apod.nasa.gov

wojYJ TIL that ELVES are a rare type of red lightning that involves red flashes with a radius of 350 km (220 mi) which only last for 0.001 second. They form when an electromagnetic pulse shoots upward and causes the nitrogen molecules to glow scarlet.
a87JJ TIL Arachnoids are large spiderweb-like structures of unknown origin that have been found only on the surface of Venus and can span 200 km
4XwEN TIL Jupiter's moon Europa is covered by a thick layer of ice, with a huge subsurface ocean of liquid water underneath it. Estimates give the ocean an average depth of 100km, and a radius of 877km. This equates to 3 times the combined volume of water of Earth's oceans.