The formation of our solar system from a singular nebula raises an intriguing question: why did each planet develop with a ...

Leonardo Testi and team investigate the initial conditions for planet formation in this special astronomy focus ...

So far, humanity has yet to find its first "exomoon"—a moon orbiting a planet outside of the solar system. But that hasn't ...

The solar system is 4.54 billion years old, based on rock dating. Gas giants (Jupiter and Saturn) likely formed first. Ice giants (Uranus and Neptune) probably formed next. Rocky planets formed last, ...

The newly identified cluster of Kuiper Belt objects lies about 4 billion miles from the Sun, offering fresh clues about how ...

The researchers said 2017 OF201 was identified in observations by telescopes in Chile and Hawaii spanning seven years. Scientists have identified an object about 435 miles (700 km) wide inhabiting the ...