This natural-color satellite image shows crisscrossing cloud patterns off coastal Africa. These distinctive lines in the sky are gravity waves, and they form when air masses get displaced upward by terrain or other conditions. In this case, dry air cooled overnight on land before moving out over the ocean. That displaced warm, humid air above the water and forced it upward, where it eventually cooled and condensed into clouds. Gravity created the ripple-like waves; as the moist air cooled, gravity again pulled it downward - leaving behind a clear sky. Once the humid air sank, the dry air pushed it up again, creating another line of clouds and continuing the cycle.  (Image credit: NASA; via NASA Earth Observatory)

Khaidarkan Sb-Hg deposit, Fergana Valley, Alai Range, Osh Oblast, Kyrgyzstan

Morcínov, Lomnice nad Popelkou, Liberec Region, Bohemia, Czech Republic

Link

Despite appearances, this is not a crashing ocean wave. In fact, it’s a planned explosion at a quarry, and that wave is more than 360,000 tons of rock and 68 tons of explosive pouring down. The scale of this is hard to imagine, and the physics of a ocean breaker and a massive wave of rocks and gas are similar enough that it’s no wonder our brains interpret them as the same event. Visual effects artists have been using this trick for decades. Rather than simulate the motion of a true fluid, many CGI effects are created from digital particles that, much like the rocks above, are similar enough to fool our eyes and our brains.  (Image credit:  K. Venøy, source; via Gizmodo)