[{"data":1,"prerenderedAt":983},["ShallowReactive",2],{"layer:exploration:extend":3},{"layer":4,"contentHash":963,"dependencyHashes":964,"approval":976,"releaseId":982},{"schemaVersion":5,"conceptId":6,"locale":7,"depth":8,"revision":5,"title":9,"subtitle":10,"summary":11,"objectives":12,"estimatedMinutes":18,"plate":19,"blocks":43,"sourceIds":958,"reviewStatus":959,"authoring":960},1,"exploration","en","extend","Beyond the horizon: exploration to today","Cook, the poles, space, the deep sea, and the questions nobody has answered yet","Carries exploration from Cook's Pacific voyage to today: the race to the poles and the treaty that followed, leaving Earth's gravity for the Moon and beyond, the deepest ocean trench, and the hardest open questions - who owns what nobody lives on, and who decides.",[13,14,15,16,17],"Tell Cook's Pacific voyage honestly: real science and a real cost to Aboriginal Australian and Maori peoples.","Explain how the race to the South Pole led to a treaty that protects Antarctica instead of a colony.","Connect leaving Earth's gravity (escape velocity) to real missions: Apollo 11, Chandrayaan-3 and Voyager 1.","State the depth of the Challenger Deep and compare it with Mount Everest and India's Matsya6000.","Argue both sides of open questions about Antarctica, deep-sea mining, space claims and uncontacted peoples.",45,{"title":20,"rows":21},"Lesson plate",[22,25,28,31,34,37,40],{"label":23,"value":24},"Depth","Extend",{"label":26,"value":27},"Reading time","≈ 45 minutes",{"label":29,"value":30},"Prior knowledge","Discover (reasons and consequences)",{"label":32,"value":33},"Goes beyond syllabus","Space law, deep-sea law, Fermi estimates",{"label":35,"value":36},"Chapters","8",{"label":38,"value":39},"Labs","Voyage map, match pairs, evidence sort, sort game",{"label":41,"value":42},"Connects to","Gravity (escape velocity)",[44,48,54,60,63,68,88,93,98,116,139,144,147,152,193,197,219,232,294,299,302,308,321,345,361,375,388,392,406,439,444,447,466,474,479,484,497,502,505,545,581,585,589,647,652,655,658,661,664,684,689,692,713,722,734,746,749,754,793,798,933,948],{"id":45,"type":46,"markdown":47},"intro-extend","prose","Discover asked why people got in boats at all, and what happened afterwards, good and bad, to everyone involved. This layer picks the story back up and carries it all the way to today.\n\nA scientist-captain charts the Pacific and, without quite meaning to, hands his own government a claim on other people's land. Two teams race on foot to the bottom of the world, and a continent ends up belonging to nobody, by treaty rather than by conquest. Humans leave Earth's gravity behind entirely, first briefly, then for good. And a probe, still talking to Earth after nearly fifty years, becomes the furthest a human hand has ever reached.\n\nBy now you have the tools for harder questions than Discover asked: who gets to decide what happens somewhere nobody lives, and whether \"leaving people alone\" is always the respectful choice, or sometimes just another decision made about them, from a distance.\n\nSome of this goes beyond what a Class 6-7 syllabus expects, on purpose: space law, deep-sea law and Fermi estimates are not usually taught this young. The lesson plate says where.",{"id":49,"type":50,"variant":51,"title":52,"markdown":53},"how-to-read-extend","callout","observation","How this layer is different","Discover and Understand build a foundation. This layer hands you real, current, contested questions and asks you to think them through rather than memorise an answer.\n\nChapter five has no single correct opinion, only the strongest case you can build for each side. Chapter six is three projects with no marks attached. Chapter seven is a puzzle you solve with a calculator and some patience. Take your time with all three.",{"id":55,"type":56,"title":57,"eyebrow":58,"navLabel":59},"ch01","chapter","Cook's Pacific voyage: a telescope and a claim","Chapter 01","1 Cook's voyage",{"id":61,"type":46,"markdown":62},"cook-intro","By the late 1760s, European ships had crossed the Atlantic and rounded Africa for over two and a half centuries. The Pacific was still mostly blank on their charts, even though it had been home to skilled Polynesian navigators for thousands of years, crossing greater distances than Columbus ever attempted, in canoes, without a compass.\n\nIn 1768, the British Admiralty and the Royal Society sent Lieutenant James Cook and the ship Endeavour into that ocean. This was the first of 3 Pacific voyages Cook would go on to command. It is worth telling properly, because it shows something the earlier voyages in Discover only hinted at: a voyage can be genuinely, carefully scientific, and still end up being used for conquest.",{"id":64,"type":50,"variant":65,"title":66,"markdown":67},"def-transit-venus","definition","Why Tahiti, and why Venus","Cook's official orders were to sail to Tahiti and observe the **transit of Venus**: a rare event where the planet Venus crosses directly in front of the Sun, visible as a small dark dot.\n\nAstronomers across the world planned to time this transit from several places at once. Comparing the tiny differences in timing, using an idea called **parallax** (the same trick that lets you judge distance by holding a finger at arm's length and blinking one eye, then the other), let them calculate the distance from the Earth to the Sun far more accurately than before.\n\nThat is real, careful, international science, and Tahiti was one of the best places on Earth to watch from. It is also, not by accident, on the far side of an ocean Britain wanted charted.",{"id":69,"type":70,"caption":71,"columns":72,"rows":75},"table-cook-voyage","table","Cook's first voyage: three parts, one ship",[73,74],"Part of the voyage","What it involved",[76,79,82,85],[77,78],"The science","Observe the transit of Venus from Tahiti on 3 June 1769, one of several stations around the world making the same measurement at the same moment.",[80,81],"The chart-making","Sail on afterwards to chart the coastlines of New Zealand and the eastern coast of a continent Europeans had not yet mapped in detail.",[83,84],"Further instructions","Once the transit was observed, Cook also had orders to look further south for useful land and, where possible, claim it for Britain.",[86,87],"The consequence","Cook's careful charts of Australia's east coast and New Zealand were later used to support British claims on land where Aboriginal Australian and Maori peoples had already been living for thousands of years.",{"id":89,"type":50,"variant":90,"title":91,"markdown":92},"mis-cook-discovery","misconception","“Cook discovered Australia”","He did not. Aboriginal peoples had lived across the continent for tens of thousands of years before the Endeavour's crew ever sighted its coast, with their own names for the land, their own knowledge of it, and their own ways of managing fire and water that outsiders are only now starting to properly value.\n\nWhat Cook did was chart a stretch of coastline in enough detail for a distant government to plan around it. That is a real and useful thing to have done. It is not the same as finding an empty place, and it did not stay a small, careful thing for very long.",{"id":94,"type":50,"variant":95,"title":96,"markdown":97},"callout-cook-consequence","nuance","Charts are not neutral","A chart looks like pure geography: coastlines, depths, hazards. But a chart is also a tool. Once Australia's east coast and New Zealand were drawn accurately on British paper, British ships, settlers and later governments used those same charts to plan landings, claim territory, and argue that the land was theirs to grant.\n\nNone of that required Cook to have intended it. By most accounts he was careful, and comparatively restrained in his dealings with Pacific peoples, more so than many captains who came after him. But the consequence of a voyage does not depend only on the intentions of the person who made it.",{"id":99,"type":100,"prompt":101,"options":102,"explanation":115},"pred-cook","prediction","Cook's first voyage carried two sets of instructions from the Admiralty: one public, one sealed and only to be opened after Tahiti. What is the most likely reason for keeping the second set secret?",[103,106,109,112],{"id":104,"label":105},"a","The Admiralty forgot to write them earlier",{"id":107,"label":108},"b","Rival nations, especially France and Spain, were also searching the Pacific for new territory, and secrecy kept Cook's further mission from them",{"id":110,"label":111},"c","Cook could not read until the ship left port",{"id":113,"label":114},"d","There were no real second instructions; historians made this up","**b.** European navies were in open competition to chart and claim Pacific territory. Keeping the search for new land quiet, at least from rivals, until the ship was already at sea, was an ordinary precaution.\n\nIt also meant the crew signed on for a voyage of astronomy, and found themselves partway through a voyage of territory as well, the same tangle of reasons riding on one ship that you met throughout Discover.",{"id":117,"type":118,"itemId":119,"prompt":120,"check":121,"hints":133,"feedback":136},"p-cook","practice","exploration.extend-cook","Cook's public orders were to observe the transit of Venus from Tahiti. What does the story of this voyage tell you about whether a voyage can be honestly scientific *and* still lead to conquest?",{"kind":122,"options":123,"correct":132},"choice",[124,126,128,130],{"id":104,"label":125},"A voyage is either scientific or it leads to conquest, never both",{"id":107,"label":127},"Both things can be true at once: the science was real, and so was the later use of the charts to support British claims",{"id":110,"label":129},"The transit of Venus observation was faked to hide the real mission",{"id":113,"label":131},"Conquest only happened on later voyages, never the first one",[107],[134,135],"Look at the table above: the science, the chart-making and the consequence are three rows of one voyage, not three separate voyages.","Ask what Cook's own intentions have to do with what a chart gets used for afterwards.",{"correct":137,"incorrect":138},"Exactly. The transit-of-Venus measurement was real, careful, useful science, done in good faith. It travelled on the same ship, and produced the same charts, as claims on other people's land. Both are true. That is the honest, uncomfortable shape of a lot of exploration.","Re-read the table: the same voyage did real astronomy and also produced charts later used for territorial claims. Neither cancels the other out.",{"id":140,"type":56,"title":141,"eyebrow":142,"navLabel":143},"ch02","Racing to the poles, and the treaty that followed","Chapter 02","2 Racing to poles",{"id":145,"type":46,"markdown":146},"polar-intro","By 1900 the map still had two blank white patches at the very top and bottom of the world. Reaching either pole meant weeks of hauling sledges across ice at temperatures that could injure exposed skin in minutes, with no way to call for help and no certainty of getting home.\n\nPeople went anyway, for the same tangle of reasons you met in Discover: rivalry between nations wanting to be first, personal ambition, and real scientific measurement of a part of the planet nobody had instruments in. The race to the South Pole in 1911-12 shows all three at once, and shows how differently a race can end for the winner and the loser.",{"id":148,"type":50,"variant":149,"title":150,"markdown":151},"callout-scott-amundsen","example","Two teams, one pole, two endings","In the southern summer of 1911-12, a Norwegian team led by Roald Amundsen and a British team led by Robert Falcon Scott both aimed for the South Pole. Amundsen's team, travelling light and fast, reached it first and returned safely. Scott's team arrived weeks later, found Amundsen's flag already there, and died of cold and exhaustion on the return journey.\n\nHistorians usually draw a lesson about planning and equipment choices here, not courage: both teams were extraordinarily brave. What matters for this topic is what came after. Nobody \"won\" Antarctica. No nation ever successfully settled or farmed it. Within fifty years, the countries with an interest in it chose a very different ending.",{"id":153,"type":154,"title":155,"items":156},"timeline-antarctica","timeline","From a bare pole to a protected continent",[157,161,165,169,173,177,181,185,189],{"time":158,"title":159,"text":160},"1911-12","The race","Amundsen's team reaches the South Pole first; Scott's team arrives later and dies on the return.",{"time":162,"title":163,"text":164},"1959","Treaty signed","12 nations agree to reserve Antarctica for peaceful scientific use only.",{"time":166,"title":167,"text":168},"1961","In force","No military bases, no weapons testing, no new territorial claims.",{"time":170,"title":171,"text":172},"1981","India's first team","India sends its first scientific expedition to Antarctica.",{"time":174,"title":175,"text":176},"1983","India joins","India becomes a party to the Antarctic Treaty.",{"time":178,"title":179,"text":180},"1989","Maitri station","India's second permanent Antarctic research station opens.",{"time":182,"title":183,"text":184},"1991","Mining banned","The Madrid Protocol bans mining in Antarctica for at least 50 years.",{"time":186,"title":187,"text":188},"2012","Bharati station","India opens a third station, its newest.",{"time":190,"title":191,"text":192},"2022","India's Antarctic Act","India passes its own law regulating Indian activity on the continent.",{"id":194,"type":50,"variant":95,"title":195,"markdown":196},"nuance-antarctica-different","Why Antarctica turned out differently","Unlike the Americas, Africa or India, Antarctica had no people already living there for ships to displace, trade with or fight. That absence made a very different outcome possible: instead of colonies, a science treaty.\n\nChapter five asks whether that model could work anywhere people actually live, and whether it will keep working even here, if something valuable enough is ever found under the ice.",{"id":198,"type":199,"tone":200,"items":201},"spec-antarctic-treaty","spec","blue",[202,205,207,211,215],{"label":203,"big":162,"value":204},"Signed","By 12 nations, agreeing Antarctica would be used for peaceful science only.",{"label":167,"big":166,"value":206},"The treaty became binding international law.",{"label":208,"big":209,"value":210},"Mining ban","50 years","Since 1991, mining anywhere in Antarctica has been banned; the ban could be reviewed around 2041.",{"label":212,"big":213,"value":214},"Years so far","35","No mining has happened in Antarctica for this many years and counting.",{"label":216,"big":217,"value":218},"India's stations","Maitri, Bharati","Opened in 1989 and 2012; India joined the treaty in 1983.",{"id":220,"type":118,"itemId":221,"prompt":222,"check":223,"hints":227,"feedback":229},"p-antarctic","exploration.extend-antarctic-ban","The Madrid Protocol banned mining in Antarctica from 1991 for at least 50 years. In what year could the ban first be reviewed?",{"kind":224,"answer":225,"tolerance":226},"number",2041,0,[228],"Add 50 to 1991.",{"correct":230,"incorrect":231},"**2041.** A review date does not mean mining will start then, only that it could be reconsidered. As of 2026 that is still about 15 years away.","Add the two numbers: 1991 + 50 = 2041.",{"id":233,"type":234,"component":235,"componentVersion":5,"config":236,"objective":292,"textAlternative":293},"lab-map-claims","interactive","voyage-map",{"voyages":237,"showWinds":291},[238,271],{"id":239,"label":240,"year":241,"from":242,"to":242,"path":243,"why":269,"consequence":270},"cook","Cook's first Pacific voyage","1768-1771","Plymouth",[244,247,250,253,256,259,262,265,268],[245,246],50.37,-4.14,[248,249],-22.9,-43.2,[251,252],-55.98,-67.27,[254,255],-17.65,-149.42,[257,258],-41.3,174.8,[260,261],-34,151.2,[263,264],-6.2,106.8,[266,267],-34.36,18.47,[245,246],"To observe Venus crossing the Sun from Tahiti, a science problem, and then to look for land in the southern Pacific for Britain.","Careful charts and scientific collections, and the beginning of British claims on lands where Aboriginal and Maori peoples had lived for thousands of years.",{"id":272,"label":273,"year":274,"from":275,"to":276,"path":277,"why":289,"consequence":290},"polar","Racing to the South Pole","1911-1912","Antarctic coast","South Pole",[278,281,284,287],[279,280],-77.85,166.67,[282,283],-83,170,[285,286],-88,175,[288,226],-90,"Rivalry between nations, personal ambition and scientific measurement, all at once. Amundsen reached the pole first; Scott's party arrived later and died returning.","Antarctica ended up belonging to nobody. Since 1959 a treaty keeps it for peaceful science, and since 1991 mining there is banned.",false,"Compare two very different outcomes: a chart later used to support a claim on inhabited land, and a race that ended in a treaty protecting land nobody owns.","A world map shows two routes.\n\n**Cook's first voyage (1768-1771):** Plymouth, round Cape Horn, Tahiti for the transit of Venus, New Zealand, the east coast of Australia, past Java, round the Cape of Good Hope, home to Plymouth. The line touches two coastlines that were soon claimed by Britain on the strength of the charts this voyage produced.\n\n**The race to the South Pole (1911-1912):** from the Antarctic coast inland to 90 degrees south. Amundsen's route reached the pole first; Scott's team followed a similar path and died on the return leg. Unlike Cook's voyage, this one led not to a claim but, within fifty years, to a treaty giving the whole continent to nobody in particular.",{"id":295,"type":56,"title":296,"eyebrow":297,"navLabel":298},"ch03","Leaving Earth: the space age","Chapter 03","3 Leaving Earth",{"id":300,"type":46,"markdown":301},"space-intro","Every voyage so far in this topic stayed on one planet. The next one did not.\n\nTo leave Earth for good, a spacecraft must reach **escape velocity**: about **11.2 km\u002Fs**, roughly 40,000 km\u002Fh, straight up. Anything slower falls back, the way a thrown ball falls back to your hand. This is not a technology limit that a better engine might one day beat; it is a consequence of Earth's gravity itself, the same force pulling every object towards the planet's centre that you meet in the Gravity topic. Go fast enough, and instead of falling back you fall *past* the Earth, all the way to somewhere else.",{"id":303,"type":304,"conceptId":305,"relation":306,"explanation":307},"conn-gravity","connection","gravity","applied_in","Every mission that leaves Earth, crewed or not, from Apollo 11 to Chandrayaan-3 to Voyager 1, works only because engineers calculated exactly how to overcome Earth's gravity: reaching escape velocity, or entering a stable orbit just below it.",{"id":309,"type":310,"items":311},"formulas-escape","formulas",[312,315,318],{"expression":313,"caption":314},"v ≈ 11.2 km\u002Fs","Earth's escape velocity: the speed needed, ignoring air resistance, to leave for good and never fall back.",{"expression":316,"caption":317},"distance = speed × time","Radio signals travel at light speed, about 300,000 km\u002Fs; multiply by the delay to find distance.",{"expression":319,"caption":320},"round trip = 2 × one-way","A question sent and an answer received takes twice the one-way light-time.",{"id":322,"type":154,"title":323,"items":324},"timeline-space","The space age, so far",[325,329,333,337,341],{"time":326,"title":327,"text":328},"1967","Outer Space Treaty","Nations agree that no country may claim ownership of the Moon or any other celestial body.",{"time":330,"title":331,"text":332},"1969","Apollo 11","Humans walk on the Moon for the first time, and return safely to Earth.",{"time":334,"title":335,"text":336},"1977","Voyager 1 launched","An uncrewed probe leaves Earth to study the outer planets, then keeps going outward.",{"time":338,"title":339,"text":340},"2023","Chandrayaan-3","India lands near the Moon's south pole, an area no other mission had reached.",{"time":342,"title":343,"text":344},"now","Voyager 1 today","Still sending data from about 165 AU away, roughly 25 billion km, after 49 years.",{"id":346,"type":199,"tone":347,"items":348},"spec-records","neutral",[349,353,357,359],{"label":350,"big":351,"value":352},"Voyager 1, now","165 AU","About 25 billion km from the Sun, the most distant human-made object, still transmitting after 49 years.",{"label":354,"big":355,"value":356},"Signal delay","23 hours","How long a radio signal from Voyager 1 takes, one way, at the speed of light, to reach Earth.",{"label":339,"big":338,"value":358},"Landed near the Moon's south pole, a region no earlier mission had reached.",{"label":331,"big":330,"value":360},"The first crewed Moon landing, and the first time humans left low Earth orbit.",{"id":362,"type":363,"title":364,"problem":365,"steps":366,"help":373},"we-voyager-distance","worked_example","How far is 165 AU, really?","Voyager 1 is currently about 165 astronomical units (AU) from the Sun. One AU, the Earth-Sun distance, is about 149,597,870 km. How far is that in billions of kilometres, and how long does a radio signal take to cross it?",[367,368,369,370,371,372],"Multiply AU by the km in one AU: 165 × 149,597,870 ≈ 24,683,148,550 km.","That is about **25 billion km**, rounding to the nearest billion.","Radio signals, like all light, travel at about 300,000 km per second.","Time = distance ÷ speed ≈ 24,683,000,000 ÷ 300,000 ≈ 82,277 seconds.","Convert to hours: 82,277 ÷ 3,600 ≈ **23 hours**, one way.","So a question sent to Voyager 1 today, and its reply, take about two days between them, purely from the travel time of light.",{"simplerExplanation":374},"Multiply the distance in AU by the km in one AU to get kilometres, then divide by the speed of light to get seconds, then convert to hours.",{"id":376,"type":100,"prompt":377,"options":378,"explanation":387},"pred-mars-delay","Mission controllers on Earth cannot fly a robot rover on Mars with a joystick in real time, watching a live picture as they steer. Why not?",[379,381,383,385],{"id":104,"label":380},"The rover has no radio",{"id":107,"label":382},"Signals between Earth and Mars take several minutes each way, so a joystick command would arrive minutes late",{"id":110,"label":384},"Mars has no atmosphere for radio waves to travel through",{"id":113,"label":386},"It is against international law to control a robot on another planet","**b.** The same light-time delay you just calculated for Voyager 1 applies to every mission, just by a smaller amount. Mars is much closer than Voyager 1, so its delay is minutes rather than hours, but minutes are still far too long for a joystick.\n\nThis is why rovers are largely told what to do a day at a time: \"drive this far, then stop and photograph that rock\", and left to carry it out and report back, rather than steered moment to moment.",{"id":389,"type":50,"variant":95,"title":390,"markdown":391},"callout-space-law","A treaty with a gap","The Outer Space Treaty says no *nation* may claim ownership of the Moon or any other celestial body. It says far less about *companies*. A handful of countries have since passed their own laws saying a company may keep resources it mines in space, and other countries argue this quietly stretches the treaty's spirit even if it does not break its letter.\n\nNobody has commercially mined an asteroid or the Moon yet, so the argument is still theoretical: words tested against no real case. That will not stay true forever.",{"id":393,"type":118,"itemId":394,"prompt":395,"check":396,"hints":400,"feedback":403},"p-escape","exploration.extend-escape-velocity","Earth's escape velocity is about 11.2 km\u002Fs. How many km\u002Fh is that, to the nearest 1,000 km\u002Fh? (1 hour = 3,600 seconds)",{"kind":224,"answer":397,"tolerance":398,"unit":399},40000,1000,"km\u002Fh",[401,402],"Multiply km\u002Fs by the number of seconds in an hour (3,600).","11.2 × 3,600 = 40,320.",{"correct":404,"incorrect":405},"About **40,000 km\u002Fh** (40,320 km\u002Fh exactly): 11.2 × 3,600 = 40,320, rounded to the nearest thousand.","Multiply 11.2 by 3,600, since there are 3,600 seconds in an hour.",{"id":407,"type":234,"component":408,"componentVersion":5,"config":409,"objective":437,"textAlternative":438},"lab-match-space","match-pairs",{"prompt":410,"mode":411,"pairs":412},"Match each space and exploration milestone to what it means.","connect",[413,416,419,422,425,428,431,434],{"a":414,"b":415},"Apollo 11 (1969)","First humans walk on the Moon and return safely",{"a":417,"b":418},"Chandrayaan-3 (2023)","India lands near the Moon's south pole",{"a":420,"b":421},"Voyager 1 (1977)","Launched; now the most distant human-made object",{"a":423,"b":424},"Escape velocity","About 11.2 km\u002Fs, the speed needed to leave Earth's gravity for good",{"a":426,"b":427},"Antarctic Treaty (1959)","12 nations agree to reserve the continent for peaceful science",{"a":429,"b":430},"Madrid Protocol (1991)","Bans mining in Antarctica for at least 50 years",{"a":432,"b":433},"Outer Space Treaty (1967)","No nation may claim ownership of the Moon or any other body",{"a":435,"b":436},"Challenger Deep","The deepest known point in any ocean, in the Mariana Trench","Match nine dates and terms from this chapter to what they mean.","Eight cards must be matched: a date or term on one side, its meaning on the other.\n\n**Space:** Apollo 11 (1969, first Moon landing), Chandrayaan-3 (2023, lands near the Moon's south pole), Voyager 1 (1977, now the most distant human-made object), escape velocity (about 11.2 km\u002Fs).\n\n**Treaties and depths:** the Antarctic Treaty (1959, science only), the Madrid Protocol (1991, mining banned), the Outer Space Treaty (1967, no national claims on celestial bodies), and the Challenger Deep, the ocean's deepest known point.",{"id":440,"type":56,"title":441,"eyebrow":442,"navLabel":443},"ch04","The deepest place on Earth","Chapter 04","4 The deep sea",{"id":445,"type":46,"markdown":446},"deepsea-intro","There is a place on Earth harder to reach than the Moon, in the sense that far fewer people have ever been there. It is not up. It is down, at the bottom of the Pacific Ocean.\n\nThe **Challenger Deep**, in the Mariana Trench, is the deepest known point in any ocean: about **10,935 m**. Only a handful of crewed dives have ever reached it, because the water pressure there is enormous, more than a thousand times the pressure at the surface.",{"id":448,"type":199,"tone":449,"items":450},"spec-deep-facts","copper",[451,454,458,462],{"label":435,"big":452,"value":453},"10,935 m","The deepest known point in any ocean, in the Mariana Trench of the Pacific.",{"label":455,"big":456,"value":457},"Mount Everest","8,849 m","For comparison: Earth's highest point above sea level.",{"label":459,"big":460,"value":461},"Difference","2,086 m","How much deeper the Challenger Deep is than Everest is tall.",{"label":463,"big":464,"value":465},"Matsya6000","6,000 m","India's crewed submersible, designed to carry people to this depth.",{"id":467,"type":363,"title":468,"problem":469,"steps":470},"we-deep-diff","Would Everest disappear in the Challenger Deep?","If you could place Mount Everest, all 8,849 m of it, at the bottom of the Challenger Deep (10,935 m), how much water would still be above its peak?",[471,472,473],"Subtract the mountain's height from the trench's depth: 10,935 − 8,849.","10,935 − 8,849 = **2,086 m**.","So Everest's peak would still sit under about **2,086 m** of water, more than two kilometres, before reaching the surface.",{"id":475,"type":50,"variant":476,"title":477,"markdown":478},"callout-deep-unknown","model_limit","What we don't know about the deep sea","Less of the ocean floor has been mapped in fine detail than the surface of the Moon or Mars. Only a small fraction of it has ever been photographed. That is itself a kind of frontier, closer than space and just as unexplored, which is one reason the question in chapter five, about who should control what is found there, matters right now rather than in some distant future.",{"id":480,"type":50,"variant":481,"title":482,"markdown":483},"callout-aha-matsya","aha","India's own deep-diving machine","Matsya6000 is a crewed Indian submersible, part of the Deep Ocean Mission, built to carry people down to about **6,000 m**: deep enough to reach most of the ocean floor, but not the Challenger Deep itself, which is about **4,935 m** deeper still.\n\nReaching the deep sea is its own kind of exploration, with its own reasons: mapping the seabed, studying life that has never seen sunlight, and looking at mineral deposits that formed nowhere near land. The next chapter asks who should get to use what is found there.",{"id":485,"type":118,"itemId":486,"prompt":487,"check":488,"hints":492,"feedback":494},"p-deepsea","exploration.extend-deepsea","Matsya6000 can dive to about 6,000 m. The Challenger Deep is about 10,935 m down. How much deeper is the Challenger Deep than Matsya6000 can currently go?",{"kind":224,"answer":489,"tolerance":490,"unit":491},4935,50,"m",[493],"Subtract Matsya6000's depth from the Challenger Deep's depth.",{"correct":495,"incorrect":496},"**4,935 m** deeper: 10,935 − 6,000 = 4,935.","Subtract: 10,935 − 6,000.",{"id":498,"type":56,"title":499,"eyebrow":500,"navLabel":501},"ch05","Whose is it, and who decides?","Chapter 05","5 Open questions",{"id":503,"type":46,"markdown":504},"ethics-intro","The four places in this chapter have something in common: nobody lives in most of them, or, in one case, somebody lives there and has clearly said they want to be left alone. That makes the ordinary rule, *ask the people who live somewhere what they want*, hard to apply.\n\nThis chapter does not give you answers. It gives you the strongest version of each side, and lets you decide what you think, and why.",{"id":506,"type":507,"title":508,"prompt":509,"options":510},"explore-ethics","explorer","Four places, four open questions","Pick one to see the strongest arguments on each side.",[511,520,529,537],{"id":512,"label":513,"chain":514,"note":519},"antarctica","Antarctica",[515,516,517,518],"No permanent residents","Treaty since 1959","Science only, so far","Mining banned to at least 2041","Nobody owns Antarctica. Since 1959, a treaty has kept it for peaceful science, and mining has been banned since 1991 for at least 50 years. **The open question:** the treaty has held for over sixty years, partly because nothing valuable enough has been found yet to tempt anyone to break it. Would it survive a major discovery? And is treating a continent as belonging to nobody really different from an older idea, that land with nobody European on it belonged to nobody at all?",{"id":521,"label":522,"chain":523,"note":528},"deepsea","The deep ocean floor",[524,525,526,527],"Outside any nation's waters","Rich in metal nodules","No mining has started yet","Rules still being written","Much of the deep seabed lies outside any country's territorial waters, in international waters nobody owns. It holds metal deposits useful for batteries and electronics, and an international body is still writing the rules for mining it. **The open question:** should those metals belong to whoever can afford to reach them first, or to everyone on Earth equally, or should the seabed be left alone the way Antarctica mostly has been?",{"id":530,"label":531,"chain":532,"note":536},"space","The Moon and asteroids",[533,534,535],"No nation may claim it (1967 treaty)","Companies are a greyer area","Nobody has mined one yet","The 1967 Outer Space Treaty says no country may claim sovereignty over the Moon or any other celestial body. It says far less about private companies, and some countries have passed laws letting their own companies keep what they mine. **The open question:** if a company spends billions of dollars reaching an asteroid, should it keep what it finds, the way a fishing boat keeps its catch from international waters? Or does that just let whoever has the most rockets take what they want?",{"id":538,"label":539,"chain":540,"note":544},"sentinelese","North Sentinel Island",[541,542,543],"Home to the Sentinelese","No outside contact wanted","India enforces a 5 km zone","North Sentinel Island, in India's Andaman Islands, is home to the Sentinelese, one of the world's few remaining uncontacted peoples. India enforces a legal exclusion zone of about 5 km around the island, and the Sentinelese themselves have repeatedly and clearly signalled that they do not want visitors. **The open question:** is staying away the most respectful thing outsiders can do, or is deciding to leave them alone still a decision being made *about* them, from a greater distance? The next block explains why the law exists at all.",{"id":546,"type":234,"component":547,"componentVersion":5,"config":548,"objective":579,"textAlternative":580},"lab-evidence-ethics","evidence-sort",{"claim":549,"categories":550,"items":554},"Nobody should be allowed to profit from resources in places that belong to no single nation: Antarctica, the deep ocean floor, and outer space.",[551,552,553],"supports","contradicts","uncertain",[555,559,563,567,571,575],{"id":556,"text":557,"category":551,"explanation":558},"e1","The 1959 Antarctic Treaty already reserves the whole continent for peaceful science, with mining banned since 1991.","A real, working example of nations agreeing not to profit from a shared place, in force for over sixty years.",{"id":560,"text":561,"category":551,"explanation":562},"e2","The 1967 Outer Space Treaty already says no nation may claim ownership of the Moon or any other celestial body.","The same principle, written into international law for space rather than ice.",{"id":564,"text":565,"category":552,"explanation":566},"e3","Metals on the deep seabed could supply materials the whole world needs for batteries and clean energy, and someone has to pay to extract them.","An argument that profit is what actually gets a resource extracted and used for everyone's benefit, not just a wealthy few.",{"id":568,"text":569,"category":552,"explanation":570},"e4","A private company that spends billions of dollars reaching an asteroid says it should keep what it mines there, or nobody will bother trying.","An argument from incentive: without the chance of profit, the expensive, risky work may simply not happen.",{"id":572,"text":573,"category":553,"explanation":574},"e5","Nobody has ever actually mined the deep seabed or an asteroid commercially, so it is hard to know what the real effect would be.","True, and worth remembering: strong opinions on both sides are still, for now, about a case that has not happened yet.",{"id":576,"text":577,"category":553,"explanation":578},"e6","Antarctica has no permanent population to ask, so there is nobody whose consent to profit from it, or not, could even be sought.","Complicates both sides: it is easier to say nobody should profit when there is also nobody obviously entitled to.","Weigh six pieces of evidence for and against the idea that nobody should profit from places outside any nation's territory.","Six statements are sorted into supports, contradicts or uncertain, against the claim that nobody should profit from resources in Antarctica, the deep ocean floor, or outer space.\n\nTwo existing treaties support the claim in specific ways. Two practical arguments, about batteries, clean energy and the cost of getting there, contradict it. Two statements point out that the debate is still mostly theoretical, since nobody has commercially mined any of these places yet.",{"id":582,"type":50,"variant":95,"title":583,"markdown":584},"callout-why-exclusion","Why the exclusion zone exists","Two separate reasons sit behind India's 5 km exclusion zone around North Sentinel Island, and both matter.\n\nThe first is disease. You met this in Discover: populations cut off from the wider world for a very long time have no built-up immunity to diseases that are ordinary elsewhere, such as measles or flu. A single visitor carrying a mild cold could set off an epidemic the Sentinelese have no defence against, echoing what happened across the Americas after 1492.\n\nThe second is choice. Every recorded encounter with the Sentinelese, going back well over a century, has ended the same way: they have made it unmistakably clear, sometimes with force, that they do not want visitors. Respecting that is treated in Indian law as respecting a people's own decision about their own island.",{"id":586,"type":587,"prompt":588},"reflect-ethics","reflection","Pick one of the four questions from the explorer above. Write the strongest argument you can for **each** side, in two or three sentences each, then say which side you personally find more convincing, and why.",{"id":590,"type":234,"component":591,"componentVersion":5,"config":592,"objective":645,"textAlternative":646},"lab-sort-openq","sort-game",{"prompt":593,"bins":594,"items":604,"seconds":226},"Sort each statement into a reason someone acted, a consequence of what happened, or an open question nobody has settled.",[595,598,601],{"id":596,"label":597},"reason","A reason someone acted",{"id":599,"label":600},"consequence","A consequence",{"id":602,"label":603},"openq","An open question",[605,609,613,617,621,625,629,633,637,641],{"id":606,"label":607,"bin":596,"why":608},"i1","Two nations wanted to be first to reach the South Pole","Rivalry between Norway and Britain, like the rivalry between Portugal and Spain earlier, pushed both expeditions to move fast.",{"id":610,"label":611,"bin":599,"why":612},"i2","The Antarctic Treaty of 1959 reserves the continent for peaceful science","A direct result of the earlier polar race and the era it happened in: nations agreed to cooperate rather than compete for territory.",{"id":614,"label":615,"bin":602,"why":616},"i3","Should a company be allowed to keep metals it mines from the deep ocean floor?","Nobody has done this yet, and the rules for it are still being written by an international body.",{"id":618,"label":619,"bin":596,"why":620},"i4","The USA and the Soviet Union competed to be first to the Moon","National rivalry, just like the polar race, was a major force behind the speed of the early space programme.",{"id":622,"label":623,"bin":599,"why":624},"i5","The 1967 Outer Space Treaty bans any country from claiming the Moon as its own","Written specifically so the Moon race would not turn into a territorial race, the way earlier voyages had.",{"id":626,"label":627,"bin":596,"why":628},"i6","Astronomers wanted to measure the exact distance from the Earth to the Sun","Cook's transit-of-Venus observation, and observations like it worldwide, were driven by scientific curiosity.",{"id":630,"label":631,"bin":599,"why":632},"i7","Voyager 1 is still sending data nearly fifty years on, further from Earth than anything else humans have made","An achievement nobody fully planned for when the probe launched in 1977 on a mission to the outer planets.",{"id":634,"label":635,"bin":602,"why":636},"i8","Is leaving the Sentinelese alone the most respectful choice, or still a decision being made about them?","There is a real case on each side, and no law or treaty settles the philosophical question.",{"id":638,"label":639,"bin":596,"why":640},"i9","India wanted a share in international Antarctic science","One reason India joined the Antarctic Treaty system and later built its own research stations there.",{"id":642,"label":643,"bin":599,"why":644},"i10","India now runs research stations at Maitri and Bharati in Antarctica","A direct, ongoing result of the decision to join Antarctic science in the 1980s.","Tell a reason someone acted apart from a consequence of what happened, and both apart from a question nobody has settled.","Ten cards drop into three bins: **a reason**, **a consequence**, and **an open question**.\n\nReasons come first: rivalry between nations, scientific curiosity, wanting a share in international science. Consequences come after: treaties, research stations, an achievement nobody quite planned for. Open questions are the ones this whole chapter is built around, and none of them has a card that clearly belongs anywhere else.",{"id":648,"type":56,"title":649,"eyebrow":650,"navLabel":651},"ch06","Projects for the curious","Chapter 06","6 Projects",{"id":653,"type":46,"markdown":654},"projects-intro","Three projects, no marks attached. Pick one, or try all three over a few weekends. Each one asks you to go and find real information, not just read this lesson again.",{"id":656,"type":587,"prompt":657},"project-port-city","Pick a port city that appears in this topic or in Discover: Kochi (Calicut), Surat, Chennai, Mumbai, or one nearer you. Find out what it exports and imports today, and to which countries (a port authority or state government website is a good place to start). Then compare that to the reason the same port mattered five hundred years ago. Has the *reason* for its importance changed completely, stayed the same, or landed somewhere in between?",{"id":659,"type":587,"prompt":660},"project-trace-good","Pick a real product you or your family buys: tea, cotton cloth, a spice, an electronic component, anything with a supply chain. Trace it as far back as you can: where is it grown or made, how does it travel, and roughly how much does the price rise at each step before it reaches a shop near you? You will not find every number. Say clearly which parts you found and which parts you had to estimate, and why.",{"id":662,"type":587,"prompt":663},"project-contact-rule","Design your own rule for when, if ever, outside contact with an uncontacted people such as the Sentinelese should be allowed: never, only in a medical emergency, only if they ask, or something else you think of. Write your rule in one sentence, then write three situations that test it, including at least one where your own rule is hard to apply. A rule that is easy to write and impossible to apply honestly is not finished yet.",{"id":665,"type":70,"caption":666,"columns":667,"rows":671},"table-projects","The three projects at a glance",[668,669,670],"Project","What you'll need","Roughly how long",[672,676,680],[673,674,675],"A port, then and now","Internet access; a port authority or government trade website","One or two evenings",[677,678,679],"Trace a traded good","A product at home; willingness to ask a shopkeeper or search online","A weekend",[681,682,683],"A rule for contact","Just this lesson and a notebook; no internet needed","One sitting, an hour or so",{"id":685,"type":56,"title":686,"eyebrow":687,"navLabel":688},"ch07","A puzzle: talking to Voyager 1","Chapter 07","7 Voyager puzzle",{"id":690,"type":46,"markdown":691},"puzzle-intro","Scientists and engineers often cannot get an exact number, so they build a **Fermi estimate**: a rough calculation, using numbers you can find or reasonably guess, that gets you within shouting distance of the truth. It is named after the physicist Enrico Fermi, famous for estimating things like \"how many piano tuners are there in Chicago\" from almost nothing.\n\nHere is one to try yourself, using numbers you already have from this lesson.",{"id":693,"type":694,"title":695,"items":696},"steps-fermi","steps","How to build a Fermi estimate",[697,701,705,709],{"title":698,"tag":699,"text":700},"Find the one hard number","Anchor","Pick the single measured fact you actually know, and build everything else around it.",{"title":702,"tag":703,"text":704},"Round generously","Simplify","Use round numbers on purpose. You are estimating the size of the answer, not its exact digits.",{"title":706,"tag":707,"text":708},"Compute in stages","Multiply, divide","Work one step at a time, checking each result makes sense before moving to the next.",{"title":710,"tag":711,"text":712},"Sanity-check the answer","Reality check","Ask: is this a sensible size? A wildly large or small result usually means a unit got mixed up.",{"id":714,"type":363,"title":715,"problem":716,"steps":717},"we-voyager-fermi","How many round trips could Voyager 1 make in a year?","A radio signal takes about 23 hours to reach Voyager 1 from Earth, one way. If mission control sent a message and waited for a reply, back to back with no gaps, roughly how many complete round trips could happen in one year?",[718,719,720,721],"One round trip = there and back = 2 × 23 = **46 hours**.","One year has about 24 × 365 = **8,760 hours**.","Round trips per year = 8,760 ÷ 46 ≈ **190**.","Check the size: 190 × 46 = 8,740 hours, close to 8,760. The answer is the right size.",{"id":723,"type":118,"itemId":724,"prompt":725,"check":726,"hints":729,"feedback":731},"p-fermi-roundtrips","exploration.extend-fermi-roundtrips","Using the same method: if one Voyager 1 round trip takes 46 hours, about how many round trips could happen in a year of 8,760 hours?",{"kind":224,"answer":727,"tolerance":728},190,5,[730],"Divide 8,760 by 46.",{"correct":732,"incorrect":733},"**About 190.** 8,760 ÷ 46 ≈ 190.4, so about 190 complete round trips fit in a year.","8,760 ÷ 46 is close to 190.",{"id":735,"type":363,"title":736,"problem":737,"steps":738,"help":744},"we-phone-compare","Compare that to a phone call across India","An ordinary phone call signal crossing India, roughly 3,000 km, at close to the speed of light (about 300,000 km\u002Fs), has a tiny round-trip delay. How many such phone-call round trips would fit inside the time of just one Voyager round trip signal (46 hours)?",[739,740,741,742,743],"One-way time across India ≈ 3,000 ÷ 300,000 = 0.01 seconds.","Round trip (there and back) ≈ 2 × 0.01 = **0.02 seconds**.","Voyager's round trip in seconds: 46 × 3,600 = **165,600 seconds**.","Divide: 165,600 ÷ 0.02 ≈ **8,280,000**.","So in the time one message takes to reach Voyager 1 and a reply to come back, about eight million ordinary phone-call round trips across India would fit. Distance in space is a completely different scale from distance on Earth.",{"anotherExample":745},"Try the same method for the Moon instead: light takes only about 1.3 seconds to reach the Moon, so a round trip there takes about 2.6 seconds, not hours.",{"id":747,"type":587,"prompt":748},"reflect-fermi","Try a Fermi estimate of your own: about how many heartbeats have you had in your life so far? Pick one hard number (your age, or a typical resting heart rate), round generously, and compute in stages the way the steps above describe.",{"id":750,"type":56,"title":751,"eyebrow":752,"navLabel":753},"ch08","Words, questions and the short version","Chapter 08","8 Wrap-up",{"id":755,"type":756,"title":757,"terms":758},"gloss-extend","glossary","Words for this layer",[759,761,764,767,771,775,779,783,786,790],{"term":423,"meaning":760},"The speed an object needs to leave a planet's gravity for good; about 11.2 km\u002Fs for Earth.",{"term":354,"meaning":762,"example":763},"How long a radio or light signal takes to travel a distance; also called light-time.","Voyager 1's one-way signal delay is about 23 hours.",{"term":765,"meaning":766},"Sovereignty","A country's authority to govern a place and make its own laws there.",{"term":768,"meaning":769,"example":770},"Exclusion zone","An area outsiders are legally kept out of.","India enforces a 5 km exclusion zone around North Sentinel Island.",{"term":772,"meaning":773,"example":774},"Uncontacted people","A community that has deliberately avoided sustained contact with the outside world.","The Sentinelese of North Sentinel Island.",{"term":776,"meaning":777,"example":778},"Submersible","A small underwater vehicle, crewed or uncrewed, built to withstand deep-sea pressure.","Matsya6000 is a crewed Indian submersible.",{"term":780,"meaning":781,"example":782},"Treaty","A formal, legally binding agreement between countries.","The Antarctic Treaty has been in force since 1961.",{"term":784,"meaning":785},"Ratify","For a country to formally approve and agree to be bound by a treaty it has signed.",{"term":787,"meaning":788,"example":789},"Parallax","The apparent shift in an object's position when viewed from two different places, used to measure distance.","Cook's transit-of-Venus observation used parallax to help measure the Earth-Sun distance.",{"term":791,"meaning":792},"Fermi estimate","A rough calculation built from round numbers, aimed at getting close to the right size of answer quickly.",{"id":794,"type":50,"variant":795,"title":796,"markdown":797},"q-open-extend","question","Open questions for curious learners","No single right answer to any of these either. Argue them out with someone.\n\n- If a treaty can keep Antarctica free of mining for over sixty years, could a similar treaty protect the deep ocean floor, or is Antarctica an easy case because nobody lives there and nothing valuable has been found yet?\n- Should a country or company that reaches an asteroid first get to keep what it mines there, the way a fishing boat keeps its catch?\n- Is leaving the Sentinelese alone the most respectful choice available, or is deciding *for* them still a decision made about them?\n- Voyager 1 will run out of power in the coming years and go silent forever, still travelling. Does an exploration that never comes home and is never heard from again still count as exploration?\n- If humans do eventually settle Mars permanently, should it belong to whoever gets there first, to no one, or to everyone?",{"id":799,"type":800,"title":801,"questions":802},"quiz-extend","quiz","Check what stuck",[803,816,829,842,855,868,881,894,907,920],{"itemId":804,"prompt":805,"options":806,"correct":107,"why":815},"exploration.extend-q-cook","What was Cook's official, scientific reason for sailing to Tahiti in 1768?",[807,809,811,813],{"id":104,"label":808},"To claim the island for Britain",{"id":107,"label":810},"To observe the transit of Venus and help measure the Earth-Sun distance",{"id":110,"label":812},"To meet the Tahitian king",{"id":113,"label":814},"To test a new kind of ship","The transit of Venus, timed from several places on Earth at once, let astronomers calculate the Earth-Sun distance using parallax.",{"itemId":817,"prompt":818,"options":819,"correct":107,"why":828},"exploration.extend-q-cookconsequence","What did Cook's charts of Australia and New Zealand later help make possible?",[820,822,824,826],{"id":104,"label":821},"Nothing; they were never used again",{"id":107,"label":823},"British territorial claims on land where Aboriginal Australian and Maori peoples already lived",{"id":110,"label":825},"A trade agreement with Tahiti",{"id":113,"label":827},"The Antarctic Treaty","Accurate charts let a distant government plan landings and claims on coastlines that had been home to other peoples for thousands of years.",{"itemId":830,"prompt":831,"options":832,"correct":107,"why":841},"exploration.extend-q-antarctic","Since 1959, what has the Antarctic Treaty reserved the continent for?",[833,835,837,839],{"id":104,"label":834},"Military bases",{"id":107,"label":836},"Peaceful scientific use only",{"id":110,"label":838},"Whichever nation claims it first",{"id":113,"label":840},"Tourism only","The treaty bans military bases, weapons testing and new territorial claims, keeping the continent for science.",{"itemId":843,"prompt":844,"options":845,"correct":107,"why":854},"exploration.extend-q-madrid","What did the 1991 Madrid Protocol add to the Antarctic Treaty?",[846,848,850,852],{"id":104,"label":847},"Permission to mine freely",{"id":107,"label":849},"A ban on mining in Antarctica for at least 50 years",{"id":110,"label":851},"A ban on all scientific research",{"id":113,"label":853},"New national borders","The ban has held since 1991 and could first be reviewed around 2041.",{"itemId":856,"prompt":857,"options":858,"correct":104,"why":867},"exploration.extend-q-escape","Why must a spacecraft reach about 11.2 km\u002Fs to leave Earth for good?",[859,861,863,865],{"id":104,"label":860},"Below that speed, it falls back to Earth, the way a thrown ball does",{"id":107,"label":862},"That is the speed of sound",{"id":110,"label":864},"It is the minimum speed radio signals can travel",{"id":113,"label":866},"Rockets cannot physically go slower than that","Escape velocity is the speed at which an object's path curves away from Earth for good instead of falling back.",{"itemId":869,"prompt":870,"options":871,"correct":107,"why":880},"exploration.extend-q-outerspace","What does the 1967 Outer Space Treaty say about the Moon?",[872,874,876,878],{"id":104,"label":873},"The first country to land there owns it",{"id":107,"label":875},"No nation may claim sovereignty over it",{"id":110,"label":877},"It belongs to the country that named it",{"id":113,"label":879},"Only the United Nations may visit it","The treaty rules out national ownership claims on the Moon or any other celestial body; it says much less about companies.",{"itemId":882,"prompt":883,"options":884,"correct":104,"why":893},"exploration.extend-q-challenger","About how much deeper is the Challenger Deep than Mount Everest is tall?",[885,887,889,891],{"id":104,"label":886},"About 2,086 m",{"id":107,"label":888},"About 500 m",{"id":110,"label":890},"About the same",{"id":113,"label":892},"About 20,000 m","10,935 m minus 8,849 m is 2,086 m.",{"itemId":895,"prompt":896,"options":897,"correct":107,"why":906},"exploration.extend-q-sentinelese","Why does India enforce an exclusion zone around North Sentinel Island?",[898,900,902,904],{"id":104,"label":899},"To protect valuable minerals there",{"id":107,"label":901},"To protect the Sentinelese from diseases they have no immunity to, and to respect their clear wish not to be contacted",{"id":110,"label":903},"Because the island is a military base",{"id":113,"label":905},"Because the island is uninhabited","Both a health reason and a choice: the Sentinelese have repeatedly and clearly signalled they do not want visitors.",{"itemId":908,"prompt":909,"options":910,"correct":107,"why":919},"exploration.extend-q-fermi","What is a Fermi estimate?",[911,913,915,917],{"id":104,"label":912},"An exact calculation using precise instruments",{"id":107,"label":914},"A rough calculation from round numbers, aimed at getting the right size of answer quickly",{"id":110,"label":916},"A rule that only physicists are allowed to use",{"id":113,"label":918},"A guess with no reasoning behind it","It uses one known fact plus deliberate rounding, checked at the end for whether the size is sensible.",{"itemId":921,"prompt":922,"options":923,"correct":110,"why":932},"exploration.extend-q-voyagerphone","One Voyager 1 round trip signal takes about 46 hours. Roughly how many ordinary phone-call round trips across India (about 0.02 seconds each) would fit into that time?",[924,926,928,930],{"id":104,"label":925},"About 8 thousand",{"id":107,"label":927},"About 8 hundred thousand",{"id":110,"label":929},"About 8 million",{"id":113,"label":931},"About 8 billion","46 hours is 165,600 seconds; divided by 0.02 seconds per phone-call round trip, that is about 8,280,000, close to 8 million.",{"id":934,"type":935,"title":936,"points":937},"summary-extend","summary","The short version",[938,939,940,941,942,943,944,945,946,947],"Cook's first Pacific voyage (1768-1771) was genuinely scientific, observing the transit of Venus from Tahiti, and its charts were later used to support British claims on Aboriginal Australian and Maori land. Both are true.","The race to the South Pole (1911-12) ended in triumph for Amundsen's team and death for Scott's. Since 1959, a treaty has kept Antarctica for peaceful science instead, with mining banned since 1991.","India has taken part in Antarctic science since 1981, running the Maitri (1989) and Bharati (2012) stations.","Leaving Earth for good needs **escape velocity**, about 11.2 km\u002Fs: the same gravity you meet in the Gravity topic, applied to a rocket.","Apollo 11 (1969) and Chandrayaan-3 (2023) both put a crew or a lander on the Moon. Voyager 1, launched 1977, is now about 165 AU away, its signal taking about 23 hours one way.","The Challenger Deep, about 10,935 m down, is deeper than Everest is tall by about 2,086 m. India's Matsya6000 submersible is built to reach 6,000 m.","Nobody owns Antarctica, the deep ocean floor, or the Moon, by treaty. Whether those treaties would hold if something valuable enough were found is still an open question.","India enforces a 5 km exclusion zone around North Sentinel Island, protecting the Sentinelese both from diseases they have no immunity to and out of respect for their clearly stated wish to be left alone.","A **Fermi estimate** builds a rough but useful answer from one known number and careful rounding, checked at the end for whether the size makes sense.","Distance in space dwarfs distance on Earth: a single Voyager round trip signal takes about as long as roughly eight million ordinary phone-call round trips across India.",{"id":949,"type":950,"sourceIds":951},"sources-extend","sources",[952,953,954,955,956,957],"exploration-britannica-cook","exploration-ats-treaty","exploration-nasa-voyager","exploration-isro-chandrayaan3","exploration-noaa-challenger-deep","exploration-britannica-sentinelese",[952,953,954,955,956,957],"needs_review",{"generatedBy":961,"notes":962},"claude-code","Draft generated locally; pending owner review. Every number computed and asserted in scratchpad\u002Fexploration\u002Fnumbers.py plus a small set of local constants (Fermi-estimate arithmetic, Madrid Protocol review year) computed and asserted in this file. Deepen\u002FExtend content goes beyond the Class 6-7 syllabus (space law, deep-sea law, Fermi estimation), flagged in the lesson plate.","ff90608ec0b54c9d5c28263fb431857b26c8bb16750b56b8215875f9f57d8a9a",{"logic:practice":965,"component:voyage-map@1":966,"component:match-pairs@1":967,"component:evidence-sort@1":968,"component:sort-game@1":969,"source:exploration-ats-treaty":970,"source:exploration-britannica-cook":971,"source:exploration-britannica-sentinelese":972,"source:exploration-isro-chandrayaan3":973,"source:exploration-nasa-voyager":974,"source:exploration-noaa-challenger-deep":975},"3d6b0fe1b15255975a32b0fcd94e8019bc959ad45cbf12e136e86149549c6878","39a0c4da8ea3e6637b0b63d8c38cb151ee52e167eae571f75affe7452f56f13a","2a8ee4ac87460b4e1175a4bb13c96b03d577db06dde95670eb7fcfe4ad787899","c7e7eaaef730a3b3d27bdd2d3ed613ea3fa67dbbb73b43f0def434174123b68e","b164f45a2c8ca08f26c450768ff0231e113e9fe45381eddb34dc6d0548596c38","77152faba057ce320cccdb7ceb233961c87b1a91d5dc1738316e65c9d8dfaae1","785b5f408cbe9c49dfc60c0b77151f39125515f054399b45b9e335cc611adf4b","fd8f0820ff0ee637ada4af7d85b11a9da6d1f4867c832b3a63593b823834a50e","220d1b1208904496d3b3078c98026058927230865f66ec11e286e4982a078458","91f24d60c79b2e44c423b9a39220c410c91492c6428db5322a1feacc6165e837","351d74370b46fd7377e53aafd65e84a1c7849d43bf8156ce0f77e5f36894ad6a",{"state":977,"reviewer":978,"selfReview":979,"reviewedAt":980,"method":981},"approved","The library owner",true,"2026-09-20T10:18:37.581Z","owner_bulk","preview-7e1cbbcc4f",1789899599081]