Wildfires can start spontaneously; vegetation can become so dry that sunlight can ignite it. Farmers also set deliberate, controlled fires, usually to clear crop residue in preparation for a new planting season. All of those fires play a role in the planet’s carbon cycle, which is why in October 2011 the newly formed NASA Fire and Smoke initiative began using NASA’s MODIS (Moderate-Resolution Imaging Spectroradiometer) to track them. The MODIS project consists of two electromagnetic measuring instruments observing Earth’s surface from the satellites Terra and Aqua, which are in polar orbits but travelling in opposite directions; together, they monitor wildfires and agricultural burns across the planet. This month was the first time ever that MODIS captured fires raging almost simultaneously around the globe.