Earth–Saturn alignment will make Saturn’s rings nearly disappear this weekend

This weekend the orbits of Earth and Saturn will combine to create an interplanetary optical illusion: Saturn’s rings will be all but invisible when viewed from Earth by observers with clear skies and a good telescope. Astronomers call the effect a ring‑plane crossing, which happens when the ultrathin rings are seen edge‑on.

For this near crossing the rings will narrow to less than 1 percent visible on Saturday before the orbital motions make them appear to widen again; the moment they look narrowest is expected at 7 p.m. Eastern on Saturday, about an hour after Saturn rises. “Saturn is a spectacular object to look at,” said Damian Peach, an English astrophotographer, and Mr.

Peach said the next opportunity to see a complete crossing will be in 2038. The disappearing rings have long confused observers: Michael Shank, an emeritus history professor, said in an email that Galileo observed Saturn in July 1610 and described it as “triple‑bodied” when his telescope could not resolve the rings, and Christiaan Huygens proposed in 1659 that the planet was surrounded by rings.

Scientists also plan to use the event: Philip Nicholson and colleagues will observe the near crossing with the James Webb Space Telescope to study the faint outer e‑ring and to look for carbon atoms, which Dr. Nicholson said would strengthen the case for habitability in the underground ocean of Saturn’s moon Enceladus.

Key Topics

Science, Saturn, Earth, Ring Plane Crossing, Enceladus, James Webb