## The IKEA Universe

I heard yesterday the sad news of Ingvar Kamprad, the founder of Swedish furniture chain IKEA.  People can be very snobbish about IKEA, but its emphasis on affordable design has been a boon for people on low incomes for many years. When I was an impoverished postdoc living in London I used it a lot, especially their Billy bookcases. I also have a very sturdy Omar in my bedroom…

I remember years ago  that while shopping in the IKEA at Neasden I discovered that they were running a competition, for which entrants had to complete the sentence:

I shop at IKEA because…

My entry completed it thus:

I shop at IKEA because it’s as cheap as fuck.

I didn’t win.

But I digress. Not many people are aware that IKEA also furnishes  important insights into modern cosmology, so I’ll try to explain here. I’ve blogged before about the current state of cosmology, but it’s probably a good idea to give a quick reminder before going any further. We have a standard cosmological model, known as the concordance cosmology, which accounts for most relevant observations in a pretty convincing way and is based on the idea that the Universe began with a Big Bang.  However, there are a few things about this model that are curious, to say the least.

First, there is the spatial geometry of the Universe. According to Einstein’s general theory of relativity, universes come in three basic shapes: closed, open and flat. These are illustrated to the right. The flat space has “normal” geometry in which the interior angles of a triangle add up to 180 degrees. In a closed space the sum of the angles is greater than 180 degrees, and  in an open space it is less. Of course the space we live in is three-dimensional but the pictures show two-dimensional surfaces.

But you get the idea.

The point is that the flat space is very special. The two curved spaces are much more general because they can be described by a parameter called their curvature which could in principle take any value (either positive for a closed space, or negative for an open space). In other words the sphere at the top could have any radius from very small (large curvature) to very large (small curvature). Likewise with the “saddle” representing an open space. The flat space must have exactly zero curvature. There are many ways to be curved, but only one way to be flat.

Yet, as near as dammit, our Universe appears to be flat. So why, with all the other options theoretically available to it, did the Universe decide to choose the most special one, which also happens in my opinion to be also the most boring?

Then there is the way the Universe is put together. In order to be flat there must be an exact balance between the energy contained in the expansion of the Universe (positive kinetic energy) and the energy involved in the gravitational interactions between everything in it (negative potential energy). In general relativity, you see, the curvature relates to the total amount of energy.

On the left you can see the breakdown of the various components involved in the standard model with the whole pie representing a flat Universe. You see there’s a vary strange mixture dominated by dark energy (which we don’t understand) and dark matter (which we don’t understand). The bit we understand a little bit better (because we can sometimes see it directly) is only 5% of the whole thing. The proportions do look very peculiar.

And then finally, there is the issue that I have ablogged about (here and there) previously, which is why the Universe appears to be a bit lop-sided and asymmetrical when we’d like it to be a bit more aesthetically pleasing.

All these curiosities are naturally accounted for in my New Theory of the Universe, which asserts that the Divine Creator actually bought  the entire Cosmos  in IKEA.

This hypothesis immediately explains why the Universe is flat. Absolutely everything in IKEA comes in flat packs. Curvature is not allowed.

But this is not the only success of my theory. When God got home He obviously opened the flat pack, found the instructions and read the dreaded words “EASY SELF-ASSEMBLY”. Even the omnipotent would struggle to follow the bizarre set of cartoons and diagrams that accompany even the simplest IKEA furniture. The result is therefore predictable: strange pieces that don’t seem to fit together, bits left over whose purpose is not at all clear, and an overall appearance that is not at all like one would have expected.

It’s clear  where the lop-sidedness comes in too. Probably some of the parts were left out so the whole thing isn’t  held together properly and is probably completely unstable. This sort of thing happens all the time with IKEA stuff. And why is it you can never find the right size Allen Key to sort it out?

So there you have it. My new Theory of the Universe. Some details need to be worked out, but it is as good an explanation of these issues as I have heard. I claim my Nobel Prize.

If anything will ever get me another trip to Sweden, this will…

### 21 Responses to “The IKEA Universe”

1. Splutter! Hot coffee everywhere!
The ikea universe is a very good name, but I feel bound to point out that the standard model does *not* say the cosmos began in a Big Bang. The model says nothing about origins, leaving the field open for people like me to blather about emergent universes, cyclic universes etc!

• telescoper Says:

There was a bang. We can see the sound waves!

• It depends on the definition, of course. I think most cosmologists think of the Big Bang as a state approximately a Hubble time ago (which seems to be a coincidence, as the naive extrapolation back to a singularity is in general not the Hubble time) in which the universe was much denser, hotter, and more uniform than today. I doubt that many if any believe that it literally began with a singularity.

Max Tegmark has a useful definition: the Big Bang is not when something started, but rather when something stopped, namely inflation.

2. “it’s”

That hurts! Call a surgeon and get it removed!

3. “I also have a very sturdy Omar in my bedroom…”

Now discontinued, there once really was* a bed called Gutvik, which speakers of German will appreciate.

* Many stories about badly chosen product names are not true; the Chevy Nova did not bomb in Mexico because it means “does not go” in Spanish. Some are true, though, or, more commonly, names are different in different countries. What is known most places as the Mitsubishi Pajero, for example (Shogun in the UK), is called the Montero in Spanish-speaking countries, since Pajero means “wanker”. Which reminds me, a bloke once seriously suggested to me that Jodrell Bank should change its name because of Cockney rhyming slang. 😐

4. “If anything will ever get me another trip to Sweden, this will…”

I once applied for a job at IKEA. I got as far as the interview (which was about 5 hours, after which I was convinced that my level of Swedish was acceptable), but didn’t get the job. Why IKEA? They are a big user of the VMS operating system.

5. “Yet, as near as dammit, our Universe appears to be flat. So why, with all the other options theoretically available to it, did the Universe decide to choose the most special one, which also happens in my opinion to be also the most boring?”

I wrote an entire paper about that. In summary: the classical flatness problem, as formulated by Dicke and Peebles (interestingly in a conference contribution; I don’t think there was ever a refereed-journal paper, though of course many refereed-journal papers have cited Dicke and Peebles), is essentially bogus. Cast in terms of “why is Omega near 1”, it is no surprise that it is not 1 million, or 1 millionth. This was the original flatness problem.

Back when Dicke and Peebles mentioned this, Omega wasn’t constrained better than to a couple of orders of magnitude. We now know that the universe is very, very close to being flat. My argument can’t explain this, though an argument due to Lake (cited in my paper) perhaps can. This is really a new, different, flatness problem. The fact that it exists has tended to confuse the issue and obscure the fact that Dicke and Peebles got it wrong, which actually Coles and Ellis (and also Evrard and Coles) come close to saying in a slightly different context. Of course, inflation can explain the new flatness problem (and thus, trivially, the older, less severe one, which of course does not imply that the older one actually exists).

• I think the best illustration that the original flatness problem is bogus is due to Adler and Overduin (Gen.Rel.Grav.37:1491-1503,2005). In particular, read section 6.

Neither my argument, nor that of Adler and Overduin, nor that of Lake (who, along with Dyer, was a doctoral student of Roeder, who in turn was a student of McVittie, a student of Eddington) has made much impact. On the other hand, as far as I know no-one has ever published a counter-argument. Usually, wrong ideas on arXiv get shot down (usually by more than one person) within a few weeks. My theory is that everyone is afraid of Rocky Kolb. 😀

6. The second link is wrong.

7. Should be ikea.com, not ikea,cin.

8. Nigel Foot Says:

I loved reading this although I didn’t understand any of the cosmology!

9. Anthony Garrett Says:

Idioten
Kaufen
Etwas
Alles

• telescoper Says:

I thought it was ‘Idioten Kaufen Einfach Alles’…

• The second is more grammatical, though “einfach” should not be capitalized, “alles” also probably not.

10. Second link is still broken!

11. Phillip: I have 2 Dicke refs for this, neither of them strictly journal refs:
Dicke, R. H. 1970. Gravitation and the Universe: Jayne Lectures for 1969. American Philosophical Society.
Dicke, R. H. and P.J.E. Peebles 1979. The big bang cosmology – enigmas and nostrums. In
General Relativity; an Einstein Centenary Survey (Eds S.W. Hawking and W. Israel) Cambridge University Press pp. 504 – 517

• The second one is the “standard reference” for this.

I’m looking for an article (some sort of historical review) which mentions Dicke arguing against a long coasting phase in order to explain the peak in QSO redshifts (now known to be a selection effect) on the grounds that it would imply fine-tuning. The article also has a picture of Dicke and I believe others as well. The irony is that while his argument is correct, it is also essentially the same as Lake’s argument against the flatness problem, since a coasting universe is significantly non-flat. Keep in mind that the radius of curvature is always in relation to the Hubble length. If the Hubble constant goes down, as in a coasting phase, then the Hubble length goes up, as do lambda and Omega, making the relative radius of curvature go down, hence a non-flat universe. Of course, during the coasting phase nothing about the physical geometry changes. Dicke apparently didn’t realize that this implies, at least for a positive cosmological constant, that it is the non-flat universe which is fine-tuned, not the flat universe.

Perhaps someone has also read the paper and provide me with the reference!

12. I have recently had a paper “A problem with the analysis of type Ia supernovae” published in Open Astron : 2017; 26; 111-119 (arXiv 11711.11237 which includes some minor corrections). The major conclusion is that an analysis of the original observations of the light curves of type Ia supernovae(i.e.without SALT2 corrections) show that there they are completely inconsistent with an expanding universe and favour a static universe. The regression equation for the widths is width=(0.998 +\- 0.004) + (0.048 +/- 0.016)z. In this this case the universe is not flat and it is not expanding.