This is my collection of little fun facts. My goal is for these to be genuinely novel, counterintuitive, or surprising: I’d hope that everybody who comes across this page already knows no more than two-thirds of them. Some facts have detailed calculations on a separate sources page.
Space and Astronomy
Earth has the best known eclipses in the universe. The Sun is 400× larger in diameter than the Moon but 390× further away on average: the apparent size ratio varies from 90% to 108%. No other satellite in the solar system comes within 10%. [sources]
The peak-intensity electromagnetic emission from the Sun is around 500 nm. This coincidentally matches the very narrow frequency window in which water is transparent, meaning sunlight can pass through water. This overlap is the visible part of the electromagnetic spectrum. [sources]
Venus spins in retrograde, so the Sun rises in the west. It does so with such a low speed that a single sidereal day on Venus lasts for 243 Earth days (longer than a year on Venus, which is only 225 Earth days). [1]
A neutron star is so dense that a piece the size of a standard die would weigh more than the entire human race. [sources]
There are more trees on Earth (3 trillion) than stars in the entire Milky Way (100 billion). [1, 2]
On average, the closest planet to Earth is actually Mercury (rather than Venus or Mars). In fact, this is true for any other planet in the Solar System! [sources]
Surprising Chronology
Sharks [450 MYA] predate grass [66 MYA], trees [385 MYA], dinosaurs [250 MYA], the Atlantic Ocean [170 MYA], and even the North Star [67 MYA]. [1, 2, 3, 4, 5, 6]
In 1997, 2007, 2017, and 2027, the sitting U.S. President was born in 1946: Clinton, Bush, Trump (first term), and Trump (second term). [1]
The first exoplanet was only confirmed in 1992. [1]
Anne Frank, Martin Luther King Jr., and Audrey Hepburn were all born in 1929. [1, 2, 3]
Charles Darwin and Abraham Lincoln were born on the same day: 12 February 1809. [1, 2]
Oxford University predates the Aztec Empire by over two centuries. [1, 2]
Nintendo was founded in 1889, the same year the Eiffel Tower was unveiled and the same year Hitler was born. [1, 2, 3]
Geography
Most cities have a “kilometre zero” point from which all distances (e.g. on signboards or GPS) are measured. In London, this is the statue of King Charles I outside Charing Cross. [1, 2]
New York City (40.7°N) is further south than Istanbul (41.0°N). In fact, Paris is further north than any major city (50K+ people) in the continental United States. [sources]
The Atlantic entrance to the Panama Canal is further west than the Pacific entrance. [1]
The Pacific Ocean is so large that it contains pairs of antipodal points (two points which are directly across the Earth from each other, as far away as possible, yet both within the same ocean). [1]
The speed of light is 299,792,458 metres per second. The latitude line 29.9792458°N passes through the Great Pyramid of Giza. [1, 2]
Language and Etymology
The names for Ethiopia, Mauritania, and Sudan can be traced back to words meaning “black” or “dark”. The names Niger and Nigeria cannot. [1, 2, 3, 4]
The word “helicopter” is derived from “helico-” (helix, meaning spiral in Greek) and “-pter” (pteron, meaning wing in Greek). “Heli-” and “-copter” do not mean anything. [1]
Biology
The average person reaches half their adult height at the age of two. [1]
Bananas and avocados are botanically berries (fleshy fruits with embedded seeds produced from a single ovary) while strawberries and raspberries are not. [1, 2, 3, 4]
Humans make up over a third of all mammal biomass in the world. Wild mammals compose only 5%, with the remaining 60% being made up of pets and farmed animals. [1]
Computers
Disk memory is over five billion times cheaper per terabyte now compared to in 1956. [1]
There is more pure gold in one ton of laptops than there is in ten tons of gold ore. [sources]
Miscellaneous
Child poverty in the UK fell from 22% to 18% thanks to the 2008 financial crisis, because the median wage (against which child poverty benchmarks are set) fell so dramatically that in relative terms many more people were close to it. [sources]