In honor of our 20th anniversary, we offer a selection of some of the most beautiful, newsworthy, interesting, and scientifically important images from the past 20 years — one for each day of the calendar year.
Chlorophyll is used by algae and other phytoplankton--the grass of the sea--to convert sunlight and carbon dioxide into sugars. These maps show chlorophyll concentrations in the ocean, revealing where phytoplankton are thriving.
Greenness is an important indicator of health for forests, grasslands, and farms. The greenness of a landscape, or vegetation index, depends on the number and type of plants, how leafy they are, and how healthy they are.