Popcorn Clouds, Brazil

This vast, impressively uniform layer of small clouds over the Amazon rain forest shown in the image above is the product of rapid plant growth. During the forest’s dry season, the plants get more sunlight. This leads to more growth and more photosynthesis, which releases water vapor into the air through transpiration. The warm, wet air rises and cools, causing the water vapor to condense into small, fluffy white clouds that resemble popcorn, particularly in the close-up below.

In this image, taken by the MODIS instrument on NASA’s Aqua satellite on August 19, 2009, the cloud cover is broken by the rivers, which don’t give off as much heat as the land does to warm the air and trigger the cloud formation.

Images: Jeff Schmaltz/NASA