This is Daphnis. It’s a moonlet and it’s also not the first time we’ve seen it. Back in 2005, a spacecraft called Cassini-Huygens was sent to Saturn and was the first to enter its orbit. We got glimpses of Daphnis situated within the Keeler Gap of the A-ring before, but nothing as close to this.
No, it’s not just a piece of space rock. In this photo, ‘below’ Daphnis is some wave-like movements and a faint string. With its weak gravitational pull, this satellite pulls towards it bits of ice and some ring material. It’s called a moonlet because it’s a satellite with a gravitational pull, but it’s roughly just the size of Mount Everest.
But yes, it is irregularly shaped. It does have an equatorial ridge, though its surface is mostly smooth.
To clear things out, contrary to cartoon depictions, Saturn does not only have one ring. It has 4 main rings, and a few faded outer ones. Here’s a photo from NASA showing Saturn’s complex ring system.
And within the A-ring, we can see the Keeler Gap which is where Daphnis is located
This amazing photo of Daphnis was taken only last week by Cassini. After its launch in 1997, the spacecraft took 7 years to get to Saturn and will finally end it’s journey this September 2017 after 13 years in orbit.