On 15 September 2017, the Cassini spacecraft ended its valiant 13-year mission by performing a kamikaze dive into Saturn's upper atmosphere. A new image released by NASA shows the exact spot where the Cassini craft was lost to us forever.
The white oval marks the spot. Image: NASA/JPL-Caltech/Space Science Institute
What's particularly cool about this image is that Cassini took it just a few hours before it dove into the ringed planet (its entry point is indicated by the white oval). The spacecraft was about 634,000km from Saturn at the time, and it shows the planet's night side. The scene appears illuminated, because it was: Saturn's extensive ring system reflects sunlight onto the planet's night side. By the time Cassini plunged into the upper atmosphere, however, this particular area had rotated into daylight.
Cassini took the images using red, green and blue filters, allowing NASA to show the scene in near natural colours. This is a very close approximation of the hues and tones found in the gas giant's turbulent atmosphere.
That Saturn's rings can illuminate the planet's night side isn't surprising, considering just how thick and wide they really are. We like to think of the rings as a kind of ethereal plane in orbit around the planet, but there's some serious substance to them. The rings consist of dust and rock, but they also contain a lot of water ice, making them bright and highly reflective.
Saturn's "peaks" on the outer edge of ring B.Image: NASA/JPL/SSI
A stunning photo taken by Cassini back in 2010 showed a 1200km-long section spanning the outer edge of its B ring. The vertical towers, looking almost like mountains and casting an impressive shadow onto the inner rings, extend for about 2.5km above the plane of the rings. Normal thickness is about 10m. Incredibly, some areas of the ring are as much as 1km thick. Icy particles are also known to clump together to form "solid" portions of Saturn's rings. The rings also affect the planet's weather.
Saturn's rings do more than just look pretty. New data from the Cassini-Huygens spacecraft orbiting the planet shows their shadow can actually change the planet's atmosphere.
Cassini may be dead, but we're still learning plenty from its historic mission.