Did You Know? | Interesting facts about the world around us.

Posted by Between the Lines • Profile • 10/21/26 at 01:30AM • Curiosity, Exploration, Discovery • See more by Between the Lines

Did You Know? | Kudos365 Curiosity series

1. The world's largest desert is Antarctica.
A desert is defined primarily by how little precipitation it receives, not by temperature or sand. Antarctica covers about 5.5 million square miles, making its polar desert larger than the Sahara.

2. Sea otters sometimes use rocks as tools.
Sea otters can place a rock on their chest while floating and repeatedly strike shellfish against it to open them. Some individuals also carry favored rocks with them, storing them in loose folds of skin beneath their forelimbs.

3. The smell after rain has a name.
That distinctive earthy scent is called petrichor. Moisture helps release compounds from soil and plants into the air. One important contributor is geosmin, a substance produced by soil microorganisms that the human nose can detect at remarkably low concentrations.

4. The deepest known point in Earth's oceans is almost seven miles down.
The Challenger Deep, in the Mariana Trench of the western Pacific, reaches approximately 10.9 kilometers—nearly 7 miles—below sea level. At that depth, water pressure is more than a thousand times the atmospheric pressure experienced at sea level.

5. The Great Lakes contain about one-fifth of the world's surface fresh water.
Together, Lakes Superior, Michigan, Huron, Erie, and Ontario hold roughly six quadrillion gallons of water. By surface area, they form the largest freshwater lake system on Earth and contain about 20 percent of the world's fresh surface water.

6. Butterflies taste with their feet.
Butterflies have chemical receptors on their legs and feet that help them identify substances when they land. Female butterflies can use these receptors to help determine whether a plant is suitable for laying their eggs.

7. Earth's inner core is about as hot as the surface of the Sun.
Temperatures near Earth's center are estimated to reach roughly 5,000–6,000°C (9,000–11,000°F). Despite this enormous heat, the inner core remains solid because of the tremendous pressure deep inside the planet.

8. The first practical traffic light appeared before automobiles dominated city streets.
A gas-powered traffic signal was installed near London's Houses of Parliament in 1868 to manage horse-drawn vehicles and pedestrians. It used semaphore arms by day and red and green gas lamps at night. Unfortunately, the device exploded the following year, injuring the police officer operating it.

Sometimes the familiar world becomes much more interesting when we look a little closer: Explore. Discover. Learn.