A new study suggests yet another theory for a possible extra planet in our solar system, likely of a size between Mercury and ...

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. Some astronomers ...

While Planet Y has been not yet been directly observed, unexpected inclinations found in the orbits of roughly 50 distant ...

The find represents the first clear detection of a baby planet taking shape within a disc of dust and gas with multiple rings. The ground-breaking discovery was made using European Southern ...

On August 24, 2006, our solar system lost a planet. It wasn't by cataclysmic destruction, but rather by the vote of the International Astronomical Union, which declared that Pluto, considered the ...

A smudge of light spotted by the James Webb telescope near Alpha Centauri A could be the planet with the tightest orbit ever to be imaged directly. A glimpse of a planet in its star’s habitable zone — ...

The widespread death of coral reefs is the first in a series of catastrophic and potentially irreversible tipping points the world may hit, according to a landmark report produced by 160 scientists ...

If you're looking up at the sky on Friday, Sept. 19 2025 and seeing some very bright stars near the moon, you might be wondering: What's the deal? What are those stars? Are they planets? The answers ...