It’s been nearly 50 years since the crew of Apollo 8 redefined our image of the planet with the famous “Earthrise” photograph. In that time, satellites have taken millions of photos of every corner of the Earth to give us an increasingly detailed picture of the “blue marble.”

In honor of Earth Day 2017, TIME partnered with scientists at the Environmental Defense Fund to create a never-before-seen animation of 21 years of nighttime imagery of the Earth. The images were the subject of a recent paper on how this luminosity correlates to almost every major indicator of a nation’s well-being, from GDP to carbon emissions. Collected by EDF researcher Jeremy Proville from Department of Defense satellite footage, the images paint a composite picture of …