A few weeks ago I watched a great video by Veritasium on the subject of asteroids of significant size that could collide with the Earth. The last part of the video includes a discussion on options for deflecting mid-size asteroids (those that would be too small to cause an extinction-level event, but would be large enough to destroy an area the size of a country like France or Germany), and basically concludes that none of the discussed options (which are multiple and quite creative) would be effective.

After mulling it over a bit, I thought of another option. What if, over a period of decades, we put some material in stable Earth orbit? In case a medium-sized asteroid is detected (hopefully months or years ahead of collision), the material could be gathered and assembled into a series of obstacles (or perhaps a big obstacle) that would be placed in the way of the asteroid. In that way, the collision would happen somewhat farther from the surface of the Earth, and hopefully the fragments of the collision will be small enough to be consumed by the Earth’s atmosphere.

There are three core assumptions on which this plan relies: 1) it is economically (and ecologically) feasible to launch a number of large masses into stable orbit; 2) it is possible to move these masses together into the trajectory of the incoming asteroid; 3) it is possible to create an obstacle from these assembled masses that can break an incoming asteroid into acceptably small pieces.

Given my ignorance of both physics and rocketry, the probability of this suggestion being practicable is very low. If you, like me, are way out of your depth in this subject, don’t much put stock on it!

And if this catches on, we could call it pebble shield.