Saturn’s New Moonlet May Give Answers About How Rings are Born
Word is that Saturn has a new moon. This small, small, small moon might actually be called a moonlet, but the research is still out on that as the cameras on the Cassini probe are not able to get a clear picture of this new moon in Saturn’s faint, icy G-Ring.
From NASA’s explanation:
This sequence of three images, obtained by NASA’s Cassini spacecraft over the course of about 10 minutes, shows the path of a newly found moonlet in a bright arc of Saturn’s faint G ring.
In each image, a small streak of light within the ring is visible. Unlike the streaks in the background, which are distant stars smeared by the camera’s long exposure time of 46 seconds, this streak is aligned with the G ring and moves along the ring as expected for an object embedded in the ring.
Cassini scientists interpret the moving streak to be reflected light from a tiny moon half a kilometer (a third of mile) wide that is likely a major source of material in the arc and the rest of the G ring. Debris knocked off this moon forms a relatively bright arc of material near the inner edge of the G ring, the most visible part of the ring in these images. That arc, in turn, leaks material to form the entire ring. –NASA
So what’s the diff between a moon and a moonlet? Moonlets are way smaller, sure; but as that is not an exact measurement, but you can think of moonlets as asteroid-sized for the most part (as small as 100 m). Moonlets are too small to have gravitational pull in so far as to collect surrounding debris in large enough quantities as to clear the surrounding space in their orbits, like a larger Saturn moon would. Because a moonlet does not create a clear view of itself, due to the other stuff around it, they are harder to see. In fact, so hard to see that moonlets of Saturn have only just recently been discovered.
These are the so-called “propeller moons” that were found in 2004 within Saturn’s A-Ring.
Before this new moonlet was noticed, the G-Ring was a mystery to scientists, as the other rings of Saturn were associated with a moon or moons. But now that a moonlet body has been found, scientists are hoping that this new moonlet can give them clues as to how rings form. Theory thus far has it that a larger moon broke up and shattered, forming the glorious rings of Saturn. The newer moonlets discovered as of late may provide clues as to their origin, but also may give scientists insight into how new moons aggregate out of smaller material and grow larger to develop a gravitational pull.
Just in case you were wondering, the rings get their letters from their sequence of discovery. Starting closest to Saturn, it goes D, C, B, A, F, G and E.
Images from NASA/JPL
Saturn, Cassani, JPL, NASA, moon, moonlet, G-ring, rings, gravity, orbit
