In time for Earth Day on Wednesday, NASA ran an online contest to let Earthlings pick the agency's top 10 accomplishments in five decades of observing the planet. The winners were announced on Tuesday, on the eve of Earth Day.
Tenth place went to auditing the flow of energy in and out of Earth via planet-orbiting tools.
"We've measured changes in the sun's energy output reaching Earth (pretty small) and the amount of energy redirected away from Earth after a massive volcano erupted into the stratosphere (a lot, but not for long)," NASA said. "With this inventory of the natural factors that heat and cool the planet, we get a better fix on the role humans play in altering climate."
A hurricane system both cools the Earth by reflecting sunlight (the white and green areas shown on the left) and warms it by trapping heat (the blue and white areas on the right).
Photo credit: NASA
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