RENO, Nev. (KRNV & MyNews4.com) -- The skies are smoky now, but when they're clear it's not strange to see vapor trails streaking the sky. Scientists say they're not harmful but some critics say they're chemicals that are dangerous to our health and the environment.
Locals gathered downtown to protest what they say is geo-engineering, an attempt to curb global warming by spraying chemicals into the air.
They say it's done through chemtrails, lines of vapor released by planes that scientists typically call contrails.
National Weather Service Meteorologist in Charge Jon Mittelstadt explains.
"It's a condensation trail that forms behind a jet due to the jet exhaust mixing with moisture in the atmosphere," he said.
Mittlestadt it's similar to how you can see car exhaust on a cold day.
But protestors like Daniel Sion say there are more than just contrails in the sky.
"[Chemtrails] look very different because they stay for hours at a time," Sion said. "They fan out and cover the entire city."
"A contrail doesn't stick around," Christopher Neilson said. "It doesn't stay in the air."
Mittelstadt said how quickly a contrail evaporates depends on atmospheric conditions and it can be anywhere from immediately to a couple of hours later.
"They will, under the right conditions, spread across the sky," Millstadt said. "At times it can cause a cooling effect because it is a cloud just like any other cloud."
But this group says they're not just like any other cloud.
"They call it weather modification, which they try to make it sound like a good thing," Neilson said.
Sion said he has found proof through the U.S. Patent Office that this technology exists.
"To create artificial clouds of aluminum for solar radiation management," Sion said. "That's what it's purported to be."
Sion said some people take this idea too far and he just wants answers, no matter if they prove him right or wrong.
"People tend to get worked up they tend to bring in a lot of political ties," he said. "We need the facts. We need to start with scientific observation."
News 4 checked into that patent
. It was filed in 1990 by Hughes Aircraft Company, which was originally an aerospace and defense contractor. It is summarized as a method of reducing global warming by introducing oxides into the atmosphere. At the time the patent was filed, the company was owned by General Motors.
Now Hughes Aircraft is owned by Raytheon, another defense contractor. News 4 will follow up with Raytheon to find out if and how this patent is being used.