.ON APRIL 2ND a gizmo resembling a snowfall machine on the deck of the USS Hornet, an obsolete aircraft-carrier moored in San Francisco Bay, started generating a moisture of salty aerosol bits. The clinical cooperation behind the project, the Marine Cloud Brightening (MCB) program, led due to the College of Washington, is examining whether such sprays may assist to slow weather modification through a type of "geoengineering". What does this condition mean-- as well as why is it therefore questionable?