Nov 15, 2015 03:30 AM
(This post was last modified: Nov 15, 2015 03:42 AM by C C.)
Leading Harvard physicist has a radical new theory for why humans exist
http://www.businessinsider.com/lisa-rand...rs-2015-11
EXCERPT: [...] Lisa Randall, a theoretical physicist at Harvard University, has a different, and novel answer, which she describes in her latest book, "Dark Matter and the Dinosaurs." [...] she posits that the extinction of the dinosaurs — necessary for the emergence of humans — is linked to dark matter. Dark matter is the mysterious, invisible matter that astronomers estimate makes up 85% of all matter in our universe. Generally, dark matter tends to be concentrated in large halos around galaxies like giant bubbles. But Randall thinks that there could also be a so-called dark disc amid the stars, planets, and gas clouds in our galaxy. If there is dark matter in Randall's hypothetical disc, then it stands to reason that the disc has a powerful gravitational influence on the objects around it — including our solar system. But our solar system is not always near the disc, which is the crux of Randall's theory.
[...] A team of astronomers made a rough estimate [...] calculating that our solar system passes through the plane of the Milky Way about once every 32 million years, which means if there's a dark disc, we pass through that at the same rate. Interestingly, there's evidence to suggest that mass extinctions in Earth's past happened within this time frame, or about once every 25 to 35 million years. [...] Randall hypothesizes that when we're passing through the dark disc, the gravity from the dark matter within influences the outer region of our solar system, called the Oort cloud. [...] If something 12 miles wide hit Earth today, it would mean the end of life as we know it. And Randall thinks that's exactly what happened to the dinosaurs 66 million years ago that opened the door for widespread primate evolution....
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Quantum Physicists Find Pi in a Very Strange Place
http://motherboard.vice.com/en_uk/read/f...-mechanics
EXCERPT: A pair of scientists from the University of Rochester has discovered something unexpected lurking far down in the mathematical depths of quantum mechanics: pi.
To be sure, pi, the endlessly repeating constant describing the ratio between a circle's circumference and its diameter, underpins much of what we understand about the physical and mathematical worlds, including quantum mechanics. But it wasn't expected to appear just out of the blue in calculations for the excited energy states of electrons in an atom, which is just what the Rochester physicists describe in a new paper published in the Journal of Mathematical Physics.
"The existence of such a derivation indicates that there are striking connections between well-established physics and pure mathematics that are remarkably beautiful yet still to be discovered," the authors write....
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Quantum dilemma: We have too many options for explaining reality
https://www.newscientist.com/article/mg2...s-meeting/
EXCERPT: It's time to put all the quantum cards on the table. That’s the view of a group of physicists who assembled in Vienna last month to present a variety of ideas, results and plans for future experiments that might help find an explanation for the weirdness of quantum theory.
Quantum physics is well known for being weird. The theory – and the experiments that have confirmed it – rip gaping holes in our concept of space, time and reality. Most physicists simply accept this as the way things are. But most of the 70 or so researchers who gathered in Austria at the Vienna symposium on “Emergent Quantum Mechanics” from 23 to 25 October were there to go deeper, and ask where the quantum laws might come from. Is quantum physics a stepping stone to a deeper understanding of reality?
“There are many people who think they are well along the path to a better understanding, but they all contradict each other,” says Aephraim Steinberg of the University of Toronto, Canada. “So maybe one of them is right – but I certainly don’t know which one.”
Steinberg presented experiments that attempt to show the paths photons take as they appear to pass simultaneously through two slits. This is because of quantum superposition – a trick in which the photon seem to be in two different states at once. The most widely accepted interpretation of quantum theory claims that this is possible because the photons only have definite properties once they have been detected. Before that, there is only a mathematical wave function describing possible outcomes of the measurement.
But Steinberg prefers to interpret the experiment in terms of so-called Bohmian mechanics, which suggests that there are pre-existing connections between all quantum particles. Each particle has an associated “pilot wave” that guides its position and momentum, so it takes a particular trajectory through the double slits. “These are very straightforward experiments that draw a connection between that model and what happens in the real world,” he says.
Many find Bohmian mechanics unsatisfactory. But discussions at the meeting made it clear that the same can be said of most interpretations – and it was....
http://www.businessinsider.com/lisa-rand...rs-2015-11
EXCERPT: [...] Lisa Randall, a theoretical physicist at Harvard University, has a different, and novel answer, which she describes in her latest book, "Dark Matter and the Dinosaurs." [...] she posits that the extinction of the dinosaurs — necessary for the emergence of humans — is linked to dark matter. Dark matter is the mysterious, invisible matter that astronomers estimate makes up 85% of all matter in our universe. Generally, dark matter tends to be concentrated in large halos around galaxies like giant bubbles. But Randall thinks that there could also be a so-called dark disc amid the stars, planets, and gas clouds in our galaxy. If there is dark matter in Randall's hypothetical disc, then it stands to reason that the disc has a powerful gravitational influence on the objects around it — including our solar system. But our solar system is not always near the disc, which is the crux of Randall's theory.
[...] A team of astronomers made a rough estimate [...] calculating that our solar system passes through the plane of the Milky Way about once every 32 million years, which means if there's a dark disc, we pass through that at the same rate. Interestingly, there's evidence to suggest that mass extinctions in Earth's past happened within this time frame, or about once every 25 to 35 million years. [...] Randall hypothesizes that when we're passing through the dark disc, the gravity from the dark matter within influences the outer region of our solar system, called the Oort cloud. [...] If something 12 miles wide hit Earth today, it would mean the end of life as we know it. And Randall thinks that's exactly what happened to the dinosaurs 66 million years ago that opened the door for widespread primate evolution....
- - - - - - -
Quantum Physicists Find Pi in a Very Strange Place
http://motherboard.vice.com/en_uk/read/f...-mechanics
EXCERPT: A pair of scientists from the University of Rochester has discovered something unexpected lurking far down in the mathematical depths of quantum mechanics: pi.
To be sure, pi, the endlessly repeating constant describing the ratio between a circle's circumference and its diameter, underpins much of what we understand about the physical and mathematical worlds, including quantum mechanics. But it wasn't expected to appear just out of the blue in calculations for the excited energy states of electrons in an atom, which is just what the Rochester physicists describe in a new paper published in the Journal of Mathematical Physics.
"The existence of such a derivation indicates that there are striking connections between well-established physics and pure mathematics that are remarkably beautiful yet still to be discovered," the authors write....
- - - - - - - -
Quantum dilemma: We have too many options for explaining reality
https://www.newscientist.com/article/mg2...s-meeting/
EXCERPT: It's time to put all the quantum cards on the table. That’s the view of a group of physicists who assembled in Vienna last month to present a variety of ideas, results and plans for future experiments that might help find an explanation for the weirdness of quantum theory.
Quantum physics is well known for being weird. The theory – and the experiments that have confirmed it – rip gaping holes in our concept of space, time and reality. Most physicists simply accept this as the way things are. But most of the 70 or so researchers who gathered in Austria at the Vienna symposium on “Emergent Quantum Mechanics” from 23 to 25 October were there to go deeper, and ask where the quantum laws might come from. Is quantum physics a stepping stone to a deeper understanding of reality?
“There are many people who think they are well along the path to a better understanding, but they all contradict each other,” says Aephraim Steinberg of the University of Toronto, Canada. “So maybe one of them is right – but I certainly don’t know which one.”
Steinberg presented experiments that attempt to show the paths photons take as they appear to pass simultaneously through two slits. This is because of quantum superposition – a trick in which the photon seem to be in two different states at once. The most widely accepted interpretation of quantum theory claims that this is possible because the photons only have definite properties once they have been detected. Before that, there is only a mathematical wave function describing possible outcomes of the measurement.
But Steinberg prefers to interpret the experiment in terms of so-called Bohmian mechanics, which suggests that there are pre-existing connections between all quantum particles. Each particle has an associated “pilot wave” that guides its position and momentum, so it takes a particular trajectory through the double slits. “These are very straightforward experiments that draw a connection between that model and what happens in the real world,” he says.
Many find Bohmian mechanics unsatisfactory. But discussions at the meeting made it clear that the same can be said of most interpretations – and it was....