Science

The Earth has a lot of mass and moves extremely quickly in its orbit around the Sun; in science speak, we say its ‘momentum’ is large.

To significantly change the Earth’s orbit, you would have to impart a very great change to the Earth’s momentum.

Not even the largest asteroids have sufficient mass and kinetic energy to make much of a difference to the Earth’s momentum.

Our planet’s binding energy is greater than its orbital kinetic energy.
This means that any object large enough to change the Earth’s orbit is also big enough to completely destroy it!


Yet, we are interested in stopping smaller, yet damaging asteroids.

NASA crashes spacecraft into asteroid, passing planetary defense test

https://www.nasa.gov/press-release/nasa-s-dart-mission-hits-asteroid-in-first-ever-planetary-defense-test