Pluto has a very elongated and tilted orbit with respect to the planet’s orbit.
REPUBLIKA.CO.ID, ARIZONA — Computer simulation shows how a dwarf planet looks like Pluto hurtling near a chaotic orbit that could potentially destroy the world. However, Pluto is lucky to be in orbit.
The ‘former ninth planet’ which is now considered a dwarf planet has an unusual orbit that is very elongated and tilted with respect to the planet’s orbit.
Reported from Space, Tuesday (26/4/2022), during 20 years of its 248-year journey around the sun, Pluto actually moves inside Neptune’s orbit. The two planets not colliding is a consequence of two properties of Pluto’s orbit, known as azimuthal liberation and latitude liberation.
The azimuthal liberation explains how every time Pluto crosses Neptune’s orbit, it is always at least 90 degrees from Neptune. Meanwhile, latitude libration ensures that when Pluto reaches its closest point to Neptune or the other giant planets, Pluto is always high above them and the plane of the solar system. Combined, these two factors keep Pluto from colliding with other planets.
Now planetary scientists Renu Malhotra of the Lunar and Planetary Laboratory at the University of Arizona and Takashi Ito of the National Astronomical Observatory of Japan have developed a better understanding of why Pluto persists in this particular orbit.
In computer simulations they found that Neptune had the greatest influence on Pluto’s azimuthal liberation, a consequence of the planet’s 3:2 orbital resonance. This means that every three times Neptune orbits the sun, Pluto orbits exactly twice. However, simulations show that Neptune has little effect on Pluto’s latitudinal liberation.
There is a factor from the planet Uranus that plays a role. Uranus acts to confuse the azimuthal and latitudinal boundaries. If orbit Pluto a consequence of the effects of these two planets alone, Pluto’s orbit would become unstable only after tens or hundreds of millions of years, resulting in Pluto colliding with Neptune (or being thrown out of solar system completely).
Jupiter and Saturn also played a role in saving Pluto’s orbit from interplanetary collisions. Although farther from Pluto than Neptune and Uranus, the gravity of the two planets is so great that they can still dominate. Jupiter alone exerts enough gravitational influence to keep Pluto’s orbit stable for at least five billion years—the duration of the simulation run.
What is surprising about this new work is how narrow this zone of stability is for Pluto and how this dwarf planet was only able to achieve it thanks to the arrangement of the planets in the solar system.
This finding also has consequences for objects in orbits similar to Pluto which also have 3:2 resonance with Neptune. Because the orbits of various populations of small objects in the Kuiper Belt beyond Neptune retain traces of how they were propelled by migrating gas giants in the early days of the solar system, they provide a unique window into the history of the solar system.
Their orbits could potentially hide evidence of the existence of a lost planet that was ejected from the Solar System billions of years ago.
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