NASA has amassed more than 1.3 million pictures of Earth as seen from the International Space Station, and about a third of them were taken at night. The space agency says those photos are the highest-resolution nighttime pictures available from orbit, but their usefulness is limited because it's not always clear exactly what the pictures are showing.
That's where you can help.
The Complutense University of Madrid is heading up a crowdsourcing project called Cities at Night to catalog the space station's nighttime imagery. The easiest part of the project, called Dark Skies ISS, asks Internet users merely to sort the images into pictures of cities, stars and other objects. Another online effort, Night Cities ISS, draws upon participants' knowledge of local geography to match bright points of light to locations on a map.
The most complicated challenge, Lost at Night, calls upon citizen scientists to identify cities in wide-angle nighttime pictures. "We don’t know which direction the astronaut pointed the camera, only where the station was at the time the image was taken," Alejandro Sanchez, a student at Complutense University, said in a NASA feature about the project. "Some images are bright cities but others are small towns. It is like a puzzle with 300,000 pieces."
The project could open up new fields of research. Nighttime satellite readings already have been used to chart the rise and fall of political leaders — and there are few better illustrations of the economic disparity between North and South Korea than the space station's picture of the peninsula's dark patch. Pinpointing the locations in NASA's nighttime pictures could help scientists track energy efficiency as well as the health and environmental effects of light pollution.
Why are the space station's pictures so good? The satellites that are capable of capturing nighttime views fly in higher orbits and typically produce lower-resolution orbits. In contrast, the space station is equipped with the European Space Agency's NightPod, a device with a motorized tripod that compensates for the space station's 17,500-mph orbital speed.
Thanks to NightPod, astronauts are capturing sharper pictures of our planet — now it's up to you and other citizen scientists to put those pictures on the map.