Physics

One reason why life can exist here. From ScienceDaily: A new study describes the first observations of the process of electron heating in Earth’s bow shock. The researchers found that when the electrons in the solar wind encounter the bow shock, they momentarily accelerate to such a high speed that the electron stream becomes unstable and breaks down. This breakdown process robs the electrons of their high speed and converts the energy to heat. … The results add an important new dimension to scientists’ understanding of Earth’s magnetic field and its ability to protect the planet from harmful particles and radiation. The research paper was published in the journal Physical Review Letters on May 31, 2018. “If you were to Read More ›

From Emily Conover at ScienceNews: The largest particle detector of its kind has failed to turn up any hints of dark matter, despite searching for about a year. Known as XENON1T, the experiment is designed to detect elusive dark matter particles, which are thought to make up most of the matter in the cosmos. Physicists don’t know what dark matter is. One of the most popular explanations is a particle called a WIMP, short for weakly interacting massive particle. More. The researchers saw no collisions with atomic nuclei in 1300 kg of chilled xenon, which is depressing. But at least they are ruling out spaces where dark matter could be. It’s frustrating because, at this point, researchers don’t know whether Read More ›

From Bill Andrews at Discover: In particular, according to a study released Monday in Nature Chemistry, an international team of scientists showed that molecules involved in photosynthesis display quantum mechanical behavior. Even though we’d suspected as much before, this is the first time we’ve seen quantum effects in living systems. … With a technique called two-dimensional electronic spectroscopy, researchers saw molecules in simultaneous excited states — quantum weirdness akin to a cat being alive and dead at the same time. What’s more, the effect lasted exactly as long as theories predicted it, suggesting this evidence of quantum biology will last. As the authors succinctly put it, “Thus, our measurements provide an unambiguous experimental observation of excited-state vibronic coherence in the Read More ›

A philosophical question to wake you up. A reader directs our attention to a 2015 piece by cosmologist Alexander Vilenkin at Inference Review (2015): THE ANSWER to the question, “Did the universe have a beginning?” is, “It probably did.” We have no viable models of an eternal universe. The BGV theorem gives us reason to believe that such models simply cannot be constructed. More. He offers the Borde-Guth-Vilenkin (BGV) theorem by way of evidence: Loosely speaking, our theorem states that if the universe is, on average, expanding, then its history cannot be indefinitely continued into the past. More precisely, if the average expansion rate is positive along a given world line, or geodesic, then this geodesic must terminate after a Read More ›

From Sophie Hebden at FQXI: A radical theory replaces the cosmic crunchers with fuzzy quantum spheres, potentially solving the black-hole information paradox and explaining away the Big Bang and the origin of time. … If the core of a black hole isn’t confusing enough, things get worse when you consider its surface—or “event horizon”—which marks an imaginary boundary surrounding the black hole. Anything that crosses the event horizon, even light, will be sucked in towards the black hole’s core and crushed into the singularity. At first it was thought that nothing that falls in to a black hole can ever escape. But in 1974, Stephen Hawking calculated that, thanks to quantum effects, black holes can slowly radiate energy from their Read More ›

From Ryan F. Mandelbaum at Gizmodo: A team of researchers from the United States and New Zealand took a look at how likely species were to go extinct and how likely new species were to appear during a 60-million-year period, long before humans evolved. Upon analyzing fossil data, it seemed to them as if astronomical cycles led to climactic effects that ultimately aligned with new species of plankton appearing and going extinct on Earth. “Our results… show that known processes related to the mechanics of the Solar System were shaping marine macroevolutionary rates comparatively early in the history of complex life,” the authors write in the study published today in the Proceedings of the National Academy of Sciences. More. It certainly Read More ›

Dark energy. From Andrew Masterson at Cosmos: The question of dark energy in one universe does not require others to provide an answer. A hypothetical multiverse seems less likely after modelling by researchers in Australia and the UK threw one of its key assumptions into doubt. Dark energy is supposed to be responsible for the accelerating expansion of our universe but current theory suggests that there should be much more than there is, so: The multiverse idea to an extent accounts for and accommodates this oddly small – but life-permitting – dark energy quotient. Essentially it permits a curiously self-serving explanation: there are a vast number of universes all with differing amounts of dark energy. We exist in one that Read More ›

From Katia Moskvitch at Quanta: The neutron-star collision was just the beginning. New data in the months since that discovery have made life increasingly difficult for the proponents of many of the modified-gravity theories that remain. Astronomers have analyzed extreme astronomical systems that contain spinning neutron stars, or pulsars, to look for discrepancies between their motion and the predictions of general relativity — discrepancies that some theories of alternative gravity anticipate. These pulsar systems let astronomers probe gravity on a new scale and with new precision. And with each new observation, these alternative theories of gravity are having an increasingly hard time solving the problems they were invented for. Researchers “have to sweat some more trying to get new physics,” Read More ›

 Inspiring Philosophy Philip Cunningham kindly forwarded this, noting that “Quantum mechanics has repeatedly confirmed the startling conclusion that (material) reality cannot exist without consciousness.” True, but defenders of a rational approach to science tend to forget that many people today are educated to think that reason and evidence are tools of oppression, that only their feelings are valid. That won’t end well, no matter what their feelings are. See also: How naturalism rots science from the head down The illusion of consciousness sees through itself. and Question for multiverse theorists: To what can science appeal, if not evidence?

And we learn some other things as well. From Suzan Mazur at Oscillations, an interview with Craig James Hogan, affiliated with Fermilab: Suzan Mazur: Thank you. There is criticism that the holographic investigation has been going on for almost 20 years, kicked off by Juan Maldacena and that there’s very little evidence so far, despite the bold headlines. That at some point in scientific investigations if the data doesn’t correlate with the experiment as modeled, it’s time to move on. I gather you don’t share that perspective. You’ve said you’re only at the beginning of the investigation. Do you see this as an emerging field like origin of life, spawning an increasing number of virtual research hubs in various parts Read More ›

From science historian James Gleick at the New York Times, reviewing astrophysicist Adam Becker’s What Is Real?: So quantum physics — quite unlike any other realm of science — has acquired its own metaphysics, a shadow discipline tagging along like the tail of a comet. You can think of it as an “ideological superstructure” (Heisenberg’s phrase). This field is called quantum foundations, which is inadvertently ironic, because the point is that precisely where you would expect foundations you instead find quicksand. … The Unfinished Quest for the Meaning of Quantum Physics When scientists search for meaning in quantum physics, they may be straying into a no-man’s-land between philosophy and religion. But they can’t help themselves. They’re only human. “If you Read More ›

From Tyler Krueger at Astronomy: Albert Einstein’s theory of general relativity is just over 100 years old, and so far it has predicted the interaction between celestial objects and the space-time field very well. There are a few troublesome spots, however, in which the theory of general relativity doesn’t agree with quantum mechanics. These gaps have confounded researchers for decades, and have sprouted a handful of hypotheses attempting to explain the dissonance. Dark matter and dark energy are the prevailing stand-in answers for this problem, but they are, as of yet, merely stand-ins. And there are some physicists that do not buy into these explanations. Erik Verlinde, a professor of science mathematics, and informatics at the University of Amsterdam, is Read More ›

From Suzan Mazur at Oscillations, an interview with Iranian-born astrophysicist Niayesh Afshordi: Niayesh Afshordi on Holographic Universe Media Spin & the Iranian Brain Drain Suzan Mazur: How close is the goal of combining Einstein’s theory of relativity and quantum physics? Something Kostas Skenderis at the University of Southampton has described as a new paradigm for physical reality. Niayesh Afshordi: We don’t know. Physicists have been chasing this goal for the past 80 years. We’d like to think that we’re closer than before. There have been new insights, theoretical and observational insights. But whether those are real, it’s difficult to say. Suzan Mazur: Your holographic universe research has been widely touted as “the first observational evidence that our universe could be Read More ›

From Cardiff University at Eurekalert: The birth of stars from dense clouds of gas and dust may be happening in a completely unexpected way in our own galaxy and beyond. This is according to an international team of researchers, including scientists from Cardiff University, who have found that long-held assumptions about the relationship between the mass of star-forming clouds of dust and gas and the eventual mass of the star itself may not be as straightforward as we think. The underlying reasons as to why a star eventually grows to a specific mass has puzzled scientists for some time. It has been assumed that a star’s mass mostly depends on the original structure – known as a star-forming core – Read More ›

Astronomer Brian Keating has a new book out, Losing the Nobel Prize, detailing the rise and fall of an apparent confirmation of cosmic inflation in 2014. From the publisher: In 2014, astronomers wielding BICEP2, the most powerful cosmology telescope ever made, revealed that they’d glimpsed the spark that ignited the Big Bang. Millions around the world tuned in to the announcement broadcast live from Harvard University, immediately igniting rumors of an imminent Nobel Prize. But had these cosmologists truly read the cosmic prologue or, swept up in Nobel dreams, had they been deceived by a galactic mirage? The latter, it would seem. A free excerpt is available at Nautilus: The broadcast from Harvard’s Center for Astrophysics captivated media around the Read More ›