The bright band in this image is a cross-section of a massive new ring discovered around Saturn, a cold, diffuse and incredibly thick band of material orbiting the planet 3.7 million miles out…..much farther out than any of the other rings and farther away even than most of Saturn’s moons.
The ring is so thick, 20 Saturns could be stacked top to bottom in its vertical height.
Effectively invisible due to its diffuse nature and low reflectivity in the dim light at Saturn’s distance from the sun, the ring was discovered by the Spitzer Space Telescope, which is sensitive to infrared light emitted by heat. Although cold – minus 316º F – the ring particles still emit enough heat to be detectable by Spitzer’s sensitive instruments.
“The particles are so far apart that if you were to stand in the ring, you wouldn’t even know it.”
– Anne Verbiscer, astronomer at the University of Virginia
Saturn’s moon Phoebe orbits within this newly-discovered disc. The dark, battered moon, orbiting Saturn in a retrograde orbit, is most likely a captured object from the outer depths of the solar system. Collisions between it and ill-fated comets over the millennia may be the source of this ring’s material.
It’s also suspected that this ring may also be the cause of the mysterious dark coating over one-half of Iapetus’ surface. Scientists have been hypothesizing about the reason behind the moon’s two-toned coloration for decades. It’s now looking like it may be the result of dark material from this hazy ring being drawn into nearby Iapetus’ orbit and striking the leading side of the moon.
Iapetus orbits Saturn in a more common prograde direction, as opposed to both Phoebe and the new ring. The material would strike it from the opposite direction, like “bugs on a windshield”.
The discovery of this huge ring was made last May, before the Spitzer telescope ran out of its coolant.
Image credit: NASA/JPL-Caltech/Univ. of Virginia