Did you know?

7 September 2026

1. 01

   Mercury has the most extreme temperature swings of any planet, reaching about 430 degrees Celsius in daytime and dropping to about -180 degrees Celsius at night, because it has almost no atmosphere to hold in heat.

2. 02

   Sea otters often hold paws with each other while sleeping on the water's surface, a behavior that keeps them from drifting apart on the currents.

3. 03

   Glass is technically classified as an amorphous solid, meaning its atoms are arranged in a disordered pattern more like a liquid than a typical crystal, even though it does not flow at room temperature.

4. 04

   The Amazon River discharges more fresh water into the ocean than any other river on Earth, carrying more water than several of the next largest rivers combined.

5. 05

   In 1947, engineers working on the Harvard Mark II computer found an actual moth trapped in one of its relays and taped it into their logbook as the cause of a malfunction.

6. 06

   The human body produces about 1.5 liters of saliva every day, which helps digest food and protect teeth from decay.

7. 07

   The first working laser was built in 1960 by physicist Theodore Maiman, who used a synthetic ruby crystal to produce a narrow, focused beam of light.

8. 08

   Starfish have no brain and no blood; they move and feed using a network of water-filled canals called a water vascular system.

9. 09

   Sound cannot travel through the vacuum of space because it needs a medium, such as air or water, for its vibrations to move through.

10. 10

    The Mariana Trench is so deep that if Mount Everest were placed inside it, the mountain's peak would still sit more than a kilometer underwater.

11. 11

    The first email was sent in 1971 by engineer Ray Tomlinson, who also chose the @ symbol to separate a user's name from their computer's address.

12. 12

    Human bone is, weight for weight, about as strong as steel, but far lighter, which is what allows the skeleton to be both sturdy and easy to carry.

13. 13

    Jupiter is so large that its volume is greater than that of all the other planets in the solar system combined.

14. 14

    One species of jellyfish, Turritopsis dohrnii, can revert its adult cells back to an earlier stage of life instead of dying of old age, making it biologically immortal.

15. 15

    A rainbow is actually a full circle of light, but people on the ground usually see only its upper half because the ground blocks the rest of the circle.

16. 16

    Iceland sits on the boundary between two tectonic plates that are slowly pulling apart, so the island grows a little wider every year.

17. 17

    The first message sent over ARPANET, an early computer network that led to the Internet, was meant to be the word LOGIN, but the system crashed after only the letters L and O were transmitted.

18. 18

    The old idea that different parts of the tongue sense different tastes has been debunked; scientists now know that taste buds across the tongue can each sense all five basic tastes.

19. 19

    Uranus spins almost on its side, tilted at about 98 degrees, likely because of a massive collision early in the solar system's history.

20. 20

    Flamingos are not naturally pink; they get their color from carotenoid pigments in the algae and small shrimp they eat.

21. 21

    Helium was discovered in the Sun's light spectrum in 1868, years before it was found on Earth, making it the only element first identified in space.

22. 22

    The Dead Sea is about ten times saltier than the ocean, which is why swimmers float on its surface almost without effort.

23. 23

    The Internet and the World Wide Web are not the same thing: the Internet is the global network of connected computers, while the Web is a system of linked documents that runs on top of that network.

24. 24

    The human body sheds tens of thousands of dead skin cells every minute, completely replacing the outer layer of skin roughly once a month.

25. 25

    The footprints left by Apollo astronauts on the Moon could last for millions of years, since there is no wind or flowing water there to wear them away.

26. 26

    Koalas have fingerprints so similar in pattern to human fingerprints that forensic scientists say the two could, in theory, be confused under a microscope.

27. 27

    Unlike most materials, a stretched rubber band contracts further when heated instead of expanding, an effect caused by how its long molecular chains respond to temperature.

28. 28

    More than 80% of the world's ocean floor remains unmapped in detail, meaning parts of the Moon's surface are better mapped than parts of Earth's own seabed.

29. 29

    The first computer mouse, invented in the 1960s by engineer Douglas Engelbart, had a wooden shell and only one button.

30. 30

    Muscles need calcium to contract but need magnesium to relax again afterward, which is why both minerals are important for normal muscle function.