THIS article about the new World Trade Center is already out of date.

The pace of construction is so swift that any status report these days gets overtaken rapidly by the arrival of new beams and columns, rebar and concrete, pipes and conduit. About 2,000 construction workers are on the job, weekends included, officials said, and that number will just keep rising. Visiting the site brings to mind the tumultuous first impressions of arrival in New York City: people, vehicles and objects are headed toward you from every direction at startling velocity, and the only prudent thing to do is to keep moving.

Two years ago, it was difficult to imagine how the Port Authority of New York and New Jersey, which owns the site of the trade center and is building most of it, could ever finish the eight-acre memorial in time for the 10th anniversary of the attack, on Sept. 11, 2011. Today, it is difficult to imagine what would stop them (though, given the site’s tortured history, the possibility shouldn’t be completely dismissed).

The great square voids in the plaza marking where the twin towers stood are fully formed and almost entirely clad in charcoal-gray granite. Enormous pumps are standing by to send thousands of gallons of water cascading into the voids, creating what memorial officials say will be the largest human-engineered waterfalls in the United States. A metal fabricator in New Jersey is incising bronze panels with the names of all 2,982 victims of 9/11 and of the trade center bombing in 1993. And last weekend, 16 swamp white oaks began to take root on the plaza. Four hundred more will follow.

But in the public’s mind, it is still “ground zero” — as in, “When are they ever going to build something at ground zero?” Or as in, “ground zero mosque,” the shorthand reference for the Islamic community center planned two blocks to the north. While much of the nation has been debating who should be allowed to build what on that site, a former Burlington Coat Factory store, little attention has been paid to the fact that things really are being built on the spot where something actually happened.