Our solar system may have a ninth planet after all, following the declassification of Pluto nearly two decades ago, ...

At a frigid -125 degrees Fahrenheit (-87 degrees Celsius), WD 1856+534 b is the coldest planet ever directly observed, ...

Pointed away from Earth about 404 miles overhead, the orbital observatory will circle the planet from north to south about 14 ...

Researchers have found a candidate for the hypothetical Planet Nine, which could be an undiscovered giant planet way out in our solar system. However, as with all ninth planet research, the new ...