How many planets could fit in the solar system?
As far-fetched as it may seem, quirks of orbital mechanics could allow hundreds of planets to be packed around a star
The concept of multiple planets sharing the same orbit in a solar system may seem far-fetched, but it is actually possible due to quirks of orbital mechanics. This idea was popularized by the science-fiction film "Journey to the Far Side of the Sun," which featured a counter-Earth hidden from view. However, no such planet exists in reality.
In a stable orbital arrangement, two planets can be found in a horseshoe orbit, where they swap positions while still orbiting the same star. This occurs because, as one planet (Planet 1) moves closer to the star, it gains more orbital energy and moves outward, while the other planet (Planet 2) loses energy and moves inward. Eventually, they swap orbits and continue on their path.
Research conducted by an international team of scientists has shown that not only can two Earth-sized planets share an orbit in a stable configuration, but up to 24 such planets can coexist within a single orbit. This is made possible through a series of orbit swaps as the planets encounter each other repeatedly over billions of years.
While these co-orbital arrangements are theoretically possible, they are incredibly rare in practice. The stable nature of these configurations ensures that the planets can safely share the same orbit without colliding or being ejected from the system.
Written by urgent.news from Scientific American's reporting — not their text. Machine-written — may contain errors; check the original before relying on it.
