Why aren't there rings around Earth?

If you’re talking about majestic ice rings, like we see around Saturn, Uranus or Jupiter, then no, Earth doesn’t have rings, and probably never did. If there was any ring of dust orbiting the planet, we’d see it.

It’s possible that there were rings orbiting Earth in the past. Some scientists think that Earth’s gravity could have broken up a comet or asteroid that got too close to the planet, but didn’t actually collide. This is similar to what happened to Comet Shoemaker/Levy 9 that eventually crashed into Jupiter. First the giant planet tore the comet up, and then the pieces crashed into the planet on a later orbit.

In the case of Earth, it might have held onto a few ice particles that would have then orbited the planet, and eventually crashed through our atmosphere and burned up. Even the smallest particles of ice or dust create spectacular meteors in the sky, so there was a ring right now, we’d see these impacts all the time.

Other scientists think that a giant asteroid impact with Earth, such as the one the killed the dinosaurs 65 million years ago, might have kicked up a huge ring of debris around the planet. This ring would cast a shadow down on the surface of the Earth, changing the planet’s climate, and could last for a few million years at most.

Finally, humans have put up an artificial ring in the past. The US Military launched 480 million copper needles into orbit around Earth in a project called Project West Ford. Scientists could bounce radio signals off the needles and communicate between two locations on Earth. This worked for a few months after launch, until the needles were too far dispersed to allow for communication. In theory, if needles were continuously launched, it would be a functioning communications system, but it’s not necessary with modern communications satellites.

So Earth probably did have temporary rings in the past after asteroid impacts or cometary flybys, but Earth doesn’t have rings today.