Buzz
While Saturn, Jupiter, Neptune, and Uranus boast rings, Earth doesn’t—but it wasn’t always this way. Surprisingly, our planet once had its own ring system.
Rings around planets consist of ice, rocks, and dust particles. They can originate from collisions that scatter debris, moons torn apart by a planet’s gravitational force, or remnants from the planet’s formation process.
For Earth, the debris that could have formed rings had a different fate. As Julia Wilde from D News explains in the video above: "Earth once had a ring, but it eventually merged to form the Moon."
The Roche limit, named after a 19th-century astronomer, explains why not all rings turn into moons. It’s the closest distance an object can orbit a planet without being destroyed by gravitational forces. For Earth, this limit is 2.5 times its radius if the object shares the same density. The Moon, located beyond Earth’s Roche limit of 11,470 miles, remains intact and unaffected.
However, this might not remain the case forever. Some theories suggest that the Moon could eventually break apart into space debris, potentially forming a ring around Earth due to the Sun’s future red giant phase. As David Powell explains on Space.com, billions of years from now, the Sun’s expanding atmosphere will cause the Moon’s orbit to decay. The Moon will gradually move closer to Earth until it reaches a point just 11,470 miles above our planet. At that stage, the Moon will disintegrate, creating a temporary ring before its fragments eventually fall to Earth’s surface.
