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Physics Forums Featured Threads

Genoa Bridge Collapse  Engineering Perspectives
The dramatic collapse of a bridge in Italy with many fatalities has been the big item of news all over Europe. I just wonder if the qualified people here can throw any light not on the specifics which would be hard for them to know, but in general... 
Basic Math Challenge  August 2018
Summer is coming and brings a new basic math challenge! Enjoy! For more advanced problems you can check our other intermediate level math challenge thread! 
Intermediate Math Challenge  August 2018
Summer is coming and brings a new intermediate math challenge! Enjoy! If you find the problems difficult to solve don't be disappointed! Just check our other basic level math challenge thread! 
Sabine Hossenfelder and Beauty in Physics
From the Vice article: "Who doesn’t like a pretty idea? Physicists certainly do. In the foundations of physics, it has become accepted practice to prefer hypotheses that are aesthetically pleasing. Physicists believe that their motivations don’t matter because hypotheses, after all, must be tested. But most of their beautiful ideas are hard or impossible to test. And whenever an experiment comes back emptyhanded..." 
Happy RNA Day!
Today (AUG 1) is RNA Day, an international celebration of one of the most versatile biomolecules in existence. What are some areas of RNA research that excite you most? Some of the most intriguing areas of current research to me (with example links for further reading)... 
How is physics knowledge used in everyday life?
What I am struggling to come to grips with is how knowing physics, the topics typically taught in a high school intro course, can be useful in everyday life. I am not looking for everyday examples of physics concepts. I mean real actual examples of using Newton’s laws or momentum in real life purposefully. Can you think of a time when you actually used your physics knowledge in everyday life? 
What makes a problem computationally NP?
As the title says, what makes a decision problem NP complex? Is it application of the definition (as in: solvable in polynomial time by a nondeterministic Turing machine)? Also, if P does not equal NP, does it mean that NP problems can only be solved in O(exp(n)) time/steps? 
Easy ways you can support Physics Forums
We are all members of an amazing community of science and math passionate people from all over the globe. However, "amazing" doesn't just happen over night or by itself. "Amazing" happens when members take pride and responsibility for the health of the community... 
Basic Math Challenge  July 2018
Summer is coming and brings a new basic math challenge! Enjoy! For more advanced problems you can check our other intermediate level math challenge thread! 
Intermediate Math Challenge  July 2018
Summer is coming and brings a new intermediate math challenge! Enjoy! If you find the problems difficult to solve don't be disappointed! Just check our other basic level math challenge thread! 
What are the frontiers of cosmology research?
I have completed post grad in Physics and in the transition phase between post grad and Ph.D. I am interested in cosmology and also completed a post grad course on Astrophysics and Cosmology. Can anyone enlighten me about what are the current debates and active topics of research going on in Cosmology? 
No metastable type IIB de Sitter vacua
Take note of today's ObiedOoguriSpodyneikoVafa 18. Curious situation: After it had influenced much the development of the string theory community’s attention and almost all of its public media perception since 2003, after what must be thousands of followup publications, the argument of KKLT 03 for a large finite number of metastable de Sitter spacetime vacua of type IIB string theory... 
Contoversy about NASA's Asteroid Tracking
Nathan Myhrvold has raised questions about the accuracy of data NASA uses to track asteroids that may impact the earth. Myhrvold is a former Microsoft chief technologist and a guy with many diverse interests.
Specifically he has questioned the size information and how it was derived. This concerns the Neowise project which was derived from the Widefield Infrared Survey Explorer (WISE) project... 
New perspectives on Mtheory
"By analyzing supertorsion and brane supercocycles, we derive a new duality in Mtheory, which takes the form of a higher version of Tduality in string theory. This involves a new topology change mechanism abelianizing the 3sphere associated with the Cfield topology to the 517torus associated with exceptionalgeneralized supergeometry. Finally we explain parity symmetry in Mtheory"... 
Rigged Hilbert Spaces In Quantum Mechanics
In discussing stuff in another thread I used the standard Dirac notion expanding a state in position eigenvectors namely u> = ∫f(x) x>. By definition f(x) is the wavefunction. I omitted the dx which is my bad but the following question was posed which I think deserved a complete answer. It was also off at a tangent to the main threads topic so really required a separate thread...
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