Major disasters attract major attention. Whenever a plane crashes or a hurricane makes landfall, the event draws international news coverage and countless internet postings. Most of the time, people take experts at face value when they try to explain the science behind why a certain event happened, but for a small and vocal segment of society, the “truth” is hardly that at all. Enter the conspiracy theorists.

No matter how silly or factually incorrect they seem, conspiracy theories represent a very real strain of thought.  Most of these theories involve politics – President John F. Kennedy’s assassination is perhaps the most famous example  – or other seemingly curious events, such as the “Roswell UFO incident” back in 1947. But some of these theories challenge very basic science.

The two main weather control conspiracy theories revolve around the thought that the United States government controls the weather through a technology called HAARP, as well as airplane-produced “chemtrails.”

HAARP, an acronym for High Frequency Active Auroral Research Program, is a large array of high frequency radio antennas located in Gakona, Alaska. The program and all associated antenna equipment, which was forced to shut down and go on hiatus this past May due to sequestration, was funded by the Air Force, the Defense Advanced Research Projects Agency (DARPA), and the University of Alaska.

The purpose of HAARP was to determine how the ionosphere, or the upper layers of the atmosphere, affects radio signals, with the ultimate goal of helping to develop more advanced radio communication technology. The project accomplished this by transmitting “a 3.6 MW signal, in the 2.8–10 MHz region of the HF (high-frequency) band, into the ionosphere,” which was then studied by various instruments on the ground to see how the ionosphere affected these radio communications.

Conspiracy theorists beg to differ. A quick Google search (which returns over 7,000,000 hits) shows that HAARP has been blamed for pretty much everything bad that’s happened since the mid-1990s – terrorist attack, car accidents, tornadoes, hurricanes, floods, earthquakes, nightmares, toothaches, bad dates, you name it – but the project is most popularly associated with its alleged “weather control” capabilities.

Several popular for-profit websites claim that they have hardware that can detect HAARP-generated energy across the contiguous United States and that severe weather will occur where these “hot spots” show up on their detectors. I’ve made a point of clicking over to these HAARP weather websites near several predicted severe weather outbreaks this year, and found that the so-called HAARP activity maps always show up a few hours after the weather models are run and the Storm Prediction Center releases their latest forecasts. Funny, that.

Before the project was suspended due to lack of funds, the University of Alaska ran HAARP’s official website, but the website no longer works as of early August. The site had the array’s exact address (Google Maps even shows that the array is located off of “H.A.A.R.P. Access Road”), pictures, information, and even several 24/7 webcams focused on the arrays with a beautiful view of the mountains in the background. The large amount of openness surrounding HAARP takes the wind out the argument that the government conducted this project in secret, like many HAARP theorists assert.

HAARP does not and cannot control the weather. While the frequencies are high powered, it doesn’t have nearly enough energy to do anything over the Lower 48, let alone specifically target communities for destruction like one would see in a science fiction movie. Both common sense and a basic understanding of meteorology debunk the conspiracy theory surrounding HAARP’s alleged ability to control the weather. But what about something closer to home; say, right above us?

Contrails, short for condensation trails, form when the hot, moist exhaust from aircraft flying at high altitudes condenses when it meets the extremely cold upper atmosphere and forms a long, narrow cirrus cloud. Contrails can make for a beautiful sky, especially during sunrise or sunset, and are indicative of particularly cold air aloft.

Contrails are harmless (as they consist of water vapor) and tend to stick around for minutes or hours, depending on how favorable the atmosphere is for sustaining such clouds. Conspiracy theorists, however, call these innocuous contrails something more sinister – “chemtrails.”

They believe that contrails are really trails of chemicals (hence the name) sprayed by aircraft for nefarious purposes, usually to control the weather, make us sick, control our minds, or cause general mischief.

The idea that aircraft that produce contrails are really spraying “chemtrails” is preposterous on its face. Airlines mostly operate based on the weight of the aircraft. The weight of the passengers, cargo, and luggage onboard is crucial for both determining how much fuel is onboard, which ultimately determines how much they pay to fill the tanks, as well as the balance of the aircraft in flight. If the plane is too heavy or the weight is distributed incorrectly, it could crash.

Liquids are heavy. One gallon of jet fuel weighs approximately 6.7 pounds. Take a Boeing 747-400, for example: a fully-loaded 747 flying from London to Hong Kong would require almost a full tank of gas – somewhere between 50,000 and 60,000 gallons of fuel. That’s upwards of 370,000 pounds of fuel in the tanks. Between the weight of the fuel, the passengers, the cargo, and the luggage onboard, there’s simply no room left for “chemtrail” chemicals even if they did want to spray us all with toxic gunk.

Some people who believe in the chemtrail conspiracy theories also swear by spraying distilled vinegar up in the air, claiming that the vinegar ascends thousands of feet in just minutes to neutralize a sky full of these wispy clouds. A quick search of “chemtrail” and “vinegar” on YouTube brings up over 3,800 hilarious videos of people seriously trying this.

The chemtrail theorists actually have more historical footing than their HAARP counterparts. Many governments and institutions across the world have experimented with cloud seeding over the last 70 or so years with the intention of forcing clouds to produce rain or to keep them from producing severe weather, with varying reports of how well these efforts have succeeded. Precipitation forms when water condenses or freezes around a nucleus (a speck of dust, sand, or even small bugs) and liquid builds up on this newly-formed droplet. Cloud seeding efforts seek to provide this nucleus around which water can condense and ultimately lead to the production of precipitation.

The problem with conspiracy theories is that it’s impossible to try to communicate to a theorist the sound science behind a project like HAARP or the cause of contrails without being waved off.

The people who want to believe the conspiracy will believe it no matter what you tell them.  If you try to explain the science and prove the theory wrong, you’re wrong, because “that’s just what they want you to think.” Participating in discussions about these theories can be entertaining, but it becomes a problem when people start pushing anti-science as a legitimate alternative to reality.

* Guest contributor Dennis Mersereau, who grew up in Woodbridge, Va., writes a weather column for Daily Kos.