Cosmology

Pions? There’s been a long-running question as to why most of the universe’s matter remains unaccounted for. According to Live Science, Now, a team of five physicists has proposed that dark matter might be a kind of invisible, intangible version of a pion, a particle that was originally discovered in the 1930s. A pion is a type of meson — a category of particles made up of quarks and antiquarks; neutral pions travel between protons and neutrons and bind them together into atomic nuclei. Most proposals about dark matter assume it is made up of particles that don’t interact with each other much — they pass through each other, only gently touching. The name for such particles is weakly interacting Read More ›

From the New Statesman: To support Minkowski’s proposal, a 2014 paper published in arXiv, says the universe had no beginning and will have no end (a “block universe”), according to a new model that applies quantum correction terms to complement Einstein’s theory general relativity. The model also helps solve the problem of dark matter and dark energy. What some cosmologists now believe is that rather than matter collapsing, causing a “Big Bang”, the matter bounced (“the Big Bounce”). Ie, they believe the universe has energy levels and goes through a cycle of collapses and bounces. “[The Big Bounce] is actually in doubt because we now know that our universe is not going to re-collapse. It is actually going to expand Read More ›

Lee Smolin, a cosmologist at the Perimeter Institute for Theoretical Physics, informs us via PBS, I believe in time. I haven’t always believed in it. Like many physicists and philosophers, I had once concluded from general relativity and quantum gravity that time is not a fundamental aspect of nature, but instead emerges from another, deeper description. Then, starting in the 1990s and accelerated by an eight year collaboration with the Brazilian philosopher Roberto Mangabeira Unger, I came to believe instead that time is fundamental. (How I came to this is another story.) Now, I believe that by taking time to be fundamental, we might be able to understand how general relativity and the standard model emerge from a deeper theory, Read More ›

Commentator Mark Davis says we should: This week is a perfect time to stoke the dormant embers of the wonder we once felt. A vehicle crafted by human hands has just left the solar system after visiting Pluto, sending us crisp photographs of a world 3 billion miles away. Just 50 short years ago, we had never sent anything out of Earth orbit. But on a sunny morning in Florida 46 years ago this week, three Americans left our world to set foot on another. I was 11 for the launch of Apollo 11. Neil Armstrong’s July 20, 1969 footprint on the moon’s Sea of Tranquillity was in the middle of my summer between sixth and seventh grade. More. I Read More ›

From physicist Jon Butterworth at The Guardian: Jan Conrad, an astroparticle physicist, claims that “The field has cried wolf too many times and lost credibility” and he worries that false discoveries are undermining public trust in science. He lists some dubious results which have caused a stir amongst physicists and the general public over the past couple of years, including the faster-than-light-neutrinos that weren’t, the primordial gravitational waves that are probably just dust, and several Dark Matter candidates which remain shrouded in uncertainty and contradiction. His argument has some merit; in some cases there is an apparent rush to release, and especially to over-interpret, provisional and sometimes incorrect data. This is sometimes done because because of rivalries and competition, the Read More ›

Because we just haven’t found the dark matter that the theory seems to require. Further to Human languages must be irreducibly complex (Can someone help us understand what this translation from German means?)—maybe it was something about how cosmology needs to change, which Neil Turok of the Perimeter Institute in Canada said plainly earlier this year. Something like: Hi, Nonsense, meet Budget: From PBS: Do We Need to Rewrite General Relativity? Astronomical observations show that there isn’t enough ordinary matter to account for the behavior of galaxies and other objects. The fix is dark matter, particles invisible to light but endowed with gravity. However, none of our detectors or experiments have ever seen a dark matter particle directly, leading some Read More ›

Further to The multiverse: Hi, Nonsense, meet Budget (This Perimeter Institute conference could be a party’s over signal; time to sweep up the streamers and bust balloons, and get back to evidence-based science): Columbia mathematician Peter Woit is following the proceedings and notes, You can follow a lot of what is going on at this conference on Twitter, here. For example, I was glad to hear about this comment from Dimopoulos There is no difference that we know right now … between the story of divine intervention and the multiverse. It’s great to see a conference on fundamental physics where the multiverse is coming in for some appropriate skepticism. Nonsense, meet Prayer Beads. He has a wonderful plan for your Read More ›

Oh and, Budget, meet Rationalization. But you two can talk later. The meeting is starting… From physicsworld.com, we hear that the Perimeter Institute at MIT North (University of Waterloo, Canada) is starting to ask some questions about crackpot cosmology. As Louise Mayor tells us, on site: Right now, top physicists from around the world are arriving in Waterloo, Canada, to attend a unique conference. Christened Convergence, the meeting is the brainchild of Neil Turok, director of thePerimeter Institute for Theoretical Physics (PI) in Waterloo, where the event will be based. I spoke to Turok to find out what motivated him to set up this conference, what makes it so special, and what he hopes it will achieve. Turok was fairly Read More ›

Further to Barry Arrington’s Chasing shadows: How long can we keep looking for dark matter?, curiously, New Scientist has been asking the same question: We’ve known we need dark matter since the 1930s, but still haven’t found it. The search can’t go on forever Even CERN’s Large Hadron Collider, our best and by far most expensive tool for finding it, has so far drawn a blank. How much longer can we keep looking? … Perhaps we have simply been looking for the wrong thing. Perhaps dark matter particles are very massive, rather than fairly light, as many assume. The first experiments are now under way to detect any such “superheavy” dark matter that might have been created when the universe Read More ›

To ask that question is to answer it. World Mag here: After decades of being touted for its mathematical elegance and adored for its explanatory power, supersymmetry was finally ready for experimental verification at Switzerland’s famous particle accelerator, the Large Hadron Collider (LHC). While the LHC made some important discoveries, most notably the Higgs boson particle (sometimes called the God particle), scientists found nothing at all to confirm supersymmetry. After many a particle was smashed, crashed, accelerated, and spun, no supersymmetric “partners” could be found—a bitter blow for physicists ready to leap to the next frontier. In the ashes of disappointment, “the specter of evidence-independent science” arose, according to Gleiser and Frank. They note that while some scientists are prepared Read More ›

Further to: Is Is Discover Mag’s blasphemy issue re dark matter really about fine tuning? (Proposing a change to our statements of the laws of gravity in order to eliminate fine tuning as a factor in our universe merely advertises how severe the problem is.) A reader sends in this snippet from The Edge: Priyamvada Natarajan, Professor in Departments of Astronomy and Physics at Yale University, focusing on exotica in the universe—dark matter, dark energy, and black holes. Now I’ve been teaching at Yale for more than ten years, so I’ve had some fantastic students and colleagues who have helped me in refining and shaping how I think. In particular, one of the things that I am after is clarity. Read More ›

From the Dark Matter Deniers. At Discover: Exploring a blasphemous alternative to one of modern physics’ most vexing enigmas. We’d have to pay to read the article, but the language intended to draw us in is surely interesting. A second career for Torquemada? Or is the whole “denialism” sturm-und-flapdoodle beginning to attract well-deserved mockery? Denialism these days usually means a willingness to address inconvenient facts. Just as quote mining usually means quoting Darwin’s followers when they let down their guard and speak honestly with each other. Follow UD News at Twitter!

From Columbia mathematician Peter Woit’s Not Even Wrong blog: Today I happened to come across a really wonderful discussion there though, and wanted to draw attention to it, even though it’s from a year ago. It’s entitled A View from an Ex-String Theorist and consists of a long piece by someone who has recently left string theory, as well as some answers to questions asked by others. If you want to understand what string theory looks like these days to good theorists who are working on it, read what “No_More_Strings” has to say. The suggestion that “string theorists” should stop calling what they do “string theory” is an excellent one. … If you didn’t have to start every grant application Read More ›

Between space exploration and lunacy, presumably: A few months ago in the journal Nature, two leading researchers, George Ellis and Joseph Silk, published a controversial piece called “Scientific Method: Defend the Integrity of Physics.” They criticized a newfound willingness among some scientists to explicitly set aside the need for experimental confirmation of today’s most ambitious cosmic theories — so long as those theories are “sufficiently elegant and explanatory.” Despite working at the cutting edge of knowledge, such scientists are, for Professors Ellis and Silk, “breaking with centuries of philosophical tradition of defining scientific knowledge as empirical.” More. If it is not empirical (evidence-based), why should the taxpayer fund it? Why should anyone care what they think? As I have said Read More ›

Because it is not about the science. Which is largely non-existent. Popular culture needs the multiverse, and string theory is the gateway drug. Here I’m busy with other things, so no possible way I can keep up with the claims about string theory flooding the media for some reason these days. It’s hard enough to find the time to read all of this, much less write something thoughtful about it… One obvious point to make though is that none of it acknowledges the obvious: the widely promoted idea that we can get a unified theory and explain the Standard Model by using a theory of strings has turned out to be an empty one. See also:Why modern cosmology not only Read More ›