1. Gravitational waves are real. More than 100 years after Einstein first predicted them, researchers finally detected the elusive ripples in space time this year. We've now seen three gravitational wave events in total.
2. Sloths almost die every time they poop, and it looks agonising.
3. It's possible to live for more than a year without a heart in your body.
4. It's also possible to live a normal life without 90 percent of your brain.
8. Earth has a second mini-moon orbiting it, known as a 'quasi-satellite'. It's called 2016 HO3.
9. There might be a ninth planet in our Solar System (no, Pluto doesn't count).
10. The first written record demonstrating the laws of friction has been hiding inside Leonardo da Vinci's "irrelevant scribbles" for the past 500 years.
12. Crows have big ears, and they're kinda terrifying.
13. The largest known prime number is 274,207,281– 1, which is a ridiculous 22 million digits in length. It's 5 million digits longer than the second largest prime.
14. The North Pole is slowly moving towards London, due to the planet's shifting water content.
15. Earth lost enough sea ice this year to cover the entire land mass of India.
17. Tardigrades are so indestructible because they have an in-built toolkit to protect their DNA from damage. These tiny creatures can survive being frozen for decades, can bounce back from total desiccation, and can even handle the harsh radiation of space.
18. There are two liquid states of water.
19. Pear-shaped atomic nuclei exist, and they make time travel seem pretty damn impossible.
21. One third of the planet can no longer see the Milky Way from where they live.
22. There's a giant, 1.5-billion-cubic-metre (54-billion-cubic-foot) field of precious helium gas in Tanzania.