LARGO — James Ipser is a professor emeritus at the University of Florida who spent most of his career in astrophysics.
Specifically, he's a theoretical physicist who has used Einstein's theories to study some of the strongest gravitational forces in the universe and how they apply to massive bodies, such as black holes and neutron stars.
But on Friday, defense attorneys called Ipser to talk about an especially tiny body — 20-pound Maria Harris — and the forces that could have killed her.
The forum was not a physics convention but the murder trial of Stephanie Spurgeon, 40. She is accused of killing Maria in 2008, on the girl's very first day at Spurgeon's home day care in Palm Harbor.
Although Ipser readily admitted "I'm not a medical person," he said basic physics does explain some important things about what did or did not happen to the 1-year-old. And Ipser said he does have expertise in the physics of accident reconstruction and even developed a University of Florida course about it.
"I'm not offering medical opinions per se. I'm talking about physics," he said. "I'm talking about forces and the potential of those forces to cause physical damage."
After Maria spent a day at Spurgeon's home day care, she appeared limp and virtually lifeless after her grandmother picked her up and drove her home.
The girl was taken to a hospital and found to have bleeding in the brain called a subdural hematoma, as well as retinal hemorrhaging and swelling of the brain.
Ipser said the U.S. government publishes an index that explains how much force to the head causes head injuries. Based on that index, he said, he was able to calculate that someone shaking Maria would have had to exert as much as 1,500 pounds of force on her to cause such injuries just by shaking her.
But that's more force than a human can muster, he said. "You can't do it." Besides, Ipser added, "That force would severely damage the neck." But Maria did not have severe neck injuries.
That means Maria did not die from shaking alone, he said.
"In my opinion, within a reasonable degree of scientific probability, it's just not possible in general that shaking without blunt impact on a hard surface would be sufficient to cause … this internal evidence of damage," he said.
Ipser did say that if someone had hit Maria's head against something, not as much force would have been needed to injure her. But there is no evidence that she had skull fractures or bruises from such an impact, he said.
During cross-examination, Ipser acknowledged that shaking was not the only theory about how Maria died. A medical report he reviewed said "repetitive force" injuries also could have been a factor.
The Pinellas-Pasco medical examiner testified earlier in the week that the cause of death was "blunt head trauma."
Although Ipser is not a medical person, other defense witnesses definitely are.
St. Petersburg radiologist Mark Herbst testified Friday that he reviewed CT scans and other images taken after Maria was rushed to the hospital. He saw evidence of swelling of the brain, called edema, and bleeding in the brain.
He said the CT scans indicated that the brain swelling began sometime between 12 hours and seven days before the images were taken — which would have been before Maria was taken to Spurgeon's day care. He said the CT scans indicated that the bleeding occurred at some time within the previous seven days, which could have been during the time she was at the day care or before.
More doctors are coming for the defense. When the trial resumes on Tuesday, pathologists Jan Leestma of Chicago and John Plunkett of Minnesota are scheduled to testify.
Staff writer Curtis Krueger can be reached at email@example.com or (727) 893-8232.