Is time
travel possible? Can one be dead and alive at the same time? Is it really possible
to live in a parallel universe? What’s The Grandfather Paradox and what is its
solution? Well you will get all those answers today in this blog. Read it till
the end.
Don’t leave
it the mid-way. I promise you will regret, because today you are going to get
something really interesting and mind blowing.
Suppose you
have somehow managed to get a time machine and you travel back in past. And you
accidentally or knowingly – that doesn’t matter – kill your grandfather before
they have kids. That would mean your mother was never born – and you are also
never born. But then who kills your grandfather? So killing any ancestor in the
past affects the whole chain of future events. Well, this is a paradox what we
actually know as ‘The Grandfather Paradox’.
As a matter
of fact this paradox first came into existence in the 1920s or 1930s – while it
gained it name ‘The Grandfather Paradox’ only in the 1950s.
Now you
necessarily don’t have to kill your grandfather – you can do anything that
would affect the future chain of events. Now, the question that comes here is –
Is it even possible to travel back in time?
Well, the
late and great scientist Stephen Hawkins said in one of his lecture on ‘space
and time wraps’ that Einstein’s theory of relativity might make it possible to
travel back in time. The theoretical possibility of this time travel is that
the wormhole loop back on itself. Wormhole is basically described as shortcuts
between two points in the space. If this wormhole loops back on itself to an
earlier point of time, it might be possible.
But even if
it’s possible wouldn’t be the Grandfather paradox a trouble? Of course, that
would be. So if you don’t want to be trapped in this trouble anymore, let’s
come to the solution of this brain-twisting, mind-boggling paradox.
But hang on. Before we come to the solution let’s play a game – that will actually help you to grasp the concept of what you are going to learn.
Well
consider a strip of paper. Now if an ant starts walking from a given side and
wants to reach the other side, it evidently has to cross the first side first.
But can you make a 2-D manifold such that it has only one side? Quite confusing,
huh?
Take a strip of paper and join one edge to the opposite edge. But before joining them give the strip a half twist and connect them. This will be a one-sided strip called – Möbius strip.
![]() |
Möbius strip |
To check whether it is
one sided or not, start making a line on anywhere of the paper with a pen and
you will eventually reach the starting print without crossing any side.
Now what’s
the relation between this Möbius strip and the grandfather
paradox?
Well, let’s
see. We represent the timeline by the surface of the Möbius strip. Now
if you write the below sequence on the strip you will get a loop. It will be
better if you do this practically.
You are
born » You travel back in time » You kill your
grandfather » Your mother is not born » You are not born » You don’t travel
back in time » You don’t kill your grandfather » You are born
![]() |
Image source: Geeks out of the box |
Now you are stuck in
the loop. And if you wrote it down on the strip continuously, you will get to
the point where you started on the paper. And to your surprise you will see
that ‘You are born’ and ‘You are not born’ are written at the same point on opposite
surfaces. Similarly other contradictory phrases will also be found on the
opposite surfaces. Now as we have taken the surface of the strip as timeline,
this means that at the same time you are born and you are not born. At the same
time you kill your grandfather and you don’t.
But, but, but – how’s
that even possible? How can you be both dead and alive at the same point of
time?
Well, that’s where we
get the concept of parallel universe or parallel timeline.
So according to this
theory – when you travel back in time, you are not actually making changes to
your own history. But you are landing on another parallel timeline. That’s
because an exact copy of something doesn’t exist anywhere in the universe. So
it basically means that in that parallel universe your grandfather is dead, so
obviously you would not be born either in that timeline.
Now physicist David
Deutsch showed that parallel timelines cannot overlap, but it is possible only
under the presence of closed time-like curve (CTC), when a wormhole curves back
on itself as I have talked about earlier. [If you want to study the topic CTC or
Wormhole you can study Wormhole on Britannica, Wikipedia, Livescience. ] But
that’s the question – can two timelines overlap? Well, it will be better to
leave that question to the scientists, as of course I don’t know that. (Ask any
scientist may be he knows) But what I can tell you is that subatomic particles
do this thing – and it’s called quantum superposition.
Now to get an idea about superposition you can imagine throwing two stones in a pond. The stones will create two waves and if they overlap with each other, it forms a complex pattern. This is the superposition of water waves.
![]() |
Superposition of water waves |
Now if you look this from
the electron point of view (you must know that electron are also waves) –
quantum waves are mathematical unlike that of water. These equations provide
information about the probability of the position of an electron or its speed.
And on that basis, we define its properties. But when an electron is in superposition,
it might be said to have two different velocities or two different positions at
a time. Well, you must know that this superposition is actually responsible not
only the properties of atoms and molecules, but also fusion and fission in the
sun and many more.
If this
superposition or the closed time-like curves or overlapping of parallel
timeline – whatever you call it – is possible, then you would be able to stay
alive even after killing your grandfather – and that also in a parallel
universe. So you have got the solution in your hand. This might be a bit
difficult to get, so you may need to read it twice or thrice.
So that's all from the Grandfather Paradox
Me in the whole story- So this is how mirror world of Doraemon looks like(●__●)... 'kill your grandfather before they have kids' BTW I really want to test this(◡ ω ◡)
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