A Dark Expletive

A news item today about BOSS (yet another observational cosmology survey) gives me an excuse to recycle an idea from an old post.

The phrase expletive deleted was made popular at the time of Watergate after the release of the expurgated tapes made by Richard Nixon in the Oval Office when he was President of the United States of America. These showed that, as well as been a complete crook, he was practically unable to speak a single sentence without including a swear word.

Nowadays the word expletive is generally taken to mean an oath or exclamation, particularly if it is obscene, but that’s not quite what it really means. Derived from the latin verb explere (“to fill out”) from which the past participle is expletus, the meaning of the word in the context of English grammar is  “something added to a phrase or sentence that isn’t strictly needed for the grammatical sense”.  An expletive is added either to fill a syntactical role or, in a poem, simply to make a line fit some metrical rule.

Examples of the former can be found in constructions like “It takes two to Tango” or “There is a lot of crime in Nottingham”; neither  “it” nor “there” should really be needed but English just seems to like to have something before the verb.

The second kind of use is illustrated wonderfully by Alexander Pope in his Essay on Criticism, which is a kind of guide to what to avoid in writing poetry. It’s a tour de force for its perceptiveness and humour. The following excerpt is pricelessly apt

These equal syllables alone require,
Tho’ oft the open vowels tire;
While expletives their feeble aid do join;
And ten low words oft creep in one dull line

Here the expletive is “do”,  and it is cleverly incorporated in the line talking about expletives, adding  the syllable needed to fit with a strict pentameter. Apparently, poets often used this construction before Pope attacked it but it quickly fell from favour afterwards.

His other prosodic targets are the “open vowels” which means initial vowels that produce an ugly glottal sound, such as in “oft” (especially ugly when following “Tho”). The last line is brilliant too, showing how using only monosyllabic “low” words makes for a line that plods along tediously just like it says.

It’s amazing how much Pope managed to fit into this poem, given the restrictions imposed by the closed couplet structure he adopted. Each idea is compressed into a unit of twenty syllables, two lines of ten syllables with a rhyme at the end of each. This is such an impressive exercise in word-play that it reminds me a lot of the skill showed by the best cryptic crossword setters. Needless to say I’m no more successful at writing poetry than I am at setting crossword clues.

Anyway, what’s all this got to do with cosmology?

Well, I was reminded of it when I attended the 2012 Gerald Whitrow Lecture by Andrew Liddle last Friday at the Royal Astronomical Society, during which he talked, amongst other things, about Dark Energy.

The Dark Energy is an ingredient added to the standard model of cosmology to reconcile  observations of a flat Universe with a matter density that seems too low to account for it.

Other than that it makes the  cosmological metric work out satisfactorily (geddit?), we don’t understand what Dark Energy really is  or why there is as much of it. Indeed, many of us would rather it wasn’t there at all, because we think the resulting model is inelegant or even ugly, and are trying to think of other cosmological models that do not require  its introduction.

In other words, Dark Energy is an expletive (though not one that’s been deleted).

Incidentally, one of the things Andrew said in his talk – and I agree with him 100% – is that in some sense we already know enough about dark energy from observations that we know we don’t understand it at all from a theoretical point of view. Bigger and better surveys, such as Euclid, producing more and more data will characterize its properties with greater statistical accuracy, but they won’t on their own solve the Dark Energy puzzle. For that we need better theoretical understanding.

My own view is that the problem of the vacuum energy is of the same character as the ultraviolet catastrophe that ushered in the era of quantum physics: a big problem that needs a big solution. What I mean by that is that it’s not something that can be resolved by tinkering with the existing theoretical framework. Something much more radical is needed.


26 Responses to “A Dark Expletive”

  1. Anton Garrett Says:

    Furthermore there is a difference between swearing and foul language. (The Victorian euphemism for foul language, “uttering oaths”, makes the distinction clearer.)

  2. If say cosmic acceleration is the equivalent of the ultraviolet catastrophe, what we want is a few other bits of jigsaw puzzle – equivalents of the photo-electric effect, brownian motion, or the Balmer series. Otherwise we will be inundated with lots of lovely whacky new ideas and won’t know which is right…

  3. “It’s amazing how much Pope managed to fit into this poem, given the restrictions imposed by the closed couplet structure he adopted.”

    The German word for poetry is “Dichtung”. This also means “compression”, i.e. compressing a lot of meaning into a small space. A similar construction is the English “pun”, which is related to “pound” in the sense of “pounding an additional meaning into the word”.

  4. Fairport Convention have an album entitled Expletive Delighted, with a cover showing black bars over the musicians’ mouths. It’s an instrumental album.

  5. Bryn Jones Says:

    Andrew Liddle called in his lecture for significantly increased funding for theoretical research in cosmology. I’m not sure I’d agree entirely as the last thing we need is more speculative theories that are beyond observational tests. What we need is new theory that is relevant. It is unclear whether we are now at a time in history when significant relevant theoretical developments can be made.

    It’s also unclear whether the analogy with the ultraviolet catastrophe in physics at the end of the 19th century applies fully here. What happened with the ultraviolet catastrophe, of course, was that quantum theory quickly came along as a response. However, it is not clear that we are about to get a similar theoretical leap in explaining modern cosmological observations. Maybe we shall get it, aided by extra funding. On the other hand, perhaps we shall not. Who knows?

    • Maybe to come up with good theories which can be tested one needs some funding. 🙂

      Obviously, we can’t know whether the parallel with the ultraviolet catastrophe is correct or not since in that case the solution was completely unexpected. Before quantum theory came along, it was also not clear that a theoretical leap was soon to come.

      On the other hand, since it was just a few years ago that the mz relation was finally used to measure the cosmological parameters, one could argue that, until that time, practically all of theoretical cosmology was beyond observational tests. As Longair wrote in an article for the QJRAS (how I miss that journal!), when he started, there were only two-and-one-half facts in cosmology, as Peter Scheuer told him. When he wrote the article, there were 9. Today, cosmology is data-driven.

      One reason why there is so much progress in cosmology today is because in the times before there was much data, all one could do was theory, so when the observations came along, it was literally textbook stuff to interpret them. (Not to belittle the efforts, of course: there was a tremendous amount of work in observing, data reduction, coordinating things and battling Rocky Kolb—enough to be worth a Nobel Prize, in fact—but the point is that last year’s Nobel Prize wasn’t awarded for theory.)

    • Yes, the change in cosmology over the past few decades has been dramatic, starting with number counts of radio galaxies and the discovery of the cosmic microwave background, up to the data-driven situation today.

      I like the history of science: we can look back at how people found themselves confused in the past, but can do so knowing the truth. The history of science can provide parallels with the current state of science. The only trouble is that we do not which examples from history are the parallels to our situation today.

  6. So are none of the theoretical ideas so far put up by the order(1000) theoretical cosmologistsworking on the problem in, out and way out of the mainstream radical enough?

  7. Start by throwing out the big bang model, and you have something. Seems silly to hold onto it when we are finding new ways for the universe to expand with out it. Big Bang theory violates pretty much every law of physics, and has little to no predictive power.

    • telescoper Says:

      The Big Bang model accounts for the vast majority of cosmological observations quite successfully and doesn’t violate any laws of physics – how could it? It’s based on them!

      • Big bang theory was invented to explain cosmic expansion. It violates conservation of mass, conservation of energy, and all laws of thermodynamics. Even with that you need to bolt on “inflation” to make it actually work. It seems that with these new ways for the universe to expand under dark energy/matter, you don’t really need the big bang to explain expansion anymore. When new data comes in, you need to question your original assumptions at some point. Big bang may turn out to be correct in the end, but accelerated expansion of the universe in the future was not something that the big bang predicted. Far from it. Whoever steps up and explains what is really going on, will be someone who is willing to think outside the box of standard big bang cosmology.

      • telescoper Says:

        Rubbish. The Big Bang theory is consistent with conservation of energy (when expressed in the appropriate relativistic fashion) and with other aspects of thermodynamics. The basic equations involving accelerated expansion were derived by Friedman and Lemaitre in the 1920s, before the expansion of the Universe was established via observations. Read a textbook. I’ll accept criticisms of the theory when they are apt, but not from someone who doesn’t know what they are talking about.

      • I just wish Telescoper would instead use that level of criticism against those people who criticise, on the basis of little understanding, anthropogenic global warming on his blog.

  8. Please explain how the big bang is consistent with the 2nd law of thermodynamics. Please explain the abundance of matter over anti-matter in the context of the big bang. What known and tested physics can account for the magic period called inflation that is required to even get the big bang model to work. Did the big bang predict the existence of dark matter/dark energy? These are all valid reasons to question the big bang as it stands today.

    • telescoper Says:

      No. They’re not. If you took the time even to a cursory google you would find answers to your questions about the baryon asymmetry and the 2nd law of thermodynamics; there’s a lot of literature on both of those topics. It’s not my job to do the work for you.

      Inflation is a relatively recent and more speculative addition to the Big Bang theory. The inflaton field has not yet been identified. There’s no really convincing proof that inflation actually happened, although it’s a very neat idea and is based on good physical arguments. This is work in progress. If we knew all the answers we wouldn’t have to keep working at it.

      As for predictions, the Big Bang requires the existence of dark matter and dark energy in order to reconcile theory and observations. I don’t think you can say that it predicts them and I don’t even think dark energy has been proven to exist yet. They’re things we don’t understand. What we need is more work and more evidence. That’s science for you.

      Incidentally, did the theory of natural selection predict the existence of the armadillo? If not, do you reject the idea?

  9. I am afraid that the constellation of Taurus is the most promising place to look for dark matter.

  10. Speaking of supersymmetry: I claim that my wife is a superpartner.

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