Astronomers have discovered more than 300 exoplanetary systems that have three or more known planets. Most of these planets are about the same size and spaced close together, earning them the moniker ...

Add Yahoo as a preferred source to see more of our stories on Google. An illustration showing Planet Nine, a hypothetical, undiscovered planet in our solar system. New research now suggests the ...

Is there a massive undiscovered planet on the outer reaches of the solar system? The idea has been around since before the discovery of Pluto in the 1930s. Labeled as planet X, prominent astronomers ...

A team of astronomers has identified a four-planet system orbiting the red dwarf star LHS 1903 that defies conventional expectations about how planets arrange themselves around their host stars. The ...

In 2006, updated research led to Pluto being controversially demoted to dwarf planet status by the International Astronomical Union. The reasoning was that Pluto's location in the far-flung ...

An artist's impression of the planetary system surrounding LHS 1903, a small red dwarf star cooler and dimmer than our Sun. (European Space Agency) (CN) — For decades, astronomers thought they had ...

A newly studied solar system breaks the usual planet pattern, raising fresh questions about how rocky and gas planets form.

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 ...

An exoplanetary system about 116 light-years from Earth could flip the script on how planets form, according to researchers who discovered it using telescopes from NASA and the European Space Agency, ...

The newborn planetary system appears to be emerging 1,300 light-years away around a baby star known as HOPS-315. Planet-forming materials were first identified using NASA's James Webb Space Telescope.