Siraj’s Planet Y search started about a year ago when he was trying to find out whether the shape of the Kuiper Belt is flat. “The planets of the solar system have slight tilts up and down, but ...

To picture this, if Earth is one “Sun-step” away, Planet Y is about 100 to 200 “Sun-steps” out in the dark, distant part of ...

Our solar system now, once again, officially consists of only eight planets. Although largely debunked, speculation continued ...

Earth has a newly-discovered neighbor in the solar system. But the heavenly body – possibly a dwarf planet à la Pluto – isn't a frequent visitor. Located beyond Neptune, its extreme orbit ...

comets and dwarf planets (including Pluto) that orbit the sun beyond the eight known planets — but has so far evaded detection. Now, in a study published Aug. 21 in the journal Monthly Notices of the ...

Scientists have detected methane gas glowing faintly above Makemake, an icy dwarf planet smaller and farther than Pluto in space. Until now, Pluto was the only object that far out in the solar system ...

A dwarf planet nicknamed the Goblin has been discovered beyond Pluto, astronomers said Tuesday. Scott Sheppard of the Carnegie Institution for Science, one of the scientists who made the find, said ...

A recent research paper suggests that a planet may exist far beyond Neptune — less than 20 years after the previous ninth planet, Pluto, was demoted. That research paper, accepted last month for ...

The search for an unknown planet in our solar system has inspired astronomers for more than a century. Now, a recent study suggests a potential new candidate, which the paper’s authors have dubbed ...