Something Strange Happens in The Universe | Harry Cliff

If you wish to make an apple pie from

scratch, you must first invent the

universe. We have two theories of the

universe basically in physics. One that

describes the very very small, so atoms,

subatomic particles. And then we have

this grand theory of the universe as a

whole. So looking at the behavior of the

the entire universe, the visible matter

that is 5%. So that is the world we see.

If you don't include dark matter and

dark energy, the universes you end up

with look nothing like the ones we live

in. We smash particles into each other

at in this big collider. The way these

beauty quarks behave can be influenced

by the existence of new fundamental

forces, new forms of matter, new forms

of energy that we've not seen before.

Maybe it's the clue to something

something really new.

If you wish to make an apple pie from

scratch, you must first invent the

universe. What do you personally take

from that saying? I think what Carl

Sean's trying to do when he says he

actually says this in the opening part

of one of the episodes of Cosmos, which

is this big landmark TV series made in

the 1980s in the US, and it was kind of

the first big budget science documentary

series that had been made. And there's

this rather strange scene where you see

an apple pie being made in a in a

kitchen with this like 1980s synth music

track playing over the top. And then

it's brought out to Carl Sean who's

sitting at the head of this big oak

table and he kind of looks at the camera

and utters this line. If you wish to

make an apple pie from scratch, you must

first invent the universe. And the point

that the episode that he's uh starting

there is about the origin of atoms. So

it's sort of where do the atoms that

make up everyday matter come from? So

but but his point really is that you

know any object in the universe be it an

apple pie or a human being or a planet

or a star that the origins of any object

has to be traced right back through

cosmic history. And like every atom,

each atom in our bodies has this really

each one has a unique history that goes

through these incredible astrophysical

events, you know, supernovi dying stars.

And then eventually, if you really want

to understand where they come from,

you've got to go right back to the

moment the universe began with the big

bang, which ultimately created all the

matter that exists. Each of atoms.

Yeah. Every atom. So, you know, it kind

of depends on what atom we're talking

about. So, you know, if you take carbon

for example, we're carbon based life

forms. Most of the carbon in our bodies

came from stars a bit like our own sun.

At the end of their lives, when they

when they run out of nuclear fuel and

they disintegrate, they kind of waft

their atmospheres out into space in

amongst that mix of gases are carbon

atoms that were fused in the nuclear

reactions in the middle of that star.

So, you know, that's where like carbon

comes from. But if say you want to take

an element like oxygen, the oxygen that

we breathe that's in our blood, oxygen

comes from supernovi explosions, these

massive violent detonations of of much

much bigger stars uh that spread lots of

different elements through the universe,

but oxygen is one of them. Or say the

hydrogen, we have hydrogen in you know

we're mostly made of water. hydrogen is

sorry uh water is hydrogen and oxygen

and hydrogen that if you want to know

where that comes from then you've got to

go right back to the first fraction of a

second after the big bang because it's

in that first instant

that hydrogen nuclei were were formed

out of this like seething superheated

gas of subatomic particles. So, you

know, kind of depends on which atom

you're talking about, but every one of

the atoms in the body has this rich

history that goes right back through

cosmic time. In the book, you you you

showed that the atoms in apple and sugar

were forged in the hearts of stars. In

one sentence, how would you explain to a

non-scientists how stars cook the

elements for us?

So I mean the way it works is but in

some ways they're like a giant pressure

cooker a star. So star is very very big.

Uh and the reason that you know stars

have a there's a minimum size for a star

basically and the thing that drives the

the fusion what we have in the middle of

the star the thing that powers the star

are uh the nuclei of atoms fusing

together to make heavier atoms and that

process releases energy and that energy

is ultimately where starlight and

sunlight comes from. But the way it it

works, you have this big ball of

hydrogen and helium gas, at least to

start with, and this enormous crushing

force of gravity. So the gravity of all

that stuff crushes the core of the star

to very very high densities and and high

and high pressures and it causes it to

heat up. So when you squash a gas, it it

gets hot. So you probably felt this if

you've ever pumped up like a a bike tire

with a with a pump. You can feel the air

in the pump gets hotter. The same thing

happens in the middle of a star. And it

in fact gets so hot that the the atoms

that the star is made of disintegrate

and you end up with electrons which are

the particles on the outside of the atom

and then the nuclei are separated and

they're whizzing around very quickly cuz

they're you know millions of degrees.

the center of our sun is about 15

million degrees. And at those

temperatures, um, hydrogen nuclei, so

these are particles called protons,

these positively charged particles,

they're going so quick that they can

overcome the electrical repulsion that

keeps them apart and they will collide

and fuse together and they make through

a series of reactions, they build up the

next heaviest element, which is helium.

And and so that's the basic idea is you

have this hot environment nuclei

colliding fusing to make heavier atoms

and that process releases energy. It's

in the same way that uh actually a a

thermonuclear weapon a lot of its energy

comes from similar sorts of fusion

reactions between light elements. So

we've sort of as human beings managed to

recreate this power in an uncontrolled

way on earth but it's ultimately the

source of you know the energy that comes

out of stars but also the origins of the

elements. You you say that about 95% of

the cosmic receipt is still made of

mysteries ingredients dark matter and

dark energy about dark energy even we

have no idea if dark energy really

exist. Yeah, we we we're in this very

weird situation in in cosmology at the

moment

where we we have two theories of the

universe basically in physics. One that

describes the very very small so atoms,

subatomic particles, the theory of

particle physics and that theory is

really successful and it describes

basically everything that we can see

around us in the universe very very

precisely. And then we have this grand

theory of the universe as a whole. So

looking at the behavior of the the

entire universe of objects as big as

galaxies and stars uh the what's called

the standard model of cosmology and that

theory in to make uh sense of what we

see in the night sky as you say we need

these two mysterious substances to exist

dark matter and dark energy and we know

a little bit about them in the sense

that we know what their effects are. So

they're quite different. So the the the

atomic matter in the universe, the

ordinary matter, the stuff we're made

of, the visible matter, that is 5%. So

that is the world we see. When we look

into the sky and we look around us,

we're only seeing 5% of the total

contents of the universe. Then you've

got dark matter is about 27%. So roughly

five times more of it than the stuff

we're made from. And dark matter we

think is some kind of particle or maybe

set of particles that forms these big

clouds uh inside which galaxies form. So

you can think our galaxy the milky way

which is this spiral of stars. It sits

inside this much bigger spherical cloud

of dark matter. This and it this this

cloud is invisible but it has a very

strong gravitational effect. And so we

can see the influence of of dark matter

from the way its gravity pulls on

visible objects. So it moves uh galaxies

and stars through the universe and it

bends light. So we can kind of see that

it's there from its gravitational

effect. But it's basically dark matter

is required to explain why galaxies

remain stuck together, why they don't

disintegrate because you need the extra

gravity to hold the galaxies together.

Um so that's dark matter. So we don't

know. It's some kind of particle or set

of particles but we have not found them.

We don't know what they are yet and we

would really like to know. Dark energy

is something actually almost the kind of

opposite in a sense. So dark energy is

the remaining 68% of the universe and

this is some kind of repulsive

anti-gravity. It's pretty well accepted

by most cosmologists as existing cuz you

this there was this discovery made in

the late '9s which is

that according to the original big bang

theory the way the universe begins and

then evolves is you have this very rapid

expansion of spaceime at the beginning

of the universe which is the big bang

and then as the universe gets bigger and

expands the gravity of all the stuff in

the universe so all the galaxies and

stars should put the brakes on the

expansion should slow it down and

eventually start to pull pull things

back together again. That's sort of what

you would expect to see. But in the

1990s, uh, astronomers found that if you

measure the the speed that the universe

is expanding as a function of distance,

you find that it's actually getting it's

accelerating. So, it's expanding faster

and faster as time goes on. And so, it's

kind of it's the opposite of what we

would expect. It's a bit like you throw

a ball into the air, you expect the ball

to come back down. Instead, what we see

is the ball is accelerating towards the

sky. And so the only way to explain

that, well, one of the ways to explain

that is to say, well, there is some kind

of extra force in the universe, a

repulsive force that is driving galaxies

further and further apart from each

other. So gravity is a sort of an

attractive thing. This is some kind of

anti-gravity that it only becomes

obvious at very very large distances

when you're talking about the scale of

the whole universe. So this this for

that we the way dark energy is thought

of is is energy that exists in the

vacuum of space. So empty space itself

contains dark energy and we really don't

know what it is. We kind of know what

its properties are. The fact that it

gives you this repulsive force, but

again we we have no idea fundamentally

what causes this this to happen. And

it's one of the big unsolved problems in

physics. Do you believe that we will

ever get that information? Um I think

we've got a decent chance of finding out

what dark matter is or at least what

some of it is. There are lots of

experiments going on to look for dark

matter particles. So I work on the Large

Hadron Collider which is this big

particle accelerator uh at CERN near

Geneva on the Swiss French border and my

colleagues there are looking to see if

in the collisions that we create these

particle collisions we smash particles

into each other at in this big collider

what we hope is we may see a dark matter

particle being created in those

collisions or coming out of those

collisions. We haven't seen it yet, but

but maybe there are experiments deep

underground down mine shafts where

they're looking to see if you can detect

dark matter particles drifting through

the earth. There are telescopes look out

into space looking for the effects of

dark matter. So there's a whole range of

scientific experiments being conducted

at the moment really trying to find this

stuff. So I think there's a you know so

far we haven't had any luck but we keep

going. Hopefully in the next few years

we will see something and and we'll

start to get some understanding of this

dark matter universe that we've not seen

before. Dark energy is more difficult I

think um because as I said the effects

of dark energy only become apparent at

very very large scales so scales of the

whole universe and its effect at like

everyday scales. So the effect of dark

energy in in the room that we're in is

completely minuscule. It's it's almost

irrelevant. You it's impossible to

detect. You can only really see it when

you look at the universe as a whole. So,

it's much more difficult to come up with

laboratory experiments that you can do

to find out what dark energy is

fundamentally. But what we what

astronomers can do is look at the way is

to make precise more and more precise

measurements of how stars and galaxies

are moving in the in the sky, how the

universe is evolving. And that can give

us clues as to the nature of dark

energy, what it might be. And there have

been some interesting results in the

last few years that are starting to hint

that dark energy may be a bit uh a bit

more interesting than we originally

thought that it may change with time in

a way that we didn't anticipate. So we

we can still get more information, but

whether we'll find out uh exactly what

it is in the near future, I think it may

be some way off. Something is missing in

a big bang to right. Yeah. Well, I mean

you we're missing we're missing these

two ingredients. So to to make sense of

the of the history of the universe, the

model of the universe, this big bang

theory, you need dark energy and dark

matter. The if you try to I mean so what

you know there's a group of um

physicists, a community of physicists

who spend their time building simulated

universes. So they will like in a

computer they'll put in the ingredients

of the universe and they'll run a

simulation of what should happen after

the big bang and they'll look at you

know galaxies forming and and clusters

of galaxies forming. And what you find

is if you don't include dark matter and

dark energy the universes you end up

with look nothing like the ones we we

live in. And you actually need these

things to explain why the universe is

the way they it is. So they're essential

ingredients to our standard cosmological

theory. And that's why it's so important

to find out what they are. You work on

LHCB experiment at CERN. What exactly is

it? I work well LHCB is one experiment

as we call it on this big 27 km ring the

the large hadron collider. So at CERN

Geneva you have this enormous ring 27 km

in circumference buried underground and

what it does is it accelerates subatomic

particles called protons to almost the

speed of light and then it crashes them

into each other and these collisions

take place inside gigantic detectors. So

these are a bit like huge

cathedralsized digital cameras and their

job is to record what happens in these

collisions and there are four places on

this big 27 km ring where the collisions

take place and at those four points you

have these big detectors. So LHCb is one

of those four. And and what we're

looking at LHCB, broadly speaking, the

the LHC bit stands for large hydron

collider cuz that's the big collider.

And B stands for beauty. Um which isn't

the kind of kind of beauty you're

familiar with from like everyday. It's

the name of one of the a name of a type

of fundamental particle called a beauty

quark, which is this uh exotic

fundamental particle that doesn't

normally exist in the universe. uh but

you can create them in the collision. So

you get lots and lots of these beauty

quarks made and we study these beauty

quarks. We are often read or hear that

you are on the trail of new physics.

Exactly. Yeah. So the reason we're

interested in these things is that the

way these beauty quarks behave can be

influenced by the existence of new

fundamental forces, new forms of matter,

new forms of energy that we've not seen

before. So they're they're a very very

like promising way to try to discover

something beyond our current theory. So

for example that if dark matter does

exist um then the existence of dark

matter can influence the way that these

beauty quarks behave in the experiment

and by making precise measurements we

can see potentially the indirect

influence of these dark matter particles

or maybe something we've never even

imagined before. new forces in in

physics it's generally said there are

four fundamental forces there's gravity

which we sort of talked about that you

know attracts planets magnetism gravity

uh two kinds of electromagnetism gravity

and the last one is we think of

electromagnetism as one force now really

since the 19th century so that's one

then there are two uh other forces

called the weak and the strong force

which are forces that really only become

apparent when you get down to something

the size of an atomic nucleus. So the

nucleus of an atom which is really

really small. So these forces the strong

force its job basically is it glues the

particles that make up the nucleus

together and it's very very strong. Uh

that's why it's called the strong force.

And then there's the weak force which is

as it the name suggests much weaker. And

the weak force is responsible for

processes like radioactive decay. So

when an unstable atom decays into a

lighter atom the weak force is often

involved. Um so we have four forces and

these are described by well three of

them. We don't include gravity in

particle physics because we don't have a

a quantum theory of gravity yet. But we

have a very good theory of the other

three electromagnetism weak and strong.

But there potentially could be more

forces than that in in nature. And you

might argue say dark energy in some ways

is a is a fifth force potentially

already. We have some evidence for that.

But at LHCB we're also looking for

additional forces that we haven't seen

before. So forces that might mediate

different sorts of particle interactions

at very very very short distances. So

when you zoom in really really small

just in the same way as we zoomed in the

atom we discovered the weak and the

strong forces. If you zoom in closer you

may see that deep deep down there are

other forces at play. And and if we find

something like that, it would help us to

better understand why we have uh the set

of particles and the set of forces that

we do in nature and it would be a sort

of step on the road to a more unified

complete theory of physics. So you know

that's one of the other promising things

that you might see at the LHCB

experiment. Don't you think that

promoting such controversial

uh theories, hypothesis expose physics

to the charge of of being

unfalsifiable? Uh no, I don't think so

at all. I mean, you know, what we're

doing uh I mean there are there are some

theories that are criticized for being

unfalsifiable, but that's not the the

whole point of doing an experiment is to

test your hypothesis. So you know there

are various theories that have been

proposed that go beyond what we call the

standard model. So beyond our best

theory of particle physics and sometimes

those involve new particles or new

forces. And the key thing is that those

theories make predictions about what you

would see at say the large hadron

collider and then as experimentalists

our job is to go out and test those

predictions and see if we see them and

if we don't well then that theory is

falsified. So that this is this is you

know this is experimentally driven

science. There's also another way of

looking at it which is you know we don't

just do experiments to test theories.

Sometimes we do experiments just to look

just to see what's there. And you know

one way of thinking about the large

hadron collider is it's kind of like a

giant microscope. It's it's zooming in

down and down to smaller and smaller

distances. And in the same way when we

build a bigger telescope like the James

web you look out into space you see new

things you never saw before. When you

zoom in, you also see new things at

smaller and smaller scales. So, we're

just kind of exploring this unexplored

terrain at very very short distances to

see what might be there. Sabil Hosel

argued that a new physics may never

arrive and that we stuck with a theory

of everything that explain nothing. Do

you agree? Yeah. I mean, I I don't know

what theory Sabine is referring to

there. It may be that she's talking

about string theory or something. I mean

there's different types of new physics,

right? About a new physics. Okay. I mean

I think you know new physics is as I

said it's a catch all. It just means

anything that we haven't seen before. So

when we say new physics we just mean

something new literally. It doesn't it

doesn't describe some particular theory

or some particular set of particles. And

as scientists you know what we're trying

to do is find new stuff. That's the

whole point of doing of doing science.

So this idea that we're we're stuck

with, you know, a theory that we'll

never be able to extend, I mean, that

has never been true in the history of

science before. And there have been

times in the past where people have

said, you know, oh, it's there's no

point going on. We've discovered

everything. There's nothing new to find.

And actually, I don't think Sabine is

actually saying that anyway. That's not

that's not her view. I don't think she

has a critique of particular types of

science. So she she doesn't really think

the big colliders are going to tell us

anything new. and she has her reasons

for saying that. I disagree, but you

know, there's a legitimate debate to be

had about that. But, you know, I I'm

certainly not that pessimistic. I think

that there is, you know, the only way we

will continue to discover things about

the universe is to carry on doing

experiments and as many different sorts

of investigations as we can to extend

the frontiers of our knowledge. Can your

experiment answer the fundamental

questions about the origin of the life

in the universe? Uh, probably not about

life in the universe. That's a sort of

different issue I suppose. I mean um but

what we might be able I mean you know

beginning beginning yeah well I mean I

wouldn't say that our experiment is

going to tell you the ultimate answer to

everything but it may contribute

something to our our picture of the

history of the universe. So you know

there isn't there isn't any one

experiment that's going to reveal you

know exactly how everything began. But

the whole purpose of science, you know,

physics, cosmology is to add more and

more information to the story. So, you

know, we we have suspected that the

universe, for example, began with the

big bang since the 1920s or there have

been suspicions. And over the last h

100red years, the evidence for that has

built and built and built and we have a

richer and richer description of how

that happened. And we can have a pretty

confident story about how far back

towards the big bang we can go in

understanding what went on. But there

are big things we still don't know. So

you know one one example of that is we

do not know how the physical matter that

we're made of came into existence.

There's this basic problem with the with

cosmology and with particle physics

which is that our current theories

suggest that in the very first moments

of the big bang matter should have been

completely annihilated in a reaction

with something called

antimatter and we end up with the

universe with nothing in it. But

obviously we exist the universe exists.

So that suggests there's some flaw in

our understanding. There's some flaw in

our theory. So there's, you know,

there's a piece of the puzzle to be

filled in there and that is a one

question that LHCB is very interested

in. And it's unlikely that we will

single-handedly answer that question,

but we may provide evidence that will

help scientists in the future with other

experiments with new theories build a

better picture. So science is

incremental. It's not, you know, it's

very rare you get some massive

revelation and everything changes or you

suddenly understand something. It's

usually you understand a little bit more

and a little bit more and occasionally

have a bigger breakthrough and and it

that's it's that process of building on

the acquired knowledge of thousands of

people over a long period of time that

gets you to ultimately a deeper and

deeper understanding of of the universe.

Your new book space oddities opens with

the line something weird is happening in

the universe. What is the most weird

phenomenon in the cosmos for you today?

Yeah, so this my second book was called

Space Oddities and it's it's about these

things we get in physics called

anomalies. So an anomaly is something

that doesn't fit. It's like a weird

thing you see. You don't know what it

is. Maybe it's nothing. Maybe it's a

mistake in your experiment. Maybe it's

like some funny fluke in your data. Or

maybe it's the clue to something

something really new. So I mean

anomalies have played a very important

role in the history of science and the

history of physics in particular. We

talked about the big bang. The the thing

that persuaded people really that the

big bang actually happened in the 1960s

was this strange anomaly in a radio

telescope. So a telescope that looks at

the sky and radio waves. And two

American astronomers discovered this

strange microwave buzz in their radio

telescope that they couldn't get rid of.

They thought it was noise interference.

Eventually they realized it was the

remnant of the radiation from the big

bang. So the light from the fireball of

the big bang they were picking up and

that really clinched the argument the

big bang happened. So we're always on

the lookout for these sorts of anomalies

because they can precage like a big

change of understanding. I mean just to

pick one that's out there at the moment.

In cosmology there is this anomaly uh

over how fast the universe is expanding.

So, as we said, the big bang, the

universe expands, and you can measure

how fast it's expanding. And basically,

there are these two different ways of

doing that. One is you look out into the

universe, you look at stars and

galaxies, you measure how far away they

are, you measure how fast they're

moving, and that gives you a measure of

the expansion rate of the universe. What

we call like a local measurement using

stuff nearby kind of well, still very

far away, but nearby inverted commas.

The other way you can do this is to make

measurements of the early universe. So

to look at this light from the big bang,

infer the properties of the early

universe from that light and then use

your theory, the big bang theory to run

the clock forward to the present day and

predict the expansion rate, how fast

universe is expanding. And these two

methods give different answers and they

give answers that are different by quite

a lot. And what this is suggesting is

that there is something missing from our

understanding of the the history of the

universe or missing from our

cosmological theory. Now, that could be

weird forms of dark matter. It could be

unexpected forms of dark energy. It

could be even be modifications to the

laws of gravity. We don't we don't know

the answer yet, but that that's the kind

of thing that could give us a big change

in our understanding of the history of

the universe. That's one thing that's

weird that I think is pretty exciting

and still an unresolved mystery at the

moment. You end space oddities with the

humble tension. What is it humble

tension? Well, so that the thing I just

talked about this this this anomaly over

the expansion of the universe, the speed

of the expansion, that is what we call

the Hubble tension. So it's it's exactly

that. So the reason it's called the

Hubble tension is that Edwin Hubble,

American astronomer of the late 1920s,

was the first person to demonstrate that

the universe appears to be expanding.

And um there is a number that captures

the speed of the expansion and it's

called the Hubble constant. So it's a

number basically that tells you if a

star is you know 100,000 lighty years

away how fast should it be retreating

from us according to the expansion of

the universe. So this this is a number

that basically measures expansion speed

and it's measurements of the Hubble

constant from looking at galaxies and

local stuff and looking at the big bang

that don't agree and that's where this

anomaly ultimately comes from. Maybe

that's a simple question but but from my

point of view very important. What

discovery from your work at CERN has

been your biggest success for you? For

me? Yeah. For you? The thing I think the

thing that I've worked on that's

probably the most exciting. There's

maybe two answers. One thing I write

about in the book is that um we've seen

a load of anomalies at LHCB in our data

and these are in the way these beauty

quarks behave. So basically these beauty

quarks decay into different particles.

We measure how they decay and we compare

that to the theory. And for a long

period, well, still actually for the

last decade or more, we have been seeing

anomalies in these beauty quarks that

don't agree with the predictions of the

standard model, our current best theory.

And so I've worked a lot on these

anomalies over the last five, six, seven

years, and it's been really exciting.

So, we've sort of seen some of these

anomalies get stronger, some of them

disappear because we discovered there's

some problem in our experiment, but

there's still this unsolved mystery

about what is going on with these beauty

quarks. So, that's still what I work on

now. So, we haven't yet like there

hasn't been a big breakthrough. We

haven't like proven for sure that

something is going on, but it's looking

very interesting. And so, it's it's more

I probably wouldn't point to a single

achievement yet. It's more a journey

that we're still going on to try to

resolve this mystery. And it's been it's

been very interesting. If it turns out

this is real, that would be a huge a

huge breakthrough. But we're a way away

from being able to say that for sure

just yet. If I was going to pick a a

single big achievement of the Large

Hadron Collider as a whole, it would be

the discovery of the Higs Bzon. So

that's a discovery that I personally

wasn't involved in. It was made by two

different experiments at CERN called

Atlas and CMS. But the discovery of the

Higs Bzon is the last fundamental

particle predicted by the standard

model. And it's it's really absolutely

central to our understanding of the

universe, how the universe is made up,

how it began. And and so this this

discovery from in 2012, it was a huge

moment because it kind of completed this

theory that we have, but it also marks

the beginning of a new era of explan

exploration in particle physics where

we're going to start to be able to ask

questions that we couldn't ask before.

So as a single achievement for the whole

project I would point to that the Higs

bzon I think do you believe uh that we

will ever answer the question how matter

is transformed into

consciousness inside a human brain. Oh I

mean I have to say I'm not a

neuroscientist and so I'm I I'm very

unqualified to talk about this. I I mean

whatever conscious as a physicist my

view would be whatever consciousness is

it's something that arises from the

ordinary interactions of atoms and

particles there's nothing special

fundamentally about consciousness it's

presumably some complicated interaction

of neurons in in the brain so I know you

know Roger has has sort of particular

has has in the past argued that there's

a role for quantum mechanics in

consciousness I think most

neuroscientist are quite skeptical of

that of that view. Um and I think

physicists also should be quite cautious

about expounding on areas of science

about which they are not really experts.

Um and that there's a tendency in

physics. I think physicists you know are

you know often they're quite clever

people and they regard themselves as

being quite clever people and so they

kind of think well I I can do physics

therefore I can also do neuroscience and

I can also do chemistry and I can also

do all these other things. So I would I

would slightly hold back from saying,

you know, I I have no expertise in this.

So I wouldn't say what the answer is. Um

but I I'm sure that whatever the answer

is, it doesn't lie in new forms of

exotic physics. It will be something to

do with neuroscience, brain chemistry,

what have you. And and what as a sort of

observer of this debate, if I have

anything to say, it's probably that I

think one of the problems with

consciousness is it's very difficult to

define what we really mean by it in the

first place. and it's not obvious, it's

not often clear to me what question is

even being asked. Uh, and I think that's

part of the challenge. It's quite a

nebulous idea. Um, which makes attacking

it quite difficult. And it's also

obviously a subjective experience. You

know, consciousness is something that I

experience or at least I tell you that I

experience, but you have no real way of

knowing whether or not I'm really

conscious or if I'm just a machine that

acts as if it's conscious. In the same

way that I have no way of really knowing

whether the difference between

consciousness and free will for example.

Yeah. Right. Well, I do I do have a view

on free will which is there is no such

thing. Yeah. I I think there is no such

thing as free will because there's no

way we are biological machines. We are

machines. We take in inputs and we have

decision-m circuitries in our brain that

respond to inputs and something happens.

But we don't have a control over it. I I

don't believe it's possible to have

chosen a different choice than we do.

Basically, it's inevitable through the

laws of physics. Well, we not

inevitable. That's the wrong way of

putting it.

Because the reason I say this is if you

go down to the micro scale and you look

at the behavior of

particles, fundamentally those particles

and their behavior is ruled by quantum

theory. And quantum theory says that

that is of any sorry that there is cause

not chaos exactly but its statistics or

it's probability. So when two particles

interact there are a range of possible

outcomes in quantum mechanics and then

one of them happens at random according

to some probability distribution

effectively. So every quantum process is

like rolling a dice or flipping a coin.

There is no mechanism to control the

outcome of the dice roll. It's either a

six or a five or a four. But it happens

with a even probability. So there is no

mechanism fundamentally by which a human

brain could choose one outcome or

another because it is just following the

laws of quantum mechanics that occur

probabilistically. So you know we do

make decisions in the same way that an

algorithm makes decisions. You can give

a neural network or any kind of machine

algorithm here are the inputs. tell me

an answer. You know, for example, is

this a picture of a cat or is it a

picture of a dog? And the internal

circuitry of that algorithm will tell

you, I think it's a cat or a dog. But it

doesn't mean that the algorithm has

chosen to say cat or dog. It inevitably

says cat or dog based on the inputs. And

I think that's how our brains are as

well. You mean we are butterfly effect?

No, not we're butterfly, but we are sort

of our brains are very complicated and

they they do make decisions for sure,

right? They they make choices, but they

they make the choices that the only

choices that they can make. There's

there is no mechanism in physics for

which it would be possible when you're

faced with two choices to actually one I

think you inevitably choose the one you

choose with a little qualifier to say

quantum mechanics might tip you randomly

in the other direction sometimes but

it's not possible to have made another

choice you just follow what happens in

fundamental physics kind of in a in a

probabilistic way so I would say that we

don't have free will but we have the

impression of being able to choose. I

suppose it seems like we choose to us,

but I don't think we really do. How do

you look at AI development today?

I'm agreeing with Dez's um comments

around the role that it's the end of the

human race.

Oh god. Again, not an expert. I mean,

all I all I would say I mean my my

experience you are a physicist. Not in

AI. I mean I use hide AI today. I use AI

but I'm a user of it rather than a a

person who works in this world. So I

mean I I had I was quite skeptical of AI

and the sort of hype around it until a

couple of years ago when chat GPT3 was

released and then you suddenly see okay

this is actually a very powerful tool.

So I think it's going to it already is

being incredibly disruptive and I think

we are still at the very beginning of

you know the impact of of what it's

going to what it's going to do. Just in

my day-to-day work you know we we've

been using things like in particle

physics been using uh machine learning

neural networks etc to identify

different particles or process our data

for a long time for for more than a

decade. So that's sort of familiar, but

I think large language models are are a

different thing entirely. And their kind

of ability to, you know, for example, a

lot of what I do day-to-day is writing

computer code. And I'm not a very good

computer coder. I'm not really very

interested in computer coding. I'm a

physicist, but I use it because I have

to because that's how we do physics in

in particle physics at least. But what

AI lets me do is, you know, I can say,

well, I want to write an algorithm that

does this that, you know, analyzes this

variable in some data set and plots a

graph. And, you know, I could sit down

and type that out and it would take me a

few hours. Or I can just go to an AI and

say, "This is what I want to do. Here's

the data." It produces a lovely bit of

Python or C++ for me, which I can then

run, and if it doesn't work, I can

quickly debug it, and I've saved myself

half a day, basically. So that's the

sort of impact that I'm seeing at the

moment. So I think it will lead to a

very it should lead to a huge increase

in scientific productivity at least in

in my area. So I think we will be able

to get a lot more done much more quickly

thanks to AI. There's another question

of you know do we get to a point where

we're actually giving AI bigger

strategic things to do. So not just

write me this bit of code but coming up

with say the scientific questions we

should be asking in the first place and

and actually going off and trying to

figure those out itself. Now that I feel

sort of a bit more uncomfortable about

because where's the role for a scientist

then? is do we just delegate all our

thinking to a machine and we're just

people who sit there and ask it

questions and it tells us the answer and

and the danger there is this this is

captured very nicely by Douglas Adams in

in the Hitchhiker's Guide to the Galaxy

where there's this advanced civilization

who build this giant computer to to

answer the question of what they call

the the great question of life the

universe and everything so the origins

we're why are we here basically I

suppose and the computer goes away and

thinks for millions of years and

eventually it comes back and says, "I've

got an answer, but you're not going to

like it. It's 42." So, you probably

heard this joke before. So, this

basically it gives this numerical answer

and they don't know what it means. And

there's a danger, I think, that even if

a computer can answer scientific

questions, maybe we won't be able to

understand the answers it gives us. Um,

so who knows? But I think it's going to

be transformative. As to whether it's

going to wipe us out, well, I I just

hope that this is regulated in a way

that avoids the worst outcomes of of AI.

But I think one thing that seems very

likely is it will have a huge disruptive

effect on economics on the way we

structure the jobs market and and we

need to manage that for sure. But by by

the way the physicist approach is so

sad. Free will doesn't exist. God

doesn't exist.

I don't know. I don't know if I agree

with that. I think there's beauty in

that view of the world. Don't you feel

that crisis in your life? Well, no. I

think what makes you know you talk about

like when you die that's it. I think

that makes life precious. It mean and

there's this extraordinary fluke, right,

that the chances of you existing as an

individual are absolutely tiny. And I So

my partner and I, we just had a our

first child a few months ago. And like I

quite often find myself looking at her

and thinking, you know, if things have

been very slightly different, you would

be a different person. You're like a one

in a not even a million, a one in some

vast number improbable. You know, the

chances of you coming together out of

particles and atoms to be you is so

unlikely and you get to exist in the

universe for a few decades and look

around and enjoy it. And I think the

finitness the unlikeliness of that

happening and also the finitness of life

is what makes it kind of magical and and

exciting and valuable. I think if we

live forever or we kind of go on

something beyond that that isn't

necessarily a kind of a a a more

beautiful way to sort of look at the

world. I I think the fact it's finite is

what makes it precious. When you look at

new physics, what's behind the corner?

Well, I don't know. And that's why we

look, right? I mean, if I could tell you

that, we wouldn't need to do the exam.

But what do you expect? What do I

expect? Um, well, I can tell you what

we're going to try to do. I mean, what

we're going to find, I can't tell you.

So at the LHC we are about to upgrade

the entire accelerator. Well the

accelerator itself which will create

something a new machine basically called

the high luminosity LHC which is a

collider that produces more collisions

many many more collisions than before.

So we'll get much much more data much

more rapidly in the next few years. So

we're going to run that till 2041 more

or less. after that it's really up for

grabs and and the the there's a decision

happening this year actually in Europe

about what the long-term plan for

particle physics is and what a lot of

people are now getting behind is the

idea of a gigantic new collider three

times bigger than the large hadron

collider that will allow us basically to

zoom in even smaller so to smaller and

smaller distances to understand things

like the Higs bzon dark matter all these

other sorts of questions so that will be

a a a project of half a century shared

between European nations and hopefully

other international partners and that's

where the focus will be in the decades

beyond 2040. So we have to think in

particle physics we have to think very

long term because these machines are

huge and expensive and they take huge

international teams to build and so

we're already thinking about you know

what we're going to be doing in 2070

which seems kind of crazy cuz I'll

probably be dead by then or at least

I'll be in old people's home. Um, so

that's what's around the corner for us.

But in terms of science more broadly, I

think you know in in physics there's a

lot of excite exciting stuff happening

in cosmology. You have the James Webb

Space Telescope which is transforming

our understanding. There are new

telescopes being built coming online in

the next few years that are going to

tell us more. We have gravitational wave

astronomy which is really still at the

beginning. You know, we only discovered

gravitational waves a decade ago and and

that's opened a whole new view of the

universe. So it's in a really exciting

time. As for what we're going to find

though, we we just don't know. But

that's why we explore. So, I keep my

finger crossed for your future Nobel

Prize. Well, maybe maybe not me on my

own, but maybe shared with 10,000 of my

colleagues. We'll see. Ha!