Nature Definition and 730 Threads

Hello! Please help: A world line is given to us. It is known that it is a geodesic. The metric, however, is not known. Since we don't know the metric, it should not be possible to tell whether the geodesic is spacelike/timelike/null (Right?) But since the geodesic is known (x,y,z,t), we can find...

How can the fact that ##\hat x## and ##\hat p## are Hermitian be used to prove that ##\hat x - \frac{i}{m \omega} \hat p## and ##\hat x + \frac{i}{m \omega} \hat p## are adjoints of each other?

I am looking forward to joining discussions here. My Backgroud is 2 years "applied physics", 5 years education for teaching in visual communication (art), 15 years experience as a database software developer. Now I am looking for a job as a software tester. Software Testing is similar to being...

Homework Statement http://pastebin.com/aS3vTR2V Homework Equations N/A The Attempt at a Solution I'm confused about what I need to do for the BlobFinder constructor. Someone told me that I should “initialize the ArrayList blobs”, then “create a 2D array of booleans called marked, having the...

why light shows both particle and wave nature?

This question has been bugging me for long. Specifically I'm wondering about it in the context of Pressure-Tempreature phase diagrams. With these diagrams you can deduce stuff like the Clausius-Clapeyron equation and stuff like that. But certain things confuse me, e.g.: There is this mental...

I am in nature,and I am watching hawks motion. I knew it before and saw it live now,that when the hawk see the animal that wants to eat,close its feather to go faster. I made a thought,and I would like to tell me if it is correct or anything is missed. I think that closing its feather,make air...

How many of the 26 basic constants of nature and more (beyond the standard model) where the values range can be said to be quantum eigenvalues and the exact constant being the *collapsed* one? In other words, Can you refer to the exact value as collapsed (quantum) one from the eigenvalues (or...

I am 30. I am right in the middle of my lifetime, more or less. And I wonder if half a life is enough to grasp Physics by the horns and learn all about nature? I totally love physics, the beauty and mystery that the universe truly is. I actually feel empty without reading or seeing something...

Great article posted at NPR today on scientific theory: http://www.npr.org/blogs/13.7/2015/03/04/390672748/do-fairies-live-in-the-multiverse

I know there is a previous post here about this, but it didn't seem to cover the angle I am getting at... I understand sound to be vibrations that travel through a medium such as air or water. However, what actually generates these vibrations? For example, hitting a piece of steel with a rod...

I'll begin by saying that while I find it all extremely fascinating, I am a complete outsider to the world of physics and mathematics, so please forgive my ignorance if what I'm asking makes no sense at all. I have two questions about the nature of “space.” According to what I believe was...

But for oxides reducing nature decreases down a group. We say non metallic oxides are acidic but for hydrides it is opposite, What's the appropriate reason?

...and what form may they found normally? Somebody asked me just how many of the particles we know are possible (say, delta baryons) can be found in nature and what is their usual state - are there many particles to be found outside of atoms? Although there are enough "abundance of elements"...

Homework Statement My question is similar to this one (https://www.physicsforums.com/threads/metric-function-composed-with-concave-function.566338/), I think. I have a concave function f: [0, \infty) \rightarrow [0, \infty) where f(0) = 0, f(x) > 0, x \neq 0 and I need to show that this...

Hi all. i am new in quantum mechanics and i am having difficulties in understanding wave nature of matter. what is exactly mean of it when we say wave nature of matter. Does it mean matter also move in waveform, oscillating or something else. How matter waves move? And please don't give examples...

I guess that nature do not care about "directions". If I'm performing an experiment on (for example) light the result is invariant on the direction of the laboratory. So why we observe directionality on the nature that we are observing around us? Why "things" are definitively not symmetric...

Just a simple question regarding the nature of a compact set X in a metric space S: Does X necessarily have to be infinite? That is, are compact sets necessarily infinite? Peter***EDIT*** Although I am most unsure about this it appears to me that a finite set can be compact since the set A...

Higgs Field theory successful explains the origin of mass. Like mass, charge is also a fundamental property of particles, it is similar to mass in many ways, like quantized, electrical force vs gravitational force. So, I wonder what is the origin of charge, how much understanding modern physics...

Hi everyone. In a thought experiment that I like to frequent, an important question arises. Is tolerance (the body's natural resistance to the effects of drugs) a technique that we've evolved to not grow too content with our current situation? Or, do the laws of chemistry determine that...

I've loved science for a long time. In fact it was one of my favorite subjects in school and was inspired to go for marine biology in collage. Admittedly I didn't cut it and left that path. I still look to educate myself and experiment. I'm writing papers to define myself and what I want in...

Just came across this youtube video discussing Quantum Biology It features Paul Davies and Seth Llyod. It debates whether biology makes use of non-trivial quantum effects to improve performance and/or perform functions that cannot be accounted for classically. I'm posting it here and asking...

Is Our Mathematical Universe by Max Tegmark any good, as a work of popsci? Apparantly it's related to some TOE thing Tegmark's got, is that one actually something legitimate? (Edit: Sorry if this isn't appropriate for this forum!)

A thought came to me while pouring antifreeze into my car today. As I pour in the anti-freeze it fills to the brim and takes awhile to flow through the cooling-system. However, if I choke the hose a few times it for some reason swallows the antifreeze faster. Is this similar to the bottle-neck...

One of the advantages of not all speaking the same language is that a great, dead but legendary mathematician might still author a book. It's only recently translated, apparently: https://www.amazon.com/dp/1470417014/?tag=pfamazon01-20

Hello fine. I'm studying logic and great difficulties to understand its principles, and should prove some theories involving the laws of identity of sets of mathematics using the method of natural deduction, they are: a) A ∪ ∅ = A b) A ∩ ∅ = ∅ I am trying as follows, but I can not solve...

I know that photons and other particles of comparatively smaller dimension show dual nature. But why? Can someone help me? :confused:

The objective of this post is to: (i) generate a discussion of whether results of the double-slit experiment address solely the nature of matter, or do the results also address the nature of probability; and (ii) to determine if there have been any comparably structured experiments outside of...

I am interested in how physicists view time, and in any thought experiment (eg. anti-matters time direction, spinning black holes that may have the time dimension no longer orthogonal to the three special directions, delayed quantum eraser experiment that might permit backwards in time...

I was wondering what people thought of the Cheshire Cat experiment published in the July 2014 issue of Nature Communications: http://www.nature.com/ncomms/2014/140729/ncomms5492/full/ncomms5492.html. The conclusion is that "any probe system that interacts with the Cheshire Cat system weakly...

Alright, I need to put my question in the context of the probably ubiquitous example of a conductor rod moving perpendicularly over a magnetic field to generate an emf between the two sides of the rod. That emf is equal to BLv (magnetic field, length, velocity) according to my book(studying for...

Hello, I am 14.So entirely an amateur.Obviously, I do not want to fall into the, "I am a complete amatuer of your subject but assume my findings will change the world" cliche. Anyway, I recently did some work in correlation to the nature of primes.If you would like to read it, you can...

Hi I am having a rough time with this questoin . Homework Statement Question: A student enters Best Buy prepared to buy a pair of speakers. Before he does so, he conducts an experiment with them. He places the speakers 4.0 m apart and connects a signal generator to both speakers that produces...

I have some confusion about multiple scattering. We always say that the problem of single scattering is always deterministic in nature.But while modeling the problem of multiple scattering, we take that the problem is stochastic in nature. I don't understand why. Why multiple...

De broglie had proposed that matter had wave character. Which wave does he mean? Transverse or longitudinal?

I have a few questions about the nature of the universe. I'll start with the first question: What was the size of the universe in Photon epoch? (in meters or light years) How can it be calculated? On the Internet, unfortunately I did not find accurate data. Sorry for my english - it is...

i am studying finite fields and trying to get an idea of the nature of finite fields. In order to achieve this understanding I am bring to determine the elements and the addition and multiplication tables of some finite fields of small order. For a start I am trying to determine the elements...

What is the nature of the force of gravitation? Is it electrostatic,magnetic or something else? According to the law of gravity.. gravity exists between atoms to planets and planets to supernovae, How does gravitation occur? If possible, don`t paste links of references...just quote them.. I`ll...

I was wondering today's how does the helicopter worked? Rotorcraft? I was wondering is their a bug that flys similar to the helicopter?

It is given in my book that the phenomenon of black body radiation can be used to prove the particle nature of light. They have also mentioned that the wavelength-intensity relationship "cannot be explained satisfactorily on the basis of wave theory of light." But why? Thanx in advance...

Hi, I am reading about the quantum model of the atomic structure, and recently encountered the Schrödinger’s model. However I am a bit confused about the nature of the electrons. Can we think of an electron a wave or as a particle when it is inside an atom? I know that in Schrödinger’s...

Hi, I'm trying to understand what the nature of gravity is. I know it is a force, and I know that heavy objects tend to attract other object, but why? It seems that this is because spacetime is bent. I don't really know what that means because my knowledge about spacetime is limited...

This may come off as worded odd. However, what is the nature of vortexes? they seem to be an apparent part of nature everywhere. From pulling a plug on a drain to the shape of solar systems and galaxies. Is there a specific formula which accounts for this phenomena. It's something that has...

Homework Statement If Hamiltonian ##\hat{H}## is hermitian show that operator ##\hat{\rho}=\frac{e^{-\beta\hat{H}}}{Tr(e^{-\beta\hat{H}})}## is statistical.Homework Equations In order to be statistical operator ##\hat{\rho}## must be hermitian and must have trace equal ##1##...

Neutron stars formed from supernova events are prohibited from becoming black holes because it is thought that the gravitational force is not enough to overcome Fermi degeneracy of the neutrons or quark gluon soup at the core of these objects, however, addition of more mass can overcome this...

Uncertainty principle -- Nature of observer About the fact that electrons have a determined position only after having been observed/measured, I don't understand how they make the difference between being watched by an eye/instrument or any non-measuring object just sitting there.

Hi there! As you might find out from the question I have regarding the subject of gravity, I didn't have formal education into specialized science subjects. Just a bit of high-school knowledge may apply. I do have a general interest in Physics and it gets me thinking every time. Normally I will...

How is the carbon in carbon dioxide electrophilic? There is no partial positive charge on the carbon in carbon dioxide because the molecule is symmetrical.

I've been thinking about science academia as an employer, or a profession, rather than as a vocation. It's full of very high aptitude people who do a lot of work for very little money. Why? They say they enjoy it, and maybe many do. As do I. However the nature of the work doesn't seem...

Let \normalsize S[y] = \int ^{a}_{b} f[y, \dot{y}, x] dx be the functional i want to minimize. Why does \normalsize f (inside the integral) take this specific form? Would i not be able to minimize the integral, \normalsize S , if f had any other form instead of f = f[x, y, \dot{y}] ?