Methane leak detection, Aliso Canyon. Paired images showing aerial detection (left) and satellite detection (right) of methane plumes (red) from the Aliso Canyon gas leak near Porter Ranch, California, USA. Methane is a potent greenhouse gas. This is the first time such leaks have been observed from space. The images were acquired 11 days apart in January 2016 by NASA's AVIRIS (Airborne Visible/Infrared Imaging Spectrometer) instrument on a NASA ER-2 aircraft at 6.6 kilometres altitude (left) and the Hyperion instrument on NASA's Earth Observing-1 satellite (right). Measurement noise is also present at right.