curid=14640471 |
6,389 | Mars has a relatively pronounced orbital eccentricity of about 0.09; of the seven other planets in the Solar System, only Mercury has a larger orbital eccentricity. It is known that in the past, Mars has had a much more circular orbit. At one point, 1.35 million Earth years ago, Mars had an eccentricity of roughly 0.00... | https://en.wikipedia.org/wiki?curid=14640471 |
6,390 | Mars approaches Earth in a synodic period of 779.94 days. Earth orbits the Sun the closest to Mars's orbit around the Sun, and Mars orbit is the second closest to Earth after the orbit of Venus. Therefore, their closest approaches, the inferior conjunctions, are the second closest for Earth after those with Venus, and ... | https://en.wikipedia.org/wiki?curid=14640471 |
6,391 | During the late nineteenth century, it was widely accepted in the astronomical community that Mars had life-supporting qualities, including the presence of oxygen and water. However, in 1894 W. W. Campbell at Lick Observatory observed the planet and found that "if water vapor or oxygen occur in the atmosphere of Mars i... | https://en.wikipedia.org/wiki?curid=14640471 |
6,392 | The current understanding of planetary habitabilitythe ability of a world to develop environmental conditions favorable to the emergence of lifefavors planets that have liquid water on their surface. Most often this requires the orbit of a planet to lie within the habitable zone, which for the Sun is estimated to exten... | https://en.wikipedia.org/wiki?curid=14640471 |
6,393 | The environmental conditions on Mars are a challenge to sustaining organic life: the planet has little heat transfer across its surface, it has poor insulation against bombardment by the solar wind due to the absence of a magnetosphere and has insufficient atmospheric pressure to retain water in a liquid form (water in... | https://en.wikipedia.org/wiki?curid=14640471 |
6,394 | "In situ" investigations have been performed on Mars by the "Viking" landers, "Spirit" and "Opportunity" rovers, "Phoenix" lander, and "Curiosity" rover. Evidence suggests that the planet was once significantly more habitable than it is today, but whether living organisms ever existed there remains unknown. The "Viking... | https://en.wikipedia.org/wiki?curid=14640471 |
6,395 | Scientists have proposed that carbonate globules found in meteorite ALH84001, which is thought to have originated from Mars, could be fossilized microbes extant on Mars when the meteorite was blasted from the Martian surface by a meteor strike some 15 million years ago. This proposal has been met with skepticism, and a... | https://en.wikipedia.org/wiki?curid=14640471 |
6,396 | Mars has two relatively small (compared to Earth's) natural moons, Phobos (about in diameter) and Deimos (about in diameter), which orbit close to the planet. The origin of both moons is unclear, although a popular theory states that they were asteroids captured into Martian orbit. | https://en.wikipedia.org/wiki?curid=14640471 |
6,397 | Both satellites were discovered in 1877 by Asaph Hall and were named after the characters Phobos (the deity of panic and fear) and Deimos (the deity of terror and dread), twins from Greek mythology who accompanied their father Ares, god of war, into battle. Mars was the Roman equivalent to Ares. In modern Greek, the pl... | https://en.wikipedia.org/wiki?curid=14640471 |
6,398 | From the surface of Mars, the motions of Phobos and Deimos appear different from that of the Earth's satellite, the Moon. Phobos rises in the west, sets in the east, and rises again in just 11 hours. Deimos, being only just outside synchronous orbitwhere the orbital period would match the planet's period of rotationris... | https://en.wikipedia.org/wiki?curid=14640471 |
6,399 | The origin of the two satellites is not well understood. Their low albedo and carbonaceous chondrite composition have been regarded as similar to asteroids, supporting a capture theory. The unstable orbit of Phobos would seem to point toward a relatively recent capture. But both have circular orbits, near the equator t... | https://en.wikipedia.org/wiki?curid=14640471 |
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