“It is remarkable that mind enters into our awareness of nature on two separate levels. At the highest level, the level of human consciousness, our minds are somehow directly aware of the complicated flow of electrical and chemical patterns in our brains. At the lowest level, the level of single atoms and electrons, the mind of an observer is again involved in the description of events. Between lies the level of mole…
Freeman Dyson Has Died
81–90 of 267 posts
Re: Freeman Dyson Has Died
#82Started writing "later” in life: “Life begins at 55, the age at which I published my first book,” he wrote in “From Eros to Gaia,” Never got his PhD. Taught physics at Cornell. Thoughts on climate change: "Relishing the role of iconoclast, he confounded the scientific establishment by dismissing the consensus about the perils of man-made climate change as “tribal group-thinking.” He doubted the veracity of the climat…
I think Dyson was misunderstood in his criticism of climate science - he admitted that he didn't study the science itself, but he was concerned about how the scientific culture in the field seemed to be working
Re: Freeman Dyson Has Died
#83Earlier quoted context omitted.
Huh, I'd be curious to see that source. I know he somewhat recanted the idea of a Dyson sphere , as it is completely impractical even with unimagined technology (re: tensile strength of the materials, and preventing such a megastructure from falling into the sun whenever a rock hits it). But he later proposed the idea of a Dyson swarm , an extremely large array of solar-sucking satellites orbiting the sun as an idea…
One thing that's slightly interesting about Dyson Sphere's is that spherical shells of matter exert exactly no gravitational pull at any point in their interiors. That is, the integral of gravitational pull over the whole shell is identically 0 for every point inside the shell.* This goes for any force that falls off by the inverse square rule, e.g. the electrostatic force. In short, there's no practical way to stick…
think about the 2d equivalent - a ball rolls down a hill because the potential gradient directs it that way. a ball sitting on a flat pedestal isn't being pulled in every horizontal direction at once by some forces that are proportional to the height of the pedestal. it's not being pulled horizontally at all
there is zero space-time curvature within the sphere, it's "flat", so there's no force. nothing is "cancelled out", force is the derivative of energy with respect to space. it's like a 3d pedestal (or rather, a cylinder excavated from the earth with a flat bottom)
Re: Freeman Dyson Has Died
#84About 4 years ago, I was a grad student in astrophysics at Princeton. Dyson worked at the Institute for Advanced Study which, while not officially part of the university was essentially an extension of the various departments (shared colloquiums, any researcher there was a valid thesis adviser, etc.). The grad students have a tradition (or used to) called “Thunch” (Thursday Lunch) where they invite someone to come ha…
I've met him and his other daughter. They are/were wonderful people. There were a lot of "solutions" using nuclear weapons looking for a problem. There was a proposal to blow a new canal through nicaragua, to blast harbors into Alaska, etc. My roommate's father showed me his paper that anticipated fracking: drill a deep well in oil shale, through a small nuclear weapon in the bottom, blow it up and watch as the press…
Total was floating the idea of doing just this in Alberta a recently as the past decade. The science really seems to work but the idea of a small nuclear explosion in your backyard (on purpose is a hard sell (even for the relatively open-to-nuclear French!)
Re: Freeman Dyson Has Died
#85A few years ago, I asked Freeman Dyson what we should teach our children so there would be more Freeman Dyson's. He gave a surprising answer.
He said we should teach children to genetically "play" with plants. He thought we needed that kind of creativity as a human species if we would ever be able to populate the asteroid belt. He said that most of the surface area of the solar system is in the asteroid belt -- but the only way we could really live out there was if we could create warm blooded plants.
Re: Freeman Dyson Has Died
#86Earlier quoted context omitted.
Or to look at it from a different angle, their fall is caused by their old age decline which in turn triggers their terminal decline. I've seen it throughout my family, once confined to bed at old age one's decline accelerates quickly. It's perhaps that the lack of movement that has some spiraling effect on their health. More and more people should not stop doing sports when they get older, they should do sports less…
I wonder how much of this depends on how big a change there is in movement? Would a lifelong couch potato for whom their post fall movement is only a few percent less than what it was before the fall be less affected than someone who had been very active before their fall and had to cut their movement by 95%?
Yes, good point. On the other hand I wonder if there is any person who aged well who had been a couch potato their whole life. I've seen very old people who were no longer very active but had been very active throughout their life. They still had some light and slow walks on a daily basis !!
Movement helps with digestion is something I learned from firsthand experience. Due to a broken leg I was confined to a bed for nearly 2 months and remember bowel movements were extremely affected. Movement helps with arthritis, helps the brain, helps the bones.
Also, the lymph system requires breathing and movement from the body's muscles to help move fluids and remove waste from the body.
Re: Freeman Dyson Has Died
#87Earlier quoted context omitted.
That quote is mindblowing. I don't think I've ever heard an argument for free will on a sub-atomic level. It never crossed my mind that that was a position someone could conceivably hold. But it's weirdly comforting- it almost feels religious- and I'm now thinking about how that would affect emergence.
I don't know where I first heard that view, but I've long thought it was the only one that was plausible - where else could free will come from? is it supposed to sneak into physics somehow at a higher level?
Another plausible view is that it never sneaks in. Nondeterminism would only lead to free will if the mind somehow controlled the nondeterministic outcomes. We know the brain can't do that, so it's clearly a metaphysical question if you want to go further (the mind would have to be an agent distinct from the brain.) The answer to a metaphysical question is not always "no," but you will never be able to prove it.
Re: Freeman Dyson Has Died
#88I think last week someone mentioned the dyson sphere with a link to wiki. It said he regretted they named it after him.
Huh, I'd be curious to see that source. I know he somewhat recanted the idea of a Dyson sphere , as it is completely impractical even with unimagined technology (re: tensile strength of the materials, and preventing such a megastructure from falling into the sun whenever a rock hits it). But he later proposed the idea of a Dyson swarm , an extremely large array of solar-sucking satellites orbiting the sun as an idea…
I tried following the link on the wiki page but it actually is a dead end, so I am not sure about it anymore
Re: Freeman Dyson Has Died
#89"When I listen to the public debates about climate change, I am impressed by the enormous gaps in our knowledge, the sparseness of our observations and the superficiality of our theories" "We have no reason to think that climate change is harmful if you look at the world as a whole. Most places, in fact, are better off being warmer than being colder. And historically, the really bad times for the environment and for…
the ridiculously hot summers in Australasia resulting in bushfires, famine and drought... seas taking over the cities are all demonstrable effects of climate change. Did he live in UK? Yea the winter was milder I guess.
There are plant species that are dependent upon fire for reproduction. Such species begin to die if all fire is suppressed.
https://en.wikipedia.org/wiki/Pyrophyte
https://www.gardenguides.com/97493-eucalyptus-trees-australi...
https://www.bushheritage.org.au/species/grass-trees
https://www.nationalforests.org/our-forests/your-national-fo...
https://www.quora.com/What-seeds-need-fire-to-germinate-like...
https://thekidshouldseethis.com/post/why-the-giant-sequoia-n...
When the Iraqis set the Kuwait oil wells on fire as they left, it was predicted that they would burn for years and be a global environmental disaster. They were put out in six months. This was never celebrated. The news just moved on to something with more drama.
In the aftermath of the fires, the combination of ash and water used to put many of them out caused the desert to bloom like no one had seen in at least twenty years. This also was not widely promoted as some kind of good news.
When I was pursuing environmental studies, there was a cartoon in one of my textbooks depicting microbes giving off oxygen and some of the microbes protesting that they were destroying their environment and needed to stop. Microbes that off-gassed oxygen are how we got an oxygen atmosphere on earth.
One of my professors once said "We're like fleas on the butt of a dog trying to figure out which way the dog is going."
The truth is we don't really know as much as some people like to pretend we do and we do present stories in a biased fashion. The people who are convinced we are hurtling towards our doom generally don't want to have a rational discussion of the evidence. They are too busy trying to insist that our lives are in imminent danger and there's no time for rational discussion, we must do something to stop this.
Re: Freeman Dyson Has Died
#90A book called something like 'Quantum Mysteries for Bluffers' described his work on QED this way:
Feynman, Schwinger and Tomonaga independently discovered quantum electrodynamics. Then Freeman Dyson explained it -- to the first three!