How many detectable alien civilizations are out there in our galaxy? In 1961, astronomer Frank Drake developed an equation to estimate the number. Now data journalist David McCandless, who gave the talk “The beauty of data visualization” at TEDGlobal 2010, has created an information graphic for the BBC calculating the Drake Equation -- with a twist. It’s interactive, and you can be as optimistic or skeptical as you like as you set the value of each variable in the equation.
an interesting study
