The mystery of time travel has been solved.
Humankind has built a machine
that can move through time.
You can go back in the past
and witness any event in history.
Or you can uncover the mysteries of the future.
But only one person can make the journey,
and you're going to be the first person
to travel through time.
Get ready for a trip like never before,
because where we're going,
we don't need roads.
Today, time travel technology doesn't exist.
But there are many theories that
explain how it could be possible.
According to Einstein's Theory of Relativity,
as you approach the speed of light,
time will slow down for you
relative to the rest of the world.
And the theory also says
that gravity bends time.
The stronger gravity is,
the slower time will move.
General relativity also suggests
the existence of wormholes.
These are passages through spacetime
that can span billions of light-years.
What if we could build a machine
that could approach the speed of light,
travel near a black hole
with it's immense gravity,
or move through a wormhole?
Even though you can travel through time,
it'll be hard to know what lurks on the other side.
Be prepared for any type of danger.
How much do you know about where
and when you're traveling to?
The amount of oxygen in the atmosphere
is constantly changing.
If you arrive somewhere,
and the oxygen levels are too different
than what you're used to,
it could be hard to breathe.
You might want to bring a
portable oxygen concentrator for your trip.
Another thing you'll want to consider
are diseases and illnesses.
You could be exposed
to a slew of foreign viruses
that existed in that time period.
Catching a disease is bad enough,
don't catch one in another time period.
Figure out which diseases you might encounter.
Learn about the proper precautions
you'll need to take.
And if you want to be really cautious
about the illnesses you might face, wear a suit.
No, not the suit you'd wear to work.
You're not time travelling to your next interview.
A hazmat suit can help
to protect you from airborne diseases.
Ok, you're suited up,
and the machine's booting up.
Is there anything that you
shouldn't do before you step in?
I know it might be tempting
to go back in time to see dinosaurs,
or to fix a mistake you made in the past.
But by doing so, you'd create time paradoxes.
Altering the past could drastically
change our current timeline.
Even just being in the past
and not doing anything
might change the present.
And in the worst case scenario,
triggering a chain of events
could affect your past relatives.
This could stop your grandparents,
or parents from ever meeting.
And as a result, prevent you from being born.
You'd face a fate worse than not surviving.
You'd cease to exist.
But, traveling forward in time is also possible.
Technically, the astronauts aboard
the International Space Station
are living in the future right now.
This is because they're
constantly moving at 8 km/s (5 mi/s).
Because of time dilation,
the astronauts are about
13 milliseconds in the future, compared to us.
Oxygen concentrator and hazmat suit?
Check.
Don't travel to the past?
Check.
Looks like you're prepared to go on
our trip to the future.
Now that we've figured out
when you should time travel to,
it's also important to know where.
Will you end up in the same spot?
Or will you end up somewhere
completely different?
Are you traveling through a wormhole,
or rematerializing into another time?
Trust me when I say that
you'll want to go somewhere open and empty.
When your body reintegrates,
whatever's occupying the space
could mix in with you.
Objects, bugs, or even other people
might get stuck inside your body.
A better way of time traveling
could be with an enclosure
that protects you from the environment.
That way you don't materialize somewhere
that you wouldn't want to be.
You've plotted your course.
The machine revs up,
and in a blinding flash,
you're in the future.
Everything around you has changed,
but there's something wrong.
There's nobody around. Not a soul in sight.
Your machine is gone, there's no turning back.
You're stuck in the future,
and you're the last person on Earth.