1

The Eiffel Tower becomes 15 centimeters taller during summer. -u/justsomeone1002

2

If you sever the connections between the two halves of the brain, amazingly, they will still function on their own but they can no longer communicate. It led to some very interesting discoveries about the role of the left and right brain. “Split-brain” patients would appear to behave normally following surgery and reported feeling fine. -u/largerandbrighter

3

Whales were originally land mammals who lived and hunted on coasts, that eventually evolved to leave the land behind, but then evolved again to become amphibious and make use of the land, THEN EVOLUTION PUT THEM AS FULLY AQUATIC AGAIN LATER ON. Whales have tiny little bones near their spines that are remnants of the lower legs they had when they were land mammals. And their closest land mammal relative is the hippopotamus! -u/Alleged3443

4

Your brain actually only has cells to detect red, green, and blue light. So what happens when we see yellow? We see yellow because our eyes detect a mix of red and green and our brains average it to equal yellow. So yellow light exists but our brain is sort of guessing what it looks like since we don't actually have yellow receptor cells. -u/Kairos385

5

The Earth's core is hotter than the surface of the sun! -u/GroundbreakingEnd621

6

Humans are likely the cause of the extinction of Elephants in America. They used to live in California, and their range decreased as time went on. The last elephants lived on islands off the coast, and they were killed out in a giant fire, that is suspected to have been started by some early humans. -u/mrenglish22

7

People who spend more time at elevation, such as those who are frequent flyers or live places like Denver, are more likely to die of cancer due to higher exposure to cosmic rays. -u/jeremiahs13

8

Propane is actually odorless the smell comes from another chemical called Mercaptan (CH4S) -u/DemonGuitar

9

Helium is mined and is non renewable. Once released into the air it rises up through the atmosphere and is lost to space. -u/johngknightuk

10

As recently as 1930, Radium was used in food items, water, chocolates, toothpaste, toys, lights, cosmetics. When inserted into the urethra, some believed it helped cure impotency. All of these were going on before it was discovered that Radium causes cancer. -u/Back2Bach

11

Bees can see ultraviolet light and plants have different patterns accordingly - to ensure pollination. -u/Fl1p1

12

There are more combinations of a deck of cards than there are particles in the entire Earth. Not just molecules or even atoms, individual protons, electrons, etc. To put it bluntly, you can safely bet that when you shuffle a deck of cards that combination of cards has never been created before ever or ever will be. -u/ThePhabtom4567

13

Mitochondrial endosymbiont theory. Mitochondria (the powerhouse of the cell) used to be a a free living prokaryotic cell. It was engulfed by a bigger cell. The bigger eukaryote took care of the little prokaryote and in exchange the little prokaryote became the mitochondria and provided energy! -u/Pairaboxical

14

The average cloud weighs about 500 tons, 80 elephants weigh the same. -u/realaliceredlips

15

Woolly mammoths existed until 3900 years ago. A population of around (iirc) 500 individuals survived on an island near the coast of Siberia, away from humans. Lack of diversity caused many unfortunate DNA mutations though, i.e. increasing their risk of diabetes. -u/blobsnobglob

16

Bears lose basically zero muscle or bone mass in hibernation, scientists believe unlocking their genetic code is the key to long term space travel in zero gravity conditions without adverse effects on astronauts. -u/ImpSong

17

The extinction of dinosaurs was not even close to be the worst of that type. The one before, at the end of Permian period, wiped out 97% of all life on Earth. Talk about hard reset... -u/Tilian1986

18

Sharks have been on Earth longer than Saturn has had rings. -u/rodeler

19

Crows are the smartest species of bird with the intelligence of a human 7 year old. They can make lever tools to solve complex problems, use currency, visit their grandparents, and can remember a face for at least 5 years and can mimic sounds they hear. They can also pass the snack test: a test where you offer them a small portion of food with the promise of a larger portion if they decline it. Human toddlers and most primates can't pass this test. They're also self aware. -u/Sol-Blackguy

20

You have ear crystals that work with your ear fluid to maintain your sense of balance. idk why. but it's there. -u/feverdream-helpdesk

21

Clarence Dally was one of Thomas Edison’s favorite employees, whom frequently demonstrated Edison’s newly invented “fluoroscopy machine”. This was way before anyone knew of the dangers of radiation, thus no safety measures were in place. Due to the high amount of radiation Dally received in a short period of time, he began suffering from visible radiation damage (Mostly Desquamation) to his hands, arms, and face. Dally required many skin grafts, and had to amputate his entire left hand, as well as multiple fingers on his right hand. In a final attempt to save his life, Dally had both arms fully amputated, however this was not enough to stop the spreading carcinoma. Clarence Dally soon died from mediastinal cancer, and he is thought to be the first radiation-induced death in history. After the death of his beloved friend and assistant, Thomas Edison abandoned his research on fluoroscopy. When asked about it, Edison said “Don’t talk to me about X-rays; I am afraid of them”. -u/abbyhatesall

22

there have been two Appalachian mountain ranges. the first had time to form, get huge, then get worn all the way down to a flat plain, then a second mountain range formed in the same spot. -u/norrinzelkarr

23

Every 7cm of water cuts radiation dose in half. -u/Apprehensive-Neck-12

24

The Australian aboriginals have stories dating back to when they lived alongside megafauna. -u/anzara2Y5

25

Astronauts on the space station have little to no sense of thirst. Most wear timers to remind them to hydrate regularly. It's a zero gravity thing. -u/Scrappy_Larue