60 Fun Facts About Weird Science

On which planet does a single rotation take longer than a full trip around the Sun?

A Venusian sidereal day lasts 243 Earth days, while its year is only about 225.

Which planet is the only one in the Solar System less dense than water?

It is about 30 percent less dense than water despite being 95 times Earth's mass.

Because of its 3:2 spin-orbit resonance, one sunrise-to-sunrise day on the innermost planet lasts how long?

That works out to roughly 176 Earth days from one sunrise to the next.

A matchbox full of neutron-star material would weigh roughly how much?

That is about the mass of a half-cubic-kilometre chunk of the Earth's crust.

The molecular cloud Sagittarius B2 near the Milky Way's centre contains large amounts of what?

It holds ethanol, methanol and vinyl alcohol, plus ethyl formate, the ester that gives raspberries their flavour.

Solar eclipses look perfect because the Sun is about 400 times wider than the Moon and also 400 times what?

The coincidence will not last: the Moon is slowly drifting away from Earth.

Viewed from space, what colour is the Sun?

Atmospheric scattering is what makes it look yellow, orange or red from the ground.

What colour are sunsets on Mars, thanks to fine dust scattering the light?

Mie scattering by red dust does the opposite of Earth's Rayleigh scattering, leaving blue hues around the setting Sun.

On Uranus and Neptune, methane is thought to be squeezed into what, which falls through the interior?

This 'diamond rain' may help drive the convection behind Neptune's magnetic field.

Roughly how many solar neutrinos pass through each square centimetre of your body every second?

Almost all of them pass straight through the entire Earth without touching anything.

How many hearts does an octopus have?

One systemic heart pumps blood round the body and two branchial hearts push it through the gills.

Which microscopic animals survived ten days exposed to the vacuum of space in 2007?

In their dehydrated 'tun' state they also tolerate temperatures from −272 °C to 149 °C.

Which jellyfish is called 'immortal' because it can revert from an adult back to a juvenile polyp?

In theory the cycle can repeat indefinitely, though individuals still get eaten or fall ill.

Which Australian marsupial's cube-shaped droppings won a 2019 Ig Nobel Prize for Physics?

The cubes are thought to stop the droppings rolling off the rocks and logs where they mark territory.

The platypus hunts with its eyes, ears and nostrils closed. What sense does it rely on instead?

It is also one of the very few venomous mammals, thanks to a spur on the male's hind foot.

By slowing its heart rate, a sloth can hold its breath underwater for up to how long?

That is longer than a bottlenose dolphin manages.

In a zero-oxygen atmosphere, how long can a naked mole-rat survive apparently unharmed?

It also lacks pain sensitivity in its skin and is remarkably resistant to cancer.

Which North American amphibian winters frozen solid, with no heartbeat, breathing or brain activity?

Up to 70 percent of its body water turns to ice, and it thaws out in spring and hops away.

The oldest known individual of which species was estimated at 392 years old, give or take 120?

The species is thought to live at least 272 years, making it the longest-lived vertebrate.

The peacock mantis shrimp's strike creates what in the water, hitting prey a second time?

Its club accelerates at over 10,000 g and hits with a force of about 1,500 newtons.

The flash from a pistol shrimp's collapsing bubble implies a temperature above roughly what?

That is not far off the surface temperature of the Sun, though it lasts only a fraction of a second.

The bombardier beetle defends itself by spraying a chemical mix that reaches roughly what temperature?

Hydrogen peroxide and hydroquinones react explosively inside the beetle and pop out of a rear valve.

Which animal's heart rate can drop to just two beats per minute during a deep dive?

The heart of one stranded blue whale weighed 180 kilograms, the largest of any animal.

What colour is horseshoe crab blood, harvested to test for bacterial contamination?

Copper-based hemocyanin does the job that iron-based hemoglobin does in us.

Where are a butterfly's taste receptors located?

Females use them to check whether a leaf will feed their caterpillars before laying eggs on it.

Which mammals may live more than 200 years, making them the longest-lived of all?

They also have the longest baleen plates of any whale, up to five metres.

When startled, some sea cucumbers defend themselves by doing what?

The process is called evisceration, and the organs grow back.

Why do zebras have stripes, according to the theory with the most supporting evidence?

In experiments, horses dressed in zebra-print coats attracted far fewer landing flies.

Which fungus takes control of a carpenter ant's behaviour and then grows a fruiting body out of its head?

Alfred Russel Wallace discovered the 'zombie-ant fungus' in 1859.

Modern estimates put the microbial cells in and on a human body at roughly how many compared with human cells?

The old '10 to 1' figure was revised down in 2016.

A 2014 study suggested the average human nose can distinguish roughly how many different odours?

The old textbook figure of 10,000 came from impressionistic findings in the 1920s.

Human stomach acid sits at roughly what pH, similar to that of carrion-eating carnivores?

The acid is secreted at a pH as low as 0.8 before being diluted in the stomach.

Bananas are slightly radioactive because of which isotope?

One banana is worth about 0.1 microsieverts, though the potassium is excreted rather than accumulated.

Toxoplasma gondii changes rodents' behaviour so they are more likely to be eaten by what?

Cats are the only hosts in which the parasite can reproduce sexually, so the manipulation helps it complete its life cycle.

Chili peppers burn mammals but not birds. Which receptor in birds simply does not respond to capsaicin?

That suits the plant: birds swallow the seeds whole and spread them, while mammal molars destroy them.

The Mpemba effect is the surprising observation that, under some conditions, which liquid freezes faster?

It is named for a Tanzanian student who noticed hot ice-cream mix froze first in 1963.

What can superfluid helium do that ordinary liquids cannot, at about 20 cm per second?

In this state its flow is limited not by viscosity but by a critical velocity, so it siphons itself out.

Lightning heats nearby air to about what temperature, several times hotter than the Sun's surface?

An average bolt carries about 30,000 amperes and a gigajoule of energy.

At the triple point, about 0.01 °C and a pressure of roughly 611 pascals, what does H2O do?

The point was so precise it once helped define the kelvin.

Since 20 May 2019, the kilogram has been defined by fixing which fundamental quantity?

The ampere, kelvin and mole were redefined the same day.

The speed of sound in fresh water is roughly how many m/s, over four times its speed in air?

That is why whales can hear each other across entire ocean basins.

Vantablack, once billed as the world's darkest material, absorbs up to what share of visible light?

It is grown as a forest of carbon nanotubes by chemical vapour deposition at 400 °C.

A popcorn kernel pops when the steam inside reaches about what temperature and pressure?

The starch inside then puffs to 20 to 50 times the kernel's original size.

The hottest air temperature ever recorded on Earth, 134 °F (56.7 °C), was measured in 1913 where?

The same spot logged a ground-surface temperature of 201 °F in 1972.

Which continent is technically a desert, receiving the equivalent of only about 150 mm of water a year?

The dry conditions preserve meteorites so well that ones over a million years old have been found there.

What is a leading explanation for reports of fish and frogs raining from the sky?

In 1987 three towns in Gloucestershire, England, reported showers of tiny pink frogs.

The largest known living organism spans 3.5 square miles of Oregon forest. What is it?

The Malheur National Forest 'humongous fungus' may weigh as much as 35,000 tons.

Pando, in Utah's Fishlake National Forest, looks like a forest of 47,000 trees but is actually what?

It is regarded as the heaviest tree on Earth, spanning about 106 acres.

What did the slime mould Physarum polycephalum recreate in a 2010 experiment using oat flakes laid out as Tokyo?

The brainless organism linked the flakes with a network as efficient as the engineered rail system.

Mature sunflower heads do not track the Sun. Which direction do they end up facing all day?

Only young flower buds swing from east to west and reset overnight.

Mimosa pudica, the 'sensitive plant', reacts to a touch by doing what within seconds?

The movement is costly for the plant and interrupts photosynthesis, but seems to deter grazers.

Why does properly stored honey not spoil?

Edible honey has been found in ancient Egyptian tombs.

The glass frog gets its name because the skin on its underside is transparent enough to reveal what?

The translucent legs also blur its outline against leaves, making birds less likely to attack.

Axolotls are studied intensely because they can regrow which of these?

Their 32-billion-base-pair genome, published in 2018, was the largest animal genome sequenced at the time.

What finally explained the 'sailing stones' that leave long tracks across Death Valley's Racetrack Playa?

Timelapse footage published in 2014 showed the rocks moving after more than a century of speculation.

What gives Antarctica's Blood Falls its red colour, first spotted in 1911?

Iron-rich hypersaline water from a pool under about 400 metres of ice rusts on contact with air; explorers first blamed algae.

By how much does hagfish slime expand within 0.4 seconds of hitting seawater?

The slime clogs a predator's gills; the hagfish then ties itself in a travelling knot to scrape the goo off its own body.

How many people were suffocated when Cameroon's Lake Nyos belched a cloud of carbon dioxide in 1986?

Magma 80 km below the lake leaks CO2 into the water; degassing tubes installed from 2001 now vent it safely.

What is a 'brinicle', sometimes nicknamed an icy finger of death?

As sea ice forms it expels dense, super-cold brine that sinks and freezes the water around it into a downward-growing tube.

How many types of photoreceptor cell can a mantis shrimp's eye have, against four in humans?

They see from deep ultraviolet to far-red plus polarised light, and their punch accelerates at around 10,000 g.