Posted tagged ‘Cosmology’

The Most Exciting Sentence I’ve Read This Decade…

March 18, 2014

…Would be this one:

 We find an excess of B -mode power over the base lensed- CDM expectation in the range 30 < ` <  150, inconsistent with the null hypothesis at a significance of >  5 δ.

That’s from the abstract to this paper, released yesterday, in which the team using the BICEP microwave detector at the South Pole reports on their analysis of three years of data taken from 2010-2012.

So what’s that all about?  It’s the best evidence yet that a fundamental pillar of Big Bang cosmology is right, that a concept named inflation does in fact describe what happened within the first instant of the formation of our universe.  Here’s how Alan Guth, the inventor of the idea describes it:

This theory is a new twist on big bang theory, proposing a novel picture of ho the universe behaved for the first minuscule fraction of a second of its existence.

The central feature of the theory is a brief period of extraordinary rapid expansion, of inflation,  which lasted for a time interval perhaps as short as 10^-30 seconds.  During this period the universe expanded by at least a factor of 10^25, and perhaps a great deal more. [Alan Guth, The Inflationary Universe, p. 14.]

Guth’s initial version of inflation theory has been refined significantly since its origins in the late 1970s, and in its modern form inflation has become part of the basic toolkit of cosmological investigation.  The universe we observe doesn’t make sense unless something occurred to explain, for just one example, the way the universe looks basically the same everywhere, when viewed on the largest scale.  Inflation as the idea has evolved has become the best available explanation (though there have been competing models) for this and other observed cosmological properties.  But the challenge has been to find some tell-tale sign that shows* that inflation actually happened.

It’s been clear for a long time where such signs might lie:  in the cosmic microwave background (CMB),  a snapshot of the cosmos taken at a moment called “recombination,” when the universe cooled down enough to permit electrons and protons to come together to form (mostly) neutral hydrogen atoms.  Photons — light — that up till that moment had been embraced in electromagnetic dances with charged particles were then unshackled to fly freely through space, carrying with them the traces of where they’d been just before that liberation — which came just 380,000 years after the big bang.


Over time (13.8 billionyears), thatextremely hot (energetic) spray of light has cooled to 2.7 Kelvins — 2.7 degrees above absolute zero — and is now detectable as those very long wavelengths of light called microwaves.  This  microwave background was identified in 1965 as a generalized blur covering the entire sky; increasingly sophisticated measurements have revealed more and more detail.  Over the last twenty fiveyears those observations have turned into a probe of what happened between the big bang and the flash of the CMB itself:  each newly precise measurement constrains the possible physics that gave rise to the details thus revealed.  Step by step, each new level of detail narrow the options for what could have occurred during the big bang era — and the chain of events that lead from cosmic origins to us becomes increasingly clear.

In the 1990s,  improving resolution of CMB images revealed spots on the sky where there is slightly more energy in that microwave background — corresponding to regions in the early universe with slightly more matter-energy than surrounding regions.  Such variations account for why there are lots of galaxies full of stars in some places, and vast voids in other:  over millions and billions of years, gravity can work on very slight variations in initial density to sort matter into that kind of pattern.

With the advance of both space and ground based microwave imagers, it’s become possible to sample the CMB in vastly greater detail, and thus uncover much more than the simple (easy for me to say) evolution of structure in the universe.  For example, CMB researchers have identified several acoustic peaks in the background — literally, the ringing of the early universe, pressure waves produced by the interaction of light and matter in the very early universe.  The particular properties of those peaks reveal basic facts about the universe — and help distinguish between different theories about how we get the cosmos we inhabit from the big bang whose traces we see in the CMB.

Before today, the state of play was that CMB results were most consistent with the  predictions of inflation, compared with other candidate ideas.  At the same time though, observations that are consistent-with are not the same as direct observations of the cosmological equivalent of the miscreant’s fingerprints on the knife.  That’s what the BICEP results deliver.

In simplest terms:  modern theories of cosmic inflation say that immediately after some tiny perturbation occurs that marks the birth of a universe, it gets pulled apart by inflation — which you can think of as negative gravity, a gravitational field that stretches space-time.  The inflationary episode is so powerful that it expands the infant universe by orders of magnitude in fractions of a second — as some say, inflation provides the bang in the big bang — and it’s so violent that as space-time undergoes such wild tugs, ripples form.  Those ripples are gravitational waves — predicted by Albert Einstein, inferred from the behavior of pulsars, but never detected directly.  An observation of such primordial fluctuations, variations in the strength of the gravitational field from point to point in the early universe, would offer the first direct glimpse of traces of an inflationary episode marking the birth of our cosmos.

And that’s what BICEPs results contain:  the team led by John Kovac at the Harvard – Smithsonian Center for Astrophysics, Clem Pryke at the University of Minnesota, Jamie Bock at Caltech/JPL, and Chao-Lin Kuo of Stanford and SLAC report the detection of the signature of gravity waves in the CMB with the properties corresponding to those predicted to be produced by inflation.

In slightly more detail, the BICEP experiment observed a particular pattern of polarization in the light (microwaves) of the CMB that inflation would be expected to produce.   (Many more details:   web resources from the BICEP team and partner institutions;  quick semi-technical gloss on the results from Sean B. Carroll;  Matt Strassler’s take; Dennis Overbye’s account in the NYT.)

One key caveat before the wind up:  this is one result from one group.  It is reported with great confidence (that five sigma claim).  But something this big needs independent confirmation — data from the Planck satellite for example, or more ground based observations from other microwave detectors.  This isn’t yet a done deal.

Such confirmation (or disproof) will come fairly quickly — a few years at most.

In the meantime, assuming the data do hold up, what would that mean (forgive me) more cosmically?

At the very least:  that we now understand in previously unattainable detail how our current habitat emerged from nothing (or better, “nothing”).  That the idea of a multiverse — other patches of space time that underwent an inflationary episode to form island universes of their own — has now gained a boost (if one patch of space-time can inflate, so could others)….

…or to put in mythic terms:  there is grandeur in this view of life (the cosmos).  Paraphrasing an old friend, astronomer Sandra Faber, with this new, richer, more fully realized picture of the birth of the universe we have once again enriched that creation story that only science tells, the one that connects the earth we inhabit today with a process of cosmic evolution that we now can trace back all the way to just the barest instant this side of the point of origin.

A good day.

*To a close approximation — this is physics.  You want certainty, become a mathematician.

[Thanks to Dr Katherine J. Mack of the University of Melbourne, aka @AstroKatie, who helped make sure no egregious errors slipped through.  Any mistakes, major or minor, that remain are mine, all mine.]

Image:  J. W. M. Turner, The Beacon Lightc. 1840

PS:  Bonus video showing one of the founding architects of inflation theory receiving news of the result:

Cosmology does note equal Cosmogony — or why Andrew Sullivan has got to stop invoking his cartoon of science when he seeks to defend his faith.

June 1, 2010

Another post resurrected from the month (or so) of my discontent:

From Sullivan, an essaylet on the nature of God and the foundations of faith, which contains this argument:

For me, the core argument for some force behind the universe, revealed metaphorically in Scripture, is affirmed by science as we currently have it. Our universe came from nothing and is still expanding. What conceivable force made this possible?

I know Sundays are slow days in the blogging trade, but this is just awful.  Not as private faith, mind you — Sullivan has repeatedly affirmed his particular form of belief; it clearly is meaningful to him, rich in both emotional weight and in sufficient intellectual plausibility (to him) not to offend his personal experience.  But as an attempt to assert a less particularist claim, awful just begins to describe the rhetorical catastrophe above.

Unsurprisingly, what gets this blog’s goat is the invocation of science in defense of a cosmological Godhead.  Which means I’ll pass over in sort-of silence the bit of sleight of  hand in the first clause of the quoted passage, the notion that a metaphor of God (“some force behind the universe”) is the essence of what the text of scripture reveals of the deity.*

That said, the real sin of thought and word in the passage I quote comes when Sullivan writes the argument for a force behind the universe (whatever that actually means) “is affirmed by science as we currently have it.”

This is a nonsense. What does he mean by a force?  Is it anything like the meaning of the concept as it emerged in the specific science — physics — whose subdiscipline, cosmology, he is about to invoke?

Well, no, obviously.  And to give a little flesh to that blanket dismissal, consider Nobel laureate and my MIT colleague Frank Wilczek’s meditation on the notion of force as Isaac Newton first cobbled it together.

Some years ago, he wrote a three part essay, “Whence the Force of F=MA” in which he described force as a culture, or perhaps better, as a language. [Links here to all three sections] Sullivan would, I think, find some of what Wilczek writes quite comforting:

…the law of physics F=ma comes to appear a little softer than is commonly considered. It really does bear a family resemblance to other kinds of laws, like the laws of jurisprudence or of morality, wherein the meaning of the terms takes shape through their use. In those domains, claims of ultimate truth are wisely viewed with great suspicion; yet nonetheless we should actively aspire to the highest achievable level of coherence and explicitness. Our physics culture of force, properly understood, has this profoundly modest but practically ambitious character. (Essay III in the series)

If laws of morality and laws of physics are kissing cousins, as Wilczek seems to imply, perhaps there could be something to Sullivan’s claim (hope? — ed.) that the force of which physicists speak might have something to do with the Sullivan’s metaphor of God.

I’m putting thoughts in Sullivan’s mind here, of course, but the point I’m making is that analogies are tricky, and the use of implied ones even more so.

But the problem for Sullivan’s case is that Wilczek did not say that the content of  moral or civil laws mirror, even imperfectly, that of physical ones.  Rather, he simply stated that physics, more than usually understood, makes use of one of the most valuable habits of thought in the humanities:  some of what physicists “know” they learn through using an idea, rather than explicitly grappling with its inner tensions.

That’s fine, and true, and it is surely a trick used across lots of different intellectual approaches.  But for all of Wilczek’s kind bob in the direction of another division of the academy, when he gets down to the actual issue of  why such a “soft” concept of force has persisted in the famously “hard” discipline of physics, his answer embraces the nitty gritty of life as physicists actually lead it:

By comparison to modern foundational physics, the culture of force is vaguely defined, limited in scope, and approximate.  Nevertheless it survives the competition, and continues to flourish, for one overwhelmingly good reason: It is much easier to work with. We really do not want to be picking our way through a vast Hilbert space, regularizing and renormalizing ultraviolet divergences as we go, then analytically continuing Euclidean Green’s functions defined by a limiting procedure, . . . working to discover nuclei that clothe themselves with electrons to make atoms that bind together to make solids, . . . all to describe the collision of two billiard balls. That would be lunacy similar in spirit to, but worse than, trying to do computer graphics from scratch, in machine code, without the benefit of an operating system. The analogy seems apt: Force is a flexible construct in a high−level language, which, by shielding us from irrelevant details, allows us to do elaborate applications relatively painlessly. (Essay I)

I don’t want to put Wilczek in the position, even seemingly, of arguing with an essay written years after his.  But the point he makes here makes a mockery of all sorts of woo that follow from the fact that physicists are willing to accept a certain level of imprecision in order to do real work.  (Think Deepak Chopra, et al.)

For Sullivan, there are all the usual sins of woo-mongers here.  There is sloppiness of language.  He writes of a “force behind the universe” — which means … what?  Is it the quality that has powered the expansion of our observable patch of the universe since the Big Bang?  If so, it ain’t “behind” anything.

There is the mixing of categories.  Is he talking about a question of origins, of what triggered the current expansion?  More likely, I think, though Sullivan is, as is usual for writing that attempts to draw this kind of false connection between a specific problem in science and much broader question in some other domain.  If so, then Sullivan is mistaking a partial lack of knowledge for affirmative evidence of an immanent purposefulness to weight the scales our way, towards a universe in which we could emerge.

But this form of the old God of the Gaps argument misses the real action in modern cosmology.  For the point is that however much some questions may be incompletely understood  — the nature of the inflaton field, perhaps, or the implications of the certain concepts in Brane Theory and related studies for the question of the uniqueness of the Big Bang —  Big Bang cosmology is driven by a combination of theory and observation that works to describe the phenomenon(up to a point…which is why there are still jobs for cosmologists).

All of which is to say that just  because Sullivan cannot actually grasp the structure of contemporary physics, that does not mean he is free to ascribe any interpretation that makes him feel happy to what he thinks physics is talking about these days.  (By “free” I mean plausible, even remotely correct.  Obviously he, like me and any of us, is free to spout whatever nonsense we choose).

Even so, Sullivan is at least on familiar, if very shaky ground, when he asserts that a metaphoric interpretation of modern physics offers comfort, at least, if not outright confirmation, to a metaphoric vision of some concept of wholeness which we may conveniently call God.  That could fall, I guess, within my “whatever gets you through the day” category, as long as I am not asked to assent to any specific claim about the human condition based on the latest work on extra dimensions or the arrow of time.  (Hi, Lisa!Hi, Sean!)

But then there is this :

The second question is the nature of that force. The core revelation of Jesus – and the Buddha, for that matter, in some respects – is that the force is good, not evil. There is hope. Death is not what it seems. Love prevails. In this tragic, fallen, cruel world, this is not an easy doctrine. It cannot be inferred from the evidence. Which is why it is the gift of faith, from some source so deep, so great and so benign it defies any human description. Even metaphor fails.

[lease note that I have not cut anything from this passage — the two quotes above follow immediately one to the other.]

Most of this is just embarrassingly bad writing. (See, e.g. the phrase “some source so deep, so great and so benign it defies any human description.”  To me, at least, this reads like the religious version of Regency Romance prose — lots of heaving and heavy breathing around but not on the point at hand. But maybe I’m just in a bad mood…)

Still, whatever you think of the prose here, the claim that because Sullivan cannot imagine a purely physical account of the origins and evolution of the universe, therefore his prior assumption must be the correct interpretation is an appalling lapse of logic, an argument so bad it makes me wonder if all the stuff we hear about the Oxford Union as Parris Island for debaters is pure nonsense.

Here’s Sullivan’s syllogism:  Science tells us that there is a mysterious force within the universe.  (Assumption not in evidence — at least in the spiritual sense.) That force is good (ditto) — which I know, because Jesus told me so.  (But that’s what you wanted to confirm, I thought, independent of scriptural assertion).  Therefore, I’m not going to really die, and the world, despite all the evidence we have, is one in which love triumphs.  (Errr, no.  Not on the evidence as presented here.)

I mean, I get it.  I do.  Andrew Sullivan believes in the traditional promise of Christianity.  In that promise, Jesus was more than a man; his death was transformative of the reality of death for all humanity.  That transformation establishes the fundamental predominance of love over evil in the universe, for no matter what grotesqueries may overtake us on this earth, redemption will be found in the next.

But that has nothing to do with science, with physics, with that branch of physics and allied disciplines that studies the history of the cosmos.  It has nothing to do with the concept of force as it is used within that inquiry.  There is nothing to support this fervid hope within the anisotropy map produced by the WMAP satellite.  No measurement, no mathematics can tell you that Jesus left his tomb before three days passed and walked among his disciples, bearing his good news about the ephemeral nature of mortality.  (I’m not even going to go into the bizarre reading of Buddhism that Sullivan compresses in so few words; it ain’t worth it.)

Sullivan might respond that this is what he means when he talks of the “gift of faith.”  But if that were truly what he meant, then why the claim that science “affirms” this view of the spiritual nature of the forces that have shaped the physical universe?

Because, I think, he knows that what he’s really saying is that this is something he feels very deeply, and that it therefore must be true — and he wishes he had something more to convince his readers (and perhaps himself) that it is so.

But it doesn’t, which is or ought to be fine:  if faith has any meaning it is that it is an individual commitment.

I’ve belabored this enough, I think.  Sorry to natter on so long.  I just hate these attempts to claim the authority of science in support of what I think of as the Dorothy mode of thought:  click your heels hard enough and any magic can come true.

*All I’ll say is that Sullivan is correct when he asserts that metaphoric interpretations are the only contemporary readings of scripture that are compatible both with modern scien and what is often termed the “problem of evil.” But despite what seems to me that obvious truth, the countervailing fact is that a very large number of religious people, including the hierarchy of Sullivan’s own church, not to mention many in the rabbinate that leads the tradition in which I grew up, do not see the Bible as exclusively, or even centrally metaphorical.  In those settings, God did tell Abraham to kill Isaac;* Jesus really did rise from the dead.

Certainly, there is no shortage of metaphor even within a plain reading of much of the Bible, and plenty of sophisticated and subtle religious thinkers have recognized the central importance of using metaphor to interpret scripture.  (Read the French philosopher Emmanuel Levinas’s reeadings of Talmud if you want to see this kind of exegesis performed at the highest level.)

But I still think it is not so much disengenous as it is internal evidence of Sullivan’s own religious difficulties that he leaps to the metaphor whilst ignoring more direct readings of the scriptures and the teachings of his faith as he seeks to avoid the implications of purely materialistic accounts of the fate of mortal humans in this universe.

All that’s a fancy way to say what I and others have said before: ascribing to particular religious beliefs the qualities you wish they had doesn’t actually change the nature of such religious claims as they actually make their way into the world.  And if you haven’t noticed that for an awful lot of people these days the term “God” is a simple literal descriptor, then you aren’t (or are choosing not to) pay attention.

Images:  Michaelangelo, “The Last Judgment” 1537-1541.

John McLure Hamilton, “The Billiards Match,” before 1936.

WMAP data mapped onto an ecliptic projection, five years of data, 2008.

The Stupid, It Burns…Crunchy Con takes on Cosmology Edition

October 16, 2009

I usually lie back and enjoy Roy Edoroso’s  Rod Dreher takedowns.  There are too many massive fails out there to write everytime something stupid this way comes.  Besides, Roy practically owns Mr. Crunchy at this point;  it is as if the Crunchster’s only reason for being is not, as he imagines, to serve as an incarnate vessel for divine sparkles, but to offer an inexhaustible spring of risible material for Edoroso decant  as needed.

But, led by the Hon. Mr. Edoroso himself to the latest of Mr. Dreher’s bizarre complaints — that Bill Maher is not scientific enough to receive atheist of the year honors (sic!) — I came across this howler, left for lesser jaws to masticate.  Dreher quotes one Mark Shea approvingly, passing on this nugget of insight:

Nobody will ever die from thinking God created the universe or having some doubts about the proposition that hydrogen is a substance which, if you leave it alone for 13.5 billion years, will turn into Angelina Jolie.

Shea, I find, is a verbose (sure you want to pick up that stone, sinner? — ed.) and — how to put this? — surpassingly simple thinker, at least when it comes to anything that might actually threaten that part of his faith that depends on traditional readings of Genesis 1 and 2.

If you click through the link you’ll find an almost completely unembellished argument from design, presented (with the necessary leaven of scripture) without any apparent awareness of the fate of all such arguments to date. (Please note that that link takes you to a representative gutting by a committed believer of one of the recent design arguments.)

But never mind that.  Just stop for a moment and look at the above.  How many errors packed into a single sentence, just 20 words?

While I suppose I must give Shea props for confining his proposition to the relatively safe ground of disputes about cosmogenesis, it is certainly true that believers who question the precise form in which  God created the universe have died at the hands of those who differed from such views.  (And just to make my point clear:  I’m not trying to restart the tedious argument over who killed more, religious zealots or anyone else.  Rather, I’m simply pointing out that the claim that belief does not have consequences, include the deaths of those who differ in belief, is nonsense.

“hydrogen…if you leave it alone for 13.5 billion years…” (actually 13.7 billion in the most recent results — but that’s not the kind of error I’ mean).  This is the real howler.

The last forty five years of cosmological research have shown that whatever else is going on, you take the primordial mix of about 80 percent hydrogen, almost all the rest helium, with  a scattering of lithium…and the universe does everything but leave it alone.  It does so in most of the interesting ways under the influence of gravity, or local variations in the shape of spacetime, if you want to go all Albert on me.  See this handy Wikipedia article for the timeline and links to deeper inquiry as your interests dictate.

Once you get to star formation within those handy collections of matter called galaxies,* you can see how the universe, by not leaving hydrogen alone, makes all kinds of outcomes possible, including but not limited to the conditions that permit the formation of earth-like planets.

That process starts once the temperature at the center of a nascent star reaches ten million degrees kelvin, at which point hydrogen in the star begins to fuse — the nuclear burning that produces the heat and light of a star.   Next comes several really big steps I’m leaving out here to produce the heavy elements… but for a fun tour with a bit more detail, may I immodestly suggest you check out chapters five and six in this NOVA film, wherein you will see how stellar fusion leads to bouillabaisse.

“…into Angelina Jolie.”  This, of course, is another hit of the argument from design masquerading as a pitiful simulation of pop-culture hiptitude.  Yes it may be difficult to imagine that the glory of a Hollywood beauty could simply happen by chance, (and perhaps it might be fair to say that in many cases it clearly does not, but one must sadly note that the designers involved are all too human).

But the notion that you can’t get to something as complicated and aesthetically appealing as Ms. Jolie, or a beautiful mountain landscape, a kitten…or whatever, is simply the old teleological mistake:  the assumption that because we see a particular outcome to a process then that the process must have been directed to that one end.

That’s a mistake in formal logic; and it is belied by any number of empirical observations.  My favorite, given the significance of eyes to the history of the those who would reject Darwin for design, lies with discovery of (a) the evolutionary pathways leading to the mammallian eye and (b) the finding that eyes evolved several times in different lineages, processes that exploited different biochemical and structural resources.  See this link for an overview and further links to lots of resources.

Finally, back again to the beginning, but with a twist:  “Nobody will ever die..about the proposition…” that the universe has evolved and that human reason can penetrate the events that drove that process.  Well, actually, people die all the time because of doubt and distrust of science produced by exactly this kind of smug and willed — really intended — ignorance.

Here’s one example:  anti vaccine nonsense is a contributor, still relatively minor but tragic, to the worldwide death total from vaccine-preventable diseases.

Here’s another:  significant excess deaths due to extreme weather events are a well documented phenomenon.  Consider Europe in 2003, or Hurricane Katrina in 2005.

Among the more robust predictions of global warming science is that any “average” temperature increase will actually manifest itself in part through an increase in the amount of severe weather we will experience.

It follows, therefore, that unchecked global warming will lead to excess deaths in the future…a prospect made more likely by sustained denialism by those whose iron rice bowl stays whole only so long as they know not that which it is impolitic, or simply ideologically unacceptable, to have known.

And so on.  The larger point is simple:  science is not simply a bucket of facts, out of which it is possible to choose the bits you like  — antibiotics! genetically engineered crops! my iPhone!   Rather, it is a body of knowledge, a (many) theoretical frameworks, a method for knowing.  Its results are always in some degree provisional,** but its approach is not.

To say that you can’t both deny cosomological evolution and accept biochemistry is not a claim of dogma; rather it reflects the hard fact of experience that when you choose to pursue only those scientific ideas that give you comfort, you lose.  Your ability to find out crucial knowledge of the material world suffers in significant ways.

One last aside:  I do not line up with those in the “new atheist” camp who find any engagement with religion essentially simple minded.  But this stuff is — and it’s dangerous.  Seriously:  pace Mr. Shea, people do die from ignorance and it’s Twainian companion, certain knowledge of things that ain’t so.

In that context, I believe that the duty to rip apart this kind of nonsense lies very much in the thinking-religious camp.  As a general rule, if you don’t want to be characterized by the worst arguments made in your name, be the first and best debunkers.

*Galaxies are really the object of interest here.  As the film linked above portrays, they act as kind of cook pots — vessels in which the heavy elements produced by one generation of stars are available to get swept up in the next generation, until they accumulate to the point that interesting chemistry and ultimately, at least once, biochemistry, can take place.

**though mostly much less so than anti-science skeptics would have it.

Images:  Mihály Zichy, “Falling Stars,” 1879

Leonardo Da Vinci, “Mona Lisadetail, 1503-1519.

Sunday Stuff 1: Cosmology meets New Age Nonesense — Karadzic edition

July 27, 2008

Sean Carroll finds perverse pleasure — which I share in war criminal/face of evil* Radovan Karadzic’s reinvention of himself as a new-age healer.

Sean notes the quantum connection that Karadzic tried to make in his spiel — and this appropriation of a remarkably hard-headed body of science is an unfortunate byproduct of the fact that the language in which quantum theory is often popularized lends itself to all kinds of folly.

But I was struck by what seemed to me a new wrinkle in nonsense. Sean rightly snorts at the parody of quantification in this passage:

“It is widely believed our senses and mind can recognise only 1% of whatever exists around us. Three per cent we understand with our hearts. All that remains is shrouded in secrecy, out of the reach of our five senses; however, it is within our reach in the extra-sensory manner,” he [Karadzic] wrote in one article.

This is familiar enough — one of the standard moves used when purveying such stuff is to cloak it in trappings that suggest a science-like precision. But Sean missed a more specific potential source for the “numbers” (sic) in Karadzic’s “analysis” (sic-er) — one that now joins quantum theory as the unintential wellspring for silly-season stuff in our culture.

It’s all cosmology’s fault, of course. WMAP’s, in particular.

One of the most reported findings from the first round of analysis of the WMAP plot of the CMB was that the particular details of the hot and cold spots on that map permit a calculation of the composition of the universe — how much of the mass-energy it contains came in particular forms. It turned out that, rounding off as the early press did, 73 percent came in the form of dark energy; 23 percent or so as dark matter, and the remainder, roughly 4 percent, is ordinary matter.

You can see where this is going, can’t you?

Karadzic allows human capacity — senses and heart, to perceive four percent of reality. The rest is beyond our direct observation, and must be accessed by magic.

I can understand why Sean, a cosmologist, would shy away from this hideous conclusion: but what if modern cosmology, an extraordinary intellectual and technological achievement, making measurements at a precision that a generation or two ago would have been pure fantasy, producing observations about nature with exceptional rigor (which cannot be said of every branch of physics, at least not yet)…what if all this great work is just so much fodder for murderous quacks.

More to do on public engagement with science I would say…but then I would say that, wouldn’t I?

*Karadzic may be the face of evil. According to American negotiator Richard Holbrook, evil itself comes personified in the form of Ratko Mladic, Karadzic’s partner in crimes against humanity.

Mladic is still at large.

Image: WMAP Five Year Microwave Sky.

Friday (Isaac) Newton Blogging: Monday Cosmology Edition.

June 2, 2008

Update:  See correction below.**

(Cross-posted at Cosmic Variance.)

Let me just admit up front that I am a glutton for punishment.

Exhibit A: last year I read the Principia for pleasure.*

That’s not exactly right– it is more accurate to say that in the context of writing a book on Isaac Newton’s role as currency cop and death penalty prosecutor, I found myself reading the Principia as literature rather than the series of proofs it appears to be. Just like John Locke, who had to ask Christiaan Huygens if he could take the mathematical demonstrations on faith (Huygens said he could), I read to see what larger argument Newton was making about the ways human beings could now make sense of material experience. (This is, by the way, the only connection I can imagine that Locke and I share.)

What I got out of the exercise, more than anything else, was a reminder of how something we now mostly take for granted is in fact truly extraordinary: taken all in all, it seems genuinely remarkable that cosmology exists at all as a quantitative, empirical science.

That is: it is not obvious – or at least it wasn’t, all that long ago, that it would ever be possible to treat the universe as a whole as an object of study – especially given our very constrained vantage point from within that which we want to examine.

Most accounts of the story of modern cosmology more or less unconsciously downplay the strangeness of the claim that we can in fact make sense of the universe as a whole. They begin – mine did — with Einstein and the 1917 paper “Cosmological Considerations in the General Theory of Relativity, (to be found in English translation here.) Cosmology in this telling becomes more or less an inevitable extension of a recent advance in theoretical physics; the change in worldview precedes this extension of the apparatus of general relativity into a new calculation.

I recant: though I certainly wrote my version of this basic tale, reading Newton has reminded me of the much more radical change in the understanding of what it is possible to think about that had to precede all that cosmology (among much else) has achieved.

It certainly was not clear that the universe as a whole was subject to natural philosophical scrutiny in 1684, the year of Edmond Halley’s fortunate visit to Trinity College, Cambridge, and his more-or-less innocent question about the curve traced by a planet, assuming “the force of attraction towards the sun to be reciprocal to the square of their distance from it?  that would produce an elliptical planetary orbit with the sun at one focus.

An ellipse  inverse square relationship, Newton told Halley.

How did he know?

Why – he had calculated it.

By 1686, Newton had extended and revised his off-the-cuff answer into the first two books of Principia, both titled “The Motion of Bodies.” These pursued the implications of his three laws of motion through every circumstance Newton could imagine, culminating in his final demolition of Cartesian vortex physics.

But even though he had worked through a significant amount of mathematical reasoning developing the consequences of his inverse square law of gravitation, he left the ultimate demonstration of the power of these ideas for book three.

Books one and two had been “strictly mathematical,” Newton wrote. If there were any meat and meaning to his ideas, though, he must “exhibit the system of the world from these same principles.”

To make his ambitions absolutely clear Newton used the same phrase for the title of book three. There his readers would discover “The System of the World.”

This is where the literary structure of the work really comes into play, in my view. Through book three, Newton takes his audience through a carefully constructed tour of all the places within the grasp of his new physics. It begins with an analysis of the moons of Jupiter, demonstrating that inverse square relationships govern those motions. He went on, to show how the interaction between Jupiter and Saturn would pull each out of a perfect elliptical orbit; the real world, he says here, is messier than a geometer’s dream.

He worked on problems of the moon’s motion, of the issues raised by the fact that the earth is not a perfect sphere, and then, in what could have been a reasonable resting point for the book as a whole, he brought his laws of motion and gravity literally down to earth, with his famous analysis of the way the moon and the sun influence the tides.

Why not stop there? The story thus far had taken gravity from the limits of the observed solar system to the ground beneath each reader’s feet. More pragmatically – it told a story whose significance Newton’s audience would have grasped immediately: the importance of understanding the rules governing tides was obvious enough to the naval powers of the day.

No matter. Newton kept on going. The last section of his world-system turned to the celestial and seemingly impractical: the motion of comets, in an analysis of the track of the great comet of 1680

Newton presented his findings through two different approaches: one produced by collecting all the data points he could of traveler’s observations and plotting the comet’s track against those points; and the other in which he selected just three points and calculated the path implied.

The two analyses matched almost exactly, and both showed that this comet did not complete a neat, elliptical orbit. Rather, it traced a parabola.

Newton knew what he had done. He was no accidental writer. A parabola, of course, is a curve that keeps on going – and that meant that at the end of a very long and very dense book, he lifted off again from the hard ground of daily reality and said, in effect, look: All this math and all these physical ideas govern everything we can see, out to and past the point where we can’t see anymore.

Most important, he did so with implacable rigor, a demonstration that, he argued, should leave no room for dissent. He wrote “The theory that corresponds exactly to so nonuniform a motion through the greatest part of the heavens, and that observes the same laws as the theory of the planets and that agrees exactly with exact astronomical observations cannot fail to be true.” (Italics added).

And now, finally, to get back to the point: this, I would argue, was the essential first and in some ways the most difficult step in the foundations of cosmology. With it Newton transformed the scale of the universe we inhabit, making it huge, perhaps infinite. Even more important, he demonstrated that a theory that could not fail to be true made it possible to examine one phenomenon — matter in motion under the influence of gravity — throughout all space.

That thought thrilled Newton’s contemporaries – Halley caught the mood in his dedicatory poem to the Principia, writing that “Error and doubt no longer encumber us with mist;/….We are now admitted to the banquets of the Gods;/We may deal with laws of heaven above; and we now have/The secret keys to unlock the obscure earth….” To catch a distant echo of that euphoria, just imagine what it would have been like to contemplate that ever receding comet, fifteen years into its journey towards who knew where at the time of Newton’s writing, and know that its behavior was knowable through an extraordinary act of human invention.

It’s a whole ‘nother story to ask what it would take to create a similar sense of pride and pleasure in a general audience today. But just to get the discussion going, I’d suggest that one of the oddities of contemporary cosmology as presented to the public is the degree to which the universe at large has become more homey; the very success in making the argument that there is a continuous scientific narrative to be told from the Big Bang to the present makes it harder to see just how grand a claim that is.

So, to end with an open invitation to this community: what would make current physical ideas as powerful and as intelligibly strange as Newton was able to make his story of a comet traveling from and to distances with out limit?

Last housekeeping notes: in one of the more premature bits of self-promotion in publishing history, the Newton material discussed above derives from my book, tentatively titled Newton and the Counterfeiter, coming early next year from Houghton Mifflin Harcourt (and Faber, for those of you across the pond).

Also – my thanks again to Sean Carroll for welcoming me to Cosmic Variance.

*If you are minded to pick up a copy of Principia, get this edition. Not only is it a well made book, easy to look at, well printed, with clear diagrams, it comes with the invaluable guide to reading the Principia written by I. Bernard Cohen. Accept no substitutes.

**Thanks to reader and award-winning physics teacher David Derbes for catching my inversion of the problem Halley put to Newton.  Let this be a lesson to me:  blog in haste; check one’s notes at leisure; repent in public.

Image: Woodcut by Jiri Daschitzsky, “The Great Comet of 1577.” Source: Wikimedia Commons.