Evidence is growing for the existence of Planet 9 -- a world perhaps 10 times the mass of Earth and 20 times farther from the Sun than Neptune.

October 4, 2017

The Super-Earth that Came Home for Dinner

It might be lingering bashfully on the icy outer edges of our solar system, hiding in the dark, but subtly pulling strings behind the scenes: stretching out the orbits of distant bodies, perhaps even tilting the entire solar system to one side.
If a planet is there, it's extremely distant and will stay that way (with no chance -- in case you're wondering -- of ever colliding with Earth, or bringing "days of darkness").It is a possible "Planet Nine" -- a world perhaps 10 times the mass of Earth and 20 times farther from the sun than Neptune. The signs so far are indirect, mainly its gravitational footprints, but that adds up to a compelling case nonetheless.
One of its most dedicated trackers, in fact, says it is now harder to imagine our solar system without a Planet Nine than with one.
"There are now five different lines of observational evidence pointing to the existence of Planet Nine," said Konstantin Batygin, a planetary astrophysicist at Caltech in Pasadena, California, whose team may be closing in. "If you were to remove this explanation and imagine Planet Nine does not exist, then you generate more problems than you solve. All of a sudden, you have five different puzzles, and you must come up with five different theories to explain them."..
Note: Some would say this is Planet 10.
The decision to strip Pluto of its planet status and rebrand it as a dwarf planet was controversial, and remains so to this day. The debate stems from a revolution in our understanding of the solar system and shows that science is always evolving.