Stunning new images from NASA's Cassini spacecraft show a dramatic change of seasons on Saturn, as well as the last glimpse of its huge, warm polar vortex.

The images were taken on May 19, 2017, as Cassini made its final close pass by Saturn before plunging into the planet's atmosphere on September 15.

The images show Saturn's northern hemisphere in the midst of summer. The sun is shining directly on the planet's north pole, and the polar vortex has disappeared.

The polar vortex is a massive, rotating storm that forms at Saturn's north pole during the winter. The storm can be as large as the United States and can reach speeds of up to 100 miles per hour.

The polar vortex disappears during the summer when the sun's rays begin to warm the planet's atmosphere. The warm air rises, causing the vortex to collapse.

The Cassini spacecraft has been studying Saturn and its moons since 2004. The spacecraft has made a number of important discoveries, including the detection of water vapor in Saturn's atmosphere and the discovery of a new moon, Methone.

Cassini will end its mission on September 15, when it plunges into Saturn's atmosphere. The spacecraft will burn up in the planet's atmosphere, and its remains will be scattered across the planet's surface.

The end of the Cassini mission will mark the end of an era in planetary exploration. Cassini has been a major source of information about Saturn and its moons, and its findings have helped us to better understand the solar system.