A new study by scientists from the University of Illinois showed that attempts to deflect asteroids can be dangerous: space objects can fall into the so-called “gravitational gaps” and after years or decades again go on a collision course with the Earth, reports Science Alert.
Gravitational gaps are regions of space where the gravitational force of planets can change the orbit of a passing asteroid. Even if an asteroid is deliberately pushed away by a space mission, hitting such a “gap” can return it to its former dangerous path.
NASA expert Rakhil Makadia notes: “We must make sure that the asteroid does not fall into one of these keyholes. Otherwise, the threat will return after some time.”
Makadia’s team created “probability maps” that show the most dangerous zones for each asteroid to collide with Earth after deflection. To build such maps, data on the shape, mass, rotation and surface of a space object are needed, which can be obtained during missions or with the help of ground telescopes.
Similar maps have already been created for the Bennu asteroid. As an example of future missions, researchers mention DART to deflect asteroid Dimorph and ESA’s Hera mission, which should reach the collision site of DART with Dimorph in December 2026.
Scientists warn that in the future, asteroid threats may be even less predictable, so control and accurate calculations will be critically important for the safety of the Earth.