Snow are able to grow to hundreds of micrometers or millimeters in size at the expense of the water droplets by the Wegener–Bergeron–Findeisen process. The corresponding depletion of water vapor causes the ice crystals to grow at the droplets' expense. These large crystals are an efficient source of precipitation, since they fall through the atmosphere due to their mass, and may collide and stick together in clusters, or aggregates. These aggregates are snowflakes, and are usually the type of ice particle that falls to the ground. Although the ice is clear, scattering of light by the crystal facets and hollows/imperfections mean
Atmosphere of Mars freezing point of water. With the higher temperature, running water could have carved out the many channels and outflow valleys that are common on the planet. It also might have gathered to form lakes and maybe an ocean. Some researchers have suggested that the atmosphere of Mars may have been many times as thick as the present one of Earth; however, research published in fall 2015 advanced the idea that perhaps the early Martian atmosphere was not as thick as previously thought. Currently, the atmosphere is very thin. For many years, it was assumed that as with Earth, most of