Imagine being able to travel to any point in time.
Where would you go?
And what would you do?
You could witness
some of the greatest moments in history
or even change history.
You could travel into the future.
Or you could even save John F. Kennedy
from being assassinated.
So how could we travel through time?
Well,
no one that we know of has figured this out yet, but
physicists have a couple of theories about
how we might do this.
It could involve us either traveling at the speed of light,
jumping through a black hole, or
some other crazy method.
And yes, though it is
theoretically impossible to travel back in time,
let's just say we can do it anyways.
Oh, and also,
we won't be jumping through any black holes.
Instead, we're giving you a magical pocket time machine
that can take you to any point in time.
So, what's your first stop?
Naturally, you'd probably want to go to some of the most
critical moments in human history.
Maybe you'd want to go to WWII,
and see what it was really like.
You could prevent things like Pearl Harbor from ever happening
by informing the Americans that the Japanese are going to attack.
It's unlikely they'll believe you,
considering you're a complete stranger,
but who knows.
If successful,
you could end up saving millions of lives.
Or if you're not that bold,
you could just sit back and
live in the world.
Grab a drink with some soldiers,
or just hang out in the 1940s
and avoid the war altogether.
For our next stop,
let's go help tear down the Berlin Wall.
You won't necessarily be influencing this part of history,
but you'll certainly be a part of it.
How cool is that?
And after this
we can go further back in time,
to Paris in the late 1800s.
Then, let’s jump forward a bit
and hang out with the Beatles.
Now, that was all fun and good,
but it's probably time to head back to your current day.
But when you get back,
you quickly notice that world looks a bit different.
Earthquakes are happening,
radiation is everywhere,
and cities are completely destroyed.
You're now living in an apocalypse.
This is due to the butterfly effect.
You may have heard of this before.
The classic example is that
a butterfly on one side of the world in the Jurassic age
can cause a tornado to happen in 2004.
Now obviously,
butterfly wings can't directly cause a tornado,
but this example shows that
all actions in the past
have consequences in the future.
No matter how big or little,
all actions will ripple through space and time.
Of course,
killing baby Hitler or
showing people cellphones in the past before they're invented
will greatly impact the future.
That much is obvious when we look
at huge turning points in history.
What's not so obvious
is the idea that
any little thing we do impacts the future.
So let's say we don't participate in WWII,
or stop any crazy events from happening.
We just go to the past and simply observe,
walk around, maybe even buy a coffee.
When we come back to our current time,
things might still look vastly different
than when you left.
If you simply exist in the past,
it can alter and change things in the future,
no matter how little you do.
Here's an example of the butterfly effect
potentially at work in our real world.
The U.S. rail system is an
oddly specific size of
4 feet and 8.5 inches wide.
Why is that?
Well,
the people who built the railroads were used to
making wagons that were that size.
The wagons originally came from England,
where they made them that specific size
due to the grooves in the road.
If the wagons were any wider,
they could get damaged,
so they settled on 4 feet, 8.5 inches.
The reason the roads were this way was because
2,000 years before this,
Roman chariots made these first roads
as they were conquering the area.
And the reason the chariots were this size?
Because it was the size needed fo two horses to fit on a single chariot.
So when you think about the reason
the United States has railroads like this,
it's because of horses.
More specifically, the size of their butts.
This just goes to show
how decisions we made in the past,
no matter how little or inconsequential they might seem,
could seriously change the future.
We can also think of it
as the decisions we're making right now
will greatly impact the future.
So what if watching this video today,
is preventing a World War
hundreds of years from now?
And what if,
instead of being a time traveler,
you met one?
Well, that sounds like a story for another WHAT IF.