Matter Definition and 1000 Threads

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...

This paper states that gravity gravitates, to me that is mind boggling, i can not even understand how these additive effects may alter cosmology. arXiv:1509.06682 Let us start by recalling how interaction energies work in relativistic gravity. It is well known that gravity gravitates in...

This maybe a general science question but I'll put it here. When we say that an element has so-and-so properties, how do we know those are the only properties it has. For example:- We say an element has properties like electron affinity, electro-negativity etc. How do we know these are the only...

Is the presence of Dark Matter noted in Milky Way or somewhere around solar system??

I'm wondering if someone can give a more detailed history of Dark Matter than what I've found on Wikipedia. How did Fritz Zwicky determine that a galaxy was in 'equilibrium' given the uncertainty of a line-of-sight measurement of velocity? How did he determine the mass given the variables of...

I have been looking into Dark Matter recently and how we know really little about it to even try to identify what it is clearly. But Dark Matter obiously has mass which means that in some way it must be interacting with the Higgs Field. So could studying the Higgs Boson and comparing its...

Given enough time Boltzmann freak structures will appear, assembled from drifting matter, in the maximum-entropy universe if it is static, I.E. not expanding to eventually sweep all matter into the far horizon. In a lecture...

I have just been accepted to pursue an advanced degree (Masters) in Physics with a specialization in condensed matter. I have some questions regarding this field (Google results are somewhat outdated). (1) What exactly does a condensed matter physicist study? I know it is the study of...

Does the E8 theory that offered and posted by Antony Garrett Lisi,can explain the qualities and the source of the dark matter and dark energy in the universe?

As observed in published space maps, I have noted that dark matter is present only in those region which already have visible mass around them. Is this really a fact or just my wrong belief?

As opposed to antimatter, that is. The whole search for the asymmetry of matter vs antimatter seems to rest on the implicit assumption that what we observe is matter, not antimatter, no? Is there a way of distinguishing from afar between the two?

I thought this paper is worth citing it gives a good overview of Dark matter, it maybe a little out of date but it is still a good readhttp://arxiv.org/abs/1006.2483

We know that in the Baryogenesis happened a asymmetry between baryons and antibaryons.Here Is matter only BM(baryonic matter) or BM+DM. If its only BM so we have extra DM which its a matter.So the Baryogenesis solved ? (Here of course it can't be solved cause there's a big difference between...

Is there any dark matter where no baryonic matter (which here the galaxies).I mean are we observe dark matter only around the matter ? Or dark matter can be anywhere (In empty space which there's no baryonic matter around)

I am doing research and I need to find the dark matter density of Galaxies or dust clusters (It can be any type of thing) which the distance from Earth will be ≅4000 Mpc.Here the picture Think the radius of sphere.

Dear Friends! Probably more than a decade back understanding tells us : If the average matter density of the universe happens to be smaller than a critical value,then the galaxies will never come to a halt and turn back(Open Universe).Which will imply cold and lonely death. If on the...

Hi, I am approaching my A-levels in 1 time (currently in Year 11) , and so I would have to pick my A-level subjects which will then lead me on to my University (2 years later). I am practically obsessed with Theoretical Physics and I have already learned high-level mathematics and so on, not to...

I chose frame this question in this way because I was not convinced with the answers given for the question "What is Matter?" in this forum. We hear so much about how everything is made of matter, but the answer, more often than not, is just the common definition, as found in Wikipedia: "The...

Hey, my name is Roy and I'm new to Physics Forums. I'm a retired medical and aerospace test engineer, now currently a freelance artist (kind of opposites right?) and I joined Physics Forums to hone my understanding of physics and ask the right questions in an ever expanding field of inquiry...

Some times I think space and Matter most to be different on others places and maybe equations need to be fit, but to find dark matter, what do we need to have here?

bcrowell submitted a new PF Insights post Will All Matter Be Converted to Photons? Continue reading the Original PF Insights Post.

In this problem, they solve for i, and at first, it looks like it will be i*2* square root of 3... Then he puts 2 sqrt of 3 times i. Can it also be 2i sqrt of 3?

[Moderator's Note: This thread was split off from a previous thread because of a change of topic.] It doesn't. Matter influences the curvature of spacetime locally; the curvature of spacetime propagates to distant locations; and the curvature of spacetime at those distant locations tells the...

basic question- neutrinos pass through matter because they are only subject to the weak interaction whereas photons interact with matter because they are subject to EM? Does the small mass of the neutrino contribute to this - if there was a neutrino with the mass of a proton how differently...

Dark matter particle candidates are being searched at CERN and the various dark matter models are being probed by cosmological simulations. The usual way to probe models via cosmology is to plug a candidate into a cosmological simulation and then compare the results with observations. Yet...

Preface: I have a B.S. in Applied Physics and minors in Biomedical Engineering and Mathematics. At this point my intention is to go into industry rather then academia. The project I am working on now, and might be able to turn into a M.S. thesis, is in bioinformatics, more specifically using...

What I have read about antimatter amounts to about this much: -Each particle is paired with an antiparticle, and when they meet, they annihilate. -When a particle and antiparticle annihilate, they produce energy and gamma rays. -It is hypothesized that before the Big Bang, there was an equal...

Simpel question: does an atom consists of matter and charge? Yes/no?? If no Then what?

There are not found the WIMPs until now. Ma be the effect of Dark Matter is because of a defect in topology otherwise than time dilation in General Relativity. The lattice gauge theory formulated on a grid or lattice of points in space and time is successfully used in the quantum...

I was searching Dark Matter and I found this site is that can be true ? Dark matter can be a act like a pion ? http://right.is/space/2015/07/deja-vu-new-theory-says-dark-matter-acts-like-well-known-particle-2117.html

This paper, http://arxiv.org/abs/1507.06282, The Duhem-Quine thesis and the dark matter problem, may be of interest to those curious about how and why dark matter has gained general acceptance by cosmologists

In general photons are not candidate for dark matter. From the other hand stars constantly change matter into radiations (photons among them). And we can not measure radiation that does not hit us (although we can try to calculate it because radiation from star goes with same intensity in each...

I am told that even macroscopic objects like footballs obey the wave equations of quantum mechanics. Is there any experimentally based reason to believe this, or is it just said as a way of generalizing the theory?

In wikipedia says Physical baryon density: ##Ω_bh^2=0.02230±0.00014## and Physical dark matter density:##Ω_ch^2=0.1188±0.0010## Matter density:##Ω_m=0.3089±0.0062## so If we collect baryonic matter density and dark matter density we...

<<Mentor note: Thread split from Is Dark matter homogeneous in Universe?>> Not to be rude... but how do you know it even exists? Dark matter is a place holder used to make a hypothesis work mathematically with actual observations. Dark energy... Ditto. And the original hypothesis itself is...

I learned that dark matter distrubition is homogeneius and isotrophic in cosmic scales. I searched some galaxies dark matter distrubition.And I am actually suprised. Why cause every galaxy has a different ratio of dark matter baryonic matter distrubition. In cosmic scales baryonic...

Is Dark matter homogenenius in Universe ? I don't think so but I don't know any idea about it. Thank you