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Nature

2,233 cards. Each one is a 40-second story with a five-minute read behind it. Page 21 of 38.

1201. The world's favourite climate map was drawn by a botanistWhen Wladimir Köppen sorted Earth's climates in 1884, he started from plants. His five big groups, labelled with letters from A to E, track the kinds of vegetation that thrive und…
1202. The clay behind fine porcelain is named after a Chinese hillside villageKaolin, the soft white clay that made Chinese porcelain famous, takes its name from Gaoling, meaning High Ridge, a village near the porcelain city of Jingdezhen. A French Jesuit, …
1203. In karst country, rivers vanish underground and reappear with new namesSlovenia's Ljubljanica is nicknamed the river of seven names because it keeps disappearing into the ground and resurfacing somewhere else. That is typical of karst, landscapes car…
1204. Lagoons line about 15 percent of the world's coasts, often under other namesNorth Carolina's Pamlico Sound, Scotland's Montrose Basin and England's Fleet behind Chesil Beach are all lagoons, whatever they are called. These shallow waters, cut off from the…
1205. Nobody can say exactly where a pond ends and a lake beginsEarth may hold around 304 million lakes and ponds, yet there is no internationally agreed rule for telling the two apart. Nine in ten of those water bodies cover a hectare or less…
1206. Jade is not one stone but two quite different mineralsCall something jade and you might mean either of two unrelated rocks. Nephrite is built from calcium and magnesium; jadeite from sodium and aluminium. Both are tough, carvable and…
1207. The grain of a rock tells you how fast its magma cooledGranite has crystals big enough to see because its magma cooled slowly, deep underground, wrapped in insulating rock. Basalt is fine-grained or glassy because lava froze fast in o…
1208. Geologists long insisted Meteor Crater was volcanic, not a cosmic hitIn 1903 a mining engineer named Daniel Barringer was sure the huge pit he owned in Arizona had been punched by something from space. Most geologists thought a volcanic steam blast…
1209. Earth's solid mantle flows, just far more slowly than pitchNobody has ever drilled through Earth's crust, yet we know the planet has a liquid outer core and a solid inner one. Earthquake waves gave it away. The rock of the mantle is solid…
1210. The s in island is a spelling mistake from the fifteenth centuryEnglish speakers once wrote iland, from an Old English word distantly related to Latin aqua, water. In the 1400s writers wrongly linked it to the French isle and slipped in a sile…
1211. Piano keys helped wipe out Kenya's elephant herdsFor a century, the white keys of pianos were faced with elephant ivory. A single Connecticut river valley once processed up to 90 percent of America's imported ivory, largely for …
1212. Is rain enough to fill a river? A 1600s experiment on the Seine said yesFor centuries nobody could prove that rainfall alone kept rivers flowing. Then Pierre Perrault measured the rain over the Seine's catchment against the river's flow and showed the…
1213. Only 0.3 percent of Earth's fresh water sits in lakes and riversEarth holds an estimated 1.386 billion cubic kilometres of water, yet 97.5 percent is salty. Of the small fresh share, most is locked in ice or hidden underground. Just 0.3 percen…
1214. Technically we are still living in an ice age that began 34 million years agoBecause Earth still has permanent ice caps, geologists say we are inside the Late Cenozoic Ice Age, under way for some 34 million years. The idea of vast ancient glaciers first ca…
1215. A fighter plane lost in Greenland in 1942 was found under 81 metres of iceWhen a P-38 Lightning crash-landed on Greenland's ice in 1942, nobody expected it to vanish. Fifty years later it was dug out from beneath 81 metres of new ice. Ice sheets are sti…
1216. Floating ice shelves act as brakes on the glaciers behind themAn ice shelf is a slab of glacier ice, up to a kilometre thick, floating on the sea while still attached to land. It looks passive, but it holds back the glaciers feeding it. When…
1217. Melting icebergs fizz like soda, a sound nicknamed Bergie SeltzerGlacier ice can be up to 10 percent trapped air, squeezed into bubbles as old snow compacts. When an iceberg melts, those bubbles burst one by one with a popping fizz. Scientists …
1218. How rain becomes a hot spring, and sometimes a geyserNobody agrees how warm a spring must be to count as hot: definitions range from anything warmer than its surroundings to above 50 degrees Celsius. What they share is the heat sour…
1219. Why Hawaii's islands get older toward the northwestIn 1963 J. Tuzo Wilson proposed that Hawaii formed as a tectonic plate slid slowly over a hot patch beneath it, leaving a trail of volcanoes behind. The idea explains why Hawaiian…
1220. Air doesn't really 'hold' water vapour, and a vacuum proves itWe talk about warm air holding more moisture, but the nitrogen and oxygen barely matter. A vacuum can take up almost exactly as much water vapour as the same space filled with air…
1221. Nautical charts deliberately hide the deep water, and that is the pointA sea chart is not a faithful map of the seabed. It is biased toward the shallowest depths, because its job is keeping ships off rocks, not showing the true shape of the bottom. A…
1222. Pumping groundwater has shifted the tilt of Earth's axis by 79 centimetresAbout 99 percent of the world's liquid fresh water sits underground, in the pores and cracks of rock and soil. Some of it is over a million years old. People now pump so much that…
1223. The soft mineral in your walls also grows crystals 11 metres longGypsum is one of the softest common minerals and ends up in drywall, chalk and plaster. In a Mexican mine cave kept at 58 degrees Celsius, though, it grew crystals up to 11 metres…
1224. One vast loop of air builds the rainforests and the desertsNear the equator warm air rises, flows toward the poles about 12 to 15 kilometres up, then sinks around 30 degrees latitude and returns as the trade winds. This loop, the Hadley c…
1225. Hailstones probably don't get their onion layers by bouncing up and downSlice a big hailstone and you find rings like an onion. The old explanation said stones yo-yo repeatedly through the storm, gaining a coat each trip. Field studies and theory now …
1226. Francis Galton named the anticyclone, the weather system behind clear skiesThe big H on a weather map marks sinking air. As it descends it warms and dries, clearing away cloud, which is why highs usually bring sunny days, cold nights and sometimes smog o…
1227. When does a hill become a mountain? Nobody officially agreesGeographers once drew the line at 1,000 feet, British hillwalkers at 2,000, and the Great Soviet Encyclopedia at 200 metres of relative height. The US Geological Survey eventually…
1228. From molten rock to living planet: Earth's first billion yearsEarth took shape about 4.54 billion years ago, roughly a third of the universe's age, and spent its youth molten, battered and nearly oxygen-free. Yet zircon crystals 4.4 billion …
1229. The Holocene: 11,700 years of 'wholly new' time, and the epoch geologists refused to replaceEverything humans have ever written happened inside one geological epoch, the Holocene, which began around 11,700 years ago as the last ice sheets retreated. In March 2024, after …
1230. One square metre of Estonian meadow held 76 plant speciesOld meadows shaped by centuries of grazing and mowing rank among the most species-rich habitats on the planet; a single square metre in Estonia set a European record with 76 plant…
1231. Nobody agrees how big a stone can be and still count as gravelGeologists usually call any loose, rounded rock fragment over 2 millimetres gravel, with no upper limit. American soil scientists stop at 80 millimetres, the German scale runs to …
1232. The oxygen we breathe began as poison for Earth's early microbesAround 2.4 billion years ago, cyanobacteria were releasing a waste gas that most life on Earth could not tolerate. As free oxygen built up in the air and shallow seas, it probably…
1233. A greenhouse traps heat one way; Earth's atmosphere does it quite differentlyStrip away the heat-absorbing gases and Earth's average surface would sit near minus 18 degrees Celsius. Instead it hovers around 15, a 33-degree gift from a thin fraction of the …
1234. A Song dynasty official found seashells in a mountain cliff and deduced a vanished coastAround a thousand years ago, Shen Kuo noticed a horizontal band of clam shells running along a cliff hundreds of miles from the Pacific. He concluded the spot had once been a shor…
1235. The air above your head carries a constant 120 volts per metreNear the ground there is always a downward electric field averaging about 120 volts per metre, part of a planet-wide circuit carrying roughly 1,800 amperes that returns upward thr…
1236. A geyser is a natural pressure cooker, and Iceland once coaxed one awake with soapGeysers need heat from nearby magma, a water supply and underground plumbing with just the right narrow throat. The cooler water on top acts like a pressure-cooker lid until the h…
1237. New England's stone walls are full of boulders carried for miles by iceMany rocks stacked into New England's old field walls are glacial erratics, stones dragged far from their home bedrock by ice sheets. Glaciers act as both sculptors and delivery t…
1238. Geologists class glacier ice as a rock, and it flowsTo a geologist, glacier ice is a metamorphic rock made almost entirely of one mineral, sitting just below its melting point. It creeps downhill under its own weight, stores about …
1239. Some of Earth's oldest surviving rock is banded gneiss over four billion years oldOn an island about 300 kilometres north of Yellowknife in Canada sits the Acasta Gneiss, metamorphosed between 3.58 and 4.031 billion years ago and among the most ancient intact p…
1240. Add water and granite melts at roughly half its dry temperatureDry granite needs about 1,215 to 1,260 degrees Celsius to melt at surface pressure. Deep in the crust, with water present and a few hundred megapascals of pressure, it can melt at…
1241. A magnetic shield may have saved Earth's air from the fate of MarsAbout 3.5 billion years ago Earth switched on its magnetic field. The young Sun was blasting out a solar wind roughly 100 times stronger than today's, and without that shield our …
1242. Scratch it, drip acid on it, even lick it: how geologists identify mineralsA geologist's toolkit is surprisingly hands-on. Rubbing a mineral across unglazed porcelain leaves a coloured streak that betrays its identity. A drop of hydrochloric acid makes s…
1243. India's Kosi River can shift its channel 730 metres in a single yearFloodplains are built by rivers that refuse to stay put. As a channel swings through its meanders, it gnaws one bank and lays sediment on the other, and some rivers move astonishi…
1244. Fog droplets are tiny floating ponds where bacteria grow and divideFog is a cloud that has come down to ground level, but recent research shows it is also a living habitat. Droplets in overland fog hold bacterial concentrations comparable to lake…
1245. Solid rock can bend like a rug, from tiny crinkles to mountainsRock layers laid down flat can end up curled into arches, troughs and zigzags. Geologists call these folds, and they range from microscopic crinkles to structures the size of moun…
1246. A medieval forest didn't need trees, just a king who hunted thereWhen the Normans brought the word forest to England, it was a legal term for land reserved for royal hunting, whether or not trees grew on it. That confusion survives: there are m…
1247. Frost on a window is a fractal caught between one and two dimensionsThe fern-like patterns frost paints on a cold window are fractals. Because the ice crystals can only spread across a flat pane, the patterns have a fractal dimension between one a…
1248. You can visit the Upper Cretaceous but never the Late CretaceousGeologists keep two parallel vocabularies. The Late Cretaceous is a stretch of time, so nobody can go there. The Upper Cretaceous is the rock laid down during it, so you can stand…
1249. Sea level is lumpy: the true shape of Earth dips and bulges by 110 metresImagine the oceans at rest, free of currents and winds, extended under the continents. That surface, the geoid, is not a smooth ellipsoid. It rises and falls by up to about 110 me…
1250. Geologists hammer golden spikes into cliffs to mark the edges of timeTo define where one slice of Earth's history ends and the next begins, geologists choose a precise point in a real rock face and call it a golden spike. The boundary that closed t…
1251. Feldspar is so common in the crust that its weathered remains make most mudFeldspar minerals crystallise in almost every kind of igneous rock, but they form at high temperatures and fall apart easily at the surface. Water breaks them down into clays, whi…
1252. Some floods are deliberate, from rice paddies to wartime defencesMost floods are disasters, but people also drown land on purpose. Farmers flood paddies to grow rice, Dutch engineers designate fields to take a swollen river's overflow, and armi…
1253. Earth's inner core grows by about 80,000 tonnes of iron every secondNearly 2,900 kilometres beneath our feet lies an ocean of molten iron and nickel about 2,260 kilometres deep. As the planet slowly cools, its base freezes onto the solid inner cor…
1254. El Niño was named by Peruvian fishermen after the Christ ChildWarm water showing up off Peru around Christmas gave El Niño its name, the Boy. Today the term describes one phase of a Pacific-wide swing in winds and sea temperatures that bring…
1255. Almost every emerald is flawed, so jewellers grade them by naked eyeDiamonds are judged under tenfold magnification, but emeralds are so often riddled with inclusions and cracks that an emerald counts as flawless if nothing shows to the unaided ey…
1256. Humans now drive soil erosion 10 to 40 times faster than natureErosion is natural: water, wind, ice and gravity have always carried soil and rock from one place to another. But farming, deforestation, roads and sprawl have multiplied the glob…
1257. Most of the world's estuaries are younger than farmingWhen the last ice age ended and seas began climbing roughly 10,000 to 12,000 years ago, oceans flooded valleys carved by rivers and glaciers. Those drowned valleys became today's …
1258. The Great Dying wiped out about 81 percent of marine speciesAround 252 million years ago, at the close of the Permian, life suffered its worst known catastrophe. Roughly four in five marine species and an estimated 70 percent of land verte…
1259. Meteorologists call a storm a bomb when its pressure plunges fast enoughIf a mid-latitude storm's central pressure drops by more than a millibar an hour, forecasters call it explosive cyclogenesis, and the storm earns the nickname bomb. These extratro…
1260. Geologists still describe faults using words borrowed from old minesThe two sides of a sloping fault are called the hanging wall and the footwall because miners working a tilted ore seam stood on one and had the other hanging overhead. Even the la…

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