 Scientific explanations for why you're seeing ghosts. When you experience shifts in the electromagnetic field, it can mess with your head. A researcher published a study on a girl who claimed to see the Holy Spirit at night. They discovered that an electric clock on her nightstand was emitting strong electromagnetic pulses. Once the clock was removed, her apparitions stopped. Extremely low sounds out of the range of human hearing can make us feel like there's another presence in the room. The fear frequency causes feelings of discomfort, and it can create optical illusions because it makes your eyeballs vibrate. Exposure in a mold or carbon monoxide can cause hallucinations and feelings of fear. They're more likely to be present in older buildings, which is why they seem haunted. But if none of these apply to you, maybe it really is a ghost.