Questions tagged [matter]
The matter tag has no usage guidance.
244
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1answer
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Matter-antimatter reactions
It's widely known that, using famous equation $E=mc^2$, we can estimate energy in nuclear reactions, matter-antimatter reactions (the most powerful in the universe), etc.
It's also known that, in the ...
0
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1answer
20 views
Pressure of (cold matter)
The first pages of Weinberg's Cosmology state that matter, cold matter like dust has zero pressure. I find it very disturbing. Does 'cold matter' also include fluids since hot matter is radiation, ...
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0answers
23 views
Incorporating matter effects on active-sterile neutrino oscillation with mathematica
I recently wanted to study the effect of a constant matter potential on a simple 2-flavor active-sterile neutrino oscillation system using Wolfram Mathematica, but I encountered a big problem in the ...
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0answers
42 views
What proof do we have that dark matter is matter? [duplicate]
The Dark matter page on CERN's official website describes dark matter as if it were regular matter just with some mysterious properties. This was a surprise to me because every time someone mentions ...
2
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0answers
16 views
What is the critical volume/mass of non-deuterated water that appears blue to our eyes?
A glass of water appears clear, but a swimming pool appears blue. At some point there must be a switch and I am wondering if anyone knows what that point is (or if its so gradual we can't tell). Does ...
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2answers
75 views
What happens to matter if it is left undisturbed for a long time? [closed]
What happens to matter if it is left undisturbed for a long time?
Since the question isn't clear enough, here's an experiment: If we put some non-radioactive matter in a box and slow the speed of the ...
0
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1answer
57 views
What if there was no baryon-antibaryon asymmetry in our universe?
We know that the universe goes through different evolutionary phases: radiation, matter and later dark energy epoch.
What would happen if there was no baryon-antibaryon asymmetry? How would the ...
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0answers
24 views
Matter Standing Waves means 0 probability?
de Broglie standing waves are waves that represent the probability of finding an electron somewhere. In an atom, these waves must become standing waves in order to ensure that no destructive ...
2
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0answers
43 views
Is every object in the universe really expanding? Even small scale objects like humans? [duplicate]
So I was asked a question by someone that "if everything in the universe is expanding, then the lens we use to look at stellar objects is expanding as well, meaning we shouldn't be able to tell the ...
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2answers
128 views
If everything is made up of atoms, what is vacuum made up of? [duplicate]
Do empty space in our universe exist or it is all filled with dark matter or some other unknown matter?
0
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2answers
48 views
Does the wavelenth of matter waves depend upon the kinetic energy of the particle or object?
Do the properties of the waves (wavelength,frequency) emitted by a particle or object depend upon the velocity, or as to say its kinetic energy? Is the De Broglie equation $E = h \nu $ applicable to ...
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1answer
56 views
Could matter be simply spatial geometry, and nothing else? [closed]
As it will become evident by my question, I have no degree in physics or math.
Question: could matter be nothing more than the curvature of space? In that case, different atoms and different ...
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2answers
32 views
What happens if matter particle and antimatter particle both carry no charge were to collide elastically?
I read that particle carrying charge is able to interact with photon so that when electron and positron collides they may be converted into pure photons, then what about neutron-antineutron collision? ...
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0answers
26 views
Neutrino oscillation in earths matter: electron-, proton- and neutron density
I want to incorporate an estimate of a matter effect in atmospheric neutrino oscillations into a model including active and sterile neutrinos. Since neutrinos are not only created in the atmosphere ...
5
votes
3answers
125 views
Cosmological Inflation: If Photon expands, why not other matter?
I keep repeatedly reading in many Stack Exchange and Quora questions that space of universe expands but particles (matter) don't, see e.g. this Phys.SE post. The reason given is that particles are ...
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0answers
23 views
Clarification on Phase wave derivation in De Broglie's paper
De Broglie's paper refers to his theorem
A periodic phenomenon is seen by a stationary observer to exhibit the
frequency $ν_1=h^{-1}m_0c^2\sqrt{1-\beta^2}$ that appears constantly
in phase ...
6
votes
3answers
2k views
What is the meaning of “matter” in physics?
What is the meaning of matter in physics? By defining matter in terms of mass and mass in terms of matter in physics, are we not forming circular definitions? Please give a meaning of "matter" in ...
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5answers
120 views
In general relativity, is there a difference between matter-energy and spacetime?
This is the third time I try to formulate a question in a proper format so as to understand what is going on with gravitational waves at a physical level.
I am told that a spacetime oscillation and/...
0
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1answer
68 views
Could six copies of the universe exist only interacting by gravity? [closed]
The ratio of dark matter to matter is roughly in proportions $1:5.4$
This suggests that if there were about 6 Universes placed in the same space that were completely invisible to each other, except ...
2
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1answer
50 views
contradiction between total photon energy in the universe and early matter antimatter ratio
When looking at the energy count in the Universe, on one hand we are told dark energy 68%, dark matter 27%, regular matter 5%, neutrinos and photons a very small fraction (trace like).
https://en....
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0answers
15 views
If the universe is expanding, then the distance between the atoms must increase, which should result in decrease in density of everything [duplicate]
In the expansion of universe theory, it is already written that the scale of universe is itself expanding, which means the consequence for expansion of universe is not that atoms are growing in size, ...
1
vote
1answer
59 views
“Pure” Yang-Mills and the absence of light matter
I am researching various models of Neutral Naturalness which involve the addition of an additional gauge group whose matter content is uncharged under SM color. Many of these theories state that their ...
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0answers
77 views
Can we say there is literally nothing like vacuum [closed]
OK am trying to find out the meaning of vacuum since particle do exist everywhere even where all 'matter' has being removed am certain the definition of vacuum doesn't make sense with particles can ...
0
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1answer
33 views
When a solid is dissolved in a liquid, is it still a solid, what about individual atoms or molecules in a vacuum? [duplicate]
I am trying to gain a better understanding about states of matter, the last paragraph is the most important one to be answered.
It is my understanding that when a solid is dissolved into a liquid, ...
1
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1answer
26 views
What is the minimum amount of matter do I need to call it “bulk” matter?
I had been reading about bulk properties, but was confused what should the minimum amount of matter be for these properties to hold.
For eg: Intensive thermodynamic variables will not remain ...
0
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1answer
44 views
As space expands does the density of matter remain same or increase? [duplicate]
I learned that space is always expanding. Even between sun and earth, it's just gravity is stronger.
Imagine space as graph paper and there is a square object that fills it.
Space expands, 1x1 cell ...
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3answers
87 views
Why Neutrino is a ghost particle?
why neutrinos are called ghost particle.why it is not affected by strong magnetic field. why it does not interact with matter. why it does not interact with gravitational field? I am unable to ...
4
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5answers
166 views
Why are matter fields predominantly fermions?
Apart from the Higgs, all matter is made up of fermions. Is there any obvious reason why that is?
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1answer
63 views
Minimal quantity of substance to reveal its physical state properties
What is minimal quantity of matter required to reveal its physical state properties? I.e. number of particles/atoms when their collection can be considered as liquid, solid, gas or plasma.
I am aware ...
2
votes
1answer
55 views
Euler-Lagrange equations for electrodynamics: matter vs. gauge field change
I know how to derive Maxwell's equations from a Lagrangian density via the Euler-Lagrange equations, but I'm bothered by one little detail.
Variation of the Lagrangian seems only to be done with ...
1
vote
1answer
28 views
How quickly is momentum transferred through an object? [duplicate]
If there was a pole, that was a light year long, out in space. (Away from all physical interference.)
If we pushed one end of it, would the other end move instantly? And does it's speed depend on ...
0
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0answers
21 views
Do hydrogen and anti-helium annihilate one another? [duplicate]
So far I know that electron and positron annihilate each other completely and release energy, how about matter hydrogen atom with 1 proton and 1 electron come into contact with antimatter anti-helium ...
3
votes
2answers
62 views
Intuition for why matter dominated expansion is faster than radiation domination?
In a matter dominated universe $a_{\rm mat.}(t)\sim t^{2/3}$, while in a radiation dominated universe, $a(t)_{\rm rad.}\sim t^{1/2}$. Therefore, a matter dominated universe is expanding more quickly, ...
0
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2answers
62 views
Do antiparticles behave opposite of the particle?
If antiparticles have opposite charge to that of the particle, will their interaction be completely opposite?
For example, an electron and a proton are attracted to each other, will a positron and a ...
14
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2answers
1k views
Can matter be described as the result of the curvature of space, instead of vice versa?
Can matter be described as the result of the curvature of space, rather than the curvature of space being the result of matter, and energy being the cause of the curvature of space?
14
votes
5answers
2k views
Does a rock use up energy to maintain its shape?
A rock sitting on land, the ocean floor, or floating in space maintains its shape somehow. Gravity isn't keeping it together because it is too small, so I'm assuming it is chemical or nuclear bonds ...
18
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4answers
3k views
Could quantum fluctuations spawn real matter?
Would it be plausible for fluctuations in the QED vacuum to spawn actual matter (such as quarks, electrons the constituents of a hydrgen atom) given enough time and space?
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1answer
100 views
Are particles an abstraction of energy, or their matters do indeed exist?
I'm trying to understand from where the first particles in quantum mechanics came from, and while doing research I got this information from an article about the origin of matter:
In the beginning,...
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1answer
76 views
Probability of Photoelectric and Campton decrease as photon energy increases, WHY? [closed]
Why Probability of Photoelectric and Campton decrease as photon energy increases??
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1answer
76 views
What happen if an electron meets another electron? [duplicate]
A person give me an idea for my physical problem, and I think the answer of this question would be the next step for its answer
I only want to know what they are doing with each other if they meet ...
-2
votes
1answer
82 views
If energy can't order itself, how did energy get ordered or made? [duplicate]
In the universe we see that hydrogen (bound up energy) is found in a highly concentrated ordered state in some places and it's highly dispersed in most other places. There is a natural progression ...
0
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2answers
86 views
What decides ductility of a substance- youngs modulus or the plastic limit of the substance? [closed]
Given two materials A and B such that a has higher young modulus as well as plastic
limit than B , which of the two is more ductile?
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2answers
87 views
Are matter and energy dependent on each other? [closed]
If matter creates energy and energy creates matter can one exist without the other?
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2answers
153 views
How can 0-dimensional particles or 1-dimensional strings be 3D matter? [closed]
According to the latest information we got
String theory is a theoretical framework in which the point-like
particles of particle physics are replaced by one-dimensional objects
called strings....
1
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1answer
53 views
Working with Reciprocial Lattice
In solid matter physics the lattice structure can equivalently be described via standard Bravais modelling but also by considering it's reciprocial lattice. Mathematically the reciprocial lattice can ...
1
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2answers
95 views
Does dark-matter attract itself with gravity as light-matter does, and if so where are the dark stars and galaxies?
Does dark-matter interact with gravity like light-matter does, or does dark matter interact only with light-matter via gravity?
0
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1answer
71 views
Basic energy question
How do we know something contain energy or not?
P.S.: I don't really understand how energy should be interpreted. Until today I always thought that energy is some kind of magic that makes stuff ...
4
votes
2answers
82 views
Physical mechanism by which the body removes weight during long-term human weight loss [duplicate]
I'm trying to confirm the method by which the body physically loses weight during "long-term" weight loss. I'm specifying "long-term" here because obviously there are lots of ways to temporarily lose ...
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0answers
39 views
Acceleration from scalar-matter coupling in classical field theory
I have came across a text where an interaction term in a classical Lagrangian is presented that couples a matter density $\rho$ and a scalar field $\phi$ as
\begin{equation}
\mathcal{L}_{\text{int}} =...
3
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1answer
198 views
Temperature Required to give Particles of Matter Speed comparable to the speed of light
We know that at 0 K, particles of matter almost stop vibrating/moving completely. Also, as we increase temperature of the system, the particles gain energy (in the ...
