The centennial of Carson's birth occurred in 2007. On Earth Day (April 22), "Courage for the Earth: Writers, Scientists, and Activists Celebrate the Life and Writing of Rachel Carson" was released as "a centennial appreciation of Rachel Carson's brave life and transformative writing." It contained thirteen essays by environmental writers and scientists. Democratic Senator Benjamin L. Cardin of Maryland had intended to submit a resolution celebrating Carson for her "legacy of scientific rigor coupled with poetic sensibility" on the 100th anniversary of her birth. The resolution was blocked by Republican Senator Tom Coburn of Oklahoma, who said that "The junk science and stigma surrounding DDT—the cheapest and most effective insecticide on the planet—have finally been jettisoned." The Rachel Carson Homestead Association held a May 27 birthday party and sustainable feast at her birthplace and home in Springdale, Pennsylvania, and the first Rachel Carson Legacy Conference in Pittsburgh with E. O. Wilson as keynote speaker. Both Rachel's Sustainable Feast and the conference continue as annual events.