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Physics Forums Featured Threads

One of my wheelchair motors overheats and stops working
I use an electric wheelchair to get around and can only walk a few steps with a wheeled walker. Yesterday I went to my local out of town ASDA, a 1.5 mile trip approx through an alley/Public Footpath, I have done this many times before. This time I was about 3/4 of the way there and the chair started to judder and slow down and pull to the right. It then stopped... 
Young Edison, or Edison's cat
Today, I'm enjoying a very good book about the young Thomas Alva Edison when he was 1015 years old. I just came across this fun anecdote that I can't resist sharing. It reminds me of the many threads we get here on PF asking about novel ways to generate electricity. 
New result in high temp superconductivity
This suggests the possibility no new theory beyond BCS is necessary.
I’m interested especially in comments by members who work in this or related fields. 
Magnetic flux is the same if we apply Biot Savart?
Initially I am aware that magnetic flux is conserved due to divergence of magnetic field is zero and for long solenoid, magnetic field inside is uniform. So magnetic field intensity (B) at point P,Q,S, T,R,U(in the attachment) must be same. But my question is : can we obtain the same magnetic field intensity at point S or R again at the point P or U using biot savart rule for constant current? 
What false hints of new physics were most notable?
Sometimes experimental or observational evidence from credible physicists points to new physics and then turns out to be wrong due to statistical flukes, experimental error or a theoretical analysis mistake. What cases of this happening do you find most notable, what showed that the hints were unfounded, and why do you find them most notable? I'll start with four, to which you can add your own... 
Is there a local interpretation of ReehSchlieder theorem?
Nonphilosophically inclined experts in relativistic QFT often insist that QFT is a local theory. They are not impressed much by arguments that quantum theory is nonlocal because such arguments typically rest on philosophical notions such as ontology, reality, hidden variables, or the measurement problem... 
Freeman Dyson's 1972 paper "Missed Opportunities"
I just stumbled upon the wellwritten 1972 paper "Missed Opportunities" by Freeman Dyson. Dyson argues that over time, people have become worse in following the mathematical hints inherent in the structure of physical theories. As an example, he compares the developments in both mathematics and physics following Newtonian physics with the "failure" to discover special relativity based purely on the transformation properties... 
Beauty of old electrical and measuring things, etc.
Even as a kid, I saw beauty in old devices. That made me want to understand how they worked. I had lots of old things that I keep and now reviving. Old things need to work to see the beauty. Here's what I've done so far. Here's a close up look at the meters, gauges and other measuring things... 
Dark Matter and who will discover it first?
While the subject has been talked about to death by many a researcher, who will discover the first dark matter scientific paper that will prove beyond theory that describes it in detail. The real discoverer will undoubtedly be the hero of physics, astrophysics, and cosmology and be awarded surely the Nobel Prize for science. Any notables that today seem on the cusp of it's discovery? 
LHC starts up in 2018
Yesterday the first beams this year circulated in the LHC. As every year, the machine operators start with a single low intensity bunch, checking that everything still works properly, and adjusting some parameters where the conditions changed over the winter shutdown. Meanwhile they slowly increase energy, protons per bunch and number of bunches, and finally the focusing of the beams... 
SuperKEKB/Belle II start up
This year we have two big particle physics accelerators running. SuperKEKB is an upgrade of KEKB, and the Belle II experiment at the accelerator is an upgrade of  you guessed it  Belle. It is located at KEK*, close to Tokyo in Japan, and it is starting up for the first time now. SuperKEKB is a Bfactory... 
Galaxy with no dark matter? (NGC1052DF2)
"The object, with the catchy moniker of NGC1052DF2, appears to contain no dark matter. If this turns out to be true, it may be the first galaxy of its kind  made up only of ordinary matter. Currently, dark matter is thought to be essential to the fabric of the Universe as we understand it."  BBC 
Interference puzzle  Where does the energy go?
A laser beam is split into two identical beams which impinge on a halfsilvered surface from opposite sides. The reflected wave is out of phase with the transmitted wave. There is destructive interference on both outputs. Where does the energy go? Normally when someone asks this question of an interference experiment I am the first to say... 
Quantum Theory for highschool students
I believe this could be interesting to many people here who are interested in quantum theory but are not (yet) professional physicists: "We present a conceptually clear introduction to quantum theory at a level suitable for highschool students attending the International Summer School for Young Physicists (ISSYP) at Perimeter Institute..." 
Bohr's complementarity is completed with entanglement?
Earlier this week, I found a very interesting paper pop up on the arXiv headed by Joseph Eberly, a notable figure in quantum optics and entanglement. In it, they look at the common treatment of waveparticle duality as a tradeoff between whichslit distinguishability, and the visibility of the resulting interference pattern...
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