vania-janet/multiturn-rag-retrieval-data huggingface dataset:
Diamond
Through studies of carbon isotope ratios ( similar to the methodology used in carbon dating , except with the stable isotopes C - 12 and C - 13 ) , it has been shown that the carbon found in diamonds comes from both inorganic and organic sources . Some diamonds , known as harzburgitic , are formed from inorganic carbon originally found deep in the Earth 's mantle . In contrast , eclogitic diamonds contain organic carbon from organic detritus that has been pushed down from the surface of the Earth 's crust through subduction ( see plate tectonics ) before transforming into diamond . These two different source of carbon have measurably different C : C ratios . Diamonds that have come to the Earth 's surface are generally quite old , ranging from under 1 billion to 3.3 billion years old . This is 22 % to 73 % of the age of the Earth .
Earth
During the Neoproterozoic , 7002750000000000000 ♠ 750 to 580 Mya , 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 the Cambrian explosion , 7002535000000000000 ♠ 535 Mya , there have been five mass extinctions . The most recent such event was 7001660000000000000 ♠ 66 Mya , when an asteroid impact triggered the extinction of the non-avian dinosaurs and other large reptiles , but spared some small animals such as mammals , which at the time resembled shrews . Mammalian life has diversified over the past 7001660000000000000 ♠ 66 Mys , and several million years ago an African ape - like animal such as Orrorin tugenensis 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 .
Main sequence
The amount of fuel available for nuclear fusion is proportional to the mass of the star . Thus , the lifetime of a star on the main sequence can be estimated by comparing it to solar evolutionary models . The Sun has been a main - sequence star for about 4.5 billion years and it will become a red giant in 6.5 billion years , for a total main sequence lifetime of roughly 10 years . Hence :
Rodinia
In 2009 UNESCO 's IGCP project 440 , named ' Rodinia Assembly and Breakup ' , concluded that Rodinia broke up in four stages between 825 -- 550 Ma :
Devils Tower
During the Paleocene Epoch , 56 to 66 million years ago , the Rocky Mountains and the Black Hills were uplifted . Magma rose through the crust , intruding into the existing sedimentary rock layers .
Mesopotamia
From Sumerian times , temple priesthoods had attempted to associate current events with certain positions of the planets and stars . This continued to Assyrian times , when Limmu lists were created as a year by year association of events with planetary positions , which , when they have survived to the present day , allow accurate associations of relative with absolute dating for establishing the history of Mesopotamia .
Plate tectonics
Tectonic motion is believed to have begun around 3 to 3.5 billion years ago .
Precambrian
It has been proposed that the Precambrian should be divided into eons and eras that reflect stages of planetary evolution , rather than the current scheme based upon numerical ages . Such a system could rely on events in the stratigraphic record and be demarcated by GSSPs . The Precambrian could be divided into five `` natural '' eons , characterized as follows :
Seafloor spreading
h ( t ) ∼ h 0 − 350 t ( \ displaystyle h ( t ) \ sim h_ ( 0 ) - 350 ( \ sqrt ( t ) ) )
Geologic time scale
The following table summarizes the major events and characteristics of the periods of time making up the geologic time scale . This table is arranged with the most recent geologic periods at the top , and the most ancient at the bottom . The height of each table entry does not correspond to the duration of each subdivision of time .
Black Hills
`` Making a concentric ring around the core is the metamorphic zone . The rocks in this ring are all very old , as much as 2 billion years and older . This zone is very complex , filled with many diverse rock types . The rocks were originally sedimentary , until there was a collision between the North American continent and a terrane . This collision , called the Trans - Hudson Orogeny , caused the original rocks to fold and twist into a vast mountain range . Over the millions of years , these tilted rocks , which in many areas are tilted to 90 degrees or more , eroded . Today we see the evidence of this erosion in the Black Hills , where the metamorphic rocks end in an angular unconformity below the younger sedimentary layers .
Book of Enoch
Correspondence of weekly day in the Qumran year Months 1 , 4 , 7 , 10 Months 2 , 5 , 8 , 11 Months 3 , 6 , 9 , 12 Wed 8 15 22 29 6 13 20 27 11 18 25 Thurs 9 16 23 30 7 14 21 28 5 12 19 26 Fri 10 17 24 8 15 22 29 6 13 20 27 Sat 11 18 25 9 16 23 30 7 14 21 28 Sun 5 12 19 26 10 17 24 8 15 22 29 Mon 6 13 20 27 11 18 25 9 16 23 30 Tues 7 14 21 28 5 12 19 26 10 17 24 31
Geologic time scale
In Ancient Greece , Aristotle ( 384 - 322 BCE ) observed that fossils of seashells in rocks resembled those found on beaches -- he inferred that the fossils in rocks were formed by living animals , and he reasoned that the positions of land and sea had changed over long periods of time . Leonardo da Vinci ( 1452 -- 1519 ) concurred with Aristotle 's interpretation that fossils represented the remains of ancient life .
Rocky Mountains
Periods of glaciation occurred from the Pleistocene Epoch ( 1.8 million -- 70,000 years ago ) to the Holocene Epoch ( fewer than 11,000 years ago ) . These ice ages left their mark on the Rockies , forming extensive glacial landforms , such as U-shaped valleys and cirques . Recent glacial episodes included the Bull Lake Glaciation that began about 150,000 years ago and the Pinedale Glaciation that probably remained at full glaciation until 15,000 -- 20,000 years ago .
Mauna Kea
Mauna Kea is one of five hotspot volcanoes that form the island of Hawaii , the largest and youngest island of the Hawaiian -- Emperor seamount chain . Of these five volcanoes , Mauna Kea is the fourth oldest and fourth most active . It began as a preshield volcano driven by the Hawaii hotspot around one million years ago , and became exceptionally active during its shield stage until 500,000 years ago . Mauna Kea entered its quieter post-shield stage 250,000 to 200,000 years ago , and is currently dormant . Mauna Kea does not have a visible summit caldera , but contains a number of small cinder and pumice cones near its summit . A former summit caldera may have been filled and buried by later summit eruption deposits .
Mitochondrion
Recent measurements of the molecular clock for mitochondrial DNA reported a value of 1 mutation every 7884 years dating back to the most recent common ancestor of humans and apes , which is consistent with estimates of mutation rates of autosomal DNA ( 10 per base per generation .
Uluru
The similar mineral composition of the Mutitjulu Arkose and the granite ranges to the south is now explained . The ancestors of the ranges to the south were once much larger than the eroded remnants we see today . They were thrust up during a mountain building episode referred to as the Petermann Orogeny that took place in late Neoproterozoic to early Cambrian times ( 550 -- 530 Ma ) , and thus the Mutitjulu Arkose is believed to have been deposited at about the same time .
Seafloor spreading
h ( t ) ∼ h 0 − 390 t ( \ displaystyle h ( t ) \ sim h_ ( 0 ) - 390 ( \ sqrt ( t ) ) )
Radioactive decay
A sample of C has a half - life of 5,730 years and a decay rate of 14 disintegration per minute ( dpm ) per gram of natural carbon .
Rodinia
Rodinia formed at c . 1.23 Ga by accretion and collision of fragments produced by breakup of an older supercontinent , Columbia , assembled by global - scale 2.0 -- 1.8 Ga collisional events .
Tooth decay
no data < 50 50 - 60 60 - 70 70 - 80 80 - 90 90 - 100 100 - 115 115 - 130 130 - 138 138 - 140 140 -- 142 > 142
History of calendars
The two cycles of 13 and 20 intermesh and are repeated without interruption : the cycle would begin with 1 Imix , then 2 Ik , then 3 Akbal and so on until the number 13 was reached , at which point the number cycle was restarted so 13 Ben would be followed by 1 Ix , 2 Men and so on . This time Imix would be numbered 8 . The cycle ended after 260 days , with the last day being 13 Ahau .
Radioactive decay
On the premise that radioactive decay is truly random ( rather than merely chaotic ) , it has been used in hardware random - number generators . Because the process is not thought to vary significantly in mechanism over time , it is also a valuable tool in estimating the absolute ages of certain materials . For geological materials , the radioisotopes and some of their decay products become trapped when a rock solidifies , and can then later be used ( subject to many well - known qualifications ) to estimate the date of the solidification . These include checking the results of several simultaneous processes and their products against each other , within the same sample . In a similar fashion , and also subject to qualification , the rate of formation of carbon - 14 in various eras , the date of formation of organic matter within a certain period related to the isotope 's half - life may be estimated , because the carbon - 14 becomes trapped when the organic matter grows and incorporates the new carbon - 14 from the air . Thereafter , the amount of carbon - 14 in organic matter decreases according to decay processes that may also be independently cross-checked by other means ( such as checking the carbon - 14 in individual tree rings , for example ) .
List of oldest trees
There are three tables of trees , which are listed by age and species . The first table includes trees for which a minimum age has been directly determined , either through counting or cross-referencing tree rings or through radiocarbon dating . Many of these trees may be even older than their listed ages , but the oldest wood in the tree has rotted away . For some old trees , so much of the centre is missing that their age can not be directly determined . Instead , estimates are made based on the tree 's size and presumed growth rate . The second table includes trees with these estimated ages . The last table lists clonal colonies in which no individual tree trunks may be remarkably old but in which the organism as a whole is thought to be very old .
Halley's Comet
1P / Halley ( Halley 's Comet ) Halley 's Comet on 8 March 1986 Discovery Discovered by Prehistoric observation ; Edmond Halley ( recognition of periodicity ) Orbital characteristics Epoch 17 February 1994 ( 2449400.5 ) Aphelion 35.082 AU Perihelion 0.586 AU last perihelion : 9 February 1986 next perihelion : 28 July 2061 Semi-major axis 17.834 AU Eccentricity 0.96714 Orbital period 75.32 yr Mean anomaly 38.38 ° Inclination 162.26 ° Longitude of ascending node 58.42 ° Argument of perihelion 111.33 ° Earth MOID 0.0638 AU ( 9.54 million km ) Physical characteristics 15 × 8 km , 11 km ( mean diameter ) Mass 2.2 × 10 kg Mean density 0.6 ( estimates range from 0.2 to 1.5 g / cm ) Escape velocity ~ 0.002 km / s Sidereal rotation period 2.2 d ( 52.8 h ) ( ? ) Albedo 0.04 Apparent magnitude 28.2 ( in 2003 )
Halley's Comet
In 1989 , Boris Chirikov and Vitaly Vecheslavov performed an analysis of 46 apparitions of Halley 's Comet taken from historical records and computer simulations . These studies showed that its dynamics were chaotic and unpredictable on long timescales . Halley 's projected lifetime could be as long as 10 million years . These studies also showed that many physical properties of Halley 's Comet dynamics can be approximately described by a simple symplectic map , known as the Kepler map . More recent work suggests that Halley will evaporate , or split in two , within the next few tens of thousands of years , or will be ejected from the Solar System within a few hundred thousand years . Observations by D.W. Hughes suggest that Halley 's nucleus has been reduced in mass by 80 -- 90 % over the last 2000 -- 3000 revolutions .
Mount St. Helens
Mount St. Helens is geologically young compared with the other major Cascade volcanoes . It formed only within the past 40,000 years , and the pre-1980 summit cone began rising about 2,200 years ago . The volcano is considered the most active in the Cascades within the Holocene epoch ( the last 10,000 or so years ) .
Geologic time scale
The Neptunist theories popular at this time ( expounded by Abraham Werner ( 1749 -- 1817 ) in the late 18th century ) proposed that all rocks had precipitated out of a single enormous flood . A major shift in thinking came when James Hutton presented his Theory of the Earth ; or , an Investigation of the Laws Observable in the Composition , Dissolution , and Restoration of Land Upon the Globe before the Royal Society of Edinburgh in March and April 1785 . It has been said that `` as things appear from the perspective of the 20th century , James Hutton in those readings became the founder of modern geology '' . Hutton proposed that the interior of Earth was hot , and that this heat was the engine which drove the creation of new rock : land was eroded by air and water and deposited as layers in the sea ; heat then consolidated the sediment into stone , and uplifted it into new lands . This theory , known as `` Plutonism '' , stood in contrast to the `` Neptunist '' flood - oriented theory .
History of calendars
Calendars in antiquity were usually lunisolar , depending on the introduction of intercalary months to align the solar and the lunar years . This was mostly based on observation , but there may have been early attempts to model the pattern of intercalation algorithmically , as evidenced in the fragmentary 2nd - century Coligny calendar . Nevertheless , the Roman calendar contained very ancient remnants of a pre-Etruscan 10 - month solar year .
Maya calendar
The Long Count calendar identifies a date by counting the number of days from the Mayan creation date 4 Ahaw , 8 Kumk'u ( August 11 , 3114 BC in the proleptic Gregorian calendar or September 6 in the Julian calendar - 3113 astronomical dating ) . But instead of using a base - 10 ( decimal ) scheme like Western numbering , the Long Count days were tallied in a modified base - 20 scheme . Thus 0.0. 0.1. 5 is equal to 25 and 0.0. 0.2. 0 is equal to 40 . As the winal unit resets after only counting to 18 , the Long Count consistently uses base - 20 only if the tun is considered the primary unit of measurement , not the k'in ; with the k'in and winal units being the number of days in the tun . The Long Count 0.0. 1.0. 0 represents 360 days , rather than the 400 in a purely base - 20 ( vigesimal ) count .
Atom
There are a few trace atoms on Earth that were not present at the beginning ( i.e. , not `` primordial '' ) , nor are results of radioactive decay . Carbon - 14 is continuously generated by cosmic rays in the atmosphere . Some atoms on Earth have been artificially generated either deliberately or as by - products of nuclear reactors or explosions . Of the transuranic elements -- those with atomic numbers greater than 92 -- only plutonium and neptunium occur naturally on Earth . Transuranic elements have radioactive lifetimes shorter than the current age of the Earth and thus identifiable quantities of these elements have long since decayed , with the exception of traces of plutonium - 244 possibly deposited by cosmic dust . Natural deposits of plutonium and neptunium are produced by neutron capture in uranium ore .
Observable universe
The word observable in this sense does not refer to the capability of modern technology to detect light or other information from an object , or whether there is anything to be detected . It refers to the physical limit created by the speed of light itself . Because no signals can travel faster than light , any object farther away from us than light could travel in the age of the Universe ( estimated as of 2015 around 7010137990000000000 ♠ 13.799 ± 0.021 billion years ) simply can not be detected , as they have not reached us yet . Sometimes astrophysicists distinguish between the visible universe , which includes only signals emitted since recombination -- and the observable universe , which includes signals since the beginning of the cosmological expansion ( the Big Bang in traditional physical cosmology , the end of the inflationary epoch in modern cosmology ) .
Exoplanet
In December 2013 a candidate exomoon of a rogue planet was announced . No exomoons have been confirmed so far .
Venus
NASA obtained additional data in 1978 with the Pioneer Venus project that consisted of two separate missions : Pioneer Venus Orbiter and Pioneer Venus Multiprobe . The successful Soviet Venera program came to a close in October 1983 , when Venera 15 and 16 were placed in orbit to conduct detailed mapping of 25 % of Venus 's terrain ( from the north pole to 30 ° N latitude )
Exploration of Mars
Viking 1 lander site ( 1st color , July 21 , 1976 ) . Viking 2 lander site ( 1st color , September 5 , 1976 ) . Viking 2 lander site ( September 25 , 1977 ) . ( False color image ) Frost at Viking 2 site ( May 18 , 1979 ) . Martian sunset over Chryse Planitia at Viking 1 site ( August 20 , 1976 ) .
Chernobyl disaster
We arrived there at 10 or 15 minutes to two in the morning ... We saw graphite scattered about . Misha asked : `` Is that graphite ? '' I kicked it away . But one of the fighters on the other truck picked it up . `` It 's hot , '' he said . The pieces of graphite were of different sizes , some big , some small , enough to pick them up ...
Alan Shepard
In a 2010 Space Foundation survey , Shepard was ranked as the ninth most popular space hero ( tied with astronauts Buzz Aldrin and Gus Grissom ) . In 2011 , NASA honored Shepard with an Ambassador of Exploration Award , consisting of a Moon rock encased in Lucite , for his contributions to the U.S. space program . His family members accepted the award on his behalf during a ceremony on April 28 at the U.S. Naval Academy Museum in Annapolis , Maryland , where it is on permanent display . On May 4 , 2011 , the U.S. Postal Service issued a first - class stamp in Shepard 's honor , the first U.S. stamp to depict a specific astronaut . The first day of issue ceremony was held at NASA 's Kennedy Space Center Visitor Complex .
Rub' al Khali
On 25 February 2006 , a scientific excursion organized by the Saudi Geological Survey began to explore the Empty Quarter . The expedition consisted of 89 environmentalists , geologists and scientists from Saudi Arabia and abroad . Various types of fossilized creatures as well as meteorites were discovered in the desert . The expedition discovered 31 new plant species and plant varieties , as well as 24 species of birds that inhabit the region , which fascinated scientists as to how they have survived under the harsh conditions of the Empty Quarter .
Moon landing
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History of Antarctica
Discoveries included Commonwealth Bay , Ninnis Glacier , Mertz Glacier , and Queen Mary Land . Major accomplishments were made in geology , glaciology and terrestrial biology . As
Mount St. Helens
U.S. President Jimmy Carter surveyed the damage and said , `` Someone said this area looked like a moonscape . But the moon looks more like a golf course compared to what 's up there . '' A film crew , led by Seattle filmmaker Otto Seiber , was dropped by helicopter on St. Helens on May 23 to document the destruction . Their compasses , however , spun in circles and they quickly became lost . A second eruption occurred on May 25 , but the crew survived and was rescued two days later by National Guard helicopter pilots . Their film , The Eruption of Mount St. Helens , later became a popular documentary .
Chernobyl disaster
During the construction of the sarcophagus , a scientific team re-entered the reactor as part of an investigation dubbed `` Complex Expedition '' , to locate and contain nuclear fuel in a way that could not lead to another explosion . These scientists manually collected cold fuel rods , but great heat was still emanating from the core . Rates of radiation in different parts of the building were monitored by drilling holes into the reactor and inserting long metal detector tubes . The scientists were exposed to high levels of radiation and radioactive dust .
Chicxulub crater
He knew Pemex had drilled exploratory wells in the region . In 1951 , one bored into what was described as a thick layer of andesite about 1.3 kilometres ( 4,300 ft ) down . This layer could have resulted from the intense heat and pressure of an Earth impact , but at the time of the borings it was dismissed as a lava dome -- a feature uncharacteristic of the region 's geology . Penfield tried to secure site samples , but was told such samples had been lost or destroyed . When attempts at returning to the drill sites and looking for rocks proved fruitless , Penfield abandoned his search , published his findings and returned to his Pemex work . Penfield
Venus
On 18 October 1967 , the Soviet Venera 4 successfully entered the atmosphere and deployed science experiments . Venera 4 showed the surface temperature was hotter than Mariner 2 had calculated , at almost 500 ° C , determined that the atmosphere is 95 % carbon dioxide ( CO 2 ) , and discovered that Venus 's atmosphere was considerably denser than Venera 4 's designers had anticipated . The joint Venera 4 -- Mariner 5 data were analysed by a combined Soviet -- American science team in a series of colloquia over the following year , in an early example of space cooperation .
Spider web
After the launch on July 28 , 1973 , and entering Skylab , the spiders were released by astronaut Owen Garriott into a box that resembled a window frame . The spiders proceeded to construct their web while a camera took photographs and examined the spiders ' behavior in a zero - gravity environment . Both spiders took a long time to adapt to their weightless existence . However , after a day , Arabella spun the first web in the experimental cage , although it was initially incomplete . The
Spider
In 1973 , Skylab 3 took two orb - web spiders into space to test their web - spinning capabilities in zero gravity . At first , both produced rather sloppy webs , but they adapted quickly .
Mars
Once spacecraft visited the planet during NASA 's Mariner missions in the 1960s and 70s , these concepts were radically broken . The results of the Viking life - detection experiments aided an intermission in which the hypothesis of a hostile , dead planet was generally accepted .