Saturn’s outermost ring can’t be spotted easily, but in 2009 NASA’s Spitzer Space Telescope picked up on the faintest signature of infrared light radiated off a band of dust. Now, a different telescope has figured out that the band extends about 4 million to 10 million miles from the planet, Ken Croswell reports for Science.
To put that in perspective, Croswell explains, "If Saturn were the size of a basketball, the ring from one side of the planet to the other would span two-thirds the length of a football field."
The update comes from NASA’s infrared-detecting WISE satellite, which measured the ring more precisely than when it was spotted in 2009. The spacecraft’s mission is to scan the entire sky in infrared, a wavelength that reveals the dim glow of the coolest stars and the darkest asteroids and comets.
The ring appears to be debris from the moon Phoebe spread over a huge area, so researchers call it the Phoebe ring, Christopher Crockett writes for Science News. Individually, the dust specks are tiny, the researchers report in the journal Nature, but their collective infrared glow is just enough to spot. The researchers modeled the movement of dust grains of many sizes to show the extent of the vast ring.
Still, it’s very sparse. The passengers of a spaceship flying through it may not even notice, Doug Hamilton of the University of Maryland told Nell Greenfieldboyce at NPR. "[Y]ou wouldn't see anything," he says. "If you were actually immersed in the ring, you'd see absolutely nothing."