Jun 23, 2017 03:08 AM
This one is in addition to the as yet unseen Neptune Size planet ('Planet 9') to replace Pluto.
The new one ('Planet 10') would be approximately Mars sized, out in the Kuiper belt. It hasn't been directly seen either, and like Planet 9 is hypothesized based on what appear to be its gravitational effects.
Apparently there's quite a bit of solar system out there beyond Neptune. If we factor in the Oort cloud, where comets are thought to come from, these things may extend way-out into interstellar space, a light year or more away yet still in very tenuous orbits around our Sun.
https://www.space.com/37295-possible-planet-10.html
The new one ('Planet 10') would be approximately Mars sized, out in the Kuiper belt. It hasn't been directly seen either, and like Planet 9 is hypothesized based on what appear to be its gravitational effects.
Apparently there's quite a bit of solar system out there beyond Neptune. If we factor in the Oort cloud, where comets are thought to come from, these things may extend way-out into interstellar space, a light year or more away yet still in very tenuous orbits around our Sun.
https://www.space.com/37295-possible-planet-10.html