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

Astronomers have found a compact solar system whose planets line up in a way that, according to current models, should not be possible. Around the small star LHS 1903, a dense rocky world orbits on ...

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 ...

This story is part of Short Wave's series Space Camp about all the weird, wonderful things happening in the universe. Check out the rest of the series. If you were born in the last century you might ...

Mercury is the smallest planet in our solar system. Explore its size, extreme temperatures, core structure, and comparison with Pluto.

Since the 1990s, scientists have discovered approximately 6,100 planets outside our solar system, called exoplanets.

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 ...

For millions of years, a frozen wanderer drifted between the stars before slipping into our solar system as 3I/ATLAS—only the ...