President Obama celebrated the 40th anniversary of Earth Day today by inviting environmental supporters to the White House Rose Garden and urging them to help build on the "immense progress" of the past four decades. "I'm grateful for the good fight so many of you have fought," Obama told the crowd. He cited an environmental agenda that includes assistance to new "clean energy" programs, as well as a climate change that would restrict emissions of greenhouse gases. He also referenced the political opposition to his plans, including those who say his climate bill would cripple U.S. industry. "I think we all understand the task ahead is daunting," Obama said. Before the reception, Obama also celebrated a beyond-the-Earth experience: He welcomed crew members from the recently returned Endeavor space shuttle mission.