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Physics Forums Featured Threads

Some Questions on Differential Forms and Their Meaningfulness
I've been trying to get a meaningful understanding of the benefits of using differential forms. I've seen examples of physics formulas that are reduced to a very simple declarative form relative to their tensor counterparts. However to me it just seems like a notation change to implied tensor indices... 
Propane heater behavior
I have one of these propane heaters. As months go by, it has an increasing habit of spazzing out. It will frequently do this in a strong gust. But with even a little wind, and more often when it is set on low, it will spontaneously and startlingly begin screaming like a rocket engine. When it does so, the mantle immediately starts cooling... 
Intermediate Math Challenge  May 2018
Math Challenge threads are back! To kick things off we have a set of "intermediate" math challenges! For more basic problems you can check our other basic level math challenge thread! Please read and adhere to the rules posted at the top of the challenge thread. Enjoy! 
Basic Math Challenge  May 2018
Math Challenge threads are back! To kick things off we have a set of "basic" math challenges! For more advanced problems you can check our other intermediate level math challenge thread! Please read and adhere to the rules posted at the top of the challenge thread. Enjoy! 
What type of bacteria evolved into mitochondria?
An important step in the evolution of plants, animals and other complex, multicellular forms of life was eukaryogenesis, the evolution of eukaryotes. Eukaryotes are one of the three major classifications of life (alongside singlecelled bacteria and archaea), and are characterized by cellular compartmentalization, an extensive membrane network inside of the cells, and the presence of mitochondria... 
STEM Bibles List
By STEM I mean science, technology, engineering and math. By a bible, I mean a book which is comprehensive, big and heavy (both physically and intellectually), authoritative, and generally highly respected in the community as the standard book that contains moreorless everything one need to know about the subject... 
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?
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