Pluto Atmosphere (IMAGE) Southwest Research Institute Caption When Pluto passed in front of a star on the night of August 15, 2018, a SwRI-led team of astronomers measured the abundance of Pluto’s atmosphere, shown here in New Horizons 2015 flyby data, as it was briefly backlit by the well-placed star. These data indicate that the surface pressure on Pluto is decreasing and that its nitrogen atmosphere is condensing, forming ice on its surface as the object moves away from the Sun. Credit NASA/JHU-APL/SwRI Usage Restrictions Images/videos may be used by the media and the public for educational and informational purposes only License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.