Since 1972, 27 leap seconds have been added to Coordinated Universal Time to keep pace with Earth's slightly irregular spin. Because these adjustments disrupt computer networks, the international metrology community decided in 2022 to scrap them by 2035. The irony: in recent years Earth has tended to speed up, raising the prospect of a first-ever subtracted second. Melting ice, which slows the spin, is delaying that moment.
On 27 August 1883, the eruption of the Indonesian volcano Krakatoa was heard as far away as Rodrigues Island, nearly 4,800 km away. Its pressure wave was picked up by barometers worldwide and circled the globe several times. The tsunamis that followed killed more than 36,000 people.
The deepest known point in the ocean, Challenger Deep, lies roughly 10,900 m below the Pacific surface. Drop Everest in and its summit would still sit about 2 km underwater. Down there, the pressure is more than 1,000 times what you feel at sea level, roughly a tonne pressing on every square centimetre.