A a group of scientists in Scotland are publishing a paper in the journal Advances in Space Research
that contemplates using asteroid dust to shield the Earth from solar radiation, thus mitigating the effects of global warming.
The idea has some problems, however.
The plan, according to Space.com, would be to capture an asteroid -- 1036 Ganymed, for preference -- and use a mass driver to throw out material from it to move it to the L1 point, the Earth Moon Lagrange Point that lay directly between the Earth and moon. Then the same mass driver would create a stream of asteroid dust that would surround the Earth and block out enough solar radiation to cancel out the effects of global warming, giving the world enough time to switch from a carbon based energy economy to something else.
According to JPL, 1036 Ganymed is the largest known Earth-approaching asteroid, with a diameter of about 32 kilometers. It is an S type asteroid, meaning that it is composed of metallic iron mixed with iron- and magnesium-silicates. Space.com states that the asteroid has a mass of 130 million-billion kg. Using it as a source of a dust shield would create a cloud of 5 million-billion kilograms stretching about 2,600 kilometers wide.
According to Space.com, the scientists behind the proposal concede that politically moving such an enormous mass close to Earth would be difficult at best. An accident or a miscalculation could cause 1036 Ganymed to hit the Earth, which would end human civilization
and likely a considerable amount of the biosphere.