A new look through decades-old data has unveiled some of the most compelling evidence yet of a hidden ninth planet in the far reaches of our solar system, far beyond ...

As these planets wander through the outer solar system, their paths are determined by a delicate balance of forces. If the timing is right, some of these wandering bodies might become permanently ...

In rare find, astronomers identify a planetary sextuplet where six members of the system circle their star in a harmonious pattern with orbital periods that occur in simple, whole-number ratios ...

The chance of a planet forming in the outer reaches of the solar system – a hypothetical Planet Nine – could be as high as 40 per cent, but it would have been a rough start ...