My younger boy John Dominic came home the other day, declaiming how good the books were on sale at Broadway Books. In point of fact, it was his way of getting to go on a walk with me and Michael Kepler, his older brother. When Michael Kepler said he didn’t want to go, my going to look at the books John Dominic himself had said were good, got a pass from John Dominic.
Well, when I went anyways, there were books I bought because I felt sorry for Broadway Books to have to get rid of such a stinker. But there was one, called The Universe [J. Brockman, ed., Harper Perennial 2014], which precipitated this post.
It is as good a report as we can get on what’s the state of play in scientific cosmology (the one that astronomers do; that science of cosmology) today. John Brockman, the editor, has assembled quite a few scientific readers [ examples, only a few: Ways of Knowing, Creativity, Greatest Inventions of the Past 2,000 Years, The Next Fifty Years, The New Humanists, among others] earlier in his career, and for this one he has got Brian Greene, Alan Guth, Andrei Linde, and Frank Wilczek — the last is he who explains cosmology to the readers of Physics Today, and I have learned quite a lot from his essays.
So I opened the book and decided to share with you, the reader, the first part of what was written by Lawrence Krauss. Wikipedia says:
[Lawrence] Krauss mostly works in theoretical physics and has published research on a great variety of topics within that field. His primary contribution is to cosmology as one of the first physicists to suggest that most of the mass and energy of the universe resides in empty space, an idea now widely known as “dark energy”. Furthermore, Krauss has formulated a model in which the universe could have potentially come from “nothing,” as outlined in his 2012 book A Universe from Nothing. He explains that certain arrangements of relativistic quantum fields might explain the existence of the universe as we know it while disclaiming that he “has no idea if the notion [of taking quantum mechanics for granted] can be usefully dispensed with”. As his model appears to agree with experimental observations of the universe (such as of its shape and energy density), it is referred to as a “plausible hypothesis”.
This guy focuses on just the unexplained, central issues in cosmology. He is respected by his peers. The fact that he serves as faculty member at Arizona State University does not do justice to his prestige within the field.
His first sentence addresses his prestige:
I just returned from the Virgin Islands, from a delightful event, a conference in St. Thomas that I organized with twenty-one physicists.
There follows a list of names, which I spare the reader.
The point of the list of names, as the reader might expect, is to establish the professional reputation of the author, who invited them. Three Nobel Prize laureates, et cetera — all these leaders in physics (especially astrophysics) came when Krauss invited them.
I came away from this meeting
After establishing his authority, the writer tells us of the results he values
realizing that the search for gravitational waves may be the next frontier.
He then makes a rhetorical move which is unusual:
For a long time, I pooh-poohed it in my mind, because clearly it’s going to be a long time before we could ever detect them, if they’re there.
Rather than buttress his authority by saying that he’d known the search for gravitational waves was key all along, he not only denies such foreknowledge but uses a colloquialism to describe his reaction.
The thing is, this is a dog-whistle. Most observers remain to be convinced that the LIGO project will work: your Intrepid Reporter has had grave doubts that, on a plastic, moving Earth, any distance of two miles can ever be measured to the accuracy of the diameter of a proton. Mr Krauss’s demurral is a signal to other (perhaps not-necessarily professional) physicists. Now some of the top physicists in the world say, that we’re only looking for the high-frequency signal, and who knows but these organizers of the multi-billion-dollar project might be right; but if Mother Nature provides the earthquake-generating terrestrial crust with a high-frequency signal of any kind, we’re never going to find gravity waves.
Lawrence Krauss is saying he’s just a down-home guy, like you or me. He used to pooh-pooh gravity waves, too. He continues
It’s been very frustrating for particle physicists
not that, mind, our author is a particle physicist.
— and some people might say it’s led to sensory deprivation which has resulted in the hallucination otherwise known as string theory
It may not be scientific prose, to call your opponents insane — well, suffering from hallucinations — but that’s another dog-whistle. Mr Krauss is well-known in the profession of physics for having led the charge for some years against the popular theoretical school of String Theory. Here Mr Krauss is re-establishing his down-home guy kind of persona. But then he says, regarding the current state of play in cosmology, We Have No Idea.
And that could be true. But in cosmology what we’re having now is this cockamamie universe. We’ve discovered a tremendous amount. We’ve discovered the universe is flat
— that is, in a General Relativistic structure of space, there’s no curvature —
which most of us theorists thought we knew in advance, because it’s the only beautiful universe.
— our author, like most theorists, is not short on the self-confidence required to advise God on the aesthetic features of prospective universes. But that is prologue. Lawrence Krauss is going, dear reader, to get you up to speed on the latest in cosmology. His next sentence is
“But why is it flat? It’s full of not just dark matter but this crazy stuff called dark energy that no one understands. This was an amazing discovery, in 1998 or so.”
The fact is, we have yet to explain observational evidence from sixteen years ago. That’s the latest word on cosmology, ladies and gentlemen.
The administration of Portland Public Schools was at that time more generous with teacher enrichment then than it is now, so Mister Charles (everyone called him ‘Chuck’) Martell and Your Intrepid Reporter attended, at School District expense, just two Grant High School physics teachers keeping abreast of modern developments, the 1998 American Physical Science annual meeting. We heard first-hand the eventual 2011 Nobel Prize Laureate Saul Perlmutter discuss his discovery of the so-called “dark energy.”
The rest of Krauss’s piece is devoted, at some length, to saying We Don’t Know. His immediately following paragraph begins
What’s happened since then is that every single experiment agrees with this picture without adding insight into where it comes from.
We’ve got this weird antigravity in the universe which is making the expansion of the universe accelerate. Now, if you plug in the equations of general relativity, the only thing that can anti-gravitate is the energy of nothing. Now, this has been a problem since I’ve been a graduate student [emphasis added —MM]. It was such a severe problem that we never talked about it.
Here we are. The same old problem. No known solution. Problems “that we never talk about” are the genuine, the authentic ones. They are the protivopolozhnosti of the Russian Marxists — and may I say here that the writings of the Russian Marxists of the Twentieth Century are full of wisdom? Continuing directly,
When you apply quantum mechanics and special relativity, empty space has energy; the problem is, way too much energy: 120 orders of magnitude more energy than is contained in everything we see!
Lawrence Krauss is a valuable public voice for theoretical physics because he has honesty: sufficient honesty to admit We Don’t Know. This is, he says, The Worst Prediction in Physics.
Now, that’s the worst prediction in all of physics. You might ask, “If that’s such a bad prediction, then how do we know empty space can have energy?” The answer is, “We know empty space isn’t empty, because it’s full of these virtual particles that pop in and out of existence, and we know that because if you try and calculate the energy level in a hydrogen atom
— that’s junior year undergraduate school (or it was when I was a teen-aged whiz kid with oodles of potential — something which, I have to admit, now that I am 68 years old, I am no longer) material, calculating the energy levels in a hydrogen atom —
and you don’t include those virtual particles, you get a wrong answer.”
There were, ladies and gentlemen, Virtual Particles before there was Virtual Reality.
One of the greatest developments of 20th-century physics was the realization that when you incorporate special relativity into quantum mechanics
Okay, dear reader, do not panic. Your Intrepid Reporter has made a particular study of that little — ahem — transition. Let us at this point simply take Mr Krauss’s word for it that it is indeed worth a moment of silence.
you have virtual particles that can pop into and out of existence and they change the nature of a hydrogen atom —
Well, you know, when you’re a natural scientist and you start to talk about “change[ing] the nature of a hydrogen atom,” and you’re writing in a Harper Perennial Edition, and you just said it’s the — well, one of the — greatest development in 20th-century physics. . . well, the art of rhetorical device can do no more to emphasize the importance, to the speaker, of the next few words.
because a hydrogen atom isn’t just a proton and electron. That’s the wrong picture, because every now and then you have an electron-positron pair that pops into existence.
Now Your Intrepid Reporter is obliged to do a bit of Establishing Personal Authority. Go to any Portland Public School secondary school. Go to the School Library. Ask to see the most recent encyclopedia. Turn to Wolfgang Pauli, the inventor of Pauli Exclusion Principle, and look who wrote the article. C’est ça, c’était moi.
This business of an electron-positron pair coming into existence as a consequence of (ahem, drum-roll, please) quantum mechanics was sussed out first by Enrico Fermi, the teacher of my teacher of physics at Caltech, Rochus Vogt
(a major character in Collins’s book, parenthetically). Now that I see his old face again, I recall his tag line during lectures. In his strongest accent he would growl, “Fizzixs iss not chest haffinck a Tcherman akksent!” whenever he recalled learning from one of the greatest physicists of the twentieth century, Fermi. Sigh. When I wanted to name that younger son of mine “Enrico Fermi Meo” it was vetoed; I can still recall my older sister Margaret’s verdict: “a little too ethnic, don’t you think?”
Ah, but to return to Fermi’s greatest accomplishment. Really, folks, it was only one of many.
You know the Heisenberg Uncertainty Principle. You cannot know precisely both the position and velocity of a particle? The equation (∆x)(∆v) ≈ h is the way this is written: the product of the uncertainty in position (∆x) and that of the uncertainty in the velocity (∆v) is pretty much equal to Planck’s Constant — a very small number, but not zero.
Fermi rewrote that relationship. Rochus Vogt suggested, and my teacher of quantum mechanics here at Portland State University, Peter Leung (who won a University Award for excellence of teaching), confirmed, that Fermi by the use of the heuristic method of dimensional analysis came up with the equation
(∆E)(∆t) ≈ h , that is, the product of the uncertainty of the energy with the uncertainty in time, is not zero.
I leave for some other occasion the less-than-airtight mathematics of the derivation. Suffice it at this point to say, that for a very short period time you are able to have sufficient variance in the energy level that a low-energy pair of particles, the electron-positron pair — which for good measure are half matter and half anti-matter — can exist; indeed, as Professor Krauss reminds us, must exist if you want the calculations, which as a junior came out approximately right, to be exact in your first year of graduate school.
And the electron is going to want to hang around near the proton. Because it’s oppositely charged, the positron is going to be pushed out to the outskirts of the atom, and while they’re there
— some quadrillionth of a second —
they change the charge distribution [sic. original has ‘charged distribution’] in the atom [it’s calculated for the hydrogen atom, but it’s true for all atoms — MM] in a very small but calculable way. Feynman and others
You know, there are Nobel Prize winners and there are Nobel Prize winners. There was Doug Osheroff, who sat around the dorm lounge fire with the rest of us, and who improved the sensitivity of an experimental device measuring a new effect by a factor of one hundred in a few weeks — he won a Nobel. But Feynman was one of the greatest scientists of the twentieth century. Simply for Krauss to say that Feynman participated in this calculation, is to add to its cachet.
calculated that effect, which allows us to get agreement between theory and observation at the level of nine decimal places.
And just to rub it in, Krauss repeats it’s the best agreement between theory and observation in all of science here, twice.
So, you see, Krauss tells us that the vacuum energy is the Worst Problem in Physics, and that the present understanding, which we owe (I add) to Enrico Fermi and (Krauss points out) Richard Feynman, is the closest agreement ever, between what we predict and what we find. The present understanding is that the energy of the vacuum must be identically zero, and the 1998 discovery of Dark Energy challenges that.
This flies in the face of all conventional wisdom in theoretical physics. It’s the most profound shift in thinking, perhaps the most profound puzzle, in the latter half of the 20th century, and it may be so for the first half of the 21st century, or maybe all the way to the 22nd century.
And a few pages further on in his lament,
Right now, it’s clear that what we really need is some good new ideas. Fundamental physics is at kind of a crossroads. The observations have just told us that the universe is crazy but haven’t told us what direction the universe is crazy in. The theories have been incredibly complex and elaborate but haven’t yet made any compelling inroads.
so, as the sun sinks slowly in the West, ladies and gentlemen, we hear metaphorically the last words of the great anti-war novel, All Quiet on the Western Front, “Nichts neues im Westen”. Nothing new in the West. That on a day when the last of the soldiers the novel followed throughout the War had been shot and killed.