An international team of astronomers reports the discovery of two new exoplanets, a few times more massive than Earth, ...

The solar system is structured in a roughly flat plane called the ecliptic, with most planets orbiting the sun in the same direction (counterclockwise, as viewed from above the sun's north pole).

This is probably the most convincing evidence for Planet Nine so far. It is believed that this planet is five to ten times ...

The candidate for Planet Nine displayed a tiny amount of movement, which could mean it advanced further in its orbit around ...

Astronomers may have uncovered a potential candidate for the elusive Planet Nine, a hypothetical planet located far beyond ...

WD 1856+534b—a freezing world with a surface temperature of -125 degrees Fahrenheit—exists where planets are normally scoured ...

It’s 9 a.m. on Monday morning, and I’m on the sixth floor of Sterling Hall at UW–Madison. Here, in the newly formed Wisconsin ...

A planet circling at a sharp 90-degree angle to the orbits of its two host stars has now been confirmed. This discovery ...