Figuring out the day length of Earth is more complicated than you might imagine. While on average a day is 24 hours long, ...

Illustration of Cassini diving between Saturn and its innermost rings as part of the mission's Grand Finale. The spacecraft will perform a series of 22 daring orbits passing through the yet ...

When the movie begins, Cassini was 45,000 miles above Saturn's polar clouds. By the time it ends, the spacecraft's altitude was down to 4,200 miles as it approached the plane of the rings.

Since astronomer Galileo Galilei first noticed something odd about Saturn in 1610, the planet's picturesque rings have posed many fascinating puzzles. Over the past 13 years, the American-European ...

NASA's Cassini spacecraft captured this series of 21 images from within the gap between Saturn and its rings. (NASA/JPL-Caltech/Space Science Institute) ...

The Cassini spacecraft is going where no ship has gone before: On Wednesday, it begins a series of dives into the space between Saturn and its magnificent rings.

Cassini shot the gap and lived to tell the tale. The Saturn-exploring spacecraft managed to successfully fly through the 1,500 mile gap between Saturn and its rings and survive seemingly unscathed.

Cassini offered an opportunity to put a definitive age on Saturn’s rings. The spacecraft first arrived at Saturn in 2004 and collected data until it purposefully crashed into the planet's atmosphere ...

Illustration of Cassini diving between Saturn and its innermost rings as part of the mission's Grand Finale. The spacecraft will perform a series of 22 daring orbits passing through the yet ...

Cassini's data indicate that most of Saturn's rings are probably as old as the solar system itself — about 4.5 billion years. Earlier observations, during the Voyager flybys of 1980 and 1981 ...

During the final year of NASA's Cassini mission before it completed a "death dive" into Saturn's atmosphere in 2017, the spacecraft gathered as much data as possible about the planet's rings.