Matter Definition and 1000 Threads

Expanding universe or contracting matter? this may look very weird question, but what if instead of that the universe is expanding, all matter is contracting as a function of its (proper) time? Δs' = Δs_0 /F(t) The contraction of matter would effect on the length unit what we use. I am...

If waves require a medium or some kind of force carrier to propagate, how exactly do matter waves propagate?

Orodruin submitted a new PF Insights post Knut Lundmark and the Prehistory of Dark Matter Continue reading the Original PF Insights Post.

Chalnoth posted this in another discussion: "The cosmic microwave background is almost impossible to explain without dark matter (there is clear evidence of a component of matter that feels pressure, and a component of matter that does not feel pressure, which can only be true if that matter...

What is an (the?) empirically demonstrable method used for determining a substance's state of matter? If a new substance was discovered and scientist A said it's solid and scientist B said it's a liquid, how would it be demonstrably proven to be one or the other? The books I have define states...

I'm trying to understand the mechanisms of the anisotropies in the CMB. The general idea is that there are fluctuations in some field (e.g. inflation) and the baryonic and dark matter rush into the space compressing the fluid. The photon energy pushes back on just the baryonic matter while the...

I've studied in many books, from which I learned that a vacuum is not truly a vacuum, that is, virtual particles are created every time. And I had also learned that the universe is left handed, that is a small non obeying in parity symmetry(individually), resulted in production of around one in...

This is probably stupid question but is it logically possible for a universe to exist where matter is continuous and not atomic? How would such matter be stopped from collapsing to a point?

is life a matter of constantly evolving chemistry?

I am doing my undergrad research on Dark Matter and Dark Matter but have only few links of sources. Are there any online info-stores where I can get most of the discovered information on them. All related research papers and the different properties discovered about Dark Matter and Dark Energy...

Large Underground Xenon dark matter experiment and LHC have reported a null result on searches for dark matter, with new bounds. What are the implication of these new bounds on neutralinos and LSP?

Very roughly put, my limited understanding is that dark matter is postulated because of effects seen in the geometry of space similar to those created by matter. Is it necessarily true that there is some form of matter causing that spatial distortion? Couldn't it be postulated that there are...

How are the effects of antimatter on gravity different than regular matter?

Why do scientists think that dark matter annihilates just like antimatter? How is it that dark matter during annihilation can produce light when it cannot emit or absorb light itself?

Radiation dominated the universe 4,700yrs to 378,000yrs, do the facts in the literature mean there was no baryonic matter between those yrs or was there still plasma or some sort of mass?

If a bubble of quark type matter formed near the core of a magnetized neutron star, what would happen to its shape? Would it elongate along the magnetic field lines? Could it burst out of the magnetic poles of the star?

What are prerequisite courses/topics to better understand holography as applied to strongly correlated condensed matter systems? Any references/textbooks would be appreciated. I'm doing research on this topic and would like my understanding to improve. Thanks very much

I will preface my question with the fact that I am a high school student with only a general knowledge of physics, though I have learned about a variety of phenomena at the limited level of depth that I am capable of. I am curious about several concepts and observed phenomena that are...

If luminosity increases, hypothetically, for a given galaxy, would the percentage of dark matter in that galaxy be smaller? What if the colors of the stars were to turn redder? I was thinking if the luminosity were to increase, that would mean the percentage of the normal matters increases...

How do we know that the effects of "dark matter" are not merely a failure of some other aspect of general relativity? Could it be that it is not matter at all but instead some placeholder for another aspect of our universe, or is it proven that there must be some form of 'matter', so to speak...

WIkipedia says antineutrinos are candidates for dark matter. What does this mean? How is it a candidate, and how could an antiparticle even exist in large quantities in the universe? Or is it only meant to be a small piece of problem?

Hello Friends, I, Arnendu Barman, is a high school last year student. I have much confusion in Dark Energy and Dark Matter. Actually I do not understand them and I also have problem on Negative Mass. So friend please help me . Thank you...

I recently read this article about how the Higgs Boson could decay into Dark Matter particles. Why is this not being taken seriously, there must be something, and I am not a physicist, just a ninth grade student, so why is this either a good theory or bad theory? Thanks in advance! Here is the...

I was watching a documentary on this subject that I found quite interesting. They put forth an explanation of why we see mostly matter in the universe. That after the big bang equal amounts of both matter and antimatter were created and that the decay rate of antimatter was responsible for the...

scientists have observed light acting as waves on a macroscopic scale before the quantum characteristics of particles were discovered. My question is what sets apart the macroscopic wavelike characteristcs of light apart from other matter waves? This may be a stupid question but can the...

According to this paper not only is Dark Energy part of the field Dark Matter is too http://www.indiana.edu/~fluid/paper/HMW15.pdf In summary, we conclude that the dark matter and dark energy are essentially gravitational effect generated by the gravitational potential field gµν, its dual...

as described by einstein in his paper published a few days ago in 1917, photon emission can be spontaneous or stimulated. In stimulated emission, atoms can be in an 'excited' state and the passage of a photon through such a population can can cause the ejaculation of energy in the form of an...

Have we ever observed or created atoms with nuclei made up of charmed and strange quarks, surrounded by a muon "cloud" or "shell"? Or perhaps an atom with a top-and-bottom-quark-nucleus and a tau particle orbiting it?

http://arxiv.org/pdf/1507.01019v1.pdf What do you think? Not published yet, but one of the authors is a postdoc at Princeton and the other a Princeton PhD and prof at U Penn so they might know something. As far as I know, the superfluid dark matter theory is deprecated because models of the...

When we view objects in the universe our eye sees the light that traveled from said object to our eye. When we see the Andromeda galaxy we are actually seeing the Andromeda galaxy as it was 2.5 million years ago. This raises a question about matter within the visible universe: Is there a...

In another forum someone states that "cacao powder" cannot be considered as a "solid state" since "it cannot sustain shear stresses". Has this statement any basis? -- lightarrow

Is this a break though or just hot air? http://arxiv.org/pdf/1510.05534.pdf We do not claim that the Mestel (1963) disk is the answer to establishing the universality of flat rotation curves in galaxy disks; only that it has always been a telling clue that gravity does not pull the strings and...

Hello all! I am second year undergrad at a university in US. I planned to major in chemistry and took five chemistry classes (organic and inorganic) and worked at an organic chemistry lab in my first year, but didn't really like it. After searching through all areas in chemistry and physics, I...

This is a restatement of a question I have been pondering whilst helping my daughter with GCSE physics. My previous post didn't get me the closure I was after so am trying again. I have three different GCSE textbooks. All three have a simple section on the kinetic theory of particles in...

In calculations of quantities in Neutron stars with degenerate matter is usual to set temperature zero. If I'm right it means that pressure of this matter is negligible against pressure due to Pauli principle. But what about situation when the matter is in neutron star locally compressed. How...

Here is the problem link picture http://i.imgur.com/0BtcXJk.png I know that omega=density/critical density so I know I can find the value of all of those. DE is dark energy and M is matter (I'm pretty sure). I assume I have to sub that formula into equation 1, and then rearrange it to create a...

This came up whilst helping my kid with her GCSE physics so ought to be pretty straightforward. Here goes: At his level the kinetic theory of matter is taught in a simple way and one "key point" which is stated time and time again is "the particles in a gas have more energy than the particles...

In what phase of matter do individual Neutrons/Protons/Electrons exist? They are matter aren't they? So they must exist in some phase, right? Do they change phase? I'm very curious any information would be greatly appreciated. Thanks!

I've heard that all the stars, planets or other heavenly bodies constitute only a little amount of mass of the universe. And we know that the rest other thing in it is black matter that can weigh something as I don't think that light or sound waves weigh something. So is it the black matter...

I understand that, as matter approaches the event horizon of a black hole, according to the time frame of someone outside the black hole, it would slow down and, after an infinite time, stop completely at the event horizon. So, if we could observe it, all this matter would be accumulating just...

I read dark matter makes the stars in a galaxy to move about a same orbital velocity. Why isn't this applicable to our solar system?

My question is a little general, and that is how we say that a system is a critical system? for example the transverse Ising model is a critical system? I think the answer is yes, since as we change the transverse field we see that there is a phase transition between ferromagnet and paramagnet...

I have been teaching Physics at the introductory level now for over 30 years. In that time I have taught a lot of labs on friction. Using the small masses readily available in the lab and using motion detectors to measure the velocity of the objects neither I nor any of my students has ever...

http://w.astro.berkeley.edu/~mwhite/darkmatter/essay.html, A good overview of dark matter. Quote. The density of matter in the solar neighborhood is measured by sampling a uniform population of luminous stars that extends well above the disk of the galaxy. The average velocities of the stars...

35g of h2o(g) at 380K flows into 300g of h2o(l) at 300K. Cp(l)=4.18kJ/K*kg and ΔH(condensation)= -2257kJ/kg. I need to calculate the final temperature when the system reaches equilibrium. Is the heat capacity for the h2o gas different than h2o liquid? Can you calculate heat capacity using...

As I understand it, the statement of the horizon problem assumes that the uniformity of the CBR measured at opposite directions in the sky needs a mechanism to create this uniformity. I also understand that many cosmologists do not share this assumption. The purpose of this thread is to seek...

Could someone tell me about what I must have as a knowledge to study condensed matter physics ?

What is the best book that gives you the essential knowledge for condensed matter physics ?

Will particles that don't interact with normal matter (dark matter for example) emit cherenkov radiation (if light in that medium moves slower than that particle) ?

Hi, I have a question regarding decay of matter. Let's say I have a block of lead. Now imagine I sit it in a vacuum - given infinite time. What will happen to it - will it ever degrade or change. In another way does matter last forever? Also what is the correct physics term for what I am...