Scientists have claimed that an interstellar visitor, much larger than any celestial body in our solar system, could have significantly altered the orbits of the planets. The research, which has not yet been peer-reviewed but published in the arXiv preprint database, posits that this cosmic intruder, perhaps eight times the mass of Jupiter, passed very close to where Mars orbits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 said that under ideal conditions, the planets should have been in circles arranged concentrically around the Sun and in the same plane – meaning that if you looked at them edge-on, you would only see ‘a line. However, because the planets orbit the Sun in different orbits in three-dimensional space, it is almost impossible for them to come together in a straight line.
To understand this discrepancy, researchers considered a scenario about four billion years ago, when a star-sized alien object was orbiting our solar system. They ran extensive simulations across 50,000 scenarios, each spanning 20 million years, while adjusting various parameters such as the visitor’s mass, speed and closest approach to the sun.
These simulations indicated that in about one percent of 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 would produce a dynamic architecture similar to that of the solar system,” the study points out.
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Study results
The results showed that the interstellar object could have been within 1.69 astronomical units (AU) of the Sun, which is just beyond Mars’ current orbit. An astronomical unit corresponds approximately to the distance between the Earth and the Sun. This proximity would have been close enough that the visitor’s gravity could pull on our planets, pushing them down 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 centuries-old 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 suggests that a one-off event could explain these irregularities.
The scientists added that further exploration of this scenario is needed, which could detail “the effect of substellar flybys on the dynamic excitation of minor planets in the asteroid belt and trans-Neptunian belts.”