Our definition of a planet has changed over the years — causing a bit of confusion. | Credit: wasan prunglampoo/Getty Images Over the past 250 years, the number of "planets" in our solar system has ...

The official number of exoplanets—planets outside our solar system—tracked by NASA has reached 6,000. Confirmed planets are added to the count on a rolling basis by scientists from around the world, ...

The number of confirmed planets outside of our solar system—known as exoplanets—has risen to 6,000, NASA has said. There is huge variety across these distant worlds, the space agency says, with ...

We usually think of our Solar System as a calm, well-organized family of planets, but a new study suggests its early days may have been far more chaotic. Instead of the four giant planets we know ...

Our solar system is a smashing success. A new study suggests that from its earliest period — even before the last of its nebular gas had been consumed — Earth’s solar system and its planets looked ...

The search for an unknown planet in our solar system has inspired astronomers for more than a century. Now, a recent study suggests a potential new candidate, which the paper’s authors have dubbed ...

New observations may offer fresh clues into how a giant exoplanet survived the violent death of its host star — and came to closely orbit its stellar remnants. The findings could serve as a preview of ...

James is a published author with multiple pop-history and science books to his name. He specializes in history, space, strange science, and anything out of the ordinary.View full profile James is a ...

Over the past 250 years, the number of "planets" in our solar system has ranged from six to nine — and, briefly, even 11 — depending on what astronomers knew at the time and how they defined a planet.