46 | New York City unveiled plans for the first anniversary of the World Trade Center attacks, including the sunset lighting of an eternal flame by world leaders, possibly including President Bush (see p. 23). Former Mayor Rudolph Giuliani will begin a reading of the names of 2,823 victims, and Gov. George Pataki will deliver the Gettysburg Address, with emphasis on how the "brave men, living and dead, who struggled here have consecrated [the ground] far above our poor power to add or detract." The historic grounding of all air traffic also led to scientific research. David Travis and his team at the University of Wisconsin-Whitewater wondered if the exhaust trails from jets, called contrails, have any effect on the weather. They found the days were a little warmer and the nights were a little cooler after planes were grounded on Sept. 11. The scientists argued, in the journal Nature, that contrails mimic cirrus clouds in muffling temperature extremes.