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Fine tuning

Oxford conference to examine questions around fine-tuning of universe, Physics of Fine-Tuning, Crete, June 19-22 2017

Here. Our goal is to consolidate the idea of fine-tuning across disciplines such as biology, chemistry, and physics. Fine-tuning is often deemed a fact and used to reach grandiose metaphysical conclusions by philosophers, theologians, and even physicists, without a proper understanding of the underlying assumptions entailed by these arguments. As a consequence the physical and philosophical literature on this subject are rather confusing, leading to esoteric topics such as Boltzmann Brains. We intend to present a comprehensive review of the physics used for deriving fine-tuning arguments, scrutinising the current ones and uncovering new examples, thereby providing a solid foundation for future efforts to interpret this fascinating facet of Nature. We will produce a field-manual for fine-tuning and create an accompanying Read More ›

Astrophysicist: “A vibrant scientific culture encourages many interpretations of evidence”

From Avi Loeb at Nature, on the achievements and limitations of Mayan astronomy: So why, I wondered, didn’t the Mayans go further and infer aspects of our modern understanding of astronomy? They determined the orbital periods of Venus, Mars and Mercury around the Sun, but Earth was at the centre of their Universe. I came to appreciate how limiting prevailing world views can be. … I noticed this bias recently while assessing a PhD thesis. The student was asked to test whether a data set from a large cosmological survey was in line with the standard cosmological model. But when a discrepancy was found, the student’s goal shifted to explaining why the data set was incomplete. In such a culture, Read More ›

Mathematics: “Particle collisions are somehow linked to mathematical ‘motives.’”

From math and computer science writer Kevin Hartnett at Quanta: Over the last decade physicists and mathematicians have been exploring a surprising correspondence that has the potential to breathe new life into the venerable Feynman diagram and generate far-reaching insights in both fields. It has to do with the strange fact that the values calculated from Feynman diagrams seem to exactly match some of the most important numbers that crop up in a branch of mathematics known as algebraic geometry. These values are called “periods of motives,” and there’s no obvious reason why the same numbers should appear in both settings. Indeed, it’s as strange as it would be if every time you measured a cup of rice, you observed Read More ›

What next? Physical law as an alien intelligence?

Yes. From astrophysicist Caleb Sharf at Nautilus: Alien life could be so advanced it becomes indistinguishable from physics. After all, if the cosmos holds other life, and if some of that life has evolved beyond our own waypoints of complexity and technology, we should be considering some very extreme possibilities. Today’s futurists and believers in a machine “singularity” predict that life and its technological baggage might end up so beyond our ken that we wouldn’t even realize we were staring at it. That’s quite a claim, yet it would neatly explain why we have yet to see advanced intelligence in the cosmos around us, despite the sheer number of planets it could have arisen on—the so-called Fermi Paradox. … In Read More ›

Hearing less about “hard evidence” for the multiverse?

From Peter Woit at Not Even Wrong: Back in 2013 one could read lots of claims in the media that “Hard evidence for the multiverse” had been found, based on “effects of quantum entanglement between our horizon patch and others”. These claims were discussed on this blog (with a response from the authors here). A new paper by Will Kinney has now been published in JCAP, including the following conclusion about such claims: It is worthwhile to discuss in general the “concrete predictions” originally claimed by the authors of refs. [1,2], since several key claims do not survive even cursory scrutiny. For example, the discontinuity in the effective potential claimed to be correlated with voids and the CMB cold spot Read More ›

Supersymmetry a beautiful idea, lacking only evidence

Supersymmetry predicts a partner particle for each particle in the Standard Model, to help explain why particles have mass – CERN From Economist: Strictly speaking, Susy can never be formally disproved. It can always be tweaked so that sparticles appear only at energies that are just out of reach of the best existing colliders. Yet the more such tweaks are applied, the more they erode the elegance for which the theory is admired. In light of the LHC’s failure to find evidence for Susy, more physicists are arguing that the field’s obsession with the theory is a waste of time and effort. Scientists at the LHC filter the data they record by looking first for particles predicted by favoured theories, Read More ›

Was dark matter forged in Big Bang heat?

From Matthew R. Francis at Symmetry: One reason to think of dark matter as a thermal relic is an interesting coincidence known as the “WIMP miracle.”WIMP stands for “weakly-interacting massive particle,” and WIMPs are the most widely accepted candidates for dark matter. Theory says WIMPs are likely heavier than protons and interact via the weak force, or at least interactions related to the weak force. … Both the primordial light known as the cosmic microwave background and the behavior of galaxies tell us that most dark matter must be slow-moving (“cold” in the language of physics). That means interactions between dark matter particles must be low in strength. “Through what is perhaps a very deep fact about the universe,” Buckley Read More ›

Sydney: Conference on fine tuning, multiverse, and life, November 24-25, 2016

From University of Sydney: We invite you to the 2016 Fine-tuning, the Multiverse and Life Workshop, hosted at the University of Sydney. Issues of fine-tuning and naturalness are central to evaluating such physical and cosmological theories as inflation and extension to the Standard model of particle physics, including supersymmetry. In addition, our values of the fundamental constants of nature have the seemingly rare ability to support the complexity required by life. This has become an important way to test multiverse theories: the predicted observed value of fundamental “constants” depends on the values that permit the existence of observers. In light of these challenges, this workshop will bring together physicists, cosmologists, astronomers and philosophers of science for two days of invited Read More ›

Forbes regrets to inform us that there is no evidence for a multiverse yet.

From Sabine Hossenfelder at Forbes: … the LHC found the Higgs but no evidence for anything new besides that. No supersymmetry, no extra-dimensions, no black holes, no fourth generation, nothing. This means that the Higgs-mass just sits there, boldly unnatural. Enter the multiverse. The multiverse idea states that there are infinite numbers of Universes like our own, and infinite ones with differences. Not only would anything that could happen actually happen in some universe within the multiverse, but anything that can happen would happen infinitely many times. Therefore, the multiverse also contains infinitely many universes that are almost exactly like our own, including our planet, and me, and you. But in some of these other universes, a dark matter particle Read More ›

Cosmologist Larry Krauss explains a universe from nothing to an astrophysicist

Readers will remember Larry Krauss, possible Dawkins’ replacement (much needed just now): From Wintery Knight: Lawrence Krauss is a Cosmologist at Arizona State University who describes himself as an “anti-theist”. His latest book “A Universe From Nothing” has received both acclaim and criticism for its attempt to answer the question “Why is there something rather than nothing?” Debating the issue with Krauss is Rodney Holder, Course director at the Faraday Institute, Cambridge. An astrophysicist and priest by background. In a lively exchange they debate whether Krauss’ “nothing” is “nothing”, fine tuning and multiverses, scientific knowledge, miracles and the usefulness of theology and philosophy. This debate is quite entertaining, and do not be intimidated if your don’t understand science. You can understand Read More ›

Our galaxy is more symmetrical than thought

From Brian Clark Howard at National Geographic News: Published in the journal Science Advances this week, a new study reported that our surrounding area of stars, gas, and dust—called the Local Arm, Orion Spur, or Orion–Cygnus Arm—is actually about 20,000 light-years long. The immediate implications are that the galaxy is actually a little more symmetrical and regular than scientists previously thought, says one of the study’s co-authors, Mark J. Reid of the Harvard-Smithsonian Center for Astrophysics. Although a better understanding of our galaxy’s structure doesn’t necessarily mean gravity or other forces acting on us are different from what we expect, it could help us better understand large-scale features in the future, notes Reid. More. See also: Cosmologist Luke Barnes on Read More ›

Maybe solar system formed from “poorly mixed elemental soup”

From ScienceDaily: Planetary scientists have long believed that Earth formed from planetary objects similar to meteorites. Then, a decade ago, perplexing new measurements challenged that assumption by showing that Earth and its supposed “building blocks” actually contain significantly different isotopic compositions. … “These recent measurements contribute to the growing evidence that the meteorites delivered to Earth provide an imperfect match to Earth’s composition,” said Richard Carlson, director of the Department of Terrestrial Magnetism at the Carnegie Institution for Science. Carlson was one of the scientists who found the compositional mismatch between meteorites and Earth 10 years ago. “This realization opens new views both to how Earth formed and to the bulk chemical composition of our home planet.” Paper. (paywall) – Read More ›

Cosmologist Luke Barnes on fine-tuning of the universe

From Wintery Knight: Atheist Luke Muehlhauser interviews well-respect cosmologist Luke Barnes about the fine-tuning argument, and the naturalistic response to it. … In one of my funniest and most useful episodes yet, I interview astronomer Luke Barnes about the plausibility of 11 responses to the fine-tuning of the universe. Frankly, once you listen to this episode you will be better equipped to discuss fine-tuning than 90% of the people who discuss it on the internet. This episode will help clarify the thinking of anyone – including and perhaps especially professional philosophers – about the fine-tuning of the universe.More. It is a podcast with useful outline notes. Here are some of Barnes’s other articles on the subject. See also: Our solar Read More ›

Our solar system just right for life?

From Daily Galaxy: “After measuring alpha in around 300 distant galaxies, a consistency emerged: this magic number, which tells us the strength of electromagnetism, is not the same everywhere as it is here on Earth, and seems to vary continuously along a preferred axis through the Universe,” said Webb. “The implications for our current understanding of science are profound. If the laws of physics turn out to be merely “local by-laws”, it might be that whilst our observable part of the Universe favors the existence of life and human beings, other far more distant regions may exist where different laws preclude the formation of life, at least as we know it. “If our results are correct, clearly we shall need Read More ›

Journalist on fine-tuning of the universe

From David Warren at the Catholic Thing: Thirty years have now passed since the publication of an extraordinary book, by a respectable publisher (the Oxford University Press). This was, The Anthropic Cosmological Principle, by the witty British astronomer, John Barrow, and the brilliant American mathematical physicist, Frank Tipler. It included a laudatory preface by John Wheeler, co-inventor or discoverer of “black holes.” It was an attempt to overturn the Copernican Revolution: to put man back at the centre of a miraculously conceived universe, and make his fate the whole meaning of it. This universe, from its Alpha Point in what is popularly called the “Big Bang,” to an Omega Point that is darkly foreseeable, could be described in no sense Read More ›