This accumulated snow and ice eventually forms into glaciers, bodies of ice that flow under the influence of their own gravity. Its single most outstanding feature is that its near-surface environments are the only places in the universe known to harbour life. [18] Another gives 15,360km (9,540mi), too large by 20%. [159] This allows total and annular solar eclipses to occur on Earth. Defined in this way, Earth's shape is an idealized spheroid - a squashed sphere - with a surface area of about 510millionkm2 (197millionsqmi). Earth's circumference (the distance all the way around the equator) is 24,901 miles (40,075 kilometers). Eratosthenes then measured the Sun's angle of elevation at noon in Alexandria by measuring the length of another gnomon's shadow on the ground. If, instead, Columbus had accepted Eratosthenes's larger value, he would have known that the place where he made landfall was not Asia, but rather a New World. [100][101] Indeed, in Earth's early history the ocean may have covered Earth completely. [25] This is why the polar circumference of the Earth is actually 40,008 kilometres, instead of 40,000. Along these plate boundaries, earthquakes, volcanic activity, mountain-building, and oceanic trench formation can occur. Earth orbits the Sun every 365.2564 mean solar days, or one sidereal year. [170], The Moon is a relatively large, terrestrial, planet-like natural satellite, with a diameter about one-quarter of Earth's. [41][42] Between approximately 4.1 and 3.8Ga, numerous asteroid impacts during the Late Heavy Bombardment caused significant changes to the greater surface environment of the Moon and, by inference, to that of Earth. Local differences in topography, geology, and deeper tectonic structure cause local and broad regional differences in Earth's gravitational field, known as gravity anomalies. [164][165], By astronomical convention, the four seasons can be determined by the solsticesthe points in the orbit of maximum axial tilt toward or away from the Sunand the equinoxes, when Earth's rotational axis is aligned with its orbital axis. [153], Earth's rotation period relative to the Sunits mean solar dayis 86,400 seconds of mean solar time (86,400.0025 SI seconds). A nebula contains gas, ice grains, and dust (including primordial nuclides). [3] A dry atmosphere is composed of 78.084% nitrogen, 20.946% oxygen, 0.934% argon, and trace amounts of carbon dioxide and other gaseous molecules. The first continental crust, which was more felsic in composition, formed by the partial melting of this mafic crust. ", "What's so special about our Moon, anyway? [215] Most of the water is then transported to lower elevations by river systems and usually returned to the oceans or deposited into lakes. Earth's circumference is the distance around the Earth. The result is atmospheric circulation that drives the weather and climate through redistribution of thermal energy. Important changes in crystal structure within the mantle occur at 410 and 660km (250 and 410mi) below the surface, spanning a transition zone that separates the upper and lower mantle. [201] Sea water has an important influence on the world's climate, with the oceans acting as a large heat reservoir. As a result, it always presents the same face to the planet. [245][268] It is estimated that global temperatures in the year 2020 were 1.2C (2.2F) warmer than the preindustrial baseline. [133][132], The major heat-producing isotopes within Earth are potassium-40, uranium-238, and thorium-232. 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. [154] Because Earth's solar day 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. [citation needed] Thus Posidonius's measure of 240,000 stadia translates to 24,000mi (39,000km), not much short of the actual circumference of 24,901mi (40,074km). This effect is much less significant than the total energy change due to the axial tilt, and most of the excess energy is absorbed by the higher proportion of water in the Southern Hemisphere. The outer layer is a chemically distinct silicate solid crust, which is underlain by a highly viscous solid mantle. In modern times, Earth's circumference has been used to define fundamental units of measurement of length: the nautical mile in the seventeenth century and the metre in the eighteenth. Earth is about eight light-minutes away from the Sun and orbits it, taking a year (about 365.25 days) to complete one revolution. That distinction belongs to Mount Chimaborazo in the Andes Mountains in Ecuador, according to the U.S. National Oceanic and Atmospheric Administration (NOAA). [187] There are also inoperative satellites, including Vanguard 1, the oldest satellite currently in orbit, and over 16,000 pieces of tracked space debris. [3] Treating the Earth as a sphere, its circumference would be its single most important measurement. Most of Earth's land hosts vegetation,[107] but ice sheets (10%,[108] not including the equally large land under permafrost)[109] or cold as well as hot deserts (33%)[110] occupy also considerable amounts of it. What does this mean? Earth's polar radius is 3,950 miles (6,356 km) a difference of 13 miles (22 km). ", "Eratosthenes and the Mystery of the Stades How Long Is a Stade? The peak rising from Rheasilvia Crater on the asteroid Vesta, for example, is about 14 miles (22.5 km) tall. [45] Water vapor from these sources condensed into the oceans, augmented by water and ice from asteroids, protoplanets, and comets. To calculate it, follow these steps: Assume the height of your eyes to be h = 1.6 m. Build a right triangle with hypotenuse r + h (where r is Earth's radius) and a cathetus r. Calculate the last cathetus with Pythagora's theorem: the result is the distance to the horizon: a = [ (r + h) - r] [151][152], 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 the aurora. In the 20th century Antarctica had been the last continent to see a first and until today limited human presence. The field extends outwards from the core, through the mantle, and up to Earth's surface, where it is, approximately, a dipole. [46] Sufficient water to fill the oceans may have been on Earth since it formed. The Krmn line, defined as 100km (62mi) above Earth's surface, is a working definition for the boundary between the atmosphere and outer space. As a red giant, the Sun will lose roughly 30% of its mass, so, without tidal effects, Earth will move to an orbit 1.7AU (250millionkm; 160millionmi) from the Sun when the star reaches its maximum radius, otherwise, with tidal effects, it may enter the Sun's atmosphere and be vaporized.[78]. The continents later recombined to form Pannotia at 600540Ma, then finally Pangaea, which also began to break apart at 180Ma. Scientific investigation has resulted in several culturally transformative shifts in people's view of the planet. [218][219] The amount of solar energy that reaches Earth's surface decreases with increasing latitude. [12] Using the length of the rod, and the length of the shadow, as the legs of a triangle, he calculated the angle of the sun's rays. 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. Why Nautical Mile and Knot Are The Units Used at Sea? [51] There are two main models of how this initial small volume of continental crust evolved to reach its current abundance:[52] (1) a relatively steady growth up to the present day,[53] 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,[54][55] which is supported by isotopic evidence from hafnium in zircons and neodymium in sedimentary rocks. In the English measurement system, there is 1 nautical mile per 1.1508 land miles or 6,076 feet. (October 17 -21) Did you know that . But Earth and the other rocky planets are much smaller than the gas giants. [3][16], Around AD 525, the Indian mathematician and astronomer Aryabhata wrote Aryabhatiya, in which he calculated the diameter of earth to be of 1,050 yojanas. [240] Plants and other organisms take up nutrients from water, soils and the atmosphere. This lower-density air then rises and is replaced by cooler, higher-density air. It is designated by the symbol . Models predict that the Sun will expand to roughly 1AU (150millionkm; 93millionmi), about 250 times its present radius. [22] However, the method could not provide more accurate results than previous methods, due to technical limitations, and so al-Biruni accepted the value calculated the previous century by the al-Ma'mun expedition. However, from pole to pole the meridional circumference Earth is only 24,860 miles (40,008 km) around. Most of Earth's surface is ocean water: 70.8% or 361millionkm2 (139millionsqmi). "[27], Occasionally, the name Terra /tr/ is used in scientific writing and especially in science fiction to distinguish humanity's inhabited planet from others,[28] while in poetry Tellus /tls/ has been used to denote personification of the Earth. All of the planets, except for Earth, were named after Greek and Roman gods and goddesses. Mathematical Association of America", "The Eratosthenes-Strabo Nile Map. Join our Space Forums to keep talking space on the latest missions, night sky and more! [15] In 2012, Anthony Abreu Mora repeated Eratosthenes's calculation with more accurate data; the result was 40,074km, which is 66km different (0.16%) from the currently accepted polar circumference. Earth Earth is 11.0x smaller than Jupiter DATE OF DISCOVERY Unknown Unknown DISCOVERED BY Known by the Ancients Known by the Ancients AVERAGE ORBIT DISTANCE 92,956,050 miles 483,638,564 miles MEAN ORBIT VELOCITY 66,622 mph 29,205 mph ORBIT ECCENTRICITY 0.01671123 0.04838624 EQUATORIAL INCLINATION 23.4393 degrees 3.1 degrees EQUATORIAL RADIUS [234] Hence the ability of hydrogen to escape from the atmosphere may have influenced the nature of life that developed on Earth. As of 4 January 2018, the United States Strategic Command tracked a total of 18,835 artificial objects, mostly debris. Instead, most of the hydrogen loss comes from the destruction of methane in the upper atmosphere.[236]. [78][84] Earth's fate is less clear. When measured around the equator, the circumference of the Earth is 40.075 million meters. ", "Curious Kids: Why is the moon called the moon? Those numbers make Earth just slightly bigger than Venus, whose equatorial radius is about 3,761 miles (6,052 km). Mathematics Geometry Circumference Angles Earth's equator Introduction If you wanted to measure the circumference of Earth, how long would your tape measure have to be? [64] The incorporation of smaller cells within larger ones resulted in the development of complex cells called eukaryotes. [237] Therefore, life has impacted Earth, significantly altering Earth's atmosphere and surface over long periods of time, causing changes like the Great oxidation event. Earth is rounded into an ellipsoid with a circumference of about 40,000 km. The water vapor acts as a greenhouse gas and, together with other greenhouse gases in the atmosphere, particularly carbon dioxide (CO2), creates the conditions for both liquid surface water and water vapor to persist via the capturing of energy from the Sun's light. The Earth's circumference is greatest at the equator. [93], To measure the local variation of Earth's topography, geodesy employs an idealized Earth producing a shape called a geoid. When you purchase through links on our site, we may earn an affiliate commission. The orbital speed of Earth averages about 29.78km/s (107,200km/h; 66,600mph), which is fast enough to travel a distance equal to Earth's diameter, about 12,742km (7,918mi), in seven minutes, and the distance to the Moon, 384,000km (239,000mi), in about 3.5 hours. [13], Eratosthenes' method was actually more complicated, as stated by the same Cleomedes, whose purpose was to present a simplified version of the one described in Eratosthenes' book. He was also a copy editor at several newspapers. Of the four rocky planets, it is the largest and most massive. Earth radius (denoted as R or ) is the distance from the center of Earth to a point on or near its surface. Due to Earth's axial tilt, the amount of sunlight reaching any given point on the surface varies over the course of the year. Inside the Earth's crust is a liquid outer core that generates the magnetosphere, deflecting most of the destructive solar winds and cosmic radiation. Images of Earth taken from space, particularly during the Apollo program, have been credited with altering the way that people viewed the planet that they lived on, called the overview effect, emphasizing its beauty, uniqueness and apparent fragility. [198], The average salinity of Earth's oceans is about 35grams of salt per kilogram of seawater (3.5% salt). Among the Solar System's planetary-sized objects Earth is the object with the highest density. Although Chimaborazo is about 10,000 feet (3,048 m) shorter (relative to sea level) than Everest, this mountain is about 6,800 feet (2,073 m) farther into space because of the equatorial bulge. Well, the short answer is just over 40,075 km (or just over 24,901 miles). Due to gravitational separation, 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. Earth has been subject to extensive human settlement, and humans have developed diverse societies and cultures. 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. At the equator of the magnetic field, the magnetic-field strength at the surface is 3.05105 T, with a magnetic dipole moment of 7.791022 Am2 at epoch 2000, decreasing nearly 6% per century (although it still remains stronger than its long time average). Due to this recycling, most of the ocean floor is less than 100Ma old. At approximately 750Ma, one of the earliest known supercontinents, Rodinia, began to break apart. [161] Earth, along with the Solar System, is situated in the Milky Way and orbits about 28,000light-years from its center. [174] The same effect on the Moon has led to its tidal locking: its rotation period is the same as the time it takes to orbit Earth. This polar motion has multiple, cyclical components, which collectively are termed quasiperiodic motion. Earth rotates around its own axis in slightly less than a day (in about 23 hours and 56 minutes). [6] Pliny the Elder mentions Posidonius among his sources andwithout naming himreported his method for estimating the Earth's circumference. [9] Cleomedes invites his reader to consider two Egyptian cities, Alexandria and Syene (modern Assuan): According to Cleomedes' On the Circular Motions of the Celestial Bodies, around 240 BC, Eratosthenes calculated the circumference of the Earth in Ptolemaic Egypt. [193] The remaining 30% is ground water, 1% surface water (covering only 2.8% of Earth's land)[194] and other small forms of fresh water deposits such as permafrost, water vapor in the atmosphere, biological binding, etc. . Earth Videos International Space Station: This page was last edited on 13 July 2023, at 04:12. In winter, the climate becomes cooler and the days shorter. [21], A more convenient way to estimate was provided in Al-Biruni's Codex Masudicus (1037). The pedosphere is the outermost layer of Earth's land surface and is composed of soil and subject to soil formation processes. [162], The axial tilt of Earth is approximately 23.439281[2] with the axis of its orbit plane, always pointing towards the Celestial Poles. [205], The atmospheric pressure at Earth's sea level averages 101.325kPa (14.696psi),[206] with a scale height of about 8.5km (5.3mi). [111][112] Earth has an estimated 16.7millionkm2 (6.4millionsqmi) of cropland and 33.5millionkm2 (12.9millionsqmi) of pastureland. The polar circumference is also close to 40,000 kilometres because the metre was originally defined to be one ten millionth (i.e., a kilometre is one ten thousandth) of the arc from pole to equator (quarter meridian). [213] Three-quarters of the atmosphere's mass is contained within the first 11km (6.8mi) of the surface; this lowest layer is called the troposphere. [206] Water vapor content varies between 0.01% and 4%[206] but averages about 1%. Soil is crucial for land to be arable. The 45th parallel north is a circle of latitude that is 45 degrees north of Earth's equator.It crosses Europe, Asia, the Pacific Ocean, North America, and the Atlantic Ocean. James Webb Space Telescope spots 3 candidates, Truly to open 1st zero-gravity hard seltzer bar aboard astronaut training aircraft. [242] Many places are subject to earthquakes, landslides, tsunamis, volcanic eruptions, tornadoes, blizzards, floods, droughts, wildfires, and other calamities and disasters. Earth's rotational velocity also varies in a phenomenon known as length-of-day variation. [30], There are a number of adjectives for the planet Earth. [41], The gravitational attraction between Earth and the Moon causes tides on Earth. [161][n 10] This is the maximum distance at which Earth's gravitational influence is stronger than the more distant Sun and planets. Its axial tilt does undergo nutation; a slight, irregular motion with a main period of 18.6years. [120], As the tectonic plates migrate, oceanic crust is subducted under the leading edges of the plates at convergent boundaries. Our planet's shape, caused by the flattening at the poles, is called an oblate spheroid. [2] He achieved a great degree of precision in his computation. [95] This vast pool of salty water is often called the world ocean,[96][97] and makes Earth with its dynamic hydrosphere a water world[98][99] or ocean world. [29] 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). [248], Distribution and density of human population varies greatly around the world with the majority living in south to eastern Asia and 90% inhabiting only the Northern Hemisphere of Earth,[249] partly due to the hemispherical predominance of the world's land mass, with 68% of the world's land mass being in the Northern Hemisphere. About 71% of our planet is covered by water and 29% by land. From the Latin Terra comes terran /trn/,[31] terrestrial /trstril/,[32] and (via French) terrene /trin/,[33] and from the Latin Tellus comes tellurian /tlrin/[34] and telluric. [202] Shifts in the oceanic temperature distribution can cause significant weather shifts, such as the El NioSouthern Oscillation. Measuring around the equator it's 24,901 miles (40,075 km). [250] Furthermore, since the 19th century humans have increasingly converged into urban areas with the majority living in urban areas by the 21st century. [258] Large deposits of fossil fuels are obtained from Earth's crust, consisting of coal, petroleum, and natural gas. [3], The Moon and Earth orbit a common barycenter every 27.32days relative to the background stars. Earth's mass is 6.6 sextillion tons (5.9722 x 1024 kilograms). On the other hand, it is 40.008 million meters when measured from the North Pole to the South Pole. [225], Water vapor generated through surface evaporation is transported by circulatory patterns in the atmosphere. The land-based ecosystem depends upon topsoil and fresh water, and the oceanic ecosystem depends on dissolved nutrients washed down from the land. [114] Nearly 75% of the continental surfaces are covered by sedimentary rocks, although they form about 5% of the mass of the crust.[115]. Enabled by science, particularly Earth observation,[281] humans have started to take action on environmental issues globally,[282] acknowledging the impact of humans and the interconnectedness of Earth's environments. 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 12hours. Originating from earlier primates in eastern Africa 300,000 years ago humans have since been migrating and with the advent of agriculture in the 10th millennium BC increasingly settling Earth's land. [210] This last phenomenon is the greenhouse effect: trace molecules within the atmosphere serve to capture thermal energy emitted from the surface, thereby raising the average temperature. As with Roman Terra/Tells and Greek Gaia, Earth may have been a personified goddess in Germanic paganism: late Norse mythology included Jr ('Earth'), a giantess often given as the mother of Thor. [76][bettersourceneeded] 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. This was the earliest known use of dip angle and the earliest practical use of the law of sines. Measured around the Equator, it is 40,075.017km (24,901.461mi). The land surface includes many islands around the globe, but most of the land surface is taken by the four continental landmasses, which are (in descending order): Africa-Eurasia, America (landmass), Antarctica, and Australia (landmass).
From Athens To Zakynthos By Ferry,
Do You Have To Show Proof Of Hardship Withdrawal,
Average Rent In Arlington, Va,
Rich Township High School Staff Directory,
San Diego Tennis Tournament Schedule,
Articles C