Asteroids are not just wandering space rocks, but a potential threat to Earth. But what if Earth already has its own built-in defense mechanisms against them? Recent research published on the preprint server arXiv puts forward an unusual theory: Earth’s gravitational forces may serve as a secret shield against asteroids.
Our planet uses powerful gravitational interactions with other celestial bodies to break apart asteroids that approach it. These tidal forces, similar to those that explain Earth’s moon-induced tides, can be so intense that objects are disrupted by the tides, tearing them apart.
Observations of fragments of comet Shoemaker-Levy 9 after its collision with Jupiter in 1994 provided the first confirmation of this phenomenon. However, astronomers have been looking for evidence for decades that Earth or other terrestrial planets may have a similar effect on asteroids and comets.
Planetary scientist Mikael Granvik from Sweden’s Luleå University of Technology led the research that came closer to solving the aforementioned phenomenon.
His discovery is related to the search for gravitationally disturbed near-Earth asteroids (NEAS), and provides compelling evidence that our planet’s gravitational forces are not just an abstract concept, but a factor that can break asteroids into small pieces.
Based on modeling of asteroid orbits, Grunwick and colleague Kevin Walsh of the Southwest Research Institute found that collisions with rocky planets can cause asteroids to lose a significant portion of their mass, turning them into debris flows.
New data shows that small asteroid fragments, while not a threat to life on Earth, could still increase the likelihood of local collisions such as those in Tunguska and Chelyabinsk.
Granwick assures that asteroids with a diameter of less than 1 km do not pose a critical threat, but increase the risk of incidents. However, it is worth taking into account the additional risks that may arise due to the formation of new debris clouds.
