When some particle is coming from another solar system, we might realize that the world of science is fascinating in that kind of case, what gives researchers and other scientists collect the chemical data of that kind of objects. And if we would be lucky, the particle would have an origin as the part of the bigger planer, what might be destroyed in the explosion of a supernova or cosmic collision.
This kind of particles can be anyway the most dangerous things in the universe because if there is the water in mineral closure, there is a possibility that the harmful organisms can be released to the Earth if that particle would drop on our planet. There is a possibility that some kind of bugs or bacteria could survive from the explosion, the trip what takes thousands of years and the dropping through the atmosphere.
In this scenario, the core of the asteroid would cover those bacteria, which might be dangerous for us. This is the reason, why we should concern about this kind of things.
But the thing is that the term "natural origin" would mean many things. If we are thinking that some hypothetical alien would make that kind of system, the thing can be that this kind of systems would not be made for fun. And the problem is that if we would face the case, where some civilization would lose its home planet, it would turn dangerous. In the worst case, this kind of grasshopper-civilizations would conquer other planets and make other species as the slaves. And this is the thing, what might not be actually true.
Because if the civilization would land on some other planet, it would be infected by micro-organisms. In the opinion of wise men, this thing might protect the species of Earth from the invasion of other species somewhere in history. The thing is that if the other civilization would land on the planet Earth it would face trillions of bacteria, and there is a need to use the protective suit, what protects their bodies against viruses and bacteria.
