Cool Facts That More People Should Know

List Rules
Vote up all the cool facts that should be more well known.

Facts are fun. Cool facts are even better and can make you the star of any gathering. The world is a strange place, so your treasure trove of information could be unsettling facts about wild animals or jaw-dropping nuggets about nature and the human body.

Learning about such things not only sharpens your mind but also gives you fodder to share with friends and family. So here are some cool facts to wax eloquent about.

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    6,733 VOTES

    Humans Can Smell Fresh Rainfall Better Than Sharks Can Smell Blood In The Water

    Many people love the smell of fresh rain, also known as petrichor. The scent is a chemical released by bacteria of the genus Streptomyces called geosmin. The smell attracts small arthropods, which eat the bacteria and spread the spores, thus aiding in reproduction.

    Humans are very good at smelling geosmin even though they don't have strong olfactory powers. People can smell geosmin in concentrations as weak as 100 parts per trillion. In comparison, a shark can only sniff out blood in one part per million in seawater.

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    4,532 VOTES

    Overgrazed Acacia Trees Can Send Chemical Signals To Other Trees That Turn Them Lethal

    In 1990, Wouter Van Hoven, a zoologist from Pretoria University, investigated the deaths of a herd of 3,000 antelope on a South African game ranch. While observing both the antelope, called kudu, and giraffes, he noticed that the giraffes ate only a few acacia leaves from one tree and avoided anything downwind. The kudu ate everything in sight.

    Van Hoven eventually realized that acacia trees send a chemical signal to other trees. The signal is ethylene and can travel up to 50 yards, or 150 feet, warning other acacia trees. Within five to 10 minutes, the "warned" trees boosted tannin levels in their leaves, rendering them poisonous to eat. If the kudu kept eating these leaves, they perished.

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    4,910 VOTES

    For The First 60 Million Years That Trees Existed, They Did Not Decompose

    When trees first grew on Earth, they were tall but had a poor root system, so they frequently toppled over. As more trees fell, wood began to pile up on forest floors, but the bacteria and fungi that break down cellulose and make the wood decompose would not evolve until 60 million years later.

    Until then, the sheer weight of wood on top of wood turned the bottom layers first into peat, then coal.

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    3,711 VOTES

    Sharks Existed Before Saturn Got Its Rings

    Saturn is about 4.5 billion years old, but its rings are much younger. Scientists estimate the rings formed from 10 million to 100 million years ago, although it's not certain how they came into being. 

    The evolution of sharks started more than 400 million years ago, which makes prehistoric sharks and other shark-like fish chimeras (ghost sharks) older than the rings of Saturn. 

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    2,989 VOTES

    Australia Is Wider Than The Moon

    The moon's diameter is approximately 3,600 kilometers, or 2,237 miles. Australia's diameter is about 4,000 kilometers, or 2,486 miles, which means it is wider than the moon.

    The surface area of the moon, however, is much larger: 37.94 million square kilometers. The land area of Australia is 7.69 million square kilometers.

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    2,826 VOTES

    Butterflies Can Suck Nutrients From Blood, Dung, And Decomposing Matter

    Butterflies don't just delicately sip nectar from flowers; they have a dark side. To get the nutrients they need, butterflies are more than happy to get their proboscises on less savory stuff, like sap, blood, sweat, tears, and decomposing or fecal matter. 

    This behavior, called mud puddling, also common in moths, helps the insects get sodium and other amino acids missing from their plant-based diets.