A few days ago I posted pictures of “Spooky Finger Clouds“:
Some speculated that it might be contrails or something, but the explanation turns out to be more exotic.
See a day or so later:
Hey, you can see our house from here!
While they’re referred to as “gravity wave clouds,” they’re not in fact (much to my disappointment!) caused by gravity waves like those produced by colliding black holes. They’re caused by oscillations in the atmosphere where a disturbance of some sort causes moist air to rise and fall (due to gravity) much like ripples spreading out from a stone dropped into a pond.
Science! For The Win!