According to Space.com, 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.
Move an asteroid to L1 and then destroy it
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.
Problem: Moving 1036 Ganymed
Space.com suggests that moving an asteroid of the mass of 1036 Ganymed may be infeasible for the foreseeable future. Planetary Resources, a company formed to begin an asteroid mining industry, contemplates being able to move a relatively small rock of about 500,000 kilograms by 2025.
Problem: Fear of a collision with Earth
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.
Problem: No real world testing of the concept
Space.com also reports that the scientists concede that except for some computer modeling, there is no real world test that such a dust cloud would have the desired effect. Indeed, as is common with such massive, geo-engineering projects, the project is the test. What if the cloud blocks too much solar radiation, thus throwing the Earth into an ice age?
Problem: A solution in search of a problem
The whole concept of global warming, especially human caused, has been the subject of considerable controversy, with political posturing often substituting for rational science.
Former Vice President Al Gore, who won both a Nobel Prize and an Academy Award for his documentary polemic against global warming "An Inconvenient Truth," recently told a group at Hampshire College that global warming is real, it has to be addressed now, and that "97 to 98 percent" of world's scientists agree to its veracity, according to Mass Live.
According to the Washington Examiner, a group of Apollo-era astronauts and scientists condemned official statements by NASA that suggested the reality of human caused global warming, arguing that such statements were beinf made without proper scientific investigation.
Global cooling on the horizon?
Just to contemplate things, Red Orbit reports that the sun is about to go into a solar minimum cycle, which means that it will emit less solar radiation. There is a collation between solar minimums and global cooling, Perhaps the asteroid dust shield scheme would only make matters worse.
Mark R. Whittington is the author of Children of Apollo and The Last Moonwalker. He has written on space subjects for a variety of periodicals, including The Houston Chronicle, The Washington Post, USA Today, the L.A. Times, and The Weekly Standard.