Does global warming make Triton blush?

Abstract

Neptune's largest moon, Triton, is one of two satellites in the Solar System that are currently geologically active. At least two geyser-like plumes were observed by the Voyager 2 spacecraft in 1989, and dozens of streaky deposits hint at the existence of many more¹. Triton also exhibits complex seasonal changes in its 165-year journey about the Sun². Because Triton's atmosphere transports volatiles (primarily nitrogen and methane) during this seasonal cycle, its atmospheric pressure may fluctuate by up to an order of magnitude over decades³. Photometric measurements of its albedo and colour over half a century show that seasonal volatile transport has occurred⁴. There have also been indications that more extreme, short-lived changes, perhaps due to geological events, have occurred on Triton. An anomalously red spectrum was reported for Triton in 1977 (56), and global warming has now been observed⁷.