Could the Sun Capture a New Planet, Changing Life on Earth?

A new analysis suggests the Sun is capable of "capturing" much larger interstellar objects than we have seen.

Writing in the scientific journal Celestial Mechanics and Dynamical Astronomy, two American space scientists have outlined how the Sun could become a formidable kidnapper.

In the past few years, humanity has discovered two interstellar objects: the object  Oumuamua and the comet 2l/Borisov.

Although many theorize that they may have been sent by aliens, most scientists believe they are rogue objects temporarily abducted by our solar system.

Setting up a new model, researcher Edward Belbruno from Yeshiva University (USA) and former NASA Chief Scientist James Green investigated how formidable the Sun's abduction ability is.

A rogue planet, an object that could be abducted by the Sun into the inner system - (Graphic image: NASA/JPL-CALTECH).

The authors analyzed the phase space of the Solar System - a mathematical model that describes the state of a dynamical system like our own.

The phase space of the Solar System has capture points where interstellar objects can find themselves gravitationally bound to the Sun. There are two types of capture: weak and permanent.

Objects like Oumuamua and 2l/Borisov may only be 'weakly' captured, meaning they fall into regions where an object can be temporarily pulled into a semi-stable orbit. These points are typically where the outer edges of an object's gravitational boundaries meet.

Permanent capture points are regions into which the abducted object can be pulled forever or for extremely long periods of time, with the angular momentum and energy allowing it to maintain a stable orbit.

Research also shows that it's not just small objects, our Sun is powerful enough to kidnap an entire planet.

Within a radius of 6 parsecs around the Sun, there are 131 stars and brown dwarfs, not to mention a number of rogue planets, ejected from their star systems in some unfortunate collision.

According to new estimates, six of those stars will pass within 50,000 light years of us.

They would cause encounters in the Oort Cloud region surrounding the Solar System and push at least some objects in this region into the heliosphere, or even rogue planets that happen to be hanging around there.

The researchers also calculated that the phase space of the Solar System could contain 'holes' that could facilitate such intrusions. These holes are located 3.81 light-years from the Sun in the direction of the galactic center or opposite it.

In the worst case scenario, if an entire planet were to enter the Solar System, it would disrupt other planets and possibly alter the course of life on Earth.

But surely, that is only likely to happen in the extremely distant future.

However, the discovery of the Sun's "abduction" ability will provide a foundation for observatories to search for interstellar objects approaching us in the near future, and is also a great opportunity for humanity to examine a sample from another star system.