Uranus might have two undiscovered moons that orbits two of the planet's ring.

Rob Chancia from University of Idaho spotted the moons while examining images from Voyager 2 in 1986. He noticed that rings on the alpha ring, one of the brightest rings of Uranus, periodically varies.

Matt Hedman, one of the researchers, explained that they found different wavelengths looking at different patterns in the ring. He explained that there's something breaking the symmetry, Science Daily reported.

For this study, the researchers analyzed radio occultation. Radio Occultation is a technique used to measure physical properties of planetary atmosphere and ring systems.

They used this technique to look at the radio waves gathered by Voyager 2 in its trip to Uranus. They also used stellar occultation to measure the light of stars on the rings.

Their findings showed that Uranus rings were like moonlet wakes, moon structure that can be found in Saturn rings.

NASA reported that moonlets would be around 4 to 14 km in diameter.  These moonlets are the same size of the moons of Saturn, they were also hard to find because its surface is dark.

Hedman explained that they are still looking for this moons but they are certain that the moons were small. He explained that the images for Voyager 2 can't spot these moons.

Ed Stone from Caltech expressed amazement of the data scientists can gather from Voyager 2 exploration. Voyager 1 is the longest operated spacecraft of NASA.

It was launched on 1977 after Voyager 1. It is expected to join Voyager 1 in interstellar space in a few years.

The researchers believe that their findings can help explain the narrowness of Uranus' rings. They added that the moonlets might be acting as shepherd moons that keeps the rings from spreading out.

They explained that their focus is to study patterns and structures in Uranus rings. They said that they will give the study of the moonlets to other researchers.