Two years later, the world has changed in ways big and small

NEW YORK -- Yellow is still yellow, orange is still orange, red still red.

But these colors now have other, ominous meanings -- just as a cloudless blue sky, once an uncomplicated pleasure, now suggests to many in New York and Washington a morning two years ago when a clear sky gave way to an unimaginable horror.

In so very many ways, the world has changed since Sept. 11, 2001.

There are obvious, dreadful differences: There are gaps in creation where the more than 3,000 victims of the attacks once lived and breathed, and thousands of others have died in Afghanistan and Iraq.

But the changes are not all so momentous.

Because of Sept. 11, thousands rise each Sunday at the seventh-inning stretch of Major League Baseball games to sing "God Bless America." Because of Sept. 11, duct tape has found unimagined uses. Because of Sept. 11, one of the modern age's most prosaic sounds -- the drone of a low-flying airplane -- can startle and alarm.

Whenever something happens -- a shooting at New York's city hall, the breakup of the shuttle Columbia, a blackout in the Northeast and Midwest -- we ask: Have terrorists struck again?

Color-coded alerts

For answers, we look to the Department of Homeland Security, a massive federal agency (170,000 employees, a projected 2004 budget of $26.7 billion) that raises the nation's anxiety level with color-coded alerts, but did not even exist two years ago.

Even the phrase "homeland security" meant little on Sept. 10, 2001.

Now, though, it seems like it has been with us forever; it is growing harder to remember a time when the federal government could not force universities to divulge the grades and other records of foreign students, or detain people as material witnesses without charges, or hold Americans as "enemy combatants" without access to lawyers.

Mostly, Americans seem to have accepted these things as regrettable, collateral damage from a shifting war against a shadowy foe.

Librarians have been among the USA Patriot Act's fiercest critics. They have posted signs warning patrons that the FBI has the right to see records of what they have been reading, and some have taken to shredding sheets patrons sign to reserve computers for Internet access.

Major academic journals now monitor research papers, deleting anything that might help would-be terrorists devise weapons of mass destruction. At George Mason University in Virginia, Sean Gorman's doctoral dissertation will not be published; he mapped America's fiber-optic network, and no one wants his findings to fall into the wrong hands.

The landscape is littered with security barriers that weren't there in 2001.

Ralph Nasatka says the active barriers his Clinton, Md., company sells -- the kind that flip up to prevent a car from entering a secure area -- send an important message.

"Let people know they can no longer have a free hand. The door is closed," he says.

And two years into the war on terror, Americans accept that shoes can be weapons. So they line up, shoes in hand, to pass through airport security.

Or they adapt. Come this fall, Rockport shoes will have plastic shanks, and will not trigger alarms. At O'Hare Airport in Chicago, passengers can check shoes for metal by sticking their feet in special cardboard boxes (made by Boy Scouts as an Eagle Scout project).

Knitting needles are allowed on planes; sharp files on nail clippers are not. And on the New York-Washington shuttle no passengers are allowed to leave their seats.

Americans have come to accept that strangers have the right to go through their belongings as they file into a concert at Carnegie Hall or an outing at Great Adventure amusement park.

Not all the changes America has seen are a result of efforts to prevent another terrorist attack; some are spurred by efforts to survive one.

Managers of the 110-story Sears Tower, the tallest building in America, have installed chairs that can be used to wheel disabled or injured occupants down stairways.

Skyscrapers have improved emergency lighting, added X-ray screening for bags as visitors enter, improved fireproofing and conducted fire drills with a renewed seriousness. Some offices, especially in New York, have placed first-aid kits and escape hoods on desks.

Families -- again, especially those close to New York and Washington -- have gathered to discuss where they would meet in the event of an emergency that forced their evacuation. Bob Ezrol, director of Camp Taconic in the Berkshire Mountains of Massachusetts, says parents have been more insistent on staying in touch with their children by telephone since Sept. 11.

Schools -- when they aren't announcing evacuation points, where their students would be brought in an emergency -- are trying to find a teaching moment in it all. Sept. 11 (and its aftermath) has found a place between reading, writing and arithmetic.

"What is a terrorist? How does a terrorist differ from a freedom-fighter? Who decides?" asks a curriculum designed by Brown University's Choices for the 21st Century Education Program.

Students engage in role-playing discussions, arguing the cases for the Irish Republican Army, Chechen rebels and the Weather Underground.

"I think that a lot of them learn that sometimes the United States makes decisions based solely on what is best for the United States," says Nicolle Robinson, who teaches 11th grade American history at Granite High School in Salt Lake City.

Younger children, too, are learning about the attacks. In "The Man Who Walked Between the Towers," a new picture book, Mordicai Gerstein tells the story of Philippe Petit, the daredevil who walked a tightrope between the World Trade Center towers in 1974.

The last page shows today's Manhattan skyline.

The last line is "Now the towers are gone."

And they are.

Eventually, something new and extraordinary will arise at ground zero; for now, people in the narrow streets of lower Manhattan are disoriented when they climb out of the subways, for lack of a colossal landmark.

New York has suffered greatly in the past two years. It has lost 162,900 jobs since the attack, and last year 152,278 more people left New York for other places in the United States than came here from elsewhere in America.

Elana Boses, 27, is one of them. A fashion trends forecaster, she lived four blocks from the World Trade Center. Now she lives in St. Petersburg, Fla., with her mother, and sells houses. She is on medication for post-traumatic stress -- panic attacks, flashbacks -- and she is thankful for any distance she can put between her and Sept. 11.

"I'm so glad that I'm not in the city," she says. "I'm so glad that I'm in Florida and I don't have to think about things like that."

But there are indications that other Americans are thinking about Sept. 11 and putting it in perspective -- and that alone would be an enormous change.

You can see it in popular culture, especially in the continuing evolution of World Trade Center images in film. The towers were digitally expunged from the comedy "Zoolander" after the attacks; a "Spider-Man" trailer that depicted the World Trade Center quickly was pulled.

But late last year, Spike Lee's movie "The 25th Hour" opened with a view of the skyscrapers and included a scene in an apartment looking down at the site.

"What happened on Sept. 11 really traumatized Americans and we're still feeling the effects," Lee told the British Broadcasting Corp. in an interview. "New Yorkers, and Americans generally, are living in a much different world now. The threat of terrorism is an everyday occurrence, so we wanted to reflect this different world. It's that simple."

Of course, it's not that simple. Sept. 11, 2001, was a line of demarcation between the present and the past. Images of the trade center remind us of just how much things have changed.

An editor in New York has a picture on her desk of her then-6-year-old son, posing on the Brooklyn Bridge. He is smiling, squinting in the sunlight. Behind him, almost ghostly, two 110-story towers loom.

The sky is a vivid blue, with clouds.