For the first time in history, scientists are witnessing the formation of a new moon in our solar system. NASA's Cassini spacecraft has detected a new moon forming in the edge of Saturn's rings. Astronomers around the world are amazed about this incredible find, which they have named Peggy.*
It's really exciting to see this happening in real time. Carl Murray—lead author of the paper describing Peggy—says that "we have not seen anything like this before. We may be looking at the act of birth, where this object is just leaving the rings and heading off to be a moon in its own right." According to Cassini Project Scientist Linda Spilker at the Jet Propulsion Laboratory in Pasadena, California, "witnessing the possible birth of a tiny moon is an exciting, unexpected event."
The images were originally taken on April 15, 2013. They show a small icy object forming at the edge of Saturn's A ring, which is its outermost large ring. The objects' gravity disturbing the edge, creating a bright arc 750 miles (1,200 kilometers) long and 6 miles (10 kilometers) wide.
According to NASA, "the object is not expected to grow any larger, and may even be falling apart." However, the formation process and the outward movement gives us clues about the formation of other Saturn's moon, as well as the formation of planets around our home star. The movement shows how Earth may have formed deeper into the solar system, then move slowly away from the Sun.
Based on these facts, and other indicators, researchers recently proposed that the icy moons formed from ring particles and then moved outward, away from the planet, merging with other moons on the way.
According to Murray:
The theory holds that Saturn long ago had a much more massive ring system capable of giving birth to larger moons. As the moons formed near the edge, they depleted the rings and evolved, so the ones that formed earliest are the largest and the farthest out.
According to NASA, "Cassini's orbit will move closer to the outer edge of the A ring in late 2016 and provide an opportunity to study Peggy in more detail and perhaps even image it."
* Maybe they are Mad Men fans.