With its low density and unusually cool, methane-rich atmosphere, this planet offers a rare window into giant planet formation around small stars.

A newly found object could be a dwarf planet that contradicts the Planet Nine hypothesis.

A US-based trio hunting this elusive world has stumbled on what appears to be a new dwarf planet in the solar system's outer reaches.

U.S. astronomers hunting for "Planet Nine" have instead stumbled on what appears to be a new dwarf planet in the solar system's outer reaches.

It's an evocative idea that has long bedeviled scientists: a huge and mysterious planet is lurking in the darkness at the edge of our solar system, evading all our efforts to spot it.

Did it snow on Mars? New research suggests ancient Red Planet precipitation was a lot like Earth It's hard to figure out if Mars was “warm and wet” in its ancient past, but climate models give ...

Old data may hint at a new world beyond Neptune — but not the one astronomers expected.

For years, astronomers have been searching for a ninth planet in our solar system (after giving Pluto the old heave-ho and demoting it to a dwarf planet) and now researchers say they’ve found a ...

The evidence from planet K2-18b suggesting it may be teeming with microbial life is tantalising The finding isn't yet certain, and it only indirectly supports the notion that the planet harbours ...

Astronomers using NASA’s James Webb Space Telescope just gave a cosmic mystery a serious plot twist. The event in question—a sudden brightening from a star about 12,000 light-years away—was ...

The planet "splashed down" into the star, sending a giant plume of gas into space that gave the star a ring.

If Planet 9 is real, this observatory has around a 70 to 80 percent chance of finding it, he estimates, adding that it's not a sure thing because there are so many uncertainties.