Anthonares

A couple of researchers thought up a very cool idea (see this site for image credits): build a good-sized spaceship (20 tons) with a somewhat advanced propulsion system (Nuclear Electric Propulsion: using nuclear power to generate electricity used to ionize propellant and expel it at very high speeds. This form of propulsion is extremely weak, but also extremely efficient), park it next to an Earth-Threating asteroid and let the attraction between the two objects pull the asteroid away from the Earth.

This idea is elegant and likely effective. Provided their calculations are correct (their work is being published in Nature), we know that it will work because the physics involved are so simple. Detonating a nuclear bomb near an asteroid or comet, by contrast, would be much riskier, and less likely to succeed. If we were to do this it would be the first time humans have engaged in Astro Engineering. Yet it will not be the last. Empowered by a first success such as this, we could move on to moving larger bodies from further out in the solar system for the purposes of mining or terraforming. I am incapable of conceiving what the future Astro Engineers will learn in their basic courses, because permanently living in space will give those students a view of gravity that is totally different than mine. This idea, the gravitational tug, is just a glimpse of the wonders to come.