Is there a massive undiscovered planet on the outer reaches of the solar system? The idea has been around since before the discovery of Pluto in the 1930s. Labeled as planet X, prominent astronomers ...

Does our Solar System have 9 planets or only 8? Astronomers have gone back and forth on that a lot, with Pluto now being classified as a dwarf planet. However, out beyond Neptune there could be ...

Exoplanets are planets outside Earth's solar system. In 1995, a gas giant named 51 Pegasi b, which orbits a star similar to Earth's sun, etched its name in history as the first exoplanet ever ...

In an exciting breakthrough in planetary science, a recent study has increased the likelihood of Planet Nine’s existence by up to 40%. This planet, also referred to as Planet X, has remained an ...

Somewhere at the edge of the solar system a new Earth-sized world might be lurking, dubbed Planet Y. Astronomers have long proposed that there might be hidden planets beyond the Kuiper belt, a region ...

Objects such as 'Oumuamua, Borisov and recently 3I/ATLAS have opened our eyes to the reality that outsiders regularly visit our solar system — and we're about to start spotting a whole lot more of ...

Need a refresher about 3I/ATLAS? Here's everything to know about the interstellar object, including when the latest observations will be made.

Federal funding is about to run out for 19 active space missions studying Earth's climate, exploring the Solar System, and probing mysteries of the Universe. This year's budget expires at the end of ...