In 2004, scientists found Sedna, a potential dwarf planet beyond the belt, had a strange orbit around the sun that hinted another large mass was gravitationally pulling it. A 2014 study found a ...

The dwarf planet Sedna, discovered in late 2003, was the first known ETNO. Following Sedna's discovery was speculation that its odd orbit must imply the existence - and influence of - of some ...

The number of planets that orbit the sun depends on what you mean by “planet,” and that’s not so easy to define ...

Opinions expressed by Forbes Contributors are their own. Jamie Carter is an award-winning reporter who covers the night sky. Computer simulations suggest that there is an undiscovered Earth-like ...

When astronomers found a large world farther out than Pluto, it became one of the final nails in the coffin of our ninth ...