https://www.knowablemagazine.org/article...nt-missing
EXCERPT: . . . Nesvorný is one of a cadre of scientists trying to figure out how the solar system evolved in its first few hundred million years. Using complex computer simulations, researchers had assembled a narrative in which the infant planets formed relatively close together and then jockeyed for position, alternately gliding and leaping from one orbit to another. Those simulations explained many of the minute details about how the planets, asteroids and comets orbit the sun today.
Except there was one problem. The story usually ended with either Uranus or Neptune getting kicked out of the solar system, Nesvorný writes in September in the Annual Review of Astronomy and Astrophysics. Since Uranus and Neptune are quite clearly still present — spacecraft have visited both worlds, after all — that tale didn’t quite hold together. But a fifth giant planet, many researchers suspect, could be the hero that this mystery needs, and a critical missing player in the history of the solar system.
[...] The best scenario — the one that reproduced a solar system that most closely resembles the real one — was one with an extra planet that lived between the original orbits of Saturn and Uranus. The world was roughly as massive as Uranus and Neptune, or about 16 times as massive as Earth. It was this planet that could have gotten tangled with Jupiter’s orbit and been tossed out of the solar system....
MORE: https://www.knowablemagazine.org/article...nt-missing
EXCERPT: . . . Nesvorný is one of a cadre of scientists trying to figure out how the solar system evolved in its first few hundred million years. Using complex computer simulations, researchers had assembled a narrative in which the infant planets formed relatively close together and then jockeyed for position, alternately gliding and leaping from one orbit to another. Those simulations explained many of the minute details about how the planets, asteroids and comets orbit the sun today.
Except there was one problem. The story usually ended with either Uranus or Neptune getting kicked out of the solar system, Nesvorný writes in September in the Annual Review of Astronomy and Astrophysics. Since Uranus and Neptune are quite clearly still present — spacecraft have visited both worlds, after all — that tale didn’t quite hold together. But a fifth giant planet, many researchers suspect, could be the hero that this mystery needs, and a critical missing player in the history of the solar system.
[...] The best scenario — the one that reproduced a solar system that most closely resembles the real one — was one with an extra planet that lived between the original orbits of Saturn and Uranus. The world was roughly as massive as Uranus and Neptune, or about 16 times as massive as Earth. It was this planet that could have gotten tangled with Jupiter’s orbit and been tossed out of the solar system....
MORE: https://www.knowablemagazine.org/article...nt-missing