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Even [[identical twins]] with the same [[genes]] can differ in handedness: one may be [[left-handed]] and the other right-handed. Such discordance in twin studies shows that although genes influence handedness, they do not determine it alone.

About 10% of people worldwide are [[left-handed]]. A 2020 [[meta-analysis]] covering more than two million people estimated the best overall prevalence at 10.6%—confirming the familiar figure of roughly one person in ten.

In 1907, biologist [[Henry Van Peters Wilson]] pushed a [[sponge]] through silk mesh into loose [[cells]]. They regrouped in seawater and regrew into a sponge. Later experiments mixing two species found that cells sorted by species and formed separate sponges.

One reason [[Airplane|airplane]] [[Airline meal|meals]] taste flat is [[Air pressure|cabin pressure]]. Cabins mimic 1,800–2,400 m altitude and dry nasal passages. A 2010 Fraunhofer experiment found sweet and salty [[Taste|taste]] sensitivity fell ~30%, so airlines emphasize umami and tomato juice.

More than 90% of the [[Methane|methane]] [[Cattle|cattle]] produce escapes through [[Belching|belching]], not flatulence. Anaerobic microbes in the rumen ferment grass and generate methane, which exits primarily through the mouth.

[[Schrödinger's cat]] was made to criticize [[Quantum mechanics|quantum mechanics]], not explain it. In 1935, [[Erwin Schrödinger]] argued that the [[Copenhagen interpretation]] absurdly leaves an everyday cat both alive and dead. His critique became quantum theory's best-known illustration.

[[Earth]] reaches its farthest point from the [[Sun]], aphelion, in early July—the Northern Hemisphere's [[Summer|summer]]. At ~152 million km, it is 5 million km farther than in January. [[Season|Seasons]] come from axial tilt, not distance: Earth is farthest from the Sun in midsummer.

On August 9, 1945, atomic bomb [[Fat Man]]'s primary target was [[Kokura]], not [[Nagasaki]]. Smoke and clouds obscured the target through 50 minutes and three failed runs. With fuel critically low, the B-29 Bockscar diverted to Nagasaki, its secondary target.

In 1897, the [[Indiana]] House passed a bill that effectively made [[Pi|pi]] 3.2, 67–0. Its author, an amateur mathematician, thought he had squared the circle and offered free school rights. Purdue professor Clarence Waldo saw it in the Senate, explained the error, and the bill was tabled.

Sterile fly [[Maggot|maggots]] are an FDA-approved medical device. They eat only dead tissue and secrete compounds that clean wounds and kill drug-resistant bacteria. Where [[Antibiotic|antibiotics]] fail against chronic infections, maggot therapy can work. The [[FDA]] cleared it in 2004.

One gram of [[DNA]] can theoretically hold 215 petabytes — roughly 200 million movies. Its four bases act as a base-4 storage medium. In 2017, George Church's [[Harvard]] team stored a short film and images in DNA and retrieved them without errors. Properly stored, DNA can last millennia.

People with red-green [[Color blindness|color blindness]] can see green [[Camouflage|camouflage]] in finer detail. Less distracted by color, they rely on brightness and texture, making concealment easier to spot. Wartime accounts say Allied forces used colorblind soldiers as photo interpreters.

[[Human]]s are the only [[Primate|primate]] with obvious white sclera. Apes have darker sclera that hide gaze direction, but human eyes broadcast where someone is looking. The Cooperative Eye Hypothesis says this 'eye that cannot lie' helped early coordination and group [[Hunting|hunting]].

In 1696, [[Britain]] taxed houses by window count. Homeowners bricked up windows to cut the bill, leaving rooms without enough [[Light|light]] or ventilation. Doctors opposed the health effects; the [[Tax|tax]] was repealed in 1851. Bricked-up window outlines remain on old buildings.

During [[Sleep|sleep]], the [[Brain|brain]] not only stores memories — it erases them. Research from 2022–2023 found Arc and Homer1a can weaken less-active [[Synapse|synapse]] connections. Forgetting is a feature, not a bug: clearing space helps encode new [[Memory|memories]].

In 2005, Yale researchers taught [[Capuchin monkey|capuchin monkeys]] to use metal tokens as [[Currency|currency]]. The monkeys developed gambling and loss aversion spontaneously. Some males exchanged tokens with females for food.

At [[Mount Everest]]'s summit (~8,849 m), air pressure is only ~33% of sea level, so [[Water|water]] boils at about 70 °C. Since bubbles form well below 100 °C, pasta stays undercooked and eggs won't hard-boil — no matter how long you heat them on the world's highest peak.

[[Marie Curie]]'s notebooks remain in lead-lined boxes 90+ years after her death — still dangerously [[Radioactivity|radioactive]]. Soaked in [[Radium|radium]] and [[Polonium|polonium]] she handled bare-handed, readers must sign a waiver and wear protective gear. Radium's half-life is 1,600 years.

An [[Ostrich]] eye is about 5 cm across and 60 g — heavier than its [[Brain|brain]]. The eyes occupy more skull space than the brain, flattening it between them. This visual system helps spot predators from up to 2 km away: an [[Evolution|evolution]]ary trade-off for a flightless [[Bird|bird]].

During the 1962 [[Cuba|Cuban]] [[Missile]] Crisis, Soviet sub B-59 was hit by U.S. depth charges; its captain prepared a [[Nuclear weapon|nuclear]] torpedo launch. All three senior officers had to agree, but Vasili Arkhipov alone refused. His no is credited with preventing [[Nuclear war]].

The [[Dragonfly]] is a specialized aerial hunter. In one experiment, Libellula cyanea caught up to 95% of fruit flies it pursued. Its trick is prediction: its visual system and [[Brain|brain]] estimate the prey's future path, while four independent wings steer it to the intercept point.

[[Moon]] [[Dust|dust]] is razor-sharp. Earth's sand is worn smooth by water and wind, but lunar dust has never been weathered, leaving it jagged like broken glass. Apollo astronauts' suits were visibly abraded within days. Dust control is now a key engineering challenge for [[Artemis]].

The supermassive [[Black Hole|black hole]] in the Perseus galaxy cluster sends sound waves through surrounding hot gas. Each oscillation takes about ten million years, far below human hearing. In 2022, [[NASA]] pitched it up about 57 octaves and released it as the viral 'sound of the universe.'

When the [[Hubble Space Telescope]] launched in 1990, its mirror was off by 2.2 micrometers due to a miscalibrated polishing device. Its blurry images became a global embarrassment. In 1993, [[NASA]] astronauts aboard a [[Space Shuttle]] installed corrective optics, and Hubble finally worked.

Some [[Moth|moths]] fight back against [[Bat|bats]] with ultrasonic clicks. A 2009 Science study found tiger moths emit rapid clicks as a bat closes in, jamming echolocation and skewing distance estimates. This is part of a long [[Evolution|evolution]]ary arms race between bats and moths.

Aboard the [[International Space Station]], [[Tear|tears]] don't stream down a face. In [[Gravity|microgravity]], surface tension makes them cling around the eye as a growing blob, blocking vision and causing pain if unwiped. Astronaut [[Chris Hadfield]] demonstrated it on the ISS in 2013.

Most human cells pack ~2 m of [[DNA]] into a nucleus just 6 micrometres wide. Scaled across the [[Human body]], that is tens of billions of km — enough to span the Earth–Sun distance hundreds of times. DNA fits by winding around protein spools and compacting about 10,000-fold.

Each night, a [[Hummingbird]] enters torpor: its heart slows from up to 1,200 bpm to under 50, body temperature drops from 40°C to ~10°C, and metabolism falls 95%. Without this near-death energy saving it could starve before dawn; wing-muscle tremors wake it before sunrise.

A [[Venus flytrap]] doesn't snap shut on the first touch. One trigger-hair touch arms the trap; a second within 20–40 seconds fires it. This avoids wasting energy on raindrops or debris. A third touch in the window signals struggling prey and starts digestive enzymes.

A male [[cicada]]'s abdomen is almost hollow. Instead of organs, it holds a resonating chamber and a tymbal — a stiff membrane buckled by muscle to make sound. The hollow belly amplifies it. The loud African cicada *Brevisana brevis* can reach 106 decibels.

When [[Willis Carrier]] designed the first [[air conditioner]] in 1902, cooling people wasn't the goal. A New York printing plant hired him to fight [[humidity]] that warped paper and blurred ink. Chilling the air was incidental — the original patent was simply called "Apparatus for Treating Air."

[[Tears]] come in three types — basal, reflex, and emotional — with measurably different chemistry. A 1980s study found emotional tears contain more [[prolactin]] and manganese than reflex tears, supporting the hypothesis that crying may expel stress-related biochemicals.

Gray [[dinosaur]]s were artistic convention. Since 2010, scientists have inferred real colors by studying fossil [[melanosome]]s, pigment organelles preserved in feathers. The first result showed *Sinosauropteryx* had an orange-and-white striped tail; dozens of species have since gained color.

[[Mosquito]] males and females beat their wings at different frequencies, but before mating they tune toward a shared [[harmonic]]. In *Aedes aegypti*, females (~400 Hz) and males (~600 Hz) converge near 1,200 Hz. A 2009 *Science* study found this synchrony is key to mate choice.

In 1984, [[Barry Marshall]] drank [[Helicobacter pylori]] culture to prove bacteria caused stomach ulcers after medicine dismissed the idea. He developed [[gastritis]] within days, cured himself with antibiotics, and shared the 2005 [[Nobel Prize in Physiology or Medicine]] with Robin Warren.

In a 2010 Harvard study, [[IBS]] patients handed pills labelled "Placebo — inert ingredients" still improved significantly more than untreated patients. The [[brain]] responds to the ritual of swallowing a pill even without deception — triggering real neurochemical changes.

The [[International Space Station]] orbits Earth every 92 minutes, so its crew sees 16 sunrises and sunsets daily. A 45-minute day-night cycle would wreck their sleep — so [[astronaut]]s keep window shades closed and run the station on Greenwich time, regardless of the light outside.

[[Claude Monet]]'s 1923 cataract surgery removed his right eye's lens, giving him a rare ability: seeing [[ultraviolet]] light, which healthy lenses filter out. Water lily flowers glow in UV. His late paintings show it — strikingly more blue and violet than anything before the surgery.

The [[Great Pyramid of Giza]] looked nothing like today: built around 2560 BC, it was sheathed in polished white [[limestone]] from Tura — mirror-smooth, reflecting desert sun for kilometres. Medieval [[Cairo]] builders stripped most casing stones away from the 14th century onward.

'[[Big Bang]]' was named by the theory's chief opponent. British astronomer [[Fred Hoyle]] coined it in a 1949 BBC lecture to contrast his Steady State [[cosmology]] with the notion that all matter erupted from nothing at one moment. The label went global; Hoyle never accepted the theory.

Today's sweet [[watermelon]] is the result of millennia of breeding and [[genetics]]; wild varieties had pale, bitter flesh. Ancient [[Egypt]] knew watermelons well: pharaoh [[Tutankhamun]]'s tomb held 11 baskets of seeds. The red color is [[lycopene]], selected over thousands of years.

Stenocara, a [[beetle]] from the Namib Desert, collects drinking water from [[fog]]. Its wing covers mix water-attracting bumps, where droplets grow, with water-repelling channels that guide them to its mouth. Described in Nature in 2001, the structure inspired biomimetic fog collectors.

The mammalian [[placenta]] depends on a protein that came from a [[virus]]. An ancient retroviral sequence was repurposed to make [[syncytin]], which helps cells fuse at the boundary between mother and fetus. Placental mammals may partly owe their birth system to an old viral infection.

About 8% of the human [[genome]] is made of ancient [[retrovirus]] sequences. When viral DNA entered sperm or egg cells, the infection did not die with one body; it became inheritable, passed down like a [[gene]]. Our DNA carries molecular fossils from viruses that infected our ancestors.

Textbooks taught for decades that [[bacteria]] outnumber human [[cell]]s 10 to 1 — a 1972 rough estimate cited without scrutiny. A 2016 Weizmann study found about 38 trillion gut [[microbe]]s vs. 30 trillion human cells: 1.3 to 1, not 10 to 1. The number was inflated tenfold.

Some [[sea slug|sea slugs]] eat algae and keep the stolen [[chloroplast]] inside their own cells. The borrowed chloroplasts can keep doing [[photosynthesis]] for weeks or months, giving the animal a temporary solar battery.

In 2010, researchers placed oat flakes on a wet dish where cities around [[Tokyo]] would be, then added [[slime mold]]. The brainless single cell grew tubes between the food and pruned them until its network resembled Tokyo’s [[railway|rail system]] in efficiency, cost, and resilience.

A [[wildfire]] can survive winter after it seems dead. If embers burn into deep [[peat]], they can smolder under snow for months, then return to the surface when spring dries the ground. Researchers call these [[Zombie|zombie]] [[Fire|fires]].

The Herculaneum [[Scroll|scroll]] buried by the [[Volcano|volcano]] Vesuvius was a charcoal lump that would crumble if opened. In 2026, X-ray 3D scans and [[AI]] ink detection let researchers read one scroll end to end for the first time since AD 79: an ancient library opened without opening it.

[[Earth]]'s [[magnetic field]] has flipped hundreds of times; the last reversal was about 780,000 years ago. During reversals the field can weaken to under 10% of today’s strength, letting [[aurora|auroras]] appear near the equator. Since 1840, Earth’s field has already weakened by about 9%.