They're scary.

But they're probably not real.

Right?

What if it was confirmed

that ghosts were living among us?

So, do you think ghosts exist?

If you do, you're not alone.

A 2017 study

from a California university found that

over 50% of Americans

believe that a spirit of some sort

could exist.

Not only that,

but a Pew Research study found that

18% of Americans

believe they've seen a ghost.

We've all heard tons of ghost stories, but

what does science have to say about ghosts?

Unfortunately, there really isn't any concrete

scientific proof of ghosts existing,

so why do so many of us believe in them?

Nearly every ghost sighting

can be explained by science,

or some sort of logic.

One of the most interesting discoveries

explains why some people

think they feel the presence of ghosts.

It's due to infrasounds.

These are extremely low sounds that

we humans are unable to hear, but

fans, wind turbines and traffic can produce them.

Although we can't hear these low sounds,

we can feel them.

These low frequencies can trigger distinct psychological effects,

including things like discomfort,

a sense of panic,

and an overall sense of

something being out of place.

Places where people have reported many ghost sightings

also happened to have things that produced infrasound.

Once people removed infrasound-causing objects, like fans,

the ghost sightings suddenly stopped.

Funny how that works, huh?

Another reason some people think

ghosts exist

has to do with electromagnetic fields.

Researchers have found that

electromagnetic fields

may be able to influence an individual's perceptions

as well as their surroundings.

In other words, it can make them hallucinate

and see crazy things like,

ghosts!

Speaking of seeing things,

there are also reports of people

thinking they saw visions of ghosts while they slept.

This unfortunate case is known as

sleep paralysis.

It's when your mind wakes up before your body,

causing you to have a paralyzed effect while you're in bed.

This also creates a waking dream effect,

in which some people have reported

seeing paranormal figures attempting to hurt them.

We might also believe ghosts are real,

simply because we want to.

If ghosts exist,

it would mean that the afterlife is real,

which is a belief that comforts a lot of people today.

It's pretty clear that ghosts don't exist,

at least according to science,

but If ghosts were real,

we'd never have to say goodbye to our loved ones.

We could communicate with them,

feel their presence,

maybe even spend some quality time with them.

Let's assume that

every person who died on Earth,

became a ghost.

Now that would be a pretty messy situation.

Generations of people would suddenly be wandering the Earth.

So far, it's estimated there have been over 100 billion people who have died on Earth.

Right now, the Earth has 7.5 billion people living on it.

So if all those ghosts were living on Earth,

it would start to get pretty crowded.

That is assuming that the spirits could interact with the world.

Places around the world where wars have been fought could be

particularly crowded as

more people have died there.

And if we could see these ghosts,

what might they be made of?

Maybe they'd be made out of a material known as aerogel.

It's a synthetic substance that

happens to be the lightest solid known to man.

If ghosts did exist, and were visible,

you can bet they'd be made out of something like this.

With massive groups of ghosts with physical properties everywhere,

you might not be able to travel anywhere without running into one.

Sure, it might make the world a bit more exciting,

but it's probably better that ghosts don't exist.

Maybe after death,

we go on to a parallel universe.

So instead of us seeing paranormal activity,

maybe it's really just activity from a parallel universe.

Well, that sounds like a story for another, WHAT IF.