We all know someone who reckons they've seen a ghost. Maybe you think you have. Despite the millions of people who claim to have seen, or 'felt' an otherworldly visitor, no one has got any conclusive proof that they exist.
However, one theory for ghosts is less about tortured souls and more about sound. Infrasound has a frequency of sound, which is so low that human's can't hear it, but we can still 'feel' it.
Infrasound is emitted at 20Hz and is created in a number of ways, including earthquakes and nuclear bombs. Closer to home the pipes within our walls can also create it.
If humans come into contact with infrasound the low frequency can cause our eyes to vibrate and mean that we see mysterious shapes.
Some people who have been around infrasound have claimed that they felt a deep sense of dread, nausea and a general feeling of unease, which is pretty much how I felt this morning.
Featured image credit: New Line Cinema
Featured Image Credit:Topics: Ghosts