‘A precise value for the mass of the electron is one example of the sort of statistic that physicists are eager to collect. Last Wednesday in Nature, a team of German physicists reported a new electron-mass measurement that offers a precision to parts per trillion. It is a “remarkable 13-fold increase in precision,” according to Florida State University physicist Edmund G. Myers, who published an accompanying perspective on the research paper.’
Following up on the post about Einstein’s early preference for a Steady State versus Big Bang cosmology, here’s a new story, also from Nature, describing a recently discovered draft written by Einstein outlining a Steady State theory:
“A manuscript that lay unnoticed by scientists for decades has revealed that Albert Einstein once dabbled with an alternative to what we now know as the Big Bang theory, proposing instead that the Universe expanded steadily and eternally. The recently uncovered work, written in 1931, is reminiscent of a theory championed by British astrophysicist Fred Hoyle nearly 20 years later. Einstein soon abandoned the idea, but the manuscript reveals his continued hesitance to accept that the Universe was created during a single explosive event.”
Imagine sitting on your porch with a nice drink, closing your eyes, and listening to the soothing sounds of nature—the cries of birds, the rustling breeze, and the faint sound of distant waves. And by distant, I mean on the order of light years. This story from RealClearScience describes the latest developments in the long search for gravitational waves. In theory, gravitational waves are produced when extremely massive systems undergo dramatic events, such as the collision or formation of black holes. These events can send gravitational waves traveling through space, although at incredibly tiny scales. Previous attempts at detecting the waves have tried to detect the contraction of massive metal rods; the new detectors look for shifts in the interference patterns created by two intersecting, long-distance laser beams. One day a detector like this may finally “hear” the rolling waves as the Earth bobs ever so slightly in the wake of a distant black hole birth. Read here.
From Springer Select, reporting on a new paper published in History & Philosophical Foundations of Physics:
“[Einstein] then fiercely resisted the view that the universe was expanding, despite his contemporaries’ suggestions that this was the case. For example, in 1922, Russian physicist Alexander Friedman showed that Einstein’s equations were viable for dynamical worlds. And, in 1927, Georges Lemaître, a Belgian astrophysicist from the Catholic University of Louvain, concluded that the universe was expanding by combining general relativity with astronomical observations. Yet, Einstein still refused to abandon his static universe.”
Twelve million years ago, a star in the galaxy we call M82 exploded. Since M82 lies 12 million light years away, the light from that explosion just reached Earth last week, being first noticed on January 21st. You may be able to see this supernova for yourself. M82 sits high in the northern sky above the Big Dipper. As of yesterday, Sky & Telescope reports the supernova’s magnitude at 10.6, within the range of backyard telescopes. The explosion was spotted serendipitously on January 21st by a group of undergraduate students and their teacher during a brief workshop at University College London.
One of the aspects that I find most interesting about this process is the extreme juxtaposition of scales of time and space. As noted, the galaxy M82 sits 12 million light years away; therefore, the light from the supernova explosion has taken 12 million years to reach us. Yet compare these huge numbers with the supernova itself: the explosion itself lasted only a matter of seconds. A Type Ia supernova, like this one, occurs when a compact white dwarf star pulls matter (via gravity) off of a much larger companion star. Eventually, enough mass accumulates on the white dwarf so as to suddenly initiate fusion, explosively releasing tremendous amounts of energy. The explosion itself lasts for a minute or so, and the brightly glowing aftermath itself persists for weeks (which at least gives us plenty of time here to catch it). Yet this brief event sheds light and energy out into space that can overpower the luminosity of an entire galaxy and can be seen in skies of a planet—our planet—millions of light years distant and millions of years in the future.
I have not yet read it, but David Bentley Hart’s new book The Experience of God sounds promising. William Carroll reviews it at Public Discourse, and Edward Feser reacts to Jerry Coyne’s comments on it here. Hart writes:
“Any argument for or against the reality of God not so understood—any debate over an intelligent designer, or a supreme being within time and space who merely supervises history and legislates morals, or a demiurge whose operations could possibly be rivals of the physical causes describable by scientific cosmology—may prove a diverting amble along certain byways of seventeenth-century deism or eighteenth-century “natural history,” but it most definitely has nothing to do with the God worshiped in the great theistic religions or described in their philosophical traditions, or reasoned toward by their deepest logical reflections upon the contingency of the world.”
And Carroll adds:
“Hart offers mostly dialectical arguments to show the incoherence of the positions he rejects. We recognize the radical contingency of the world we experience, a recognition that is not the result of a demonstrative argument but a kind of intellectual intuition based on the immediacy of our experience. This insight into the ‘absolute contingency’ of the world eludes those who embrace a materialistic metaphysics. It is also the basis for a reflection that leads to God as the absolutely necessary being.”
In honor of St. Thomas Aquinas’ recent feast day, we have this—over at BioLogos, Fr. Austriaco argues that evolution is a fitting means of creation:
“I propose that it was fitting for God to have created via evolution rather than via special creation because in doing so, he was able to give his creation – the material universe and the individual creatures within it – a share in his causality to create. In this way, he more fully communicates his perfection to his creation, thus, more clearly manifesting his glory. As St. Thomas points out: ‘If God governed alone, things would be deprived of the perfection of causality. Wherefore all that is effected by many would not be accomplished by one.’ (Summa theologiae, I.103.6)”
Stephen Hawking announces that he suspects that black holes aren’t quite what he thought they were. To wit: he thinks that the event horizon has been mischaracterized. Classically, the event horizon marks the point of no return: the line at which the black hole’s gravity becomes inescapable. Once it is crossed, there’s no way out again. Interestingly, though, in the classical view, an astronaut crossing the event horizon wouldn’t notice anything different at first. He’d just ride along across it along with everything else traveling with him. More recent quantum mechanics–based analyses, however, have suggested that the event horizon is marked by a “firewall” of astoundingly high energy created by quantum behavior at the black hole’s boundary. But Hawking now says that the whole idea of the horizon needs to be evaluated. Other physicists remain skeptical.
Image: University College London
I do not object to this paper so much as to the reporting on it. The paper itself (Middleton, C., & Langston, M. “Circular orbits on a warped spandex fabric.” arXiv:1312.3893) is a comparison of the “orbital” paths of a marble on a stretchable fabric surface compared to the paths of masses through space as described by general relativity, which it finds to be not mathematically comparable. The image of a weight deforming a fabric surface as an analogy for how masses create gravitational fields that affect the paths of moving masses through space is often used as a popular presentation of the ideas of relativity. What puzzles me is the idea that any physicist would be, in the words of the Physics arXiv Blog, “shocked” by the realization that the analogy of marbles rolling on fabric doesn’t work exactly like masses moving through relatavistic space. I suspect that most physicists have long realized that this image is just that: a roughly approximate image that is helpful to get the basic idea, but is by no means perfect.
What is string theory? Depending on which physicists you ask, replies may include “profound” or “beautiful” — or “wrong”. Another option is found in the title of a book by physicist and mathematician Peter Woit: Not Even Wrong. The title, a phrase attributed to Wolfgang Pauli, refers to the way that string theory has, despite all the work put into it, remained not only untested but even untestable.
String theory proposes that the basic constituents of the physical universe are incredibly tiny “stringlike” structures that vibrate in multidimensional space; their vibrations give rise to the properties we observe at the higher levels of space, matter, and energy. However, as Woit explains, “More than twenty years of intensive research by thousands of the best scientists in the world producing tens of thousands of scientific papers has not led to a single testable experimental prediction of the theory.”
But I am not asking here about the content of string theory. Rather, I ask: how should we classify string theory? Is it science, or is it something else? Woit writes: “The question tends to take on two different forms. One form of the question that many physicists ask is whether superstring theory should not perhaps be described as mathematics rather than physics. A second form asks whether the theory is a science at all.” He adds that non-string-friendly physicists tend to suggest that string theory is mathematics, since it has no empirical support (at least yet); mathematicians, however, present it as physics since it is “not really a [mathematical] theory, but a set of hopes that a theory does exist”, hopes which come “out of purely physical motivations.”
Yet a third suggestion I have encountered is that the theory’s remoteness from scientific observation makes it some kind of philosophy.
Realizing that this brings up the long-running discussion about just what science is, my opinion is that the bookstores’ man-in-the-street instincts have it right: books about string theory are placed on the shelves with books about physics, in the “Science” section. String theory is neither philosophy nor pure mathematics because it concerns itself with what are supposed to be real physical objects that can be described in terms of quantifiable material properties. Because philosophy deals with the reasoned investigation of the necessary characteristics of being, rather than the contingent scientific details of particular cases of physical things, one could hold to a given philosophy of nature (say, Thomism) regardless of whether or not string theory was known to be true; therefore, string theory is not a competing philosophy. Similarly, a purely mathematical system describes abstract relationships between mathematical entities; it becomes part of a physical science when that mathematical system is applied to real physical things—the proposed existence of which is the whole heart of the question of string theory.
The problem remains, though, that any empirical evidence for string theory, however much string theory promoters wish it were otherwise, remains lacking and looks to remain lacking for the foreseeable future. I would therefore classify string theory as science and as physics, but as a purely speculative scientific hypothesis or proposal. Time will tell if it ever becomes anything more.
Weakly interacting massive particles (WIMPs) are the top candidates for dark matter, the invisible stuff that makes up about 84% of the universe’s matter. But two recent experiments designed to sniff out the elusive particles have come up empty-handed, calling previously promising results into doubt.
The Planck space observatory was shut down for good on Wednesday, ending the satellite’s four-and-a-half-year stint observing the relic light of the Big Bang, in the greatest detail yet obtained. A shutdown signal transmitted yesterday cut off the satellites transmitters, and previous signals had sent Planck coasting away from the L2 Lagrange point a million miles from Earth that had been its home since its launch. (A Lagrange point is a point of gravitational balance near the Earth, or another space body, where objects can remain in place indefinitely. Placing Planck there allowed it to remain relatively near the Earth while also being permanently on the dark side, away from the interference that would have been created if it had orbited nearer.)
But just because Planck itself has been put to rest, doesn’t mean it has nothing left to give. The first release of Planck’s CMB data came in March; another more detailed release is set for next year. The data have already allowed more precise measurements of the universe’s age (13.82 billion years) and clarified conditions in the early cosmos.
At the other end of the scale, this year’s Nobel Prize for physics went to Peter Higgs Francois Englert for the LHC’s detection of the Higgs boson. The Higgs is the last major element of the “Standard Model” of physics, and its discovery supports the Model’s correctness. But the trouble is that the LHC hasn’t found anything else particularly noteworthy that could give a clue as to which direction to pursue next.
Laura Mersini-Houghton writes in the latest issue of Nautilus in defense of the multiverse, offering, she says, empirical evidence for it. Her claims are, needless to say, controversial. Yet I would say that she has, at least, the right approach in spirit: if the “multiverse” is accepted, it should be on the basis of the observed, empirical evidence. So I leave aside for the moment the question of whether these observations are in fact evidence of the multiverse, and look at some more fundamental questions.
There are two basic mistakes that can be made regarding the multiverse:
(0) Actually, there are three mistakes, and the underlying one is to misunderstand the word “multiverse” in the first place. I’m not a fan of it. If the basic idea is correct, it just means that the universe extends beyond the “Big-Bang-begun” region that we inhabit. It is, nevertheless, a single, causally connected whole in the relevant metaphysical sense, and the “multi” part of the multiverse can thus be misleading. If the multiverse is empirically observed, it is not empirical observed evidence of more than one ontologically independent universe (which is impossible, as entirely independent universes are, by definition, unobservable), it is rather just empirical observed evidence of a bigger universe.
(1) To get to the more mundane mistakes, then, the first is to accept the multiverse as an apparent way out of the puzzle of the universe coming from nothing or being dependent on a Creator. Some think that if they can show that the Big Bang was caused by some prior physical cause, God is eliminated. This won’t work, because even if the multiverse theory is correct, every one of the classical arguments for the Creator still stands. The multiverse theory just makes the universe bigger and older; it doesn’t change its ontologically contingent status.
(2) Similarly, the second mistake is to reject the multiverse just because some people use it as an attempt to avoid the conclusion of a Creator. Those who do the latter do so erroneously; therefore, it does not follow that the multiverse is wrong. If it is wrong, it should be shown so on the basis of sound scientific reasoning, not because some people philosophically misinterpret it.
So, yet again, for the most fundamental theological and philosophical questions, the multiverse is simply irrelevant. It may be scientifically true, and thus interesting, or it may be a dead end, but it is up to science to show us, and philosophers and theologians need not be too troubled.