VSauce! I'm Jake, and after watching the movie Arrival
I started thinking about time.
But not linear time which is what we generally experience,
different concepts of time.
So I decided to talk to an expert on the topic,
Neil deGrasse Tyson, on variations of time.
TYSON: Before relativity, our concept of time was
that we are all participating in the same ticks of the clock:
one second for you is one second for me - that's linear time.
Linear means every interval is the same as every other interval
and one follows the next.
Relativity, we learned that there is no such thing as absolute time.
Time is relative, so time can be stretched,
for me relative to you.
So, time has multiple, sort of, parallel rates at which it flows,
depending on the state of who's making the measurement and the state of
who's in motion, and what conditions they are in.
Now think of time as a dimension.
TYSON: In our timeline we are prisoners of the present,
forever transitioning through our past into our future,
so we don't know of access to other points in our own timeline.
Suppose you could move around
in your timeline with the same flexibility
as moving left and right, up and down, forward and backward.
If that's the case you can revisit your own timeline.
Under those conditions you do not die.
You are always dying. You are not born.
You're always being born.
That's another kind of interesting way to think about time.
So what we don't know,
and this is a topic touched on in the movie Arrival,
if you rejoin your life at a different point on the timeline you have to ask,
do you have the benefit of the knowledge acquired after that?
JAKE: You can go from the future to the past
and maybe you'll have all the knowledge of everything because you've experienced it all
but if you go from the present to the future
would you experience everything that you would have, had you stayed in that timeline?
TYSON: That's a good question, because
if your timeline is already existing
then you cannot change your fate.
It's already writ. But suppose you had knowledge,
and could change it, then you would have this sort of pair off a whole other
timeline and it will become a very complex, sort of, fractal structure.
TYSON: So, what gets me about Terminator is
he's got to kill everybody who might be the mother of the future of the person
who overthrows the thing.
JAKE: That is always a thing, I thought, why don't they go further back in time?
TYSON: You can go further back just have one little thing change
and everything after that would change. Then it just wouldn't be as bloody.
JAKE: Yeah, it wouldn't be as fun. (Laughter)
But that actually brings up an interesting concept that I think about a lot...
I think about a lot when it comes to the Terminator
which is the Bootstrap Paradox
where them going back in time
is what starts the events happening in the first place.
TYSON: Yes, so what happens is... So Jim
particle is they show this in Somewhere in Time
did you see it? JAKE: Nope, what is it? TYSON: Okay
because it was a chick flick that's why
JAKE: And I wouldn't say I don't look like the
kind of guy who would watch a chick flick
TYSON: You are a comic book superhero guy with violence,
okay? JAKE: But hey violence isn't fun remember that
it's not fun. TYSON: Okay, so it was a
romantic love story, it had Christopher
Reeve in it actually. Some old woman comes
to him, gives him some kind of a locket
and says meet me back in time or something
okay
and he's a young guy so he figures out how
to go back in time and meet her
JAKE: Oh yeah.
TYSON: And now they're the same age and
they have a love affair and he gifts her
this locket
JAKE: Yeah. TYSON: Okay, now she has it and gives it
back to him, so this is called a Jim particle
in time travel.
Okay, so this particle was never created,
JAKE: Yes TYSON: It was neither created nor destroyed,
it only exists in this time loop. So
it's, it's counter to what we think should or
shouldn't be in the physical world to
which we've grown accustomed, of course.
JAKE: Who, where did it come from? Did it just
exist? TYSON:Yes, it just always existed. So with
you, with your Terminator loop... JAKE: Yeah?
TYSON: That his act of trying to change it sets the
things in motion and that makes it happen JAKE: Sets it off in the first place
TYSON: Right JAKE: And then it's never going
to end,
so that's the kind of thing that I have
with the example you gave and with Terminator.
Is it just one loop that will never end?
TYSON: Well you never come out of that loop.
JAKE: You never come out of it.
TYSON: Well... so in the case of
Somewhere in Time, the Jim particle
stays forever in the loop, but the
characters keep going. What you're saying
is, in the Terminator, there were events that
affected the whole world,
so does the world emerge on the other
side? I guess no, because it affected the whole
world. JAKE: Yeah, because it's stuck in this loop... TYSON: Right, but
(JAKE: And nothing continues on) if it was just some grandmother coming
back to meet something then that would
be a very contained... JAKE: But would we say then, so
this is obviously speculative, but if... So I'm Christoper Reeve,
I go back in time.., TYSON: Yes? JAKE: But does that mean everyone
around me doesn't have to be the same?
They could be different? Or are they stuck
in the same loop with me? TYSON: That wasn't
addressed in the film. JAKE: It should have
been. These are the questions I wanna
know. TYSON: These are the questions. And so in the H.G.
Wells' Time Machine
ok they dealt with an interesting
phenomenon that his love interest dies,
she's mugged or something, she's killed in the park.
This is why I have a time machine, I can fix this, so she has
her go somewhere else and not where the
mugger was going to be and then she,
like, gets hit by streetcar and dies.
He does multiple times, she dies everytime.
He concludes that certain events are just writ.
JAKE: Yeah, are fixed points. TYSON: They're just fixed points.
But, and I thought about it and I said why should
her death be any more of a significance
than the fact that the mugger now mugs someone else? It's a changed event.
JAKE: 'Cause it changes, then, the timeline for all those people.
The mugger's life is probably different.
That person who's operating the car is now different...
TYSON: Just so that you can kill off his love interest.
Yeah, just to make that one person die.
JAKE: So, it ripples.
So, I actually... The Time Machine is an interesting one 'cause, if I remember correctly.
I haven't read in a while but I've always thought was interesting how the time machine operates
But when he's in, he sees everything moving quickly past him, but I always imagined from the
perspective of someone walking by.
They're just looking at a man sitting like, in a machine
like, okay that's boring no it would be
there in an instantaneous instance so
he's actually moving through time it's not
things moving around him
TYSON: Correct, correct. Right right so in some
instances he's moving through you would never
even see it I mean it would just happen
so quickly. That's how I interpret it. JAKE: Because
I thought it was fixed in place like he's stuck
on that point in earth so he's not
moving. TYSON: So you're saying I'm here
for 10 minutes and I don't budge and so is the time machine.
JAKE: Yeah, but from us in the time machine
time because it's relative, it feels like we're
going... TYSON: Oh so they should have seen it. JAKE: Yes.
TYSON: I'll give you that. JAKE: 'Cause I always thought with
time machines, I'm just going to go to a
different point in time. Like, well, the planet's gonna be
somewhere entirely different. You're just gonna be in the middle
of space. TYSON: Well, we'll give him that, he's also
moving in space. You gotta give him that. JAKE: Oh, so now he's moving through space?
TYSON: Otherwise you can't even, you can't...
When Marty goes back to 1985, he'd be... JAKE: Well, the DeLorean can
counter that, it's a DeLorean. I mean, you know... TYSON: But if
he goes back exactly 30 years then Earth is back
where it was... JAKE: Yeah. TYSON: ...in that moment,
right? So because if he goes back less
than number of years, then he's out
in space. JAKE: Yeah. TYSON: So here's an interesting
problem: so let's say tachyon
communication exists, so I can send a
signal backwards through time. And, you're
walking down the corridor and you slip
and fall on a banana peel...
TYSON: You know, when I first saw people, you know,
cartoon characters slipping on a banana peel...
I said "First, why is a banana peel just
there, and are banana peels really slippery?"
So I kept throwing banana peels
over and trying to slip on; I never did,
and then I had to realize you have to put
the inside... JAKE: Oh yeah. TYSON: ...down. That has to face
downward. JAKE: Oh, you were doing the outside... TYSON: Yeah!
So it's not just slip on the
inner slippery surface... JAKE: Rookie mistake.
TYSON: I know, it's a complete rookie mistake.
So then I did that, I was like "Whoa, that is
really slippery." But if you
toss a banana peel
it's not gonna just open up and land
octopus-style face down on the
ground. So you slip on it... I say
"Oh, let me warn him." So I send you a text
that you get 10 seconds earlier. You're
walking down the corridor and your phone
buzzes. You pick it up and it says, "Watch
out for the banana peel". But now you're not
looking where you're walking
then you slip on any other reason that
happened when I was the reason happened
in the first but maybe you do stop me
from doing that but now you change the
future so you no longer need to send a
text message into the past so my past
self doesn't get a text message
yes what would happen is in Back to the
Future style the text will...(disappear)JAKE: Oh it slowly disappears and then
for some reason I slowly disappear
"Neil what have you done!?"
Well, it's interesting 'cause that's... well, it's the butterfly effect
Where we've changed the timeline
for all we know we could be the rippled
different universe compared to what
would have been that's like the people who
say: "If this one thing didnt't happen to
George Washington or to Napoleon or to Hitler
then all the world would have been
different." And I'm thinking okay I think
you're overcrediting this one moment
this one incident that they're losing
track of the fact that certain forces
that are operating to send culture,
civilization in a particular direction
may be robust to certain changes you
might make that you think will make all
the difference. "If we past year had not
accidentally found found penicillin then
millions of people would have died at..."
No! You know Betty Lou would've
penicillin a year later so...so you pivot
everything on this one thing and tell me
that all civilization will be different
I'm not buying it, civilization is more
robust than that and if Hitler were killed as a
child then no maybe not, the Germans were
ripe to have somebody rise up and take
control of their psyche and maybe the
circumstances made Hitler not Hitler
making the circumstance so that's why
you're worried that all of the butterfly
effect will somehow veer it this way
rather than just be a slightly different
thing but in the same overall... JAKE: Of all
these kind of things we talked about the
butterfly effect seems like the most realistic
where it'...it's not something we can really quantify but
we can say that... as you were saying; everything
happens, like there's always different
changes that just ripple throughout
history or what is going to be now
future NEIL: And I'm saying; it was not this
butterfly, it was another butterfly.
There was an article in the Journal of irreducible
results. It's where scientists who want
to take the weekend off from their
regular job think up some crazy
scientific theory that is just
completely stupid but it's
scientifically justified
so there was an article, it said: "We have captured
the actual butterfly that caused
Hurricane Hugo." And it's right in...
I think in the end I agree with Stephen
Hawking, that we will discover a new law
of physics that will prevent backwards
time travel and we don't know what that
law is or why it must exist but
everything we can imagine that allows it
totally messes everything up
you see the the protesters in the street
you know with the chant:
"What do we want? A time machine! When do
we want it?
Well, it doesn't matter. Anytime, it'll be fine. So, you
can make the argument that if a time
machine is ever invented in the future
there's no evidence of it having
manifested in our past but it shouldn't
stop us from thinking about it in fun
ways and and thinking about living in
this fixed life it's always being born
always living out and always dying
aight actually take some comfort and
then but it-it-it research that your
life is predetermined even if it is
being a prisoner of the present
transitioning from the past to the
future I have the illusion of free will
and I'm happy to live in that
illusion in the knowledge that I don't.
JAKE: Thinking about time travel when it comes to
kind of predestination or things are
predetermined in your life in this path
that you lead time travel kind of
makes it so that, it is, everything is
predetermined...(NEIL: Uhuh, that's right.) ... there's no way
to veer off this path everything you do
was if I go intelligent machine
everything was leading up to that moment the
past me will then go and go into the time
machine that lets keep happening forever
well thank you and also speaking of time
you should take some time and go check
out Startalk radio there's a link down in the the
description or there'll be something
popping up probably right between our
head link somewhere somewhere here in
space and time( NEIL: Star talk) but thank you Neil,
thank you so much (NEIL: Dude) it was a pleasure dude
and as always thanks for watching