Scientists have claimed that an interstellar visitor, much larger than any celestial body in our solar system, might have dramatically altered the orbits of the planets. The research, yet to be peer-reviewed but published in the arXiv preprint database, posits that this cosmic intruder, possibly eight times the mass of Jupiter, passed very close to where Mars orbits today, potentially affecting the orbits of Jupiter, Saturn, Uranus, and Neptune.
For a long time, scientists have stated that in ideal conditions, the planets should have lied in circles that are arranged concentrically around the Sun and in the same plane — meaning if you viewed them edge-on, you would only see a line. However, since planets orbit the Sun in different orbits in three-dimensional space, it makes it almost impossible for them to come together in a straight line.
To understand the discrepancy, the researchers considered a scenario around four billion years ago when a star-sized alien object, whizzed around in our solar system. They ran extensive simulations through 50,000 scenarios, each spanning 20 million years while adjusting various parameters like the visitor’s mass, speed, and closest approach to the sun.
These simulations indicated that in about one per cent of the cases, this cosmic guest could have reshaped the orbits of these planets to match what we observe today.
“We estimate that there is about a 1-in-100 chance that such a flyby produces a dynamical architecture similar to that of the solar system,” the study highlighted.
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Study results
The findings showed that the interstellar object might have come within 1.69 astronomical units (AU) of the Sun, which is just beyond Mars’ current orbit. An astronomical unit is roughly the distance from Earth to the Sun. This proximity would have been close enough for the visitor’s gravity to tug on our planets, nudging them into new paths.
“The scenario of a close encounter with a substellar object offers a plausible explanation for the origin of the moderate eccentricities and inclinations and the secular architecture of the planets.”
Previous theories suggested that the orbits may have been reshaped due to planetary interactions within the solar system. However, the new study challenges this belief and argues that a one-off event could explain these irregularities.
The scientists added that further exploration of this scenario was needed which might detail the “effect of substellar flybys on the dynamical excitation of minor planets in the asteroid belt and the trans-Neptunian belts”.
