Wacky Facts

Apple flesh contains lots of air pockets, making the fruit less dense than water — which is why apple bobbing works.

His 1924 work with Einstein led to Bose-Einstein statistics; particles called bosons are named after him.

Astronomers noticed Uranus drifting from its predicted path. Urbain Le Verrier calculated where an unknown planet must be pulling it, and in 1846 Johann Galle found Neptune within about one degree of that prediction on his first night of looking.

Mostly silica sand melted at around 1,700 °C with soda ash and limestone.

All the planets, moons, asteroids and comets together are a tiny fraction; Jupiter holds most of what is left. The Sun is so massive that it could hold about 1.3 million Earths by volume.

Recorded by underwater microphones in 1997, the very loud low-frequency sound sparked sea-monster theories; scientists later matched it to icequakes from breaking Antarctic ice.

Non-bird dinosaurs died out about 66 million years ago; modern humans appeared about 300,000 years ago.

Neutron stars are the collapsed cores of massive stars: more mass than our Sun squeezed into a ball about 20 km across. Their matter is so dense that a teaspoon would weigh roughly as much as a mountain.

They contain potassium-40; the “banana equivalent dose” is an informal unit to explain tiny radiation amounts.

Both are pure carbon. In diamond each atom is locked to four neighbours in a rigid 3-D lattice; in graphite the atoms form flat sheets that slide over each other — which is why graphite leaves marks on paper.

Honey is very low in water and naturally acidic, and bees add an enzyme that produces hydrogen peroxide. Together these make it extremely hostile to bacteria — sealed honey can last for thousands of years.

Botanically, a berry develops from a single flower with one ovary and has seeds inside. Bananas qualify; strawberries carry their seeds on the outside and come from a flower with many ovaries.

The brain predicts the sensation of your own movements and dampens the response. Because there is no surprise, the tickle reflex does not fire the way it does when someone else touches you.

A Martian solar day, called a “sol”, lasts about 24 hours and 39 minutes. Mission teams working with rovers have lived on Mars time, shifting their schedule by about 40 minutes every day.

Japanese researchers using ultra-sensitive cameras in 2009 found that the body emits extremely weak visible light that rises and falls during the day. It is about a thousand times too faint for our eyes to see.

The masseter, which closes the jaw, can generate very high force relative to its size, which is why human bite force is surprisingly strong. “Strongest muscle” depends on how you measure — the heart and the glutes have other claims.

The Kola Superdeep Borehole in Russia reached about 12.2 km in 1989, deeper than the Mariana Trench is deep, before rising temperatures stopped drilling.

Laid end to end, all the arteries, veins and capillaries would stretch an estimated tens of thousands of miles — often quoted as enough to circle the Earth more than twice. Most of that length is tiny capillaries.

The Sun is about 150 million km away and light travels at about 300,000 km per second, so we always see the Sun as it was roughly eight minutes and twenty seconds ago.

Astronomers saw its spectral line during an 1868 solar eclipse observed from India, before it was isolated on Earth in 1895.

If a nucleus were a marble in a stadium, the electrons would be buzzing around the outer seats.

Around 343 m/s in air and about 1,480 m/s in water.

The Indian tectonic plate is still pushing into Asia, lifting the Himalayas. Measurements suggest Everest rises by a few millimetres per year, though earthquakes and erosion also change its height.

Sound needs a medium such as air to travel. Space has so few particles that sound waves cannot travel between them in a way your ears could detect, so an explosion next to you in space would be silent.

Most substances shrink when they solidify, but water molecules lock into an open hexagonal crystal as ice. That is why ice floats, pipes burst in winter and lakes freeze from the top down, protecting the life below.

Iron expands in the heat, so the tower can grow by up to about 15 cm on hot days and shrink again in winter.

During the day the discs between the vertebrae are compressed by gravity, so you can lose about a centimetre of height. Lying down at night lets them recover.

Humans have about 400 types of smell receptors, and combinations of them let us tell apart a vast range of odours. Smell is also closely linked to memory, which is why a scent can bring back a moment instantly.

The air in a lightning channel can reach roughly 30,000 °C, while the visible surface of the Sun is about 5,500 °C. The heat lasts only microseconds, but it makes the air expand explosively — that sudden expansion is the thunder you hear.

Known as the Mpemba effect after a Tanzanian student who noticed it in 1963. Scientists still debate when and why it happens.

On the exoplanet HD 189733 b, astronomers think silicate particles form clouds, and winds of several thousand kilometres per hour could blow molten glass droplets sideways. Its deep blue colour comes from those clouds.

Claude Shannon estimated the number of possible chess games at around 10^120. The observable universe is estimated to contain about 10^80 atoms. Even a computer checking a billion games a second since the Big Bang would not get anywhere close.

The Moon has no wind or rain to erase them. Unless a meteorite hits the spot, the Apollo astronauts’ boot prints could survive for a very long time.

The giant volcano rises roughly 22 km above the surrounding plains and is about as wide as France. Its slopes are so gentle that someone standing on it might not realise they were on a mountain.

His 1928 discovery of how light scatters in liquids — the Raman effect — won the 1930 Nobel Prize in Physics. India celebrates National Science Day on 28 February for it.

Healthy soil can contain billions of bacteria per gram.

Old windows that are thicker at the bottom were made that way; glass at room temperature does not flow measurably over centuries.

At its triple point — about 0.01 °C and very low pressure — water exists as solid, liquid and gas together.

Saturn’s average density is lower than that of water, because it is mostly hydrogen and helium. It is the only planet in the Solar System less dense than water — though you would need a very large bathtub.

In computing it is often the time between system timer ticks; in physics it has been defined as the time light takes to travel one centimetre — about 33.4 picoseconds.

A newborn has around 270–300 bones and cartilage parts. Many fuse together during growth — in the skull, spine and pelvis — leaving about 206 in an adult.