Just as the Sun slips below a clear horizon, its last sliver sometimes turns green. The atmosphere acts like a prism, bending green and blue light slightly more than red. With blue largely scattered away along the way, green is what lingers for an instant after the rest of the disc is gone. A crisp, distant sea horizon gives the best chance to see it.
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.