Asteroids are not just wandering space rocks, but a potential threat to Earth. But what if the Earth already has its own built-in defenses against them? Recent research published on the preprint server arXiv puts forward an unusual theory: Earth’s gravitational forces may serve as its secret shield against asteroids.
Our planet uses powerful gravitational interactions with other celestial bodies to break apart asteroids that approach it. These tidal forces, akin to those that explain Earth’s tides caused by the Moon, can be so intense that objects undergo tidal disruption, causing them to be torn apart.
Observations of fragments of Comet Shoemaker-Levy 9 after its collision with Jupiter in 1994 provided the first confirmation of this phenomenon. However, for decades astronomers have been looking for evidence that Earth or other terrestrial planets could have a similar effect on asteroids and comets.
Planetary scientist Mikael Granvik from the Swedish University of Technology, Luleå, led the research that came closer to solving the above phenomenon.
His discovery is linked to the search for gravitationally disrupted near-Earth asteroids (NEAS), and provides compelling evidence that our planet’s gravitational forces are not just an abstract concept, but a factor capable of breaking asteroids into small pieces.
Based on modeling of asteroid trajectories, 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 streams.
New data shows that small asteroid fragments, while not posing a threat to life on the planet, may nevertheless increase the likelihood of local collisions like those that occurred in Tunguska and Chelyabinsk.
Granwick assures that asteroids smaller than 1 km in diameter are not a critical threat, but increase the likelihood of incidents. However, it is worth remembering the additional risks that may arise due to the formation of new debris clouds.