Not many people openly admit to believing in ghosts, but you’d be surprised how many actually do believe in them. Millions of people, 43% of Americans and 34% of British people think that they can see ghosts.

Are you one of them? Well, maybe you’d like to reconsider your take on the matter after you’ve heard about the real-life experience of Carrie Poppy. Poppy shared her brush with the paranormal in a recent TED talk and her sincere and animated presentation can’t help but put a smile on your face (watch it below).

At the time of her experience with her visiting ghost she was living in a tiny garden flat. One night she had the spooky feeling that she was being watched. A heavy feeling in her chest that eventually became almost painful, accompanied her unease.

Over the course of a week the feeling got worse and she became convinced that the place was haunted. She had also started to hear a “whoosh” sound, like a kind of whisper. Getting really afraid, she called a friend who told her she needs to do a cleansing ritual.

“So get some sage and burn it, and tell it to go away.”

This didn’t work and like most of us when stymied by a stubborn problem, she consulted Google and landed on a forum for ghost hunters.

One of the skeptics on the forum answered Poppy with a simple question: Have you heard of carbon monoxide poisoning?

Poppy went back to Google and found that the symptoms of gas poisoning are pressure on your chest, auditory hallucinations, and an unexplained feeling of dread.

An emergency call to the gas company confirmed a gas leak and Poppy was told that had she not called that night, she would most probably have died.

Another experience, another scientific explanation.

Vic Tandy, a British engineer and lecturer in information technology had a scary experience in a research laboratory one night. He was aware of rumors that the labs were haunted, but was not fazed by it.  He was alone in the lab when he suddenly had the unshakable feeling that someone or something else was in the room with him. Something appeared in his peripheral vision, but when he turned to look at it, it vanished.

The next day he was polishing his fencing sword in the lab, with the sword firmly gripped in a vice. He noticed the blade vibrating inexplicably. Upon investigation, he realized that a recently installed fan was vibrating and generating a low-frequency sound known as an infrasound. The infrasound was the explanation for his strange experience the previous night.

What happened the previous night? What was there with him in the lab?

It so happens that humans cannot hear infrasound because of its low frequency (20 Hertz and lower). However, the sound waves are nonetheless registered by our eyes which start vibrating. This can make things in your peripheral vision, like dust motes, appear larger and scarier than they really are. Something appeared in Tandy’s peripheral vision because his eyes were vibrating.

Studies of the effect of infrasound on humans have found that it can give you the chills and make you feel that you are being watched.

So here you have at least two scientific explanations for ghost sightings. There are more. Keep it in mind for the next time you’re alone in a creepy place.

Check out the TED talk below and let us know whether you believe in ghosts in the comments.