Official "Science News" Thread - Page 49

only_human · 2012-05-11, 03:47

Luboš Motl has a blog entry on this:Has Anton Zeilinger created a time machine?

Quote:

It follows that the probabilistic distributions for individual photons and their groups won't depend on the timing of the measurements, either. All these facts are trivially seen from the very description of the experiments and may be translated to completely rigorous and provable propositions in the quantum mechanical formalism.

I don't quite follow what he is saying but perhaps you guys can. He seems to not be shy about speaking out about new results. I referred to him back when it looked like there might be superluminal neutrinos. Here he also mentions the delayed choice double slit experiment that I was trying to recall:Delayed choice quantum eraser

cheesehead · 2012-05-11, 06:28

Quote:

Originally Posted by only_human

Luboš Motl has a blog entry on this:Has Anton Zeilinger created a time machine?I don't quite follow what he is saying but perhaps you guys can. He seems to not be shy about speaking out about new results.

He's also not shy about slandering AGW proponents. When I asked him where, exactly, one AGWer had made the statements Motl falsely attributed to him, all that happened is that my question disappeared in the moderation queue ... just as it did when I posted my question again.

ewmayer · 2012-05-13, 19:23

Fascinating:

Textbook Electrodynamics May Contradict Relativity

My snips below are from]the original Science article (linked in the above0, which requires a subscription to view fully online.

Such a simple Gedankenexperiment, too - amazing it took over 100 years for someone to come up with it (or at least think of it and not dismiss it with a "I must be missing something").

There is a way out, Mansuripur says: No torque appears in either frame if he uses a more complicated formula for forces in polarized and magnetized materials that Einstein and Jakob Laub proposed in 1908 but Einstein later repudiated.

"Die größte Dummheit meines Lebens", v 2.0?

It sounds to me - and now that I found the actual PRL article abstract, I see the author says just that - less like an issue with relatively and EM per se - Maxwell's equations are provably invariant under Lorentz transformation (in fact, that at-the-time astonishing fact helped Einstein formulate SR) - rather it sounds like there are a whole lot of dubious hypotheses built
into the physical model of magnetic materials, by way of the "force law" named after the same Lorentz. Think about it: If this were any other field but quantum physics, would the practitioners have been able to get away with wild-speculation-sounding stuff like this for so long?

in classical electrodynamics, magnetism originates from hypothetical loops of “bound” current within a material.

100 years later, those are apparently still hypothetical, accepted as fact because "the model works." Or at least, seemed to work. Until now.

--------------------

Update: A fried just sent me this, which claims to resolve the apparent paradox. I must say, the word "hidden" crops up very frequently - perhaps that is just unfortunate choice of wording by the physics community in this case:

There is a torque in the moving frame, and it does not contradict relativity.

davieddy · 2012-05-20, 23:23

Quote:

Originally Posted by ewmayer

Fascinating:

simple Gedankenexperiment

I'm currently contemplating experimenting with my "gedanken" right now.
Although I'd describe it more accurately as "tried and trusted".

D

ewmayer · 2012-05-27, 20:30

Can You Be Too Clean?: We lead super clean lives in which hand sanitizers and antibiotics are the answers to everything. But what if our war on germs was backfiring—and making us not only sicker but fatter?

My favorite quote:

"Some estimates suggest that up to 9 pounds of microorganisms colonize the food highway that begins at the average guy's mouth and ends at his butt. Revolting, yes, but also crucial."

The commensals - were they capable of publishing - might put a slightly different spin on the arrangement:

"Some estimates suggest that up to 300 pounds of sweaty, grunting, farting, fornicating 'guy' colonize the microorganism food highway that begins at the average guy's mouth and ends at his butt. Revolting, yes, but also crucial. And yet this same thankless 'guy' has no qualms about committing global microbicide anytime he feels anything amiss with his sweating, grunting, farting or fornicating processes. He is a monster, my microbial brothers and sisters ... let us rise up and put him in his place once and for all."

Uncwilly · 2012-05-27, 23:01

German teen solves 300-year old mathematical riddle posed by Sir Isaac Newton

Dubslow · 2012-05-28, 00:12

Quote:

Originally Posted by Uncwilly

German teen solves 300-year old mathematical riddle posed by Sir Isaac Newton

I would like to see an article with more actual detail. In my high school AP class we did air resistance -- it's just F $\propto$ v² for a given aerodynamic profile. It is then trivial to subtract it from gravity and solve the resulting differential equation. Therefore, that article is inaccurate; a demonstration of how bad the media is.

cheesehead · 2012-05-28, 03:50

Quote:

Originally Posted by Dubslow

I would like to see an article with more actual detail. In my high school AP class we did air resistance -- it's just F $\propto$ v² for a given aerodynamic profile. It is then trivial to subtract it from gravity and solve the resulting differential equation. Therefore, that article is inaccurate; a demonstration of how bad the media is.

The first thing that needs to be noted is that it's on Fox News.

An accurate science article on Fox News would be ...

only_human · 2012-05-28, 09:45

Stack exchange Teenager solves Newton dynamics problem - where is the paper? has a link to German site with this Google translation

Quote:

"Young Scientist"

At this year's regional competition "Young Scientist" has Shouryya Ray (class 12) with its theme "Analytical solution of two fundamental unsolved problems of particle dynamics," thrilled the jury really - a very deserving first Space and a delegation to the state competition were the logical consequence. Congratulations and much continued success!

including a picture of him standing in front of an exhibit: http://www.manos-dresden.de/aktuelle.../shouryya1.jpg

Looking at that exhibit, he mentions Kruggel & Emden 2005, and Kempe & Fröhlich 2011. Some of the graphics in the exhibit seem to match graphics in Impact of collision models on particle transport in open channel flow

only_human · 2012-05-28, 11:47

Slashdot 350-Year-Old Newton's Puzzle Solved By 16-Year-Old has looked at it. Comments point to Reddit Teen Solves Newton’s 300-Year-Old Riddle - An Indian-born teenager who lives in Germany has solved a mathematical problem posed by Sir Isaac Newton that's baffled mathematicians ever since

Quote:

I posted this over at /r/math ( http://www.reddit.com/r/math/comment...lating/c4szzld ):
Here's a forward solution (found by reverse-engineering the answer):
Consider a projectile moving in gravity with quadratic air resistance. The governing equations are
u' = -a * u * sqrt( u2 + v2 )
v' = -a * v * sqrt( u2 + v2 ) - g
where a is the coefficient of air resistance defined by |F| = ma|v|2 .
Cross-multiply and rearrange to find
a * sqrt( u2 + v2 ) * (uv'-vu') = gu'
Substitute v = su and separate variables:
a * sqrt( 1 + s2 ) * s' = g*u'/u3
Integrate both sides to get the answer:
g/u2 + a(v * sqrt( u2 + v2 )/u2 + arcsinh|v/u|) = const

xilman · 2012-05-28, 14:21

I'm surprised no-one else has posted this news yet.

For several years, Southern Africa and Australasia have been in competition to host the Square Kilometre Array, a telescope so big that each site was larger than either of the lead countries of South Africa and Australia.

The decision has been made that it will be built in each country. In consequence it will cost more but should have greater resolution for areas of the sky visible from both sites at once.

More details at http://www.bbc.co.uk/news/science-environment-18194984 and links therein.

Paul

2012-05-13, 19:23	#531
ewmayer ∂²ω=0 Sep 2002 República de California 19×613 Posts	Textbook Electrodynamics May Contradict Relativity Fascinating: Textbook Electrodynamics May Contradict Relativity My snips below are from]the original Science article (linked in the above0, which requires a subscription to view fully online. Such a simple Gedankenexperiment, too - amazing it took over 100 years for someone to come up with it (or at least think of it and not dismiss it with a "I must be missing something"). There is a way out, Mansuripur says: No torque appears in either frame if he uses a more complicated formula for forces in polarized and magnetized materials that Einstein and Jakob Laub proposed in 1908 but Einstein later repudiated. "Die größte Dummheit meines Lebens", v 2.0? It sounds to me - and now that I found the actual PRL article abstract, I see the author says just that - less like an issue with relatively and EM per se - Maxwell's equations are provably invariant under Lorentz transformation (in fact, that at-the-time astonishing fact helped Einstein formulate SR) - rather it sounds like there are a whole lot of dubious hypotheses built into the physical model of magnetic materials, by way of the "force law" named after the same Lorentz. Think about it: If this were any other field but quantum physics, would the practitioners have been able to get away with wild-speculation-sounding stuff like this for so long? in classical electrodynamics, magnetism originates from hypothetical loops of “bound” current within a material. 100 years later, those are apparently still hypothetical, accepted as fact because "the model works." Or at least, seemed to work. Until now. -------------------- Update: A fried just sent me this, which claims to resolve the apparent paradox. I must say, the word "hidden" crops up very frequently - perhaps that is just unfortunate choice of wording by the physics community in this case: There is a torque in the moving frame, and it does not contradict relativity. Last fiddled with by ewmayer on 2012-05-13 at 19:34

2012-05-27, 20:30	#533
ewmayer ∂²ω=0 Sep 2002 República de California 19×613 Posts	Article on the Human Microbiome Can You Be Too Clean?: We lead super clean lives in which hand sanitizers and antibiotics are the answers to everything. But what if our war on germs was backfiring—and making us not only sicker but fatter? My favorite quote: "Some estimates suggest that up to 9 pounds of microorganisms colonize the food highway that begins at the average guy's mouth and ends at his butt. Revolting, yes, but also crucial." The commensals - were they capable of publishing - might put a slightly different spin on the arrangement: "Some estimates suggest that up to 300 pounds of sweaty, grunting, farting, fornicating 'guy' colonize the microorganism food highway that begins at the average guy's mouth and ends at his butt. Revolting, yes, but also crucial. And yet this same thankless 'guy' has no qualms about committing global microbicide anytime he feels anything amiss with his sweating, grunting, farting or fornicating processes. He is a monster, my microbial brothers and sisters ... let us rise up and put him in his place once and for all."

2012-05-28, 14:21	#539
xilman Bamboozled! "𒉺𒌌𒇷𒆷𒀭" May 2003 Down not across 2×5,393 Posts	SKA to be shared between both sites I'm surprised no-one else has posted this news yet. For several years, Southern Africa and Australasia have been in competition to host the Square Kilometre Array, a telescope so big that each site was larger than either of the lead countries of South Africa and Australia. The decision has been made that it will be built in each country. In consequence it will cost more but should have greater resolution for areas of the sky visible from both sites at once. More details at http://www.bbc.co.uk/news/science-environment-18194984 and links therein. Paul

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
Official "Faits erronés dans de belles-lettres" thread	ewmayer	Lounge	39	2015-05-19 01:08
Official "all-Greek-to-me Fiction Literature and Cinema" Thread	ewmayer	Science & Technology	41	2014-04-16 11:54
Official "Lasciate ogne speranza" whinge-thread	cheesehead	Soap Box	56	2013-06-29 01:42
Official "Ernst is a deceiving bully and George is a meanie" thread	cheesehead	Soap Box	61	2013-06-11 04:30
Official "String copy Statement Considered Harmful" thread	Dubslow	Programming	19	2012-05-31 17:49

2012-05-27, 23:01	#534
Uncwilly 6809 > 6502 """"""""""""""""""" Aug 2003 101×103 Posts 2²×23×107 Posts	German teen solves 300-year old mathematical riddle posed by Sir Isaac Newton