The challenge of identifying interstellar meteors

This review discusses the unsolved problem of the detection of interstellar particles in the Earth's atmosphere and the presence of interstellar meteors in meteor databases. Owing to the difficulties in obtaining accurate meteor measurements and, consequently, the meteoroids' orbital parameters, the identification of interstellar meteors based on their hyperbolic excess velocities is extremely challenging. Moreover, it has to be verified whether the orbit's hyperbolicity was not produced in the Solar System. Searches for interstellar meteors have been carried out using different observational techniques for more than a quarter of a century and, although they have produced many valuable results, not a single case of a meteor claimed to be produced by an interstellar particle has proven satisfactorily convincing. The reason rests in the constraints of the meteor observations, which we outline here, using meteor datasets obtained by various techniques.