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

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 ...

Vesta, thought to be the second-largest asteroid in the solar system, could be a piece of an ancient, unknown planet, a new study hints.

If the object really is Planet Nine, it would be larger than Neptune and exist 700 times further from the sun than Earth.

Astronomers have detected a promising sign of a ninth planet lurking at the the farthest reaches of the Solar System.

Astronomers using the James Webb Space Telescope have directly detected the faint glow of a planet that’s colder than any ...

They reveal a whole new level of detail in these planet-forming systems. Breakthroughs, discoveries, and DIY tips sent every ...

A distant flicker of light from a star can reveal more than you might expect. In fact, a brief, subtle brightening in the sky ...