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5 minutes ago, archer said:


But at least that's enough time to grab your overhead luggage and exit the vehicle.


Dunno what airlines you fly.  It takes fifteen minutes before I can even stand up if I fly steerage class like usual.

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Sunset on Mars:  

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A couple of quibbles here.   Most of these are in the Venus section of the above ... the quote "only three missions" to Venus omits several Soviet Venera landers in the 1960s; no one else ha

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19 hours ago, Lord Liaden said:

Honestly, I was kinda hoping one of the scientists here could explain it. :think:

Not a scientist, but I've seen a lot of these breathless articles in which a theoretical physicist claims he's on the verge of a Revolutionary Theory of Everything. Careful reading usually reduces this to, "Ooh, I'm playing with some really pretty math!" Or, "Hey, here's a wacky notion that'll get me talked about even though I don't even have a way to turn it into math, let alone an experiment."


The article does not give me sufficient information to tell which this is, though it seems Dr Vanchurin is talking about computational structures, not asserting that the Universe is thinking.


Dean Shomshak

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Okay, I've searched my memory a bit and I think I might sorta have a notion what Vanchurin is doing. But to explain it, I have to go back to mathematician John Horton Conway's game of Life, which I read about years ago in Martin Gardner's Mathematical Games" column in Scientific American. I hope I don't mangle it too badly.


Life is played on an infinite square grid. Each square has two states, white or black. (or On and Off, whatever. Binary.) At each step of the "game," a square may change its state based on the states of its 4 adjacent squares. (I don't remember the rules, but they are very simple.)


Start with one black square and a pattern radiates out, tick by tick of the clock, growing more complex as sections interfere with each other.


Set more than one black square and the patterns become immensely complex, shifting and moving, almost like something... alive.


People playing with Conway's game found stable, repeating patterns. One such was the "glider," a small pattern that -- if it doesn't run into anything else -- re-creates itself after several steps, but moved a short distance across the grid.


Later, mathematicians found a "glider gun": a larger pattern that stably repeats, but in the process it periodically releases gliders.


And then a team of mathematicians proved the existence of an immensely large and complicated pattern that can replicate itself. It incorporates several glider guns, controlled by a "program" that turns them on an off, so the gliders travel out and collide with each other to generate the original pattern, complete with the instructions (coded into a set of black and white squares) for it to create another copy, which creates another copy, and so on. Like a living cell. All in a two-dimensional universe of squares with properties you could write on a file card.


Do you see why some of Professor Conway's fans change his initials from "J. H." to "J. H. V. H."?


Anyway, Life is a simple example of a computational system called "cellular automata." Each square is an "automaton" that takes in information and produces a result: white or black. These automaton-squares are "cellular" in that each unit only knows about what's going on in its immediately adjacent units. But even though each automaton-square has only very simple behavior, based on very limited information, the whole system of squares can generate immense complexity.


A few mathematical physicists, seeing the complex phenomena that can appear even in such a rudimentary "universe" as Life, are trying to devise systems of cellular automata whose emergent behavior will emulate the known particles and forces of physics. They hope it might reduce physics to something more coherent than the current Standard Model. IIRC one physicist devised a system that emulated an electron and positron orbiting each other, but AFAIK the approach hasn't generated any testable new predictions. Well, at this point it makes as much sense as String Theory.


I *think* Vanchurin is trying to represent forces and particles using a conmputational "universe" based on neural nets. IIRC a neural net consists of scads of little processing units that are connected to each other. Instead of forming a simple grid as in Life, though, they're connected higgledy-piggledy. And instead of flipping on or poff according to simple, fixed rules of proximity, the connections between "cells" become stronger or weaker. The network can be "trained" to do things like recognize tanks in photos despite the tanks being at different angles or partly obscured. Unlike a normal program, though, the "knowledge" to do this isn't in a distinct set of rules -- it's somehow coded into which cells are connected to which, and the strength of those connections.


(It would be very nice if someone who knows more about neural nets would chime in at this point.)


I suppose Vanchurin is trying to work out a computational system like this, of "cells" whose connections shift, as a way to model particles and forces. I can't imagine how you'd do this, but I'm not a computer scientist. As such, I can't judge whether the approach is intrinsically crazy. But it also sounds like Vanchurin hasn't gone beyond playing with math, either.


Dean Shomshak, Interested Layman

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I was hoping it meant the whole universe is a living organism, maybe conscious and thinking. IOW a scientific approach to God. (And yeah, that would also make for a cool game-world universe.)


This next is actually a serious story, but the jokes just spring effortlessly from the title: Proposed ‘Moon Ark’ would shoot sperm into space to save the Earth.

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Meanwhile in real physics, experimenters at CERN and Fermilab are getting strange results in experiments with muons. This isn't a space story as such, but particle physics has implications for cosmology, because they merge at the Big Bang.


First, what's a muon? It's a subatomnic particle whose properties are exactly the same as en electron, except it has 207 times the mass, and it decays into an electron (plus an anti-neutrino and energy) in, IIRC, two millionths of a second. Which is a long time in particle physics terms. I have neve heard any obvious reason why muons should exist, but they do.


Anyway: I heard on BBC that physicists at CERN have been going through the enormous amount of data generated by the Large Hadron Collider, looking for, well, anything interesting. One thing they checked was a certain particle decay process. Theory says it should produce equal numbers of electrons and muons (which would then decay into electrons, but that's easy to spot.) Except they don't. For every 100 electrons produced, there are only, IIRC, 85 or so muons. They don't know why.


Meanwhile, I read in the NYTimes that at Fermilab, a team of physicists have been studying the magnetic moment of the muon, which I gather has something to do with how they wobble in a magnetic field. Their calculations from the Standard Model of particle physics predicts one number; they are getting another.


This discrepancy was noticed before, when this experiment was done at the Brookhaven laboratory, but the result couldn't be replicated because the funding ran out. Now it's been duplicated.


Physicists caution that these are preliminary results. They estimate there is still a 1 in 1,000 chance the CERN result is a fluke, and a 1 in 40,000 chance the Fermilab result is a fluke. That might sound impressive to us laymen, but it's not good enough for physics. There must be further experiments and more data before these results can be called certain.


Physicists are excited, though, because these results directly contradict the Standard Model. That model became standard because it's made some very good predictions (the Higgs Boson being the biggest success), but it has problems. It's kind of a kludge. It includes more than a dozen constants whose values appear to be arbitrary. It predicts some phenomena that have not been observed, such as proton decay. It doesn't give a solid answer for what dark matter is, let alone dark energy. It doesn't incorporate General Relativity. So physicists have been sure there must be new physics to be found, but without experimental results to guide them, theorists have been spinning their wheels. Now they might have some clues.


(Further caveat: A different team of physicists, using a different technique of calculation, says their method *does* predict the Brookhaven/Fermilab value for the muon's magnetic moment. But even that might be a clue. Because if both teams are competent, the Standard Model should not be generating two different results.)


The physicists agreem though, that more experiments are needed to lock down the results and solve the Mystery of the Muons.


Dean Shomshak

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1 hour ago, DShomshak said:

For every 100 electrons produced, there are only, IIRC, 85 or so muons. They don't know why.


Dean Shomshak


I think I know why.


The muons are much more massive than the electrons which, among other things, means they have more surface area.


So inside the CERN device, the gluons are sticking to the muons at an increased rate.


The gluons in turn are sticking to the sides of the collider rather than making it around to the place where particles are counted.


One of these days, they'll figure out there's a sticky glue buildup on the insider of the collider. And when they open it up to scrape out the sticky mess, they'll find the missing muons. 

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I dare say it's because Treknobabble was trying to sound like real physics... badly.


Muons, incidentally, were discovered in 1936. They've been fairly mysterious almost from that moment, because there is no obvious reason for a "heavy electron" to exist. You can read the full story in the Wikipedia article about muons.


They're made in cosmic ray showers, though, so in Champions it might not be amiss to connect muons to cosmic ray-induced origin events.


Dean Shomshak

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MIAMI (CBSMiami) – A fireball streaking across the sky Monday night was seen from Tampa to the northwest Bahamas.

So what was it?


CBS4 Chief Meteorologist Craig Setzer said it looks like it was a very close pass of asteroid 2021 GW4. He said it was likely passing about 9,000 miles above us and briefly struck the atmosphere while moving at 16,000 mph.




This is really good news:

the Earth has a lot more air than we thought it did if an asteroid which is 9000 miles away is touching the atmosphere.

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Well, answer one: the location of the asteroid is known +/- 9000 miles. Or less dreadful, the asteroid is just the biggest hunk of a collection of stuff, and a chunk peeled off and entered the atmophere...or something else I did not think of....

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