I live in Atlanta. Hartsfield International is one of the busiest airports in the world. Hearing an airplane above is as commonplace as going to the grocery store for this city's residents.

Last night, the skies here and across America were silent.

Sometimes, the absence of something speaks volumes more than its presence.

I visited New York when I was a teenager. I remember stepping out of the train station, looking up and up and up, and seeing just this tiny square of grey sky peeking through all the towers of metal and glass. I thought: New Yorkers have no sky that they have not built themselves. I once stood upon the very tip-top of that man-made sky, on the roof of the World Trade Center, and looked down with wonder at what had been constructed.

After the dust settles, there will be a whole lot more empty sky in New York.

There is a void, a hole, a shambling pile of debris where the towers once stood. Like a missing tooth in someone's smile, our eyes are drawn to the piece of skyline that is no longer there, replaced by a dissipating plume of dusky smoke that can be seen from space.

Sometimes, the absence of something speaks volumes more than its presence.

Missing pieces are not hard to come by today. Bits are missing from each of us, as we grieve for so many reasons.

There used to be computers in those buildings. There used to be elevators, phones, paper-covered desks, photocopiers, Coke cans and coffee cups next to pictures of friends and family decorating cubicles.

There used to be people who ran those computers, drank that coffee, and occasionally called those friends and family on company time on those company phones to hear about a new baby, Uncle Frank's surgery, or the need to pick up the dry cleaning on their way home.

Yesterday, all of that changed. The mundane decisions of who to cc: on this e-mail and where to go for lunch that afternoon were replaced. The new decisions and options were chaotic and brief: to flee, to burn, to be crushed and entombed by rubble, to suffocate while praying for rescue, or to jump to a certain and comparatively quick death. A thriving center of commerce turned into a place of ash and bones in moments. Among the screams, the suffering, and the abandoned spreadsheets, the choice of how best to die was their final act of free will.

There used to be routine. September 11, 2001 was anything but routine. The pattern changed.

As the bereft parents, siblings, spouses and children know all too painfully today, those faces that once smiled from the cubicle photos, sometimes the absence of someone speaks volumes more than their presence.

Today, brave rescue workers continue the arduous and urgent task of finding survivors. Congress convenes to take action. Kind people from all over the world express their sympathies via the internet, and entire countries observe days of mourning. We are grateful to see the very best of humanity, but also sad to witness the worst of it. Good, generous people line up to give blood and attend memorial services; shopping channels and other networks suspend broadcast in recognition of the tragedy, churches stay open 24 hours, and outreach efforts are implemented on and offline. We see the enemy without and within as that element of society that always serves itself begins price gouging at the gas pumps, and wastes no time in selling t-shirts and "collectible" tragedy editions of the New York Times on online auction sites. Worse, the ignorant and fearful among us are committing racist acts of violence against innocent Arab-Americans, and many cast suspicious glances at those who even look Middle Eastern.

Many of us are a bit more thankful today that we still have a building to go to work in, and that we still have our pictures and our coffee cups. Airports remain shut down, tired workers under maximum security conditions deal with stranded, frightened travelers, and a blunt truth is quietly spoken: tighter security will do little to reduce risk despite the cost to privacy. At military bases around the country, nobody gets in or out. There are whispers of acknowledgement that our intelligence operatives are still desperately needed, and that a quantum re-education of our enemies, our allies, and ourselves must occur on many levels here and abroad if things are to get better. As we see our citizens running through New York's war zone with debris filling the air behind them, some of us are humbled to learn what it is like to experience the atrocities that people in Northern Ireland, Africa, and other areas around the world have lived with for years.

Realizations begin to set in. Naiveté and idealism are shed in favor of pragmatism; pacifists come to terms with experiencing a desire for retribution and revenge as many are roused from complacency. The extreme situation engenders extreme reactions. Shock begins to pass away for some of us, while others remain overcome with disbelief at the unthinkable happening. A survivor from the 36th floor "just wants to be 'safe' from animals like those who are quietly or not so quietly dancing at this news," and is ready to nuke Afghanistan if they are harboring the perpetrators. We feel invaded and violated: the deep sense of wrong, that nothing can justify such an act, fuels a clear, cold anger. We are anguished, yet we are also resolute. For many, patriotism is discovered as the phrase "worse than Pearl Harbor" seeps into our collective consciousness. Heroes are made and mourned.

There is no shelter from the aftermath in this sober new century. Instead, there is a poignant, creeping foreboding of a slumbering war bear finally awakened to grim necessity. There are unnerving words of warning that the numerous conveniences, freedoms, and liberties that many of us often take for granted may slip away during such a time. Awareness of the need to fight to prevent future generations from living in fear of terrorism takes hold. The evacuation of the US president and Congress and the dispatching of cruisers off our nation's shores causes both allies and rivals to quickly arrive at the conclusion that many political scientists have known all along: a world with the America they know, imperfect though it may be, is far better than a world without it.

The absence of this America and its ideals might well be far more chilling than its presence.