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

Posted by Between the Lines • Profile • 09/23/26 at 02:00AM • Curiosity & Discovery • See more by Between the Lines

Did You Know? | Kudos365 Curiosity Series

1. A single day-night cycle on Mercury lasts two Mercury years.
Mercury races around the Sun in only 88 Earth days, but its combination of slow rotation and rapid orbit produces a solar day—the time from one sunrise to the next—lasting about 176 Earth days. So two complete Mercury years pass during one Mercury day.

2. Wombats produce cube-shaped droppings.
The Australian wombat is famous for something genuinely unusual: its droppings form into small cubes. Researchers found that regions of differing elasticity in the animal's intestine help create the distinctive shape during digestion. The cubes may also be useful for territorial marking because they are less likely to roll away.

3. Lightning can heat the surrounding air to around 50,000°F.A lightning discharge can heat the air in its channel to roughly five times the temperature of the Sun's surface. That sudden, extreme heating makes the surrounding air expand explosively, producing the shock wave we hear as thunder.

4. About 97 percent of Earth's water is in the oceans.
Our planet may have rivers, lakes, glaciers, groundwater, clouds, and enormous ice sheets, but together they account for only a small fraction of Earth's total water. Approximately 97 percent is contained in the oceans—which also means that most of Earth's water is salty.

5. Some rocks in the Grand Canyon are nearly two billion years old—but the canyon is much younger.
The oldest rocks exposed deep within the Grand Canyon are about 1.8 billion years old. Yet the canyon itself was largely carved during only the past five to six million years. Even the youngest major rock layer along the canyon rims is about 270 million years old—older than the dinosaurs.

6. Hummingbirds can genuinely fly backward.
Hummingbirds aren't simply drifting backward after visiting a flower. Their unusual wing motion allows powered flight in several directions, including backward. Their remarkable maneuverability also lets them hover almost motionless in the air while feeding.

7. Antarctica is a desert.
We usually picture deserts as hot, sandy places, but a desert is defined largely by how little precipitation it receives. Antarctica is the driest continent on Earth, and much of its interior receives extremely little moisture. Its enormous expanse of snow and ice therefore includes a polar desert.

8. The Eiffel Tower changes size with the temperature.
The iron in the Eiffel Tower expands when heated and contracts when cooled. During warm weather the structure can become slightly taller; in cold weather it contracts again. Uneven heating from sunlight can even cause the top of the tower to shift slightly away from the Sun.

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