It's an astonishing claim: The tornado that ravaged Joplin, Mo., last Sunday, killing at least 125 people, was not a random act of nature but the result of an obscure military-backed research program in Alaska that shoots radio waves into the upper atmosphere.
Here's another one: The shooting rampage in Tucson last January that killed six people and wounded 13, including Rep. Gabrielle Giffords, was an elaborate government hoax that used actors to portray the victims.
And there is this: Osama bin Laden is still alive, and the raid in which daring Navy SEALs shot him dead on April 29 was fabricated to improve President Obama's chances of winning re-election.
These are three of the bogus new conspiracy theories flying across the Internet, advanced by believers who insist the evidence to support them could not be any clearer.
"Don't know about the rest of you, but I'm telling everyone I know and don't know (sales clerks, bank tellers, waiters, etc.) about the weather manipulation," a YouTube poster named "thegreenieye" wrote, responding to a video that claims last month's devastating tornado in Tuscaloosa, Ala., also was caused by the atmospheric research in Alaska.
"99.5 [percent] of people are completely unaware of this," thegreenieye wrote. "Tell everyone you know (and don't know) about it. The masses need to be informed!"
Conspiracy theories are not new, but there has been an explosion of them recently.
Jon Kay spent 2 ½ years interviewing conspiracy theorists, attending their conventions and surfing their websites to write the just-published "Among the Truthers: A Journey Through America's Growing Conspiracist Underground."
Kay initially intended to explore the so-called "truther" movement, which makes the slanderous claim the 9/11 attacks were engineered by the U.S. government, and approved by then-President George W. Bush and Vice President Dick Cheney, so the U.S. could invade Iraq and Afghanistan and curtail civil rights.
But once Kay entered the conspiracy rabbit hole he discovered a world of extreme paranoia -- a multitude of conspiracy theories nourished by the Internet and fueled, in part, by anxiety caused by tough economic times.
"I was surprised by how prevalent they are," said Kay, the op-ed editor of the National Post newspaper in Canada. "What was shocking to me when I started interviewing people was that once someone bit on one conspiracy theory, they would enter this subculture and subscribe to 10 others."
That subculture now includes the head-spinning claim that the deadly rampage in the parking lot of a Tucson supermarket on Jan. 8 was not a shooting but an event staged by the government.
The New York Times, which first reported the Tucson conspiracy theory, said believers have confronted at least one victim and asked for evidence he had been shot.
A Texas-based website making the allegation said it has been investigating to determine if the media lied about the rampage to push an "anti-gun" agenda.
"What I found shock [sic] me to the core of my being," the site's operator said in a posting.
There are several conspiracy claims blaming atmospheric research in Alaska for a series of national disasters, including the tornadoes in Joplin and in Tuscaloosa, the catastrophic earthquake in Japan and last year's earthquake in Haiti.
The High Frequency Active Auroral Research Program, run by the University of Alaska and supported by the Navy and Air Force, shoots radio waves into the upper atmosphere to study how those waves are affected and develop better communications technologies. But conspiracy theorists see it as some kind of doomsday device causing havoc across the planet.
Experts say the idea that the research could cause a rain shower, let alone a tornado or an earthquake, is ridiculous.
"The closest thing to truth is that scientists are experimenting with seeding clouds to induce rain, but there's no science behind the idea that the government can induce tornados," said Benjamin Radford, managing editor of "Skeptical Inquirer" magazine and a research fellow with the Committee for Skeptical Inquiry, a non-profit educational organization.
"This superstitious thinking dates back hundreds of years," he said. "Before people knew why disasters happen, they could attribute it to the gods. These days, they attribute it to powerful unseen government forces."
There are websites dedicated to examining and debunking conspiracy theories -- but believers will not be deterred.
Indeed, the so-called "birthers," who claim President Obama was born overseas and is a real-life Manchurian Candidate sent to destroy the U.S., are still at it, even though Obama released a copy of his "long-form" Hawaii birth certificate last month.
The conspiracy theorists now claim the birth certificate is a forgery. The new book "Where's the Birth Certificate," which claims the president is not a natural-born citizen, is No. 50 on Amazon.com's best-seller list.
Kay said one of the "depressing" aspects of his research was that he was never able to win an argument with the more than 300 conspiracy theorists and advocates he interviewed.
"It totally destroyed my faith that rational discourse will prevail," he said.
"The signature trait of conspiracy theorists is that they respond to contrary evidence by simply enlarging the conspiracy," he said. "So if I said, 'Read the 9/11 Commission report,' they said, 'The 9/11 commissioners are part of the conspiracy.' ... That kind of argument is bulletproof. There was nothing I could say that could change their minds."