All facts — Page 26

In eighteen thirty-five, the US national debt was exactly zero.

President Andrew Jackson, who hated debt and central banks, managed to completely pay off the federal debt, the only…

Ancient Romans used crushed mouse brains as toothpaste.

The writer Pliny the Elder documented this bizarre practice, believing that the ashes and tissues of rodents helped…

The Great Wall of China was built by paid laborers and soldiers.

Contrary to the popular myth that it was built by slaves, most builders were peasants doing mandatory military…

Ancient Greeks used olive oil to bathe instead of soap.

They would spread olive oil over their bodies to loosen dirt and sweat, then scrape the mixture off with a curved…

The smell of cut grass is actually a chemical distress signal from the plant.

When grass is damaged by a mower, it releases organic compounds called green leaf volatiles to warn neighbouring…

Marine phytoplankton produces over fifty percent of Earth's oxygen.

These microscopic microorganisms float in the oceans and perform photosynthesis, generating more oxygen for the…

A single mature oak tree can drop ten thousand acorns in a single year.

During so-called mast years, oaks produce an overwhelming amount of acorns to ensure that, even after being eaten by…

There is a lake in Australia that is naturally bright pink.

Lake Hillier owes its unusual colour to the presence of a microalgae called Dunaliella salina, which produces a red…

Trees can hear water and grow towards it.

Studies show that the roots of certain plants can detect the sound vibrations of flowing water and actively grow…

The corpse flower smells like rotting meat to attract flies.

This giant plant from Indonesia heats its central spike to volatilise sulphur compounds, mimicking the smell of a…

If you remove the empty space from atoms, the entire human race would fit inside an apple.

Atoms are composed of ninety-nine point nine nine percent empty space. If you compressed all the solid matter of the…

Water can remain liquid well below freezing in a state called supercooling.

If the water is very pure and lacks crystallisation nuclei where ice can start to form, it can cool to minus forty…

On the exoplanet HD 189733b, it rains molten glass sideways.

The atmosphere of this giant planet is swept by winds of eight thousand kilometres per hour, pushing condensed…

The Milky Way is moving through space at two million kilometres per hour.

Our galaxy is pulled by the gravity of massive structures like the Great Attractor, travelling at a mind-boggling…

A teaspoon of water contains more molecules than drops of water in the ocean.

Due to the tiny size of H2O molecules, a simple teaspoon contains about one and a half sextillion molecules, a number…

The sunset on Mars appears blue to the human eye.

The fine dust in the Martian atmosphere absorbs red light and scatters blue light, which reverses the effect we see…

Saturn's rings are mostly made of chunks of ice and rock.

These fragments range from the size of a grain of sand to the size of a house, reflecting sunlight and creating the…

The largest known structure in the universe is the Hercules-Corona Borealis Great Wall.

This massive galactic filament is about ten billion light-years long and contains thousands of galaxy superclusters…