The physics of 9/11 — including how fast and symmetrically one of the World Trade Center buildings fell — prove that official explanations of the collapses are wrong, says a Brigham Young University physics professor.

In fact, it's likely that there were "pre-positioned explosives" in all three buildings at ground zero, says Steven E. Jones.

Jones, who conducts research in fusion and solar energy at BYU.

"It is quite plausible that explosives were pre-planted in all three buildings and set off after the two plane crashes — which were actually a diversion tactic," he writes. "Muslims are (probably) not to blame for bringing down the WTC buildings after all," Jones writes.

Previous investigations, including those of FEMA, the 9/11 Commission and NIST (the National Institutes of Standards and Technology), ignore the physics and chemistry of what happened on Sept. 11, 2001, to the Twin Towers and the 47-story building known as WTC 7, he says.

The official explanation — that fires caused structural damage that caused the buildings to collapse — can't be backed up by either testing or history, he says.

Jones acknowledges that there have been "junk science" conspiracy theories about what happened on 9/11, but "the explosive demolition hypothesis better satisfies tests of repeatability and parsimony and therefore is not 'junk science."

• The three buildings collapsed nearly symmetrically, falling down into their footprints, a phenomenon associated with "controlled demolition" — and even then it's very difficult, he says. "Why would terrorists undertake straight-down collapses of WTC-7 and the Towers when 'toppling over' falls would require much less work and would do much more damage in downtown Manhattan?" Jones asks.

"And where would they obtain the necessary skills and access to the buildings for a symmetrical implosion anyway? The 'symmetry data' emphasized here, along with other data, provide strong evidence for an 'inside' job."

The physics of 9/11 — including how fast and symmetrically one of the World Trade Center buildings fell — prove that official explanations of the collapses are wrong, says a Brigham Young University physics professor.

Previous investigations, including those of FEMA, the 9/11 Commission and NIST (the National Institutes of Standards and Technology), ignore the physics and chemistry of what happened on Sept. 11, 2001, to the Twin Towers and the 47-story building known as WTC 7, he says.

The official explanation — that fires caused structural damage that caused the buildings to collapse — can't be backed up by either testing or history, he says.