No one hit by debris shouldn't be surpriseBy MATTHEW WAITE and CONSTANCE HUMBURG
© St. Petersburg Times
published February 4, 2003
And not one of the nearly 7-million people who live in east Texas and western Louisiana was hit.
President Bush and NASA Administrator Sean O'Keefe "expressed amazement" in their meeting Monday that no one was hurt, presidential spokesman Ari Fleisher said. That was "one small piece of good news" out of the disaster, he said.
Kim Pease, public information officer for FEMA, the agency overseeing the debris pickup, said Monday that with 12,000 pieces collected so far, he is surprised no one was hit or injured.
"Isn't that something," he said. "I think that's a good testament to the fact that we live in a rural area. We don't even have a lot of reports of buildings being damaged. Most of this stuff fell in a field."
Truth is, it would have been incredible if someone had been hit.
"It doesn't surprise me at all," said mathematics professor Robert Dobrow of Carleton College in Northfield, Minn. "The probabilities would be extremely small."
There are 27,288 square miles in the 33 counties in Texas where debris has been found. If you took every Florida county south of a line from Citrus County on the west coast to Brevard County on the east, that's the size of the debris field.
To accurately determine what the chances are that anyone would be hit by falling debris would take a mountain of data that doesn't exist: exactly how many pieces fell and where they fell; how big they were; how many people were outside when the debris landed.
Even a rough probability number for one county takes extreme simplification, said Dobrow, who teaches probability theory and also maintains the Web site Probability Web.
In Nacogdoches County in Texas, officials have found more than 1,200 pieces of Columbia. Nacogdoches County is 947 square miles, and 59,203 people were counted by the 2000 census.
Assume Nacogdoches County is divided up into 5- by 5-foot squares. There would be more than a billion of them if the county was split that way.
Now assume that everyone in the county was awake, outside and standing in one of those boxes that are evenly distributed throughout the county. Dobrow figures there was a 6.5 percent chance that someone would get hit by a piece of Columbia.
The truth is, few of Nacogdoches County's residents were outside before 8 a.m. Saturday. There wasn't a morning commute for most adults, or school for children, to get large numbers of people outside that early.
And people aren't spread out in small, evenly spaced boxes.
Dobrow said the real probability number is somewhere between small and very small.
"Something like winning the lottery or getting struck by lightning," he said. Lotto winners face odds between being one of tens of millions to hundreds of millions.
On Monday, officials collecting the debris said they were finding more in a more widespread area.
About 300 people from 30 agencies -- including the FBI, Federal Emergency Management Agency, National Transportation Safety Board and the Texas Department of Public Safety -- were being assigned to collect thousands of pieces as small as pebbles and as big as pickup trucks.
The area where wreckage was turning up grew westward, and another collection center was established at the Naval Air Station Joint Reserve Base in Fort Worth, said Michael Kostelnik, NASA's deputy associate administrator. The base is the former Carswell Air Force Base. "It turns out that the debris field is quite large and still really being determined," Kostelnik said. "Today we find there is more things further west than we anticipated."
-- Times staff writer Alisa Ulferts contributed to this report, which used information from the Associated Press.
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