Subscribe | UPI Odd Newsletter Subscribe MOSCOW, Aug. 3 (UPI) -- Researchers in Russia say they've discovered what makes crop circles -- and no aliens are involved. Speculation has abounded for years that aliens are responsible for mysterious designs that show up occasionally in fields. The phenomenon was featured in the 2002 movie "Signs." Advertisement A group of researchers say plants will bend in patterns when lightning strikes because of microwave emissions, MosNews reports. One researcher said stalks of cereals bent like crop circles when he put them and a glass of water in a microwave oven. Another researcher was experimenting outside when a device shot out artificial lightning on the grass, causing it to bend in even clockwise circles. Researchers say they are now trying to figure out where the microwave emissions come from during a lightning strike.