Of. Right.
I'm conscious that it's already lunchtime. I hope you have something to munch on at the coffee break because I'm going to
discuss what's arguably the biggest problem in cosmology and in fundamental physics,
and I'll take at least half an hour to do that. I hope you'll bear it.
So I want to start by asking if any of you here were contemporary with this man?
Does anyone know him? Yes, yes. So then you can tell me the date when when he did his best DPhil, which was the thing with Christopher Lloyd Smith.
I have 75 years was that? Is that about right? Yeah. So Ian Hinchcliffe is a distinguished particle physicist.
He's at Berkeley Lawrence Berkeley National Lab, and he is, of course, well known for his contributions to particle physics.
But he's in fact perhaps best known for having been credited with something called
Hinchcliffe Rule that says if the title of the article is a yes no question,
then the answer is no, right? Of course, if you think about it for a minute, as any logician would,
they would come up with another question, and this is a real paper submitted to the archive.
And in fact, this is their paper because it's so hedged.
His assertion is false, but only if it is true, right?
So it is in that context that I want you to see the title that I have chosen for my talk, which indeed has a question mark at the end.
And I will try and present to you the evidence, which makes me wonder if this is not subject to Hinchcliffe rule.
But you all know what this is about because this has been with us now for about twenty one years.
It made the cover of science.
It was arguably the biggest breakthrough in cosmology since the discovery of the cosmic microwave background, and it has been richly rewarded.
Various prises of Philip just talked about supernova, a binary mergers making gold.
They got their gold from Stockholm. And this has continued.
It is very much part of the establishment. This is the bedrock of the standard cosmological model.
And yet I will try and argue to you that we need to be conscious of that question mark.
In fact, I'll present to evidence that very likely the observations do not actually tell us anything about the cosmological constant or dark energy.
Now to do that, I have to take you back to how this whole business started, and it has really all got to do with measuring distances in cosmology.
Now to measure distances, you need standard candles, things which have a known wattage.
So you know from how fainter, how far they are.
And to do this, you must find some of the property of the object that tells you how bright it is intrinsically and historically.
The first such objects were so-called secret variables because they are found in the constellation of Seaforth.
And as you can see here, there periodicity you can see flashing on and off correlates with their absolute luminosity.
And this is very advantages to for using them as standard candles.
And the most at first, most dramatic use of these was by Edwin Hubble, who discovered in the outer periphery of our nearest neighbour, Andromeda.
M31 a little object there, but she has written v r for variable.
And this lady, Henrietta Leavitt, had already shown that relationship based on the previous light.
She had established that these could be used as distance indicators, and riding on that,
Hubble was able to deduce that this what was a nebula cloud in our galaxy,
because that's all we knew about the universe then, was actually another galaxy just like ours, but quite far away.
In fact, it is two and a half million light years away. Our galaxy, for comparison, is about 30000 light years in scale.
And so the universe certainly became a lot bigger. And I would say this was the beginning of what we today.
Our cosmology, physical cosmology today. Now, of course, fast forward in time, we have better instruments now in orbit.
The Hubble telescope and that's powerful enough to see a secret variable in the outer periphery of this galaxy and 100, which is in the Virgo cluster.
This is a cluster of galaxies to which we belong. And you can see it flashing on and off.
And that tells us that that galaxy is about 54 million light years away.
This is the directly calibrated distance because we can see the speed.
But if you waited a little time, then you will find that a supernova goes off in this galaxy,
as Philip said, they go off roughly once a century and a galaxy of that size.
And you can tell that it's a type one supernova.
Here is the nickel 56 decay. Of course, this is the die curve, but the real data shows also the features that, he explained.
And that allows us to now use calibrate this supernova because we know the distance to this galaxy already.
And then when we see similar supernovae further away in the universe, we know the distances.
So now we can measure distances to billions of light years.
And of course, when you are doing that, we are looking back in time, that's why this is important for cosmology and you know that we see the Sun,
as it was a little back in the past, said Drove our galaxy is about thirty thousand years ago, and yet his star is four years.
I just showed you the Andromeda nebula. That's two and half million years.
We see Virgo as it was when the dinosaurs were dying out. And in fact, when you look in the Hubble deep field,
which is the deepest view of the universe taken by our telescope, we actually look back about 12 billion years.
It's really travelling back in time. Time travel is possible only backwards.
Now you all know that when you look at those galaxies, that is another feature that is interesting.
Their spectra are all shifted towards the red as we go from a nearby star to the more distant galaxies.
And this is the redshift the fraction of change in the wavelength. And you normally would attribute this to the same.
Edwin Hubble, incidentally, has an Oxford degree. You might be surprised to know he wasn't that this department.
He actually did a degree in jurisprudence of all things, and he was a Rhodes scholar.
So he is credited with the discovery of the expansion of the universe, and here is his original,
rather sketchy data showing the correlation between the velocity and the distance.
In fact, he actually never interpreted this as the expansion of the universe.
He said that task of interpretation should be left to theories, and I'll make it clear later why his data, of course, was rather close by.
Today, we have data extending a lot further, as I mentioned.
So therefore, we are in a position to say things and draw inferences that Hubble could not have done.
And the first thing I want to emphasise is that those red chips are not due to, as one might imagine, the Doppler effect, which is familiar to us.
It's the whole new effect. It is caused by the stretching of spacetime so that when a photon is emitted from
a particular source at a given time later when you observe that same photon,
its wavelength, of course, is the same regard to the space it is moving in locally.
But the metric of spacetime has changed in the intervening time, and therefore we see it as a field on a longer wavelength.
And that is the redshift. And this picture, of course, also makes it clear that this expansion, as it is, is everywhere.
The same looks the same from any point on the sphere. So it's not really an expansion that begs the question what are you expanding into in all that?
So let's now fast forward to 1998, when this discovery of the accelerating expansion was made.
So two groups of astronomers were looking at the magnitude of titans of innervate versus the redshift.
And as you can tell from this last here,
the data were indicating that the expansion rate instead of slowing down as one might expect it does under gravity, was in fact speeding up.
But this data is perhaps not convincing enough, but it was a strong enough case that they were given the Nobel prise for it.
And when I applaud the same data in terms of the scale of the universe versus the time which is inferred from the redshift,
we don't directly, of course, see 10 billion years back in time.
We inferred from the rich ships that are measured of these objects. And that seems to indeed indicate that.
But rather than be on a girl that was only always slowing down,
the expansion has started accelerating in the last few billion years, which is really a redshift of order one.
But. Now, I'm sorry to go through all this rather quickly,
but I take it you have been exposed to it over the last 21 years and this has
led ultimately to our formulation of the so-called standard model of cosmology,
which I can right now on one page.
In two equations, much as the standard model of particle physics can be now written, the Lagrangian can be on a t shirt.
There are big differences between the two standard models, which I'll highlight. So what you have here is the metric of spacetime,
which allows you to be the simplest form possible because we are assuming that the universe is isotropic and homogeneous, as Einstein and others did.
When the theory of cosmology was first formulated nearly a hundred years ago now.
And that allows a considerable simplification of Einstein's equations,
which take that metric of spacetime and the curvature tensor that you construct from it,
and of various other objects like the DC Tensor and the scalar and so on and related to the energy momentum.
Because as you well know, that's what tells space how to curve and the curvature in correspondingly dense matter,
how to move in with those famous words.
So we can now see that sphere that I showed you earlier is depicted here with the radial coordinate being conformal time or redshift.
We are sitting on the North Pole if you like,
and we are looking at the sphere and light can only come to us on the surface of the sphere because that's all there is.
And the antiporda point is the Big Bang. That's why the Big Bang fills our entire sky, even though it is a singular point.
This geometry, non-nuclear and geometry makes that possible.
And in fact, as we go back in redshift or conformal time,
we come to a point that the universe was a thousand times smaller than it is today and thousand times therefore hotter.
And that's enough to ionised hydrogen.
So the rest of the time the universe is ionised and the photons starting out from the Big Bang at Brexit of infinity,
which is the dashed line when random walk just like the four dogs trying to get out of his star.
And then when they reach this point, they are emitted and come to us.
So this is the photosphere of the universe. We are really inside.
It's an inside out picture of a star. And we are in sight.
OK, that's that is the analogy to what you've been hearing about so far.
Now, mathematically, we can now reduce the very complicated equations that Einstein gave us to a very simple one,
which is named after Alexander Friedman by using this metric to construct this object.
And that tells us how the scale factor changes in response to the matter and the curvature and the object called the cosmological constant,
which you are allowed to add,
which we must add there, because that is reflecting the underlying symmetry general coordinate evidence that underlies general relativity.
We have no option in that matter. So if I take this equation, this is called the Hubble Barometer.
And if you divide this through, then I can rewrite it in this form.
With these matter densities written in terms of the fractional contribution it makes to the critical density as defined here.
And that scales with redshift as you see as one does that you just reflecting the dilution of matter with the expansion in the early universe,
the rapid radiation. So then that would become one if to the fold, because the results of the the stretching of the photons, as I mentioned,
then we have curvature, which goes as that square and there is omega lambda that goes as nothing because it's a constant.
And this then gives us a so-called some rule, which says that these three guys are up to one and that there are only three
terms because that is forced on us by these as you homogeneity and as a trophy.
OK. That is an assumption. But we use that some rule to infer that because matter only makes about about a third of the universe and the curvature
appears to be close to zero from the cosmic microwave background that there must be something which makes up the rest.
And that has got to be this omega lambda. And that then turns out to be 70 percent or so of the universe.
And because omega lambda is defined as lambda, over three is not square.
That means the lambda is of ordered the present day Hubble parameter square, which is a rather strange.
So you can see how omega lambda has come to be. How we got to this crazy direction that lambda has a scale of 10 to the minus 40 to G.V.,
because that is what the value of H.A. is in particle physics terms.
And so if I try to compute what this corresponds to in terms of an energy density,
I would get that it is of orders about a million electron volts into the minus 12 GV,
which of course, I don't need to tell you is a lot smaller than any scale in fundamental physics that we are aware of.
The weak scale. The Fermi scale, which is of order one hundred, gives where all the action is now.
That's where we are. We have actually gone a factor of 10. Beyond that, we are doing experiments at the TV scale.
And although this stuff is not going to affect anything we do at the Large Hadron Collider,
we have to come to this conclusion from cosmology that actually most of the universe is made of a cosmological constant at this crazy scale.
And this actually makes no physical sense, OK?
There is a cosmological constant problem, we have known about it for 80 years,
ever since one of those formulated Powley and the Lubitsch and others pointed out that the zero point energy the vacuum coupled to gravity,
according to Einstein, and therefore it had to be very, very small.
Otherwise, the universe would not exist as we find it. That's the possible logical constant problem.
Not only has the problem not been solved by the best minds since then,
we now have the astronomers telling us that it does exist at a level which is set by the present rate of expansion.
It makes no sense, it infuriates me, OK, that this is the basis of our standard cosmological model,
which is taken to be a standard model in the same way as the standard model of particle physics, which I believe has been somewhat better tested.
And that is what theme of my talk is that we have had all these satellites w my
plant and the Sloan Digital Sky Survey and the Dark Energy Survey and so on,
which are telling us that the universe is made of mostly of dark energy.
But the basic foundations of this model, which is this assumption of isotropic and homogeneity, which,
as it says here, underlie this deduction, this rather important deduction rests entirely on these assumptions.
We need to test them in the same way that the basic assumptions of the standard model of particle physics have been tested.
They have been tested at the quantum level and it is passed every test super.
What about testing the foundational assumptions of the standard cosmological model?
I think that somebody needs to do this, which is why, although I mean the part of the theory group,
I'm going to spend the rest of time telling you about astronomical data and the right way to analyse them.
So you heard all about type one supernovae. There are various possibilities for how they come to be.
You heard about the taxonomy.
We are interested in these because these are closest to being standard candles and they are measured at various wavelengths with various names,
bands and we learn all this jargon.
It's kind of hard to come to terms with the fact that although it makes sense to show the
logarithmic measure of the brightness because they do vary over orders of magnitude,
for some reason, the astronomers then multiplied by minus two point five.
I've never understood why this is very confusing, because it means the more negative the number, the brighter it is.
OK, just keep that in mind. So here we are. Various light curves, as you also saw earlier, and it is quite clear that they've got a lot of scatter.
You call that this is a log scale, right? However, Phillips, a astronomer at the Anglo-Australian Telescope,
discovered that there is a nice and b correlation between the peak magnitude and the width of this light.
Good, right? And it's slightly different, according to what band you observe them and what the colour is.
Now, this is pretty interesting, and I should emphasise that this has been made possible only because we see the right time.
You see this data points which are there before the supernova went off, and you might well ask,
how did I know that a supernova was going to go off at some random point in the sky so that I start making measurements two weeks earlier?
That is the great advance in the field that was made possible by just couple device cameras,
which can keep scanning the sky over and over again so that when a supernova does go off,
you can go back and look at the picture that you took two weeks earlier,
and that was the real advance in supernova astronomy in the 90s, which led to this discoveries.
This correlation, by the way, is not understood. Theoretically, that's the kind of thing doesn't always work on, but it is empirical.
We can use it because it works. It reduces that stature to the point where you can actually use this things as standard candles.
And James has told us about the basic underlying physics, which you can trust because it's got the word suddenly trigger mass in it.
So, you know, there is some really sound physics underlying that, and therefore we can use these as standard candles.
But in practise, we have to make corrections to the magnitudes a so-called stretch correction to stretch
literally the light burst in the fall on top of each other and the colour correction,
depending on at what redshift we measured them. Recall that when you see them at high redshift, the emission will be moved towards the infra-red.
That's why you have to go out on the Hubble Space Telescope or something to look at.
And this is the current state of art is called the salt, the spectral adaptive logic of template version two.
So there you are. It's the latest now. How does this relate to cosmology?
Well, I already showed you all the relevant formula. It's very simple. I mean, this model is 100 years old.
So the magnitude you heard about the that translates into a luminosity distance to this relationship here,
and the luminosity distance is related to the parameters of the model like all these omega three, which are omega matter or omega lambda, et cetera.
Of course, we can extract these parameters, therefore, by looking at the magnitude Rateliff relationship.
But in fact, we don't really need to look at the model because acceleration is a kinematic done.
It doesn't need you to have a theoretical model of the cosmology.
You just do a Taylor expansion of this luminosity distance. The first term is the velocity.
The second term is acceleration, which is defined like.
So it was defined with the minus sign because people expected the universe to
be decelerating and therefore they wanted you not to be a positive number.
The surprises that people claim it's a negative number. And of course, the third term is for some reason it's called the jerk and so on.
So we can do this Taylor expansion. This is a small graph.
It has got no model assumptions whatsoever other than, of course, this as a in homogeneity that attention.
So here is the data. So these people in 2014 for the first time made the data public.
740 supernovae from various different observations,
all assembled together analysed uniformly using the same template that you designate service by making the data public.
That is what science should be. It should be open. We should all be able to play.
And we can now take this data and ask if the divisions that were drawn earlier do bear up.
By the way, this column is of the mass of the host galaxy that might have an influence as well.
So this may not be the end of the story. There may be other predictions you need to make, as I've indicated here.
But for the moment, this is the state of play. They they don't correlate with each other.
They're pretty good of the. Now we got into this of three years ago yet, and Ensign was my master's student and he, you know,
students these days have to go to proper courses on statistics which most of us have never had.
And the first thing they learn is that, you know, you construct something called the likelihood, which is the probability that you are seeing.
Is this given data for as you model? And in this case, the data that you're observing at the magnitudes,
the stretch and the colour corrections for some set of parameters of the model, which I called Peter,
and it is easy to say that this tape this can be decomposed into a product of
stuff that depends on the cosmology and stuff that depends on the supernova,
because surely the two don't talk to each other, so you can assume that the variables that control the unknowns are decoupled from each other.
Now, yet they noticed immediately that when you plot the directions that the observers had been, you know,
painstakingly amassed that day, in fact, a rather reasonably described by Gaussian distributions.
This is not perfect, of course. And in principle, you can do it numerically.
What matters is the area under the curve, but it Gaussian is a good description because what that means is that this likelihood,
which affects factories as says that the observed distributions are drawn from some underlying distributions of these special colour parameters,
which are determined by the physics of the supernova.
And if what I see is a Gaussian, then it's very likely that the period distribution is also Gaussian.
And therefore, I can assume all this stuff to be Gaussian, which makes life very easy because I know how to integrate the Gaussian.
That's my training in theoretical physics going in the hand.
This is not entirely a joke because being able to derive it likelihood without running a massive Markov chain Monte Carlo, you know,
analysing and dimensional parameter space, which is the standard workhorse in cosmology,
is a big advance because you can check that what you have done is correct.
In fact, the programme is on the webpage. It's a small Python code.
You can run it. And when we did that, we found something rather amazing.
We found that the evidence is nowhere near as strong as had been claimed.
In fact,
the cantos and the omega cosmological constant verses matter plane came down and touched the line that separates acceleration from deceleration.
And this was a bit of a surprise because we had been told that these photos are way up
there and establish exhilaration to the level where it was deemed worthy of a Nobel prise.
Three Sigma is nothing in particle physics. We have animals coming and going every day, which are three sigma.
Now, people objected to this. First, they tried to claim that our analysis method was to use the words of Brad Schmid, one of the Nobel laureates.
He tweeted that it was rather unorthodox.
Yep, he was quite shocked and I, until I assured him that Brian, like me, had really never done a course in statistics in his life.
OK. It is not unorthodox at all. It was in fact called the greatest advance in 20th century statistics.
Then people would complain that, Oh look, these people only can get to this in an empty universe and the universe is not empty.
It has mattered to the right of this. Plus, the sum of these two things should add up to one, so we should be somewhere down the line way diagonally.
This is only true to the standard cosmological model. It not be true in general.
You might have other terms in the Friedman equation. You might have terms corresponding to, you know,
viscosity of the fluid filling the universe or to the so-called back reaction neutrino, whether it is.
So that is not an argument. But let me move on because I'm conscious of the time and get to this point about questioning.
The fundamental assumption is the universe actually isotropic now this is what we lecture to our students all the time,
and it is manifestly not true if you look at the sky.
So the furthest back you can look is that redshift 1000 surface, the so-called last scattering surface of the microwave background,
and that shows a huge dipole how the sky is hotter than the other half and the temperature varies in a well-defined way,
which was in fact first worked out by Stewart and Sharma.
I, in fact, came to Oxford to work with the NIA.
Sharma was also James, the supervisor, and the other people that wrote about it were Peebles and Wilkinson.
Peebles got the Nobel prise for cosmology this year, so you can see this as the distinguished history,
and this dipole is interpreted as due to our motion.
It's seen as a special relativistic effect. In fact, this is now a standard problem for undergraduates to work out that formula.
When you move through a part of black body radiation, what would you see now?
As it happens, we are actually moving in the opposite direction as we go down the centre of the galaxy.
So our velocity is actually a bit twice as much as 620.
And amazingly, this is not just us, the entire local group in the Magellanic clouds,
et cetera, we are all moving coherently towards the particular direction.
Now, why are we moving if the universe was homogeneous, then of course, there is nowhere to move to.
Every place is the same. There must be some lump of matter attracting us.
That's the received wisdom and it was given a name which was called the Great Attractor.
Right now we have looked for the Great Attractor and we should have found it within about
100 megaparsec because the claim is that although there are these enormous entities,
when you average on scales bigger than 100 megaparsec, then you can sensibly describe the universe as homogeneous.
But in fact, we don't find that this is the actual distribution of galaxies in our neighbourhood.
I've drawn for your convenience, a sphere of one hundred May opposites. We are at the centre here.
We are moving in this direction towards the shape of a cluster. But that is not the Great Attractor, as we as I show you.
And we are being fooled by something beyond shapely.
And the further away this object is, the more massive it has to be in order to make us move with the velocity that we do.
And that creates a problem for the standard cosmology. How do you create a lump of matter, which is that massive light?
So there are many ways to frame it.
My point is simply here to emphasise that the standard assumption and cosmological analysis is that we are a so-called Copernican observers.
The universe looks isotropic and homogeneous to us. And this is the same, too.
This is not the case. So let us try to get something out of the data, here is a catalogue of a previous catalogue of 557 supernovae shown on the sky.
The sizes of the squares tell you whether they are brighter than or less bright than
the brightness that they ought to be a standard candles for their known distances.
So what is evident is that these things are not all zero.
This is not a flat distribution.
And when we do this, we can actually map out the Hubble fluid ratchet because we can see the shelves of galaxies around us,
each one hosting some supernovae.
And we can therefore determine whether there is a bulk motion which is reflected in the dipole anacetrapib of the supernovae.
And these residuals are actually mapping out the peculiar velocity flow and peculiar velocity is a good
thing because the previous plot that I showed you of the galaxies may not be all the matter that there is.
In fact, we know that is five times more dark matter, which you don't see in that picture.
The only way to know the influence of all the matter is wait for it to do its stuff gravitationally,
cause things to move, and we measured those motions, right? So then we are sure that we are sensitive to all the matter.
And in fact, we find when you do this analysis in different ranges of Ratchet, as you see here, that we are actually moving.
There is a dipole anisotropy in roughly the same direction as the CMB, which is that black dot there, the dipole from this is much cruder.
Is that blue patch and that is the 90 percent confidence level and so on.
It's much less, well, determined, but what is clear is that that velocity with which we are moving is significantly higher than
the value that you expect due to just random fluctuations in the so-called lambda CDR model,
which is the standard model of the field. Now these divisions are large, but they are also uncertain.
So within one standard deviation or so, as you can see here, they are consistent.
So this did not make such an impact. Although you might worry that all this data is on one side of the plot.
That is clearly some systematic issue, and others have also found such flows on a smaller scale.
This was the deepest we went out to shapely, which is a two hundred and sixty opposites.
And we did not find any info on two shapely on the other side, which means that the thing that is pulling us is even beyond shapely.
And this was confirmed later by various people.
I just show you one set of data from the biggest such peculiar flow catalogue, which was done also at the Anglo-Australian Telescope.
And that is all still show you this the bulk velocity versus the radius.
And you see that data, which is this point here, is well clear of the dashed line, which is the expectation in the standard lambda model.
Our result was this Green Line pinpoint without Airbus with other large, they have done a much better job with the biggest sample.
Recall that for all these objects, you need independent distance measurements.
They use something called the fundamental plane, which is good to about 15 percent.
So this has been a very field fraught with lots of uncertainties and errors.
But it is now becoming pretty clear that there is a problem. We are moving much faster than we should expect to be.
In fact, we can ask how likely it is that we are moving that fast out that far and we can interrogate this large
simulations that our colleagues in astrophysics do of the formation of structure in the universe.
And we can ask how often might we find ourselves to be in this position?
And then they can quantify that statement earlier that we are not Copernican by saying
that less than one percent of observers in such a universe should see what we see.
We are definitely special.
That, you know, people have a problem with being sort of know because we started cosmology by saying the Earth is at the centre of the universe.
I think people are psychologically reluctant to accept that there is something, anything special about us.
Of course, there's nothing special about us other than the fact that we are not the same as everybody else.
The question is what does it mean for the inferences that we draw from the data?
That is important because only by that route do we come to this amazing conclusion that 70 percent of the universe is dug in.
Now, if you are in the bulk flow as this yellow patch here, then the Red Devils will tell you that you are not a Copernican observer.
You are a so-called tilted observer.
A terminology that was first introduced by a South African relative is George Ellis, who is in fact just retired to Oxford.
So you have the advantage of discussions with him and for lack of time,
I shall skip over the details of how we can then deduce that if you happen to be in such a batch and observing objects
which are in the batch and our data shows that three quarters of the observed supernovae are within this bug flow.
Then you might find that the deceleration perimeter that you measured is not just the usual one,
but as a correction done because of the bulk flow, which is the opposite sign.
And that means that you might inferred a negative number when in fact the number is actually positive globally.
OK, now the guy who has deduced this lady was Gonzaga's in this this.
He has tried to compute these terms with without success because the necessary astronomical measurements have not been made.
But there's a clear prediction that if this is true,
then we should see a dipole in the deceleration or acceleration parameter as well in the same direction that we are moving.
Is that true? Well, amazingly enough, nobody has thought of looking for this until now.
This is the sky distribution of the supernovae.
Then the giant like, like a light analysis catalogue, jails 11 40 guys and they are distributed in redshift, so half of them are pretty close to us.
These are the Sloan Digital Sky Survey. This is the Supernova Legacy Survey, disposable things that the Hubble Space Telescope at High shipped.
This is the direction you are moving towards the cmb, these are the directions of the bird flu, which are uncertain,
but close to what we discovered is that of course, this peculiar velocities are well known in cosmology and people have made corrections for them.
But what we discovered is that the people who have made these corrections astronomers have assumed that the bulk
flow simply disappears at a distance of about one hundred and fifty may about six about 500 million light years.
But our data shows that it continues to at least twice the distance and shows no signs of falling off.
Besides which you can't have a velocity, certainly stop and go to zero.
There has to be continuity right now, thanks to collaborator Ramis, who is very good at digging out what people have done with that data.
We were able to uncover this and show this picture of shame as it were.
It shows that there has been some dodgy analysis going on.
So we undo all that. And now we're in a position for the punchline,
which is that the supernova do have a clear dipole in the inferred acceleration in roughly
the same direction as the one that you're moving into the CMB that shows the dipole,
and this shows the log likelihood, which is almost flat in that direction.
And here we see the magnitude of the dipole, which is about eight OK in this, according to this definition,
which is about 50 times bigger than the monopole, which is only about minus 0.1 eight or so.
In fact, the monopole, which is what people thought all this time it was, is negligible.
It's been set it to zero and you, in fact, you get a slightly better fate, according to the so-called Bayesian information criterion.
So it's quite clear that what you're really seeing is the dipole along the direction of a local bulk flow and.
In fact, as I mentioned, we can possibly have this zero of divided this scale by 10,
otherwise this thing would just be a vertical line because this is totally negligible.
It's consistent with zero at one point four sigma.
So now whatever you might want to attribute to a cosmological constant or dark energy has a significance of 1.4 sigma.
OK? Ask yourself if you would believe that whereas this has a significance of three point nine sigma, which is rather convincing.
So we conclude that cosmic acceleration is simply an artefact of our being located in a bulk flow rather than due to anything fundamental.
Goodbye to dark energy. And I therefore can come to my conclusions, which is that, as I've just stated, this is all data driven.
I've not used any theory.
There was a theoretical motivation following from the work of cosmologists or tilted observers, but it's completely empirical.
So you have to ask yourself if you believe this by simply running the same programme
that you have done on the data and checking that you get the same results. Now,
this is the new ingredient that we are in a bug flu that is stressing out much further than you expect and that you have to deal with that adequately,
that makes us non-competitive and observers. We therefore cannot afford to analyse the data as we have been doing all this time
using a model that was set up one hundred years ago and is no longer fit for purpose.
We have to take that into account, and when we do so, we find rather astonishing results.
This is due to appear. So this is literally hot off. The press is due to appear on Monday in astronomy and astrophysics letters.
And the standard assumptions are questionable, but the good news is that some of those objects that are showed in that slide the nuclear satellite,
the Large Synoptic Survey Telescope, the square kilometre array chips, they mentioned that our department is involved in these.
This will enable definitive tests because they will provide us the kind of data that we need.
So to date, we have all these 740 or 2000 supernovae, and this history will give us 10000 supernovae per year.
Right. So I should live that long, but this is something worth waiting for.
So I leave you with the words of two famous physicist, Lev Landau, who was often wrong himself, by the way.
But that's what he thought of cosmology. But I think the last word really belongs to Wolfgang Pauli.
It's not even wrong. Thank you.