All 31 odd truths

Is a day on Venus longer than a year on Venus?

Yes. Venus takes about 243 Earth days to spin once on its axis, but only about 225 Earth days to travel all the way around the Sun. A Venusian day is longer than a Venusian year.

Would Saturn float in water?

On average, yes. Saturn's mean density is about 0.69 grams per cubic centimetre, lower than water's 1.0, making it the only planet in the solar system less dense than water. Given a big enough bathtub, it would float.

Is the Moon moving away from Earth?

Yes. The Moon drifts about 3.8 centimetres further from Earth every year — roughly the rate your fingernails grow. It is a direct measurement, not a model, taken by bouncing lasers off reflectors the Apollo astronauts left behind.

Are there more trees on Earth than stars in the Milky Way?

Yes, by a wide margin. A 2015 study in Nature put the global tree count at roughly 3.04 trillion. The Milky Way is generally estimated to hold somewhere between 100 and 400 billion stars — around ten times fewer.

Are there more possible chess games than atoms in the universe?

Yes. The number of possible chess games is estimated at around 10^120, known as the Shannon number. The observable universe contains roughly 10^80 atoms. Chess outruns it by about forty orders of magnitude.

Do octopuses really have three hearts?

Yes. An octopus has three hearts: two branchial hearts that push blood through the gills, and one systemic heart that sends it around the body. The systemic heart stops beating when the octopus swims, which is part of why they would rather walk.

Why is wombat poop cube-shaped?

Because their intestines are not uniformly stiff. Research published in Soft Matter found regions of the wombat's gut are twice as thick and four times as stiff as neighbouring regions, so contractions mould corners into the faeces over the final stretch of intestine.

Are sharks older than trees?

Yes. Sharks appear in the fossil record around 450 million years ago; the first true trees show up around 385 million years ago. Sharks predate forests by roughly 65 million years — about the same gap that separates us from the last dinosaurs.

How hard does a mantis shrimp punch?

Fast enough to boil water. A 2004 Nature study clocked the peacock mantis shrimp's club at around 23 metres per second, accelerating like a bullet. The strike drops the water pressure so sharply that vapour bubbles form and violently collapse — so prey gets hit twice.

Can turtles really breathe through their butts?

Some can. Several freshwater turtles absorb oxygen through the lining of the cloaca. The Fitzroy River turtle of Australia does it well enough to meet effectively all of its oxygen needs this way, letting it stay submerged for extraordinarily long stretches.

Do sea otters hold hands while they sleep?

Sometimes, genuinely. Resting sea otters do link paws so they don't drift apart from their raft. It is real behaviour and not a myth — but it is less frequent than the internet implies, and rafts mostly stay together by watching and listening to each other.

Can bees recognise human faces?

Yes. In a 2005 study, honeybees were trained on photographs from a standard human face-recognition test and picked the target face out from a similar distractor with better than 80 percent accuracy — and still remembered it two days later.

Have tardigrades survived in open space?

Yes. In 2007 the European Space Agency exposed dried tardigrades to the vacuum of low Earth orbit for ten days. Those shielded from solar UV revived at rates comparable to controls on the ground, and went on to lay eggs that hatched normally.

Can sloths hold their breath longer than dolphins?

Yes. Sloths can stay underwater for up to about 40 minutes by slowing their heart rate dramatically. Most dolphins manage roughly 10 to 15 minutes. The animal built for water loses to the animal built for hanging in a tree.

Do any birds have contagious laughter?

Yes. New Zealand's kea has a distinct play call, and researchers found that simply playing a recording of it puts other kea in the mood to play. It is the first known case of emotionally contagious vocalisation in a non-mammal.

Do human beings glow in the dark?

Yes, faintly. Human bodies emit a small amount of visible light as a by-product of metabolism. Researchers imaged it with ultra-sensitive cameras in 2009. It is roughly a thousand times weaker than the human eye can detect, so nobody has ever seen it.

Why can't I see the blind spot in my own eye?

Because your brain fills it in. Each eye has a patch of retina with no photoreceptors, where the optic nerve exits. You never notice the gap because your visual system invents plausible content to cover it, using whatever surrounds the hole.

Did Cleopatra live closer in time to the Moon landing than to the building of the Great Pyramid?

Yes. The Great Pyramid was built around 2560 BC. Cleopatra died in 30 BC — about 2,500 years later. The Apollo 11 Moon landing was in 1969, roughly 2,000 years after her death. She is nearer to us than to the pyramids by about 500 years.

Is Oxford University older than the Aztec Empire?

Yes. There is evidence of teaching at Oxford as early as 1096. Tenochtitlan, the Aztec capital, was founded in 1325 — 229 years later. The empire proper dates from an alliance in 1428, by which time Oxford had had colleges for over 150 years.

What was the shortest war in history?

The Anglo-Zanzibar War, fought on 27 August 1896 between the United Kingdom and the Sultanate of Zanzibar. It lasted somewhere between 38 and 45 minutes. Around 500 people died in that time, almost all of them Zanzibari.

How old is Nintendo?

Nintendo was founded in 1889, making playing cards. It is older than sliced bread, the Ottoman Empire's collapse, and both world wars. The company spent its first seventy years in paper before it ever touched an electronic anything.

Is the fax machine older than the telephone?

Yes, by 33 years. Scottish clockmaker Alexander Bain patented the first fax device — an Electric Printing Telegraph — on 27 May 1843. Alexander Graham Bell patented the telephone in 1876. We could send a picture before we could send a voice.

Was bubble wrap invented as wallpaper?

Yes. In 1957 Alfred Fielding and Marc Chavannes sealed two shower curtains together, trapping air bubbles between them, and tried to sell it as textured three-dimensional wallpaper. Nobody wanted it. Packaging was the third idea, not the first.

How much does a cloud weigh?

An average cumulus cloud holds roughly 500,000 kilograms of water — about 1.1 million pounds, or 550 tons. It floats because the air underneath it is denser than the cloud is, not because the cloud is light.

Does it ever snow in the Sahara desert?

Yes. The town of Ain Sefra in Algeria, known as the gateway to the desert, has had snow settle on its red dunes repeatedly — most famously in December 2016, the first snowfall there since 1979, and several times since.

Is there an ATM in Antarctica?

Yes — one. There is a working ATM at McMurdo Station, at 77 degrees south, operated by Wells Fargo. It is the only cash machine on the continent, it dispenses US dollars, and a technician flies down to service it roughly every two years.

Does honey ever go bad?

Sealed honey does not spoil. Archaeologists have recovered pots of honey from ancient Egyptian tombs, sealed for over 3,000 years, still edible. Three things do it: almost no water, an acidic pH, and hydrogen peroxide produced by an enzyme from the bees.

Is a banana a berry, and is a strawberry not one?

Botanically, yes on both counts. A berry develops from a single flower with a single ovary and contains seeds inside its flesh — which describes a banana. A strawberry grows from a flower with many ovaries, making it an aggregate accessory fruit.

What is the dot over the letter i called?

It is called a tittle. The word comes from the Latin titulus, meaning a heading or inscription, and it describes the small distinguishing dot over a lowercase i or j. Scribes added it so the letters wouldn't get lost in dense handwriting.

What is Scotland's national animal?

The unicorn. It is not a joke or a tourist-board invention: the unicorn has appeared on the Scottish royal coat of arms since the twelfth century, and in heraldry it is always shown bound in a gold chain.

Does the Eiffel Tower change height?

Yes. The tower is made of iron, and iron expands when it warms. Across the seasons the Eiffel Tower's height varies by up to about 15 centimetres, and in strong wind the top can sway around 6 to 7 centimetres.