The Importance of Now
time has played
a very important role in our development
as a species
ever since we first became aware of his
passing it has since grown
into a commodity that we feel that we
have ownership of
but we don’t really have control of it
we even use
language such as owning it being able to
spend it
being able to receive it give and take
it
and in fact benjamin franklin actually
aligned
time with value and gave it money
and that is in complete contrast to the
view of einstein
that said that time is actually an
illusion
now these two ideas are two that i would
like to explore over the next
talk that i give now the first question
i want to delve into in order to
understand this
is actually this one how do we
experience time
now in order to do that i’m actually
going to take us into a little world of
physics
so enjoy it with me the first view that
i want to go into
is actually relativity and the first
implication of relativity that einstein
came into
in order to do that i’m going to
introduce us to two characters
the first person is a business woman so
say she’s working in la
and the second character is an astronaut
up on the international space station
so if we take our experience of the day
we wake up in the morning because our
alarm clock says so
we then go and we get our coffee getting
ready for the day
we suddenly see in the corner of our eye
the time it’s like oh we’ve got to go to
work now
we then travel to work we get to work we
get there a little bit late
say sorry we then get another coffee we
then start going about our day
it tells us oh it’s a break time now or
we can have lunch and then it tells us
the end of the day
we get to go home we cook our dinner the
clock even tells us how long
the chicken’s in the oven for and then
it tells us okay it’s a little bit late
you should probably go to bed now you’ve
been watching netflix too long
now that regulation of our day is very
important
the same regulation of our day is
important if we are an astronaut up
there
on the international space station we
need to know when to wake up when to do
our tasks
when to then go to bed they don’t get
the same experience of the day that we
do 24 hours the sun rising the sun
setting
they go around the earth every 90
minutes
so they get a sunset and a sun rise
every 90 minutes so they need to know
the passing of time
now the problem is if we have a clock
and we send it up
and in a very simplistic view we look at
the passing of time
what we actually find is that when we’re
up on the international space station
time passes a little bit slower now that
gives us one very important implication
of relativity and that is that our
position in the universe
is important and in fact
the stronger the gravitational field
that we are in
faster we experience time now if we then
take the second
idea of relativity and in order to do
that
what we’re going to do is we’re going to
hop on a london tube
and let’s say actually when we’re on the
tube
it’s night time so it dims down the
lights what we then do
is we take out our phone and put on our
torch
now what we can actually process in our
brain
is that the light ray passes from our
torch travels down
through the carriage hits a part of the
carriage at the end and it travels back
to our eye
now in our brain we actually know that
light travels a certain speed
and we know the distance and the
distance it comes back
so our brain registers that and it tells
us how long it takes
and that’s from a very simple equation
that speed equals distance over time
if we know the speed and we can gauge
the distance
we know the time that light took to do
that
now as we’re on this tube and we’re
passing along we’re going through
stations
and let’s say that on the side of one of
these stations there’s a woman let’s
call her brenda
she’s standing there she sees this
carriage passing
and what she sees is our torch and she
sees the light
traveling along hitting the same part of
the carriage
and bouncing back to her eyes but to her
the light
has had to travel further to catch up
with the end of the carriage
and therefore come back now in her brain
she knows the speed of light it’s
exactly the same as the speed of light
that we have
but she has seen the light travel a
further distance
using the exact same calculation what we
actually find
is that to her it looked like it
traveled a longer distance
at the same speed it has now taken
longer for the light to do that
these two events occurred at exactly the
same time
and finished at exactly the same time
and what it is telling us is actually
that we
on the carriage experienced time
passing faster than she did she saw it
taking a longer time to occur which
gives us our second implication from
relativity
and that is that our emotion through the
universe
is important so we’ve now got two ideas
our position in the universe is
important for how we experience time
but so is our motion through the
universe
now i want to give you a third and final
bit of physics here
and this is entropy okay now this is a
very complicated idea entropy but i want
to try and make it simple for you
so what we have here on the bottom left
you can see a young girl
and let’s say that she is there blowing
bubbles
now as she blows bubbles the bubbles get
formed
and it floats around in the room based
on the random motion of air
now what that is telling us is that
the universe is trying to spread out
these bubbles
now why why is it doing that it’s doing
that because the
universe has a fundamental law about it
and that is it wants to take all energy
and spread it out now let’s say actually
we want to try and reverse this process
so what we do is we take those bubbles
and we try and move them back together
again so we have to reach out grab
one bring it in reach another one grab
one bring it in
and as we do that what we are having to
do is actually expel
energy to do that now we have to put
work in to go against what the universe
wants to do
and that is another fundamental idea the
universe is always trying to increase
entropy it wants to spread everything
out it explains why my desk at work is
an absolute mess
now this is because the universe
is taking energy and spreading it out
now if you
take that back to the beginning of time
the big bang
what happened ever since then is the
universe is spreading and expanding
trying to spread
the energy out and that tells us the
direction time goes
the time will always flow in the
direction
in which energy spreads out
so there are three key ideas our
position in the universe is important
how we move through the universe is
important that tells us how we as
individuals experience time but we
always
feel time flowing in one direction
forwards
we always go from young to old we never
go back
benjamin button doesn’t actually occur
now my second question then
now we have a slight understanding of
how we experience time
is to look at why is it therefore
important to us
why is time important to us now if we go
all the way back
to the stone age when stonehenge was
actually built
back then the passage of time that was
important to us was the seasons
all we cared about was when was spring
when was summer when was winter coming
when do we do the harvest when do we
have to sow our seeds
but if you come forward we then invented
sundials and we tracked the passage of
time
across the day when was sunrise when was
sunset
throughout the day when was the middle
of the day as we came forward again
we invented the clock the passage of
ours was important
and then we soon get to us now and we
have
atomic clocks we have electronic clocks
we track ever more shorter periods of
time
and that tells us that gives us the
passage of time available
to do our gps to do
our computer processing really fast
now i want to give us a little sort of
story to go along with that something
that we have ourselves experienced
so what i’m going to take us on is a
little sort of story
through messaging someone so let’s say
i’ve got
a very attractive lady in my phone call
her charlie
now i want to meet up with her so i’m
going to send her a message so i am an r
about it and i
go throughout the day and i’m like oh
i’m going to message her now i’m going
to mess you now eventually i sit down
and go i’m going to do it
i’m gonna message her so i write her a
little message i make the big decision
do i put an emoji at the end
yeah i do a nice cheeky message put a
little wink at the end
see if i can get a date i send it i get
the one tick it tells me yes
the message has sent i get the second
tick
yes she’s got it i’m then waiting there
going hmm
okay okay oh blue ticks she’s ready
i’m then waiting i’m then waiting
she’s ready why isn’t she replying maybe
i shouldn’t have put the emoji there
i really shouldn’t have done oh she’s
sending me a message back and then i get
the response
all of that because i programmed it into
this
i know it took 24 seconds but that
was really traumatic between sending the
message
and receiving the reply now that
shows us just how skewed our view of
time has become
24 seconds and we were humming and
arring we were thinking we were thinking
about the next day the next person we
were going to message
all of that though is what we
experienced now but if we go back 100
years
to 1920 imagine we were doing that same
thing then
we would ominar about what we were going
to put in our message we’d come up with
a poem or something write it down
on a piece of paper put it in an
envelope put a stamp on it put it in the
letterbox
i’d have to wait a week to get the
response that yeah we can go out for a
drink
next month but now i send that message
and i’m waiting 24 seconds questioning
my life decisions
before i get the response and go yeah
okay we’re going on a date
now all of that why is our vision
of time so skewed and it all comes down
to this
the idea that we have more transistors
now than we ever did before because we
invented computers we put more
transistors we got faster and faster and
faster and faster machines
also we have faster and faster internet
when i was younger i remember
loading up google when it used to take
ages and we get a layer of pixels
all the way through and then i’d have to
really question what i was going to type
in
and whether it was worth waiting 20
minutes to get the actual information
now i can look up anything i want on my
phone
no matter how trivial now
i’m going to take this into another
realm and that is trading on the stocks
and what i’ve got here on the screen is
the stock exchange there on the
left-hand side
okay we’ve connected it up with the wire
to two computers
okay now what happens is we’ve got a
change in prices in the stocks
and that signal is sent down the wire
and as it travels down the wire it gets
to the junction the signal goes to the
nearest computer first
we get the information then the later
computer gets it a little bit later on
now if i am in an office that is closer
to the stock exchange
i’m able to respond to that price change
faster
i can therefore trade my stocks before
it plummets or buy something before it
skyrockets to then sell it later
whereas someone further away they have
to wait half a second before they can do
that
now all of this means that we actually
have different prices
in the rental properties of offices so
the further one would be cheaper
but if i was closer to the stock
exchange it would be much more pricey
now this can be seen in the new york
skyline if you’re looking at
lower manhattan and i’ve actually got a
few pictures here going over the last
hundred years
looking at the skyline of manhattan i go
from the first one there’s only a few
high-rise buildings all around the stock
exchange but as we go forward
and we go forward through time what
we’re finding out is more and more
office space is being built
closer to the stock exchange and here
you’ve got a sky
view image and you can see this cone of
taller buildings all around the new york
stock exchange
now this idea that we have to be closer
to
the stock exchange in order to make more
and more profit
actually went to some very weird place
very recently
now what happens is we have this new
thing because of our faster computers
that we were talking about
called mass trading you can trade
thousands and thousands of stocks very
quickly
just with the press of a button on a
computer you can write programs to do
the trading for you
and that means we can make massive and
massive profit in very short periods of
time
and if we were trading let’s say in
chicago rather than in new york you
would need to have a really fast
connection
so you used to have optical fiber
connections that used to zigzag all the
way around the country to get to chicago
then companies put mass investments in
to be able to make it straighter and
straighter and stay
straighter now a straight path is as
straight as you can get
so once you’ve built this straight path
that’s the quickest any signal can ever
get
from new york to chicago however back in
2011 a scientist
actually put out there that they found a
faster than light particle they thought
it was a neutrino that went faster than
light
so suddenly we now have a way of getting
a signal from
new york to chicago faster than light
can travel which is how we use
our internet but literally four or five
months later
they had to put out that actually this
was a false detection
they weren’t actually detecting fast
unlike neutrinos now in that time
companies had invested millions of
dollars trying to look into whether or
not this was actually a feasible
way of sending signals from new york
to chicago now that just shows how
skewed we are
we’re trying to fight over milli seconds
of time
remember if we go back in time the
passage of the seasons was what was
important
now it’s milliseconds it’s nanoseconds
and even shorter than that
now my last idea now we’ve got why is it
so important to us
it’s because actually time is money
is to look at well what actually is time
now time is just the way that we track
the passage of events from one to
another
okay and if you ask a geographer a
geographer will look
at the lattices in rock and they would
say
yes that’s the passage of millions and
millions of years so to a geographer
the passage of millions of years is
important to me i just look at that and
go that’s a pretty picture
we get lots of nice different color
rocks okay
if you were to ask an astronomer what’s
important
why is time is important what is the
passage of time
they might think well let’s look at one
particular picture
now this picture if we took the hubble
space telescope
and we pointed it out into space at an
area of the sky
one tenth of the size of the full moon
what you would actually look at and you
stared at it this blank
piece of sky you’d stare at it for
months and you would get this picture
it’s called the hubble deep filled image
now in this image i’ve got it zoomed in
on the right hand side there
it’s the most distant galaxy we’ve ever
seen
about 13 and a half billion light years
away
that means the light left it 13 and a
half billion years ago
and it reached us today
and that is the furthest galaxy we’ve
ever seen now in this picture as well if
you just look at all of the dots
in that image what you actually see is
galaxies
all different distances away and we’re
seeing
layers and layers of time now
geographers
look at layers of rocks that’s millions
of years
astronomers look at that one picture and
they see layers of galaxies
showing the tracing of billions of years
so to an astronomer it’s not nanoseconds
that is important
it’s billions of years really big
difference in time there
now my last little bit is this imagine i
had a graph
okay physicists love graphs i have
time and distance so i have time on a
y-axis
and distance on an x-axis let’s put us
at the middle
because we are very egocentrical species
we are at the center of everything
so i’ve put us at the middle of this
graph and i then trace out
a cone now the cone is called a light
cone
it’s everything we can see because light
has taken time to travel to us
that cone is showing everything that we
can
see now imagine there’s an event
this event occurred outside of our light
cone
it’s further away than we can actually
see now this event
let’s say occurred 15 billion years ago
now we won’t actually expect to see that
until
light has had time to reach us so this
event that occurred
15 billion years ago will actually reach
us sometime in the future
now that brings a really weird
sort of view into our head if you think
about it something that occurred
a long time ago will not occur to us
until the future so that means the past
is actually the future and that is a
really
weird view to have of the world which
something that i want to
just leave you with and that is
what actually is time well time
is just a measure of the largest
distance
between two places thank you
you