Roger Penrose: Mass is Frequency derived from the de Broglie-Einstein relation so that there are Signals extending backward from Before the Big Bang

 Energy and Frequency are equivalent.

Energy and Mass are equivalent.

That tells you Mass and Frequency are equivalent.

Every Mass is a Clock

Penrose: If you have no mass, you wouldn't have clocks.

If we just have photons, we don't notice, they don't register the passage of time.

Particles as photons only know the light-cones not mass.

They are completely insensitive to scale - they just care about the light-cones.

Massless particles, you don't have the scale.

Conformal geometry does not have scale, it's just small angles.

You can represent infinity, if they are massless, they wouldn't notice any difference of scale or boundaries outside infinity.

If there were no mass, that's the sort of picture that makes sense.

We can squash down infinity, if you only have photons then they don't notice the difference.

The energy is in their motion and NOT in their mass - so they behave like massless things. So you can stretch out the Big Bang... and squash down infinity....

 The Remote Future extends Backwards into the Big Bang

You can imagine that the Big Bang is the continuation of something before.

it's much better way

and moreover you could do something more

you can say that the remote future well

is that the end? or can you imagine that

the remote future extends into something

else what about the big bang? maybe you

can imagine that extends backwards into

something else so this was the picture

 Signals can get through...gravitational signals... signals in the early microwave cosmic background, only explicable in terms of something going on BEFORE the BIG BANG...

Transcript

my name is roger penrose

i am an emeritus

professor at the university of oxford

and i am going to talk about black holes

singularities

and cyclic cosmology

now my talk will be mainly in

space time so i will have to talk about

four dimensions

you could here we have a picture of

three space dimensions and going upwards

my time will normally go upwards we have

the fourth dimension which is time i

also have drawn the light cone this

describes the speed of light so anything

which travels at the speed of light

would go along that light cone you have

to imagine that the spatial and temporal

dimensions

are comparable in the sense that if it

seconds for the time dimension you will

have something like light seconds for

space which isn't the normal way of

doing it but you want the speed of light

to look something reasonable in the

picture

now i'm not really concerned with the

axes i'm really concerned with the light

cone or the null cone this describes the

speed of light at any point

and this

as you go around space time it may not

have any irregularity because in

einstein's theory

of space time general relativity

you have a curved space time and so the

light cones sort of are not regularly

distributed over the whole space time so

here you have a picture which shows how

they

might vary as you go from place to place

in a general way though the time will be

going upwards

here we have a picture

of

the oppenheimer and snyder collapse this

was j robert oppenheimer of

atomic bomb fame later on but this was

in 1939

he and his student schneider described

the collapse of a dust cloud so the idea

was that in general relativity if you

have too much material squashed together

into small region

then it collapses inwards

and in this particular situation

everything was exactly spherically

symmetrical so no direction in space we

singled out above any other and you have

this spherically symmetrical body

the body also was special in that it was

what's called dust that is to say

there's no pressure so it just collapses

inwards

and the density gets more and more and

more until it becomes infinite at the

center

so this of course was regarded by many

people as a very artificial picture

there's no pressure to stop it

and everything is symmetrical so it's

got nowhere to go except straight

towards the center so the fact the

density becomes infinite at the center

that means the space-time curvature

according to einstein's theory becomes

infinite and this is what's called a

singularity where everything goes wrong

people really did not believe this was a

realistic picture not just because the

dust has no pressure but more

importantly because in a general

collapse situation there will be

irregularities which will become more

and more magnified as you get towards

the center

so it was not thought that this were a

realistic picture

however in the early 1960s people

started to find

rather strange phenomena these were what

became later known as the quasars these

are objects which sended radio signals

a such intensity

more than maybe a thousand times that of

an entire galaxy

and also they had to be relatively small

because they varied at a range which

showed that the size of them couldn't be

bigger than something like the solar

system

this is really extraordinary how could

all that energy be squashed into

something the size of the solar system

so people began to wonder whether

perhaps this oppenheimer snyder picture

might not be something

of what is happening that the material

gets so concentrated that it produces

signals

and then you maybe have a picture like

this but people didn't really believe in

the singularities

uh and in fact there was a paper written

by two russians

lichits and kalatnikov who seem to have

proved that in the general situation

when you have irregularities that the

collapse would not be straight towards

the center maybe it would switch around

in a complicated way and come swirling

out again now around about that time

again began to worry about these things

and certainly john wheeler in princeton

whom i was working with at the time was

interested in whether this was a general

situation

and for

various reasons i had my suspicions

that the literate scholatnikov paper

that singularities didn't

occur was probably maybe not correct

there was a mistake in the paper i

didn't know about the mistake

but uh i i wasn't totally convinced by

the methods they were using so i started

to think about methods of my own

which

looked at looking at sets what looks the

future of regions and so on like that

and this picture is from a paper which i

wrote

in 1964 published in 1965

in which i considered a general collapse

the it's roughly speaking the open slide

oppenheimer snider picture but i'm

considering

there's a little ring in the middle

which you have to imagine there's an

extra dimension of course because it's

four space dimensions rather than

four space time dimensions rather than

three so you you have to imagine another

dimension so that thing that looks like

a ring is really a sphere

and along that sphere the point is that

the light rays are of

converging inwards and i proved a

theorem which showed that if the light

rays start converging inwards and if the

energy doesn't go negative anywhere then

you're going to have a problem and that

you are going to have something like a

singularity quite general it's not that

this doesn't depend on the symmetry

because i was looking at complicated

situations where the future of a region

could be something like this and the

light ray start crossing over each other

and do complicated things but i was able

to develop arguments to show

that the once you have this trapped

surface this point of no return and the

collapse that there was no way of

avoiding the singularities if you had

diffusions have negative energies or

something unrealistic of that nature

a lot of people had trouble believing

this and they even thought that perhaps

this showed that general relativity must

be wrong that was not my view my view

was it really did show that we have

things like what we now call a black

hole

now

at the time this was as i say in 1964

when i gave a talk at king's college

london on this

um

dennis sharma who was a great friend and

colleague of mine in cambridge

wanted me to give a repeat of this talk

and i did give a repeat in cambridge and

at the repeat stephen hawking who was a

young graduate student at the time was

present at my repeat lecture in

cambridge not at the original one but

the repeat lecture in cambridge and

afterwards he and i and george ellis and

perhaps brandon carter

had a long talk about the details of the

arguments i was using stephen hawking

then generalized these arguments

and applied them to the big bang you see

here's another situation where according

to standard cosmology you have a

singularity where the curvatures of

space-time go infinite the densities

become infinite and it looks like a

crazy kind of situation this is at the

very beginning of the universe according

to theory

and the there was evidence

that the big bang was there this was the

evidence from the microwave background

which seemed to show that was a very

early stage of the universe when things

were actually extremely hot and dense

and it did seem to indicate that there

was this thing called the big bang now

maybe the big bang was not as you

see here

in all my pictures as i try to indicate

time is going up the picture so you have

to imagine that the bottom is the big

bang with a great explosion which

creates the universe

does it have to be this very special

singular regular situation

that the theories that people use the

models that cosmologists all use assume

exact symmetry what happens if you have

a general situation with all sorts of

irregularities and that's what stephen

hawking looked at later on we got

together and wrote a paper on this

together but most of the work on this

end was done by him developing the

arguments which i had used for the

collapse of black holes

now i began to worry about this because

what happens

in a general collapse you see here is

the very symmetrical big bang

why is it going to be symmetrical why

not irregularities but what happens in

this collapse suppose we imagine a

collapsing model of the universe

with time still going upwards and

there are irregularities now these

irregularities will cause black holes

these black holes will

congeal each other

provide bigger and bigger black holes

more and more terrible singularities an

enormous mess of a singularity nothing

like the kind of thing we saw at the

beginning

you have an incredibly

complicated and this is where the

russians also now corrected their

mistake and found that in general you

did to get very very complicated

singularities in the future now what is

so different from that

whereas in the past

we don't get the

time verse of what we expect to see in

the generic collapse in the future the

great mess that you see in this picture

here you get something very regular

which is

apparently what we see now what is the

difference between the situation in the

future and that in the past well mainly

it's because something called the Weyl

curvature

is dominates in the future and doesn't

in the past here i have a picture

somebody at the

future of this picture looking back this

is the past like cone of a point

and the light rays

become distorted by the presence of Weyl

curvature

and presence of Ricci curvature that's

according to einstein equations the

 Ricci curvature is what's created by

the matter

and the Weyl curvature is what is the

free gravity so the gravitational field

is

um described by this Weyl curvature and

the matter is described by the Ricci

curvature now the Ricci curvature is a

sort of regular

inwards focusing in all directions

whereas the Weyl curvature gives you

this great distortion

and what seems to be the case is that in

the remote future one has a dominating

curvature whereas the Weyl curvature

seems not to be

present in the very early universe now

this is very much related to the second

law of thermodynamics now here i have a

picture of how the second law of

thermodynamics

um operates the top three pictures

describe say a gas in a box where we

have a smaller box and all the material

is constrained

into this little corner you open up the

box and it spreads out through

the box so from left to right we see the

increasing of

time and the increasing of entropy

and we get a much more uniform situation

as entropy increases so that's the way

ordinary matter seems to behave but how

about gravity in the bottom three

pictures

we have on the left hand side at the

bottom we have a

maybe imagine a very big box of galactic

scale box with many many stars

initially you might imagine they're all

uniformly spread out but as gravitate

starts to operate they clump together

and form clumpy distributions and

finally you get collapse into a black

hole where the entropy goes just

shooting up enormously so as entropy

increases with gravity

the irregularities increase whereas with

ordinary matter you expect the

uniformity to be the situation with

increasing entropy so the real puzzle is

why is it that in the very early

universe you see uniformity which was

consistent with very high entropy

but on the other hand very low

gravitational entropy

very high entropy

in the matter and that's what we tend to

see

but very low gravitational entropy and i

thought this was a great puzzle so i

formulated a sort of hypothesis

that for some strange reason

the singularities in the future

had to be

zero Weyl curvature

whereas the singularities so the

singularities in the past had to have

this

zero Weyl curvature whereas the

singularities in the future the Weyl

curvature could absolutely go wild and

dominate and i like everybody else seem

to think this must be a feature of

quantum gravity you see when the

curvatures get very very big

then you start to imagine that quantum

effects will start to play a role it's

not just classical einstein theory

when the radius of curvature becomes so

so small

maybe say

10 orders smaller magnitude than the

radius of a proton or something like

that

it's the sort of scale in which you

might expect that you have um quantum

gravity playing a big role

but what's so strange about it is if

this is the case

why is it that the quantum gravity seems

to behave so differently from the past

type singularity where the Weyl

curvature seems to be zero or very close

to zero whereas in the future

singularities it seems to dominate and

go crazy

now for a long time i seem to think this

must be

a very strange kind of quantum gravity

where gravity is changing the very

structure of quantum mechanics now i do

actually believe that

there is a great puzzle about quantum

mechanics which is called the

measurement problem which is not really

explained in standard quantum mechanics

and it is my belief that when you bring

gravity in it's going to resolve that

problem so for a long time i thought

well this very strange quantum gravity

where gravity behaves very differently

from everything else maybe that's the

explanation

but then i had a different idea

it's really very hard to make that work

and i was wasn't certain certainly was

not able to make it work

let me go back to the picture of the

 light cone and now let me make it a little

bit more complete you see that picture

just described the light cones the nail

cones it did not describe

how time is behaved in general

relativity

you see time

features

here we have two of the most famous

formerly

if 20th century physics there's einstein

c equals m c squared of course and also

max planck's e equals h nu max planck's

formula tells us that energy and

frequency are equivalent

einstein's formula tells us that energy

and mass are equivalent

put the two together that tells you mass

and frequency equivalent so when you

have mass

you have automatically a frequency so

every mass is a clock

so when you want to bring clocks in the

rate of time

that's what mass does for you if you

have no mass you wouldn't have clocks

but if you do have mass that determines

these little

hill and bowl shaped surfaces i've

introduced into the light cones tell you

the ticks of a clock and here we have

two particles whizzing at different

speeds but they're related by these

surfaces which tell when the first tick

happens the second take and so on but if

you just have light-like particles in

other words photons and things like that

who don't notice that these surfaces at

all they don't register the passage of

time particles without mass

don't even know about the passage of

time they only know about the light cones

so this was a remarkable thing which

seemed to me to be important

it's also true of maxwell's equations

which describe

the classical behavior of light

and these equations are completely

insensitive to the scale they just care

about the light cones they don't care

about the scale now what happens when

you just have the light currents you

don't have the scale but you massless

particles things without mass that's

what they're interested in

well it's very interesting because

when you don't have any scale you can

consider a kind of geometry which is

called conformal geometry conformal

geometry is the geometry of small shapes

if you like of angles

and here we have a lovely picture due to

the dutch artist m c escher where he

shows with a certain type of geometries

called hyperbolic geometry don't worry

about that but the important thing about

this geometry is that you can represent

infinity

this circular boundary to this picture

represents the infinity of these

creatures so the creatures in ash's

picture

they don't

feel the boundary there they they the

mass keeps them uh so they actually know

where they are if you like they know how

big they are but if they were massless

they could go right out of the boundary

and they wouldn't notice any difference

from anywhere else if they were photons

the photons could

probe the boundary and go right through

and seem to explore some world outside

infinity very strange idea but if there

were no mass

that's the sort of picture

which makes sense so i began to think

about this and when we talk about the

whole universe it was discovered uh

at the turn of the century more or less

that there is something sometimes people

call it dark energy i call it einstein's

cosmological consonant he introduced it

in 1917 for the wrong reason

nevertheless but this seems to be the

best explanation for what's happening

in the remote future here we have a

picture

of the universe

uh in its expansion

the remote future is this exponential

expansion where this dark energy or

cosmological constant seems to dominate

and we have the big bang at the bottom

of a picture

and the feature of this is we can apply

apply the trick that escher used in his

picture and squash down infinity and

make it into a finite boundary if you

only have photons running around then

they won't notice the difference and you

can squash it down into a finite

boundary what about the big bang well

the idea is you could stretch that out

into a finite boundary as well you might

worry well there's a lot of massive

particles running around the big bang so

surely they know how big the universe is

no they don't really because it's so hot

so dense and so hot at the big bang that

they rush around so fast that the mass

of particles becomes completely

irrelevant and again you have a

situation where in effect everything is

without mass it's not actually without

mass but the mass is so unimportant at

the big bang because the energy is so

big that the energy of the particles is

in their motion according to einstein's

theory in their motion and not in the

mass of the individual particles so they

behave like massless things too so you

can apply the trick at the beginning and

stretch out the big bang and make it

into something nice and smooth and you

can squash down infinity and make it

something nice and smooth now the

advantage about this

is that you can only stretch out the big

bang and making it smooth in very very

special circumstances

my

former student and colleague paul todd

used this as a rather than using my

 Weyl curvature hypothesis saying the

 Weyl curvature is zero a better way of

doing it was to say you could stretch

out the big bang and make it nice and

smooth so i liked his way of doing it

it's much better way

and moreover you could do something more

you can say that the remote future well

is that the end or can you imagine that

the

remote future extends into something

else what about the big bang maybe you

can imagine that extends backwards into

something else so this was the picture

that modifying paul todd's idea into one

where the Weyl curvature is actually

zero at the beginning and not just

finite as he had

you can imagine that this big bang was

actually the continuation of something

before

so i'm saying that why the big bang was

so special was because it is the

conformal continuation of something the

remote future you might say this is very

hard to imagine because how could

something so cold and rarefied in the

remote future be physically like

something so hot and dense but when you

think about it it's not so strange

because when you have no mass around you

can't tell the difference between big

and small therefore can't tell the big

difference between hot and cold see when

you squash down this very rarefied

remote future it becomes hotter when you

stretch out the very hot and dense big

bang it becomes colder and they seem to

match so the model i'm putting forward a

crazy model but nevertheless it seems to

make a lot of sense that you stretch out

the big bang and then it becomes the

continuation of the remote future of a

previous eon so in this picture

what we used to think is the entire

universe the big bang being being the

beginning in the remote future being the

end

i'm saying that this is just one eon

one stage of a perhaps infinite

succession of eons one after the other

now it's also you see when i first

thought of this idea about 15 years ago

or so i thought i'd go and lecture about

this forever nobody would ever be able

to contradict me because there's no

observations against it but then i

thought well maybe there are our

observations because signals can get

through

if these signals are light signals if

they more importantly are gravitational

signals they can get through

and i thought about if you have collapse

if you have

black holes which spiral into each other

and

huge galactic scale black holes i'm not

talking about the ones that ligo sees

and we certainly see black holes running

into each other but the black holes at

centers of galaxies absolutely enormous

ones eventually will start to spiral

into each other and produce signals

which may we could see

there are also other effects which we

can see

and it's seems to be the case that there

are signals that we are seeing in the

early cosmic microwave background which

are

explicable and only only explicable as

far as i can see in terms of something

going on before the big bang which is

consistent with the picture which i've

just been showing you

it's something for the future to see

whether these things continue to support

this idea or do we see effects which

contradict the idea i think it's very

exciting because it opens up

new things in cosmology

which which has been thought of before

thank you very much

you