Theories Definition and 457 Threads

Maybe this can lead to some absurd things that make no sense, but sometimes it may be enlightening. For instance, we think that gravity is an attractive force. Maybe we can ask "What if it's really repulsive instead"? What would it take to make gravity be repulsive and still see the results...

I am not an astronomer or astrophysicist but lately, I have been reading a lot of books to upgrade my knowledge in cosmology. I have encountered two issues that I am baffled about and wonder if anyone can help me throw some light on them (1) If the planets are parts of the sun or came from...

hello, I have just started to study topological field theories but my problem is that I do not find of books really specialized in the subject, can somebody inform me what I must do?

If theories of cosmology produce a (bounce) what happens to Black holes, it is hard to imagine that these posited things being riped apart.

I have a question, but I am not sure how to express it. I have been thinking about the idea of the universe as a four-dimensional object, with time as just another dimension. I have also been thinking about David Deutsch's idea of the universe as a sequence of quantized slices or slides...

I am not as well read as most of the people in here so I thought I would ask you guys first. What work has been done in the way of developing a covariant field theory? I'm going to ramble for just a little bit so try to follow. It seems to me that QFT is built on two principles Poincare...

Recently I saw a magazine which published an article on multiverse, where our universe is just one of the many possible universes resulted from inflation. That article claimed that the notion of a multiverse is gaining momentum. I am wondering if the view is shared by the majority of the...

Ok, I have a question about this Fade'ev Popov procedure of teasing out the ghosts when one quantizes a non-Abelian gauge theory with path integrals. The factor of 1 that people insert, for some gauge fixing function f, and some non-Abelian symmetry \mathcal{G} is: 1=\int \mathcal{D}U...

In an exciting and important development, a team of respected scientists has just announced the results of a direct test of non-locality using Leggett's Inequality. An experimental test of non-local realism, by Simon Groblacher, Tomasz Paterek, Rainer Kaltenbaek, Caslav Brukner, Marek...

So far i have found two theorise of how they form, the SSPSF shock wave model ,and the Density wave model, or they may form by a combination of the two. As i am not sure how old these theories are, i wonder if there are any new insights on the subject?

Hi all, i am 17 and researching Special Relativity for my coursework. It is due in next friday so i have left it late. I have researched some basics. I was wondering if anybody could help me out with any bright ideas, and tellme anything about the theories against light speed being constant. Id...

I am interest how one might falsify a scientific theory when we consider the objection from the quine-duham thesis. We can always blame one of the hypothesis that goes to making a perdiction, when the prediction does not correspond to reality.

Marco Genovese has put out a review that fairly well summarizes where things are at in tests of Bell's Theorem. He has done similar papers previously, and the references are quite comprehensive (there are 505, and they cover the spectrum). Research on Hidden Variable Theories: a review of...

could anyone tell me about the various theories about the universe and the most accepted ones i want to know just kinda like a summary of it so that when i go for this interview and they ask me to talk about these diff theories i can give them a jist of it/them Thank you

Have there been any theories in recent decades that suggest one? Or more? I know it may seem unnecessary or even frivolous, but theories beyond the standard model are, after all, grappling with issues like how the entire universe and its four forces came to exist. Has anyone postulated a fifth...

"Phenomenological" theories: thermodynamics Hello, I was reading A. O. Barut's Electrodynamics and Classical Theory of Fields and Particles and was interested by a phrase he used, "'atomistic' physical theories - in contrast to phenomenological theories like thermodynamics - ...". What could be...

http://physicsweb.org/articles/news/10/11/16/1 Latest data from Hubble indicates that: What are the ramifications of this finding for the various TOEs we have?

Hello everyone. How does one get a theory "out"? Let's say I have theory, but I'm not a trained physicist. I can't write out my theory as a mathematical equation. I can simply put it in words. How can I get someone trained in physics to look at it and tell me whether I'm smoking crack...

I've been trying to mine the web and Wikipedia but all I can find is his personal life, former students and some scanty information about his theories. Can someone explain to me some of his theories at least? I'd like to know what made this guy in a wheelchair so famous

What are the available theories to explain the amount of energy concentrated in quasars? And what are possible problems in those theories? I don't have any background in this, I'm just trying to ascertain whether the philosophy of technology book I'm reading is still up to date. Thanks.

Hello all - While discussing Darwin's Origin of Species with a friend, I was asked, "Do you really consider that 'science' "? My response was, "Yes." But upon reflection, the conversation made me realize I do not have a good definition of what science is and is not. Even after...

hello, i have a few theories questions to ask. (i don't know where to start for question such as these...) Question: By considering the angles between the vectors, show that vector A + vector B and vector A - vector B are perpendicular when |A| = |B|. Question: Prove for any vectors A and B...

i read that there are some logicians who do not use the axiom of choice in their axioms systems. i wonder what is the math that isn't using the axiom of choice, or what theories do not use it?

Many well regarded physicist, who have wone nobel prizes or discovered many theories, never got their BS/SB/or Bsc in physics. Is it any easier to get a phd in physics without getting a undergraduate physics degree? (time wise) Math degree (2 years) Masters (1 to 2 years) phd (3+ years)...

are there theories in cosmology which do not incorporate/use the cosmological principle?

# Foucault’s experiment to measure the velocity of light supported: 1)Corpuscular theory 2)Wave theory 3)Photon theory 4)Electromagnetic wave theory It cannot be Corpuscular theory because it said that the velocity of light in a denser medium is greater than that in a rarer medium. It...

Hello I have recently read an article about tensor vector scaler theories (Te VeS), including John Moffats STVG and Philip Mannheim's "conformal gravity", available at http://physicsweb.org/articles/world/19/6/5/1 I understand that Newtonian-Einstein gravity works very well across a...

does anyone have any equations for calculating time travel without an accelration close, equal or greater than the speed of light or equations or theories that would help me understand traversable wormhole theories and how to calculate them

"Hidden variables theories", what is the main arguments that these probably isn't theories of our universe? What kind of observations in a "hidden variable theory" would be diffrent from what we observe? And why are they different? Can someone please give some basic answears and maybe point...

this just out http://arxiv.org/abs/hep-th/0605052 Generic predictions of quantum theories of gravity Lee Smolin For inclusion in "Approaches to Quantum Gravity - toward a new understanding of space, time, and matter", edited by D. Oriti, to be published by Cambridge University Press "I...

Lately the number of scientists against the big bang theory is increasing for lots of reasons espacially the growing number of hypothetical entities like dark matter, dark energy and inflation which scientists were not able to observe but only to predict by the analysis of backround...

What are the (basic) problems with main stream theories of cosmology ? i do not want crackpotery, just what the people who work in or around the field think. I am unqualified to comment and will not, i hope moderators will keep this thead to the point.

Is every scientific theory developed based on the facts obtained from careful observations/ experiments?

We've been learning about Darwins Evolution and Natural Selection theories in Class... And what I've wondered was if there were any Anti-Darwinism theories since I've seen some before yet I can't seem to find none online.. Any help will be appreciated thanks:)

How can anyone construct a theory with less than 5 % of the information, i know that you lot are very cleaver, but AE would be a dwarf to any one that can get a 100% ansewer from 5% information available.

can someone please link me to some new LEGAL pdf's on newer theories and advancements in string theory, qed, lqg etc.

Will physics be first to attain unification, or has another branch of science already done so?

The Gravity Probe B satellite has placed four (over redundant) gyroscopes in low polar Earth orbit to primarily test two predictions of General Relativity. The first effect being tested is (for the GP-B polar orbit) a N-S geodetic precession, caused by the amount a gyro 'leans' over into the...

I came across this article, which was published in the February 2004 issue of Physical Review A. "All quantum observables in a hidden-variables model must commute simultaneously" by James Malley Abstract: Under a standard set of assumptions for a hidden-variables model for quantum events...

Dear PF, Could anyone advise me where I can find the following book: Dynamical symmetry breaking in quantum field theories - Miransky, V.A. Is itt possible to download from somewhere? Cheers George

This post is motivated by some of the discussion on the "Is QM inherently non-local" thread. The goal is to demonstrate that there is a local hidden interpretation possible for any signal local theory. This interpretation will be Bell local, but not Bell realistic. So, let's say we have a set...

hello its me again i have an other question. What does the latest physics theoreies say about this: Do photons have a mass if they are in movement ? i know that they have no mass if they not in movement. whats about deBroglie? Could you please give me an explanation which i do...

Does Bell's Theorem apply to non-local HV theories? I know that Bell says it doesn't, and he has included logic intended to make separability a requirement. But consider this argument: What does it mean to say there are hidden variables? Einstein said: "I think that a particle must have...

I am looking for some information on Tooth Eruption Theories. Thank you all. :)

Here is one I am having trouble following. Can anyone help me through my confusion? Our setup is a normal Bell test using entangled photons created using spontaneous parametric down conversion (PDC). Such a setup uses 2 BBO crystals oriented a 90 degrees relative to each other. See for...

hello, i'm amit from israel, and i'd love to be an activated member in your forum. my first question - are there other theories about the beginning of the univers. except of "the big bang" (not religion)? thanks, amit

I believe Einstein said, 1.There are four dimensions to space, the normal three plus time. 2. Speed of light cannot be obtained due to an object traveling at such speeds gaining mass. The faster it goes, the more mass gained, until it reaches “infinite mass”. 3. Mass and Energy are pretty much...

Can someone explain the Omega pointe to me? In regards to the theory of the universe collapsing?

As things seem a bit slow of late i wonder if anyone would give an over view of the gravity debate, i know the Higgs is still elusive and the graviton remains un found, no axions as yet, etc, etc, but what does this mean to string and loop theories?

Waddup guys. To my understanding M-Theory is a theory which 'combines' the five superstring theories and supergravity.Also i understand that matematics is not yet advanced enough to make it work(or so I've been told) I am still not sure how this theory is meant to end up as a theory of...