In classical physics and general chemistry, matter is any substance that has mass and takes up space by having volume. All everyday objects that can be touched are ultimately composed of atoms, which are made up of interacting subatomic particles, and in everyday as well as scientific usage, "matter" generally includes atoms and anything made up of them, and any particles (or combination of particles) that act as if they have both rest mass and volume. However it does not include massless particles such as photons, or other energy phenomena or waves such as light. Matter exists in various states (also known as phases). These include classical everyday phases such as solid, liquid, and gas – for example water exists as ice, liquid water, and gaseous steam – but other states are possible, including plasma, Bose–Einstein condensates, fermionic condensates, and quark–gluon plasma.Usually atoms can be imagined as a nucleus of protons and neutrons, and a surrounding "cloud" of orbiting electrons which "take up space". However this is only somewhat correct, because subatomic particles and their properties are governed by their quantum nature, which means they do not act as everyday objects appear to act – they can act like waves as well as particles and they do not have well-defined sizes or positions. In the Standard Model of particle physics, matter is not a fundamental concept because the elementary constituents of atoms are quantum entities which do not have an inherent "size" or "volume" in any everyday sense of the word. Due to the exclusion principle and other fundamental interactions, some "point particles" known as fermions (quarks, leptons), and many composites and atoms, are effectively forced to keep a distance from other particles under everyday conditions; this creates the property of matter which appears to us as matter taking up space.
For much of the history of the natural sciences people have contemplated the exact nature of matter. The idea that matter was built of discrete building blocks, the so-called particulate theory of matter, independently appeared in ancient Greece and ancient India among Buddhists, Hindus and Jains in 1st-millennium BC. Ancient philosophers who proposed the particulate theory of matter include Kanada (c. 6th–century BC or after), Leucippus (~490 BC) and Democritus (~470–380 BC).
As title really, just an idea I had from various videos and articles I've read as an enthusiast of all things physics.
Some supporting sentences from my somewhat ignorant but perhaps not-entirely-wrong thinking:
- The velocity of stars around the periphery of galaxies, I've heard of a theory...
We are taught that the forces of attraction in a liquid are lesser than those in a solid. What is the reason? Is it because the intermolecular spaces are large or is it because the individual attractive force of the molecule is less?
I thought this may be interesting, the decades old search for Dark Mater.
arXiv:1605.04909 [pdf, other]
A History of Dark Matter
Gianfranco Bertone, Dan Hooper
Comments: 86 pages, 8 figures
Subjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO); Astrophysics of Galaxies (astro-ph.GA)...
What extra math courses should an undergrad take (or self-study) if they want to go into Quantum Optics or Condensed Matter theory?
I've already taken calculus, linear algebra, ODEs, PDEs, and complex analysis (I will also be doing a second course on linear algebra in two months time).
I have a question, and it is this: why is it that your hand can go through a gas or liquid while the same can't be done with solids? Is it because of density?
Teachers teach us that matter is particulate because on dissolving a sugar cube into water it dissolves completely without raising the level of water. The level does not rise because water has spaces between itself. This proves that water or simply a liquid is particulate. But how do we prove...
Putting aside gravity, if there were some way to stretch and twist spacetime, what effect would that have on the matter inside the volume? Say we were talking about a part of spacetime that enclosed the earth, would the Earth itself be stretched and twisted? Also, wouldn't a ruler I used be...
I am more familiar with quantum physics than cosmology so it occurred to me that I hadn't heard anyone talk about the question of symmetry with respect to dark matter. If its influence is restricted to the disc of a galaxy, but it is particle-like in structure than symmetry is violated isn't...
What is meant by the statement by Harvard scientist Lisa Randall that dark matter carries five times the energy of ordinary matter? Does E=mc2 not apply to dark matter? Does the statement refer to ordinary energy or to dark energy?
I'm a high school student deciding where to go for undergraduate school, but it's a difficult choice between a really prestigious (and expensive) college compared to another school in the top 50 from US News in physics programs that is much easier in cost. I want to do theoretical physics...
In de Broglie's original proof of the theorem of phase harmony, the frequency of the moving wave of energy mc^2 (not the internal periodic phenomenon wave) is multiplied by the following term
##freq * ( t - \frac{\beta * x}{c} ) ##
Does anyone have an idea where the fraction comes from? All...
Homework Statement
I'm currently trying to decide on a topic for my IB Extended Essay, which is essentially just a long-term essay I'll be working on for the next 8 months or so. The topic of the essay is limited to IB courses I've taken so far, in addition to a few other types of topics that...
The graph I have made of Average Orbital Distance from the Sun vs. Average Orbital Velocity illustrates a decreasing exponential function. How, if it does, would this suggest that there is dark matter present in our solar system?
Hi,
I will need to write an exam on Structure of Matter soon. The book the course is based on is Modern Physics by John Morrison. I feel like it's a bit too wordy, and confusing.
Do you know of any books that has more problems with solutions and/or many worked examples? Would a Schaum's...
Dark Matter is every where and always passing threw us right? It apparently hold everything in place in our universe. We know it there but can't detect it. We see the results, but we don't really see who's responsible. What If dark matter was basically a different type of gravity? And the...
I just took a calc 2 test and got 3/8 points on several problems that asked you to show convergence or divergence. The reason being that I didn't use the correct test of convergence? The answer was right, if you get to the point where you know the series converges, then why does it matter which...
According to de Broglie's hypothesis, the matter wavelength could be described by lamda=h/p. But which momentum, the classical p=mv, or the relativistic one p=mv(1-v^2/c^2)^(-1/2) should be used in this equation? Additionally, an even more confusing issue to me is regarding the other relation...
Hello,
Is the covariant conservation of the matter energy momentum tensor Tμν ; μ = 0 also valid in a theory of gravity having an action for the gravitational field different from the Einstein Hilbert action ?
I'm asking because in GR the einstein field equations require Tμν= Gμν
where Gμν;μ=0...
So I'm wonder
How does the annihilation occur? Does the quarks pair up like magnets for matter and antimatter? Do matter and antimatter have the same quarks?
I was wondering about this for awhile and I still don't understand what happens to the enormous amount of mass stored in a black hole when it dies. I understand this question is based on a conclusion that may be incorrect, but if anyone could shed some light on this, please do so.
Hi all,
I've just been made offers to two different institutions - one to study General Relativity and Early Universe Cosmology, and one to study particle physics phenomenology and dark matter at PhD level, and I'm having a hard time choosing!
Relativity and Cosmology is Queen Mary University...
I have worked with a professor within my Physics department for almost a full school year now on electron scattering simulations. I run some programs on my computer and analyze them with ROOT. This work has been rewarding as I have learned a lot, but I recently got offered a position in a...
We assume that Lambda, the cosmological constant or "dark energy" is constant in all of spacetime (at least all of space). But what if it was not?
A lower value of Lambda in a certain region of space would mean that space's tendency to expand there is lower, and that might have the appearance...
Recently, in a tutorial session, my professor raises this question.
Experiments show that humans don't have free will. Decisions are made by us through unconscious activity of our brain. We are just conscious about the decisions our brain make. We are not actually controlling ourselves.
I feel...
Homework Statement
When we are taking a limit of a multivariable function, why do we use the points (x,0) and (0,y) to find out if the limit doesn't exist? They are two different points, no? If they are two different points then wouldn't they go to different points on the z-axis?
If we have a...
Has there been any theories proposed that model Dark Matter as just the pressure from vacuum fluctuations? It would be just a big cosmological-scale version of the Casimir Effect, where instead of using a couple of plates separated by microns, we're using the gravity wells of galaxies to create...
In 2011 Dr. Gerald Guralnik of Brown University was involved in an ongoing Dark Matter Detection experiment, perhaps LUX? It was an international collaboration involving underground detectors. He was certain DM would be detected in 5 years - i.e., now. I was dubious, so we bet "bragging rights"...
Can you give the name of an excited book of solid state / condensed matter physics ( beside kittel and ashcroft ) ? a book than contains more talking about experimental rather than theory
How does light interact, and travel through Solid matter as matter gets thicker, in width.?In the absorbion, and emission process of light, hitting electrons, I do not really understand that much, about electron energy levels, and how they change when a lot of atoms become molecules, and them...
Hello,
I am an undergraduate at UNLV. Before, I was at a community college for a few years before I went to UNLV. I used to be art major for a few semester but I didn't like it very much so I changed it to general education as I wasn't sure what I wanted to do. Last year, I thought of becoming...
It seems that the most popular hypothesis is that dark matter consists of WIMPs. Can the existing data be described with sterile particles rather than ones that interact through the weak force? Is the only reason to prefer WIMPs that they are predicted by SUSY? (To me, as a nonspecialist, SUSY...
[Mentor's Note: Post split off from this thread: ']https://www.physicsforums.com/threads/are-tracks-in-collision-experiments-proof-of-particles.857255/]
I'm sorry, If a photon is a particle of energy, or bosom, and neither matter nor energy can be created nor destroyed, what happens to the...
I've been looking over the idea of the multiverse recently. I am trying to grasp exactly why so many physicists believe in the idea when it seems more philosophical than scientific. Are there any good indicators pointing towards the theory from QM or GR?
The gripe that I also see with it...
All of it. I make it magically disappear... I'm god, I guess.
When I remove all the matter, is there anything left? Is the nothing used to be occupied by all that matter "something"? Is the space-time sans matter, still space-time?
Since we think that 85% of the matter in the universe is Dark Matter, does it follow that around 85% of the mass of a typical black hole should be of dark matter origin?
If not, why not?
And if so, black holes are defined by only 3 parameters, mass, electric charge and spin. As far as we can...
A lot is being written about the recent aLIGO observations and in general the implications of GW research for our scientific understanding of the universe.
We read about mostly 2 grand areas where GW research can provide novel knowledge. The astronomical / astrophysical area (i.e. mapping...
I've read the postulate that there could be a huge spherical dark matter halo extending far beyond the edges of the Milky Way.
However, according to Newton's shell theorem, there is no net gravitational pull within a shell.
How do they arrive at the conclusion of a halo so huge?
As humans, we intuitively tend to interpret the things we see in our local time frame. However, the rate at which time flows at any point (or time) in the Universe is affected by the strength of the gravitational field at that point (or time). Hence when we see distant events through our...
To quote http://science.nasa.gov/astrophysics/focus-areas/what-is-dark-energy/, "It turns out that roughly 68% of the Universe is dark energy. Dark matter makes up about 27%. The rest - everything on Earth, everything ever observed with all of our instruments, all normal matter - adds up to less...
This is probably a stupid question with a very simple answer but I hope someone here can help me, I'll try to explain myself as best I can...
I was thinking about spacetime being elastic, if I place a large mass on the elastic sheet it bends around it, when i place a second mass on the sheet, as...
I don't know either, but I understand that there are people working on this.
For the sake of this discussion let us assume that energy does in fact condense into matter, and further let us assume that we have x amount of energy in watts. My question is how would one convert said amount of energy...
Hi, I’m new to the forum and I would like to ask some questions. I’m not a physicist –for some reason that I’ll always regret I chose Business Studies- and my knowledge of physics is limited to high school, physics books and documentaries; which I must have watched them all by now.
Anyway, for...
If we can not use gamma rays to detect Dark Matter what can we use?
http://www.sciencedaily.com/releases/2016/02/160203110928.htm
Studies by two independent groups from the US and the Netherlands have found that gamma ray signals from the inner galaxy come from a new source rather than from...