Researchers have detected interstellar objects in the solar system. Now, after the detection, the question is how much of the solar system is made of foreign material. The astronomers have detected a total of two interstellar visitors. One is Oumuamua (2017), and the other is Borisov shortly after that. In the solar system, these objects have spent a relatively brief amount of time.
Their arrival has raised questions about the number of interstellar objects flying through the galaxy. That number could be in the hundreds of trillions. Zooming around the Milky Way, there could be countless tiny objects. Extrasolar objects currently in orbit around the Sun has not to be detected so far. The best that can be found are micrometeoroids. But if not detected doesn’t indicate that no alien rocks are hiding in the shadows. All the large rocks in the asteroids belts are barely mapped. The process of studying rocks one by one and trying to find out foreign comets or asteroids is slow and painful. It is not known how common those rocks are.
New research tries to find out the number of captured interstellar objects coming into the solar system and how long those objects remain in the solar system. Lots of stimulations were used by the researchers. The behaviour of 276,691 objects entering the solar system was studied in all sorts of directions and speeds. The evolution of each of those simulated objects was traced within the solar system back a billion years.
It is found that most interstellar objects don’t survive long. Within the orbit of Jupiter, if they end up around the Sun, they’re very likely to have a close encounter with that giant planet. They either get tossed back out of the solar system or get eaten by the gas giant when that close encounter happens. Close to the other planets, if the foreign object ends up in orbit with a plane, the object is likely to get tossed away by the combined gravitational influences of all the original members of the solar system.
When captured by the Sun, foreign objects tend to have massive and very stretched-out orbits. An object can take multiple orbits, and it may take over millions of years to find out whether it will stay for the long term. In the solar system, foreign objects have a tough survival time. In the solar system, foreign objects do not remain long; that is one part of the puzzle. How many things are crossing into the system is being estimated by the other. If the number is large, the solar system might be full of interstellar visitors even with the pitiful survival rates. The estimate is a bit speculative.
During the formation time, the Sun was embedded in a much larger star cluster. Since to other forming stars, it was so much closer t was much more likely to capture foreign material back then. The researchers estimate that the Sun captured enough objects during its birth phase to assemble 1/1000 the mass of Earth.