Questions tagged [matter]

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Why not say a scalar potential as a function representing the matter itself? [duplicate]

[Question] Why not say a scalar potential as a function representing the matter itself? At first glance, this idea seems to make the duality, which is the biggest difficulty in understanding quantum ...
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If there was an infinite amount of matter at big bang to form an infinite universe how it was possible for a so huge amount of matter to expand?

If there was an infinite amount of matter at big bang to form an infinite universe how it was possible for a so huge amount of matter to expand? Is it better to think that the universe is spatially ...
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Mass defect and macroscopic phase transitions [closed]

Will there be a mass defect of a water 1kg boiling into vapour? When the vapour is turned back into water, do you think there will be a mass defect or we get the same mass?
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If the universe was dominated by antimatter instead of matter, would we physically notice?

I read that antimatter and matter are identical aside from their opposite charge and quantum number. Of course, the mystery of why matter dominates in our universe is an active field of research. But ...
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Matter-antimatter and annihilation

In this question, it seems posed how a particle and its anti particle can get close to each to annihilate. One answer proposed that "The force involved in annihilation is normally either the ...
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For an auxetic solid, what is the relationship between the Shear modulus and the Young's modulus?

I know that for an isotropic solid, G = Y/2(1+v) but not sure if it is the same for an auxetic solid?
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Optics and capillary

In a small capillary of radius 0.5mm, the water inside raises by 10cm above the water surface. The angle of contact is 60deg due to some impurity which does not affect density or refractive index=4/3 ...
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1 answer
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What is matter and what is mass?

In classical physics and general chemistry, matter is any substance that has mass and takes up space by having volume. (Wiki) Fair enough, so what is mass? Mass is the quantity of matter in a ...
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How do electron acceptors and donors affect molecular geometry?

I'm currently working with two molecules: Ethylene $CH_2CH_2$ and $CH_2CHCH_2$ (whose name I don't know). The question is how does doping them with an electron acceptor/donor affect their geometry? My ...
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-2 votes
3 answers
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Does the Schwinger effect prove matter and antimatter can be created from a vacuum?

Virtual particles or vacuum fluctuations are the pair annihilation/creation of matter and antimatter particles in and out of the vacuum. Theses particles are virtual, but we know they exist because of ...
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Matter is Apparently just Field Excitations, But How the Heck does that Work? [duplicate]

Ok so, around four-ish months ago, I was told by a Cosmologist that what we perceive as matter doesn't actually exist and that the alleged particles that we think it's comprised of are actually "...
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Why is the energy density of the dark energy component~magnitude as the density of matter now, when the two evolved in different time periods?

WMAP determined that the universe is flat, from which it follows that the mean energy density in the universe is equal to the critical density (within a 0.5% margin of error). This is equivalent to a ...
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Does Einstein stress-energy tensor represent spacetime or matter?

I am writing a paper entitled "On static solutions of Einstein's field equations for fluid spheres". I assume there a diagonal stress-energy tensor, $T_{\mu}^{\nu}=diag~\{\varepsilon,-p,-p,-...
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Could the hypothesis of regular matter converting into dark matter help to find out what the dark matter is? [closed]

Could the hypothesis of regular matter converting into dark matter (Dark Matter from Exponential Growth, free version available from the arXiv with a rather different title) help to find out what the ...
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What are the conditions needed for baryogenesis? [duplicate]

Physicists have created antimatter in the laboratory. But when they do, they create an equal amount of matter. That suggests that the Big Bang must have created matter and antimatter in equal ...
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Why do matter and radiation densities scale differently in expanding universe, when all matter is energy and all energy is matter? [duplicate]

I sometimes see the first Friedmann equation expressed with different terms for the density of "matter" and the density of "radiation". It is said that with an increase in scale ...
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How the universe is expanding? [duplicate]

If universe is expanding with the velocity of light then why the distance between earth and sun is constant? Also why the distance from one Galaxy to another remains constant? And so on...
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Light is made up of matter, isn’t it? [closed]

What’s the hype about all this conversation of light into matter? I mean it’s no big deal right? Light has particles (a form of matter) i.e. photons in it, so what’s the big deal in conversation of ...
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Does the expansion of the Universe cause internal stresses in solids (and other substances with similar internal resistance forces)? [duplicate]

Is my understanding correct? Weren't it for the internal resistance forces between particles in a solid object, the expansion of the Universe would continuously increase the distances between all of ...
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How come black body have more emissivity and more absorbtivity(a) at same time?

We have two definitions to look at Absorbtivity(a): the ratio of absorbed energy and incident energy on a body $a_{BlackBody} = 1$ so if i have a tourch light that gives red light, in a dark room I ...
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Is there a point where the matter goes from trying to expand to being a black hole?

Imagine a box with two characteristics: It is indestructible, it can't be deformed or torn apart. It can shrink to any precise size regardless of the opposite forces. Let's assume the box starts ...
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Why temperature of an object doesn't change when that object is in motion? [duplicate]

Temperature: Measure of random kinetic energy of molecules Here's what I'm trying to say we have two book, and we place on book on moving truck and other on ground, so according to definition our ...
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How can they say that there is an antimatter/matter asymmetry when wherever you are there can only be one of the two?

I don't think we have any way of knowing that distant galaxies are not antimatter so that there really is an equal amount of both matter and antimatter. But if you randomly, not evenly, distributed ...
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Why do we treat molecular vibrations as linear harmonic oscillations and not 3D isotropic?

Born-Oppenheimer approximation leads to this equation for the eigenfunctions and eigenvalues describing molecular vibrations: $$\left[-\frac{\hbar^2}{2\mu}\frac{1}{R^2}\frac{\partial}{\partial R}\left(...
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Does material on earth exists, that can expand endlessly in the vacuum of the space? [closed]

As far as I have learned, space is a hard vacuum. Is there any material, that can expand endlessly in space or theoretically would it be possible for a material in future to behave like this?
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Repeatedly dividing a magnet into halves

Suppose I have bar magnet and I cut it into two halves, then each of these two halves has its own north and south poles. If I continue to perform this action on each of the parts, continuously ...
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Does matter exist because of fields, or do fields exist due to matter? Can one exist without the other?

I was wondering if fields give rise to matter or is it existence of matter which gives rise to field.
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Would a human body flying into the sun extend or decrease the time the sun is undergoing fusion? [duplicate]

Obviously 1 human body is... nothing compared to the sun, so if the question is easier to answer with 1 million, 1 billion, the entire human population that has passed away in history... the amount ...
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Momentum conservation during electron-positron anihilation [closed]

If the electron is standing still and the positron is moving the cancelation produces two photons that should conserve the particles momentum. So what direction should move the photon that conserves ...
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-1 votes
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If mass changes when we go in the speed of light . So it breaks law of matter which states that matter can't be created or destroy [closed]

When go at the speed of light the mass constantly started to change which is not possible if law of matter is correct
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2 votes
1 answer
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How is information conserved when antimatter and matter annihilate each other?

According to quantum mechanics, information must be conserved. My question: How is information conserved when antimatter and matter annihilate each other? For example: Let's say there is an electron ...
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Gravity in a universe where all energy has been turned to mass [closed]

If all energy in the universe was turned to mass would gravity work?
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Are the properties of anti-hydrogen opposite to those of hydrogen?

In the series Crisis of Infinite Earths, the whole story is that there is a wave of antimatter rampaging through the multiverse. So I got interested and googled "how to create antimatter", ...
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3 votes
3 answers
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Neil deGrasse Tyson said that atoms, protons, electrons are just clouds of charge, if so, is matter really just energy? If so, how does it have mass?

First, I'm not a physicist in any way, shape, or form. My knowledge of physics is high-school level, at best, meaning it at one point was high-school level, that point being in high school, but it's ...
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1 vote
3 answers
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Why are energy and mass the same?

I am aware that energy mass are inter-convertible using the famous $$E=mc^2$$ But why is it that energy and mass are basically the same thing that takes different forms? I am looking for a ...
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Is there any evidence that atoms behave differently on other planets? [closed]

I know gravity, atmosphere density and other values would be different on other planets, but is there any evidence that intrinsic atomic properties (i.e. melting point) are different on other planets?
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Atom or Cell? Which is the basic unit of life? [closed]

As it is said that everything in this universe is made up of atoms and molecules and atoms are called the building blocks of matter. But then why the cell is called the basic unit of life, why not ...
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States of Matter misnomer

Is the phrase "States of matter" a misnomer? A "state of matter" describes the configuration/structure of atoms and molecules in an object, correct? It would not make sense to ...
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Are the constituents of the known universe matter (including antimatter) and electromagnetic radiation?

Is it correct to say that the constituents of the known universe are matter (including antimatter) and electromagnetic radiation, leaving aside the comparatively hypothetical ‘dark’ entities? This is ...
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What is the change if a droplet of water is added to another droplet of water on a flat surface

There is a tiny droplet of water lying on a flat clean surface and I add a droplet of water to the tiny droplet on the surface. How can I explain the change that might occur?
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2 votes
2 answers
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How can potential energy increase without kinetic energy during phase change?

From what I’ve come across the internet, the reason temperature remains constant during phase transitions is that the energy goes into increasing intermolecular potential energy instead of average ...
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4 votes
1 answer
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Why matter is transparent to gravitational waves? [duplicate]

I recently asked a question at Astronomy.SE related to matter-gravitational waves interactions: https://astronomy.stackexchange.com/q/43265 From related question Do gravitational waves disperse/...
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If the observable universe is only part of the universe, how do we know there is more matter than anti-matter?

I watched this youtube video about anti-matter, which says we don't know "why the big bang produced more matter than anti-matter". How do we know that more matter than anti-matter was ...
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Why the dipole interaction term in the Hamiltonian has all diagonal elements to be zero in the energy eigenbasis?

I have been studying the semi-classical light matter interaction from the book, "Light matter interaction" by Weiner and Ho. They have defined the total Hamiltonian of a two level atom ...
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Can light wrap onto itself and become stationary? [closed]

This is possibly pure nonsense. I read somewhere particles interact with themselves and this makes calculation complicated. No idea where I read it but I remember reading it. I wonder if light can be ...
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How can an electron's de Broglie wavelength be LONGER than .0024264 nanometers?

If the rest mass of an electron is about 510,998.5 ev, or .5109985 Mev, doesn't that mean that even the slowest-moving electron has a wavelength of no more than .0024264 nanons? That is the wavelength ...
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Spectral line broadening [duplicate]

From Wikipedia article Spectral line: Spectral lines are the result of interaction between a quantum system (usually atoms, but sometimes molecules or atomic nuclei) and a single photon. When a ...
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If a molecule is a collection of atoms why we can't call a molecule matter and vice versa? [closed]

if a molecule is a collection of atoms why we cant call a molecule matter and matter a molecule? what is the difference between the two? in school we are taught that matter is made up of molecules and ...
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Is electron a matter?

I know electrons are subatomic particles which make up atoms, the building blocks of matter. But is electron a matter itself? Moreover, are atoms or quantum particles matter too considering their ...
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1 vote
2 answers
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Lattice unit cells

Just wondering if anyone had any links to good web based interactive models of lattice unit cells? Especially primitive unit cells? The one I used to use was built with flash so it no longer works :( ...
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