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Nature

2,233 cards. Each one is a 40-second story with a five-minute read behind it. Page 22 of 38.

1261. Earth science rests on one bold bet: the present explains the pastNobody watched mountains rise or oceans open. Geologists reconstruct those events by assuming that the processes working today, erosion, eruptions, sediment settling in rivers, ha…
1262. A fault's width, not its length, caps how big an earthquake can getMost of an earthquake's energy never reaches us as shaking: perhaps 10 percent or less radiates as seismic waves, the rest cracks rock and heats the fault. And the biggest quakes …
1263. Parts of the Amazon grow more leaves when the rain stopsIn the tropics, dry months are not a fixed calendar fact but the shadow of a wandering band of rain. As that belt swings between hemispheres, rivers shrink, herds walk, fires spre…
1264. A town in Western Australia had to move because sand dunes swallowed itIn the 1890s the settlement of Eucla, in Western Australia, was relocated because drifting dunes were burying it. Dunes can travel startlingly fast: between 1954 and 1959 a group …
1265. Mauritania went from two dust storms a year to about eightySand grains hopping across a desert build up static charge, and that charge shakes loose even more grains. The result can be a wall of dust over a kilometre high. Saharan storms h…
1266. Ocean floor is young; some continental rock is over four billion years oldThe ground beneath us is a skin thinner than one percent of Earth's radius, floating on denser mantle rock. Seafloor is constantly made and swallowed, so none of it is older than …
1267. Inge Lehmann found Earth's solid heart by reading distant earthquake echoesIn 1936 the Danish seismologist Inge Lehmann studied records of New Zealand earthquakes and noticed waves that seemed to bounce off something deep inside the planet. She concluded…
1268. The Arctic magnetic pole is really the south pole of Earth's magnetA compass needle's north end swings toward the Arctic, and opposite poles attract. So the magnetic pole near Canada's Ellesmere Island is, strictly speaking, the south pole of Ear…
1269. Earth's mantle is hotter than molten rock yet stays almost entirely solidNear the core, mantle rock reaches about 4,200 kelvin, far above the temperature at which peridotite melts at the surface. Crushing pressure keeps it solid. Over millions of years…
1270. Nearly half of all the world's land drains into the Atlantic OceanFollow any raindrop downhill and it ends up somewhere specific. For about 48.7 percent of Earth's land, that somewhere is the Atlantic, fed by rivers from the Great Lakes to the N…
1271. By the early 1980s researchers had published over 150 definitions of droughtDrought sounds simple, yet by the early 1980s more than 150 definitions were in print. The UN climate panel now settles for drier than normal. The trouble is that dryness can stri…
1272. Death Valley's sailing stones are pushed by windblown sheets of iceOn the Racetrack Playa in Death Valley, rocks slide across a dry lakebed and leave long trails with nobody touching them. Scripps researchers finally filmed the cause: thin panes …
1273. Some Antarctic ice has stayed frozen for close to a million yearsA snowflake landing today may melt within months, but water locked in glaciers and ice sheets can stay frozen for tens of thousands of years, and deep ice in parts of East Antarct…
1274. An average thunderhead weighs about half a million kilogramsThe towering storm cloud called cumulonimbus holds roughly 500,000 kilograms of water on average, and its top can climb to 12 kilometres, sometimes 20 or more. It is the largest c…
1275. Fair-weather cumulus clouds are powered by the heat of their own condensationThe fluffy, flat-bottomed clouds of a summer afternoon run on a feedback loop. Warm air rises and cools until its vapour condenses, and condensing releases heat that pushes the ai…
1276. The word cyclone was coined by an East India Company official in CalcuttaHenry Piddington, a British East India Company official, wrote 40 papers on tropical storms from Calcutta between 1836 and 1855 and gave them a name from the Greek for circle. A c…
1277. Shakespeare's desert of Bohemia had no sand, only an absence of peopleDesert once meant an abandoned place, not a dry one. Before the twentieth century English speakers used it for any empty land, which is why a desert island needs no dunes. Today t…
1278. In Israel's Negev, dew supplies nearly half the water of some desert shrubsDew never adds up to much, rarely more than half a millimetre a night. Yet in the Negev Desert, researchers found it accounts for almost half the water in three dominant shrubs. T…
1279. Coasts cover a sliver of the ocean yet sustain most commercial fishCoastal habitats account for only about 7 percent of the world's oceans, yet at least 85 percent of commercially caught fish depend on them at some stage of life. Nearly half of h…
1280. Montserrat's jagged peaks are made of cemented river pebblesThe mountain near Barcelona whose name means jagged mountain is built from conglomerate: rounded pebbles and cobbles glued together by natural cement. Erosion carved vertical chan…
1281. Most sand on the world's continental shelves was dumped there during the last ice ageThe shallow seabed fringing the continents is really drowned land. Around 60 to 70 percent of its sediment was laid down during the last ice age, when sea level stood 100 to 120 m…
1282. Darwin predicted a sunken volcano lies beneath every atoll, and he was rightOn the Beagle voyage, Charles Darwin reasoned that ring-shaped coral atolls grow on volcanic islands that slowly sank, the coral climbing upward to stay in the light. He predicted…
1283. The Cretaceous is named after chalk, and forests then grew near the polesFor some 77 million years, the longest period of the past half-billion years, Earth ran warm and mostly ice-free. Shallow seas flooded continents, forests reached the poles, and t…
1284. Crocodiles survived the dinosaur-killing asteroid partly by eating leftoversWhen an asteroid slammed into Mexico 66 million years ago, about three quarters of species vanished, including every dinosaur except birds. Crocodilians pulled through, likely bec…
1285. Earth's continents may be the only crust of their kind in the Solar SystemPlanetary geologists sort rocky crusts into three types. Almost every world has the second kind, basalt melted from the mantle. But the continents we live on count as tertiary cru…
1286. A medieval Chinese scholar deduced climate change from buried bambooAround the 11th century, Shen Kuo found petrified bamboo underground in a region far too dry to grow it. He concluded that climates shift over vast stretches of time. Climatology …
1287. The word cloud originally meant a lump of rockIn Old English, clud meant a hill or a mass of stone. Around the 13th century people began applying it to heaped rain clouds that looked like boulders, and the metaphor eventually…
1288. Which is Earth's deepest canyon depends on how you measure itAsk for the world's deepest canyon and you get an argument. Some point to Tibet's Yarlung Tsangpo at about 5,500 metres. Others pick Nepal's Kali Gandaki Gorge, where the river ru…
1289. Carlsbad Cavern was eaten out from below by sulfuric acidMost limestone caves are dissolved by rainwater trickling down from the surface. New Mexico's Carlsbad Cavern and Lechuguilla Cave seem to have formed the other way round. Hydroge…
1290. After the dinosaurs died, sharks ruled the seas and jungles reached the polesWhen an asteroid ended the age of dinosaurs 66 million years ago, it opened the Cenozoic, the era we still live in. Early on, the planet warmed until jungles spread to the poles a…
1291. Wispy cirrus clouds are seeded mostly by airborne mineral dustThose thin white streaks high overhead are made of ice, and each crystal needs something to grow on. Research aircraft sampling cirrus over North and Central America found mostly …
1292. Clay holds its shape thanks to a thin film of waterWet clay can be squeezed into any shape and then keeps it, because its microscopic mineral plates are glued by a film of water that lets them slide yet holds them in place. Fire t…
1293. The tallest cliff in the Solar System may be 20 kilometres highOn Miranda, a small moon of Uranus, a fault scarp called Verona Rupes may drop about 20 kilometres. On Earth, rankings are messier: a cliff need not be perfectly vertical, so whet…
1294. Climate is what you expect; weather is what you actually getA single rainy week tells you about weather. Climate is the pattern underneath, conventionally averaged over 30 years, a span chosen because it is long enough to smooth out quirks…
1295. Before the 1980s, scientists were unsure whether pollution would warm or cool EarthUntil the 1980s it was genuinely unclear whether extra greenhouse gases would outweigh the cooling from airborne soot and particles. The answer is now plain. The air holds roughly…
1296. Earth's climate runs on an energy budget with sunlight as incomeNearly all the energy in Earth's climate arrives as sunlight, and some leaks back out to space. When more comes in than goes out, the planet warms; when the balance tips the other…
1297. A blizzard is defined by its wind, not by how much snow fallsA foot of snow drifting down on a still day is just a snowstorm. A blizzard needs strong, sustained wind that whips snow into near-blindness for hours. In fact, no fresh snow need…
1298. Bogs grow so slowly that losing one can take millennia to undoIn a bog, plants grow sluggishly, but they rot even more slowly, because the waterlogged, acidic ground holds almost no oxygen. Dead moss piles up year after year as peat, sometim…
1299. Sharp-edged breccia reveals that its broken fragments never travelled farPebbles tumbling down a river lose their corners quickly, mostly within the first few kilometres. So when geologists find a rock packed with jagged, angular chunks cemented togeth…
1300. A feud between two Victorian geologists took a third period to settleAdam Sedgwick named the Cambrian after the Latin form of Cymru, the Welsh word for Wales, where he studied its rocks in 1831. His friend Roderick Murchison named the Silurian just…
1301. Darwin could not explain why animal fossils seemed to appear from nowhereIn 1859, Darwin admitted a troubling gap in his theory. Trilobites and other complex animals burst into the rock record with no visible ancestors beneath them. He guessed that old…
1302. Aluminium was once worth more than gold, until chemistry cracked bauxiteBauxite, a dull reddish rock named after a village in Provence, is where nearly all our aluminium starts. Before industrial refining, extracting the metal needed costly sodium or …
1303. International law uses a semicircle to decide what counts as a bayDraw a line across the mouth of a coastal inlet, then imagine a half-circle on that line. Under the UN Convention on the Law of the Sea, the inlet is a legal bay only if its water…
1304. Some beach sand has passed through the gut of a fishNear coral reefs, fish that graze algae off rocks and coral swallow grit along with their food, digest the organic part and excrete the rest. Over a lifetime, a single fish can tu…
1305. Why no suction pump can lift water higher than about 10 metresAir pushes down with the weight of about 1.03 kg on every square centimetre at sea level. That load equals a freshwater column roughly 10.3 m tall, which sets a hard ceiling: howe…
1306. The science of air now forecasts storms on Jupiter and distant exoplanetsAtmospheric science began with weather balloons and ground stations, but its reach now includes a storm on Jupiter bigger than Earth, planet-wide dust storms on Mars and a gas gia…
1307. Darwin's elegant theory of atolls may have the story partly backwardsCharles Darwin pictured each atoll as a coral necklace left behind when a volcano sank beneath the waves. It is a beautiful idea, and still widely taught, yet newer drilling sugge…
1308. Americans say fall because the British once did, before they stoppedFall is not an Americanism. It was ordinary English in sixteenth-century England, shortened from phrases like fall of the leaf. Settlers carried it across the Atlantic in the 1600…
1309. Shouting will not start an avalanche, but a skier crossing the slope canFilms love the yodel that brings down a mountainside, but the pressure of sound is far too feeble, by orders of magnitude, to break a snowpack. The real culprits are fresh snowfal…
1310. Basalt paves most of the Solar System's rocky surfaces, including VenusMore than nine in ten volcanic rocks on Earth are basalt, and the pattern repeats elsewhere. The dark seas on the Moon are old basalt floods, the plains covering about 80% of Venu…
1311. Earth's air reaches 1500 °C high up, yet would not feel hotIn the thermosphere the thin gas can hit about 1500 °C, but a person there would not feel warm, because molecules are so scattered that each drifts about a kilometre before meetin…
1312. Earth's winds run as three giant heat engines stacked in each hemisphereThe Sun heats the tropics far more than the poles, and the air spends its whole existence trying to even that out. The result is three circulation cells in each hemisphere, one of…
1313. We owe the word electricity to a lump of fossilised tree resinRub a piece of amber and it picks up chaff and scraps of fabric. The ancient Greeks called the stone elektron, and that static trick eventually gave English the words electric and…
1314. The world's biggest island cluster by count sits off Finland, not the tropicsIndonesia spans more than 17,500 islands and about 284 million people, yet the top spot for sheer number goes to Finland's Archipelago Sea, with roughly 40,000 mostly empty islets…
1315. People have been building islands by hand for well over a thousand yearsArtificial islands sound like a Gulf megaproject, but Bahrain's Al-Sayah Island was raised around a spring at least 1,200 years ago. In Solomon Islands lagoons, families still liv…
1316. Asbestos got its name by mistake from a Roman who confused it with limeIn ancient Greek, the word asbestos meant quicklime. Pliny the Elder, according to the Oxford English Dictionary, attached it to the fireproof mineral fibre, and the error stuck i…
1317. Dinosaurs appeared in the Triassic but crocodile cousins ruled itThe Triassic opened after a mass extinction that gutted life on Earth and closed with another. In between, over 50.5 million years, dinosaurs made their debut, yet the dominant la…
1318. Over half of Earth's surface is dark, flat seafloor few people have seenAbyssal plains, lying three to six kilometres down, cover more than half the planet's surface and rank among the flattest places on Earth. Yet scientists only recognised them as d…
1319. Even perfectly clean rain is slightly acidic, but acid rain is far worseAll rain carries a little carbonic acid from dissolved carbon dioxide, so clean rain sits just below neutral. Acid rain, loaded with sulphur and nitrogen pollution, typically fall…
1320. Wind rarely carves mushroom rocks; it mostly shifts sand along the groundDesert mushroom rocks and wind caves look like the work of sandblasting gales, but geologists now blame other causes, such as uneven weathering and rainwash. Windborne sand mostly…

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