Satellite images of Earth at night have been a curiosity for the public and a tool of fundamental research for at least 25 years. They have provided a broad, beautiful picture, showing how humans have shaped the planet and lit up the darkness.
In addition to making rain and snow, clouds can have a warming or cooling influence depending on their altitude, type, and when they form. These maps show what fraction of an area was cloudy each month.
These maps depict how much hotter or cooler an ocean basin was compared to the long-term average. Temperature anomalies can indicate changes in ocean circulation or the arrival of patterns like El Niño and La Niña.
These maps show the average amount of water vapor in a column of atmosphere by month. Water vapor is the key precursor for rain and snow and one of the most important greenhouse gases in the atmosphere.
Whether started by humans (farming, logging, or accidents) or by nature (lightning), fires are always burning somewhere on Earth. These maps show the locations of fires burning around the world each month.
Snow and ice influence climate by reflecting sunlight back into space. When it melts, snow is a source of water for drinking and vegetation; too much snowmelt can lead to floods. These maps show average snow cover by month.
Have you ever wondered what it would be like to live in a different part of the world? What would the weather be like? What kinds of animals would you see? Which plants live there? By investigating these questions, you are learning about biomes.
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.
In honor of our site anniversary, we offer a selection of some of the most beautiful, newsworthy, interesting, and scientifically important images from 23 years online — one image for each day of the calendar year.