Matter Definition and 1000 Threads

Imagine an axe going through a sheet of metal, both made of the same probe. On the basic level of language - the axe goes through the sheet. On the next level of language - due to pressure, delivered by the edge of the blade, the bonds between the molecules of the metal sheet begin to tear. But...

Could dark matter form structures the way matter does?

I am about to take part in an undergraduate recruiting event at my school, and prospective undergraduates were invited to ask questions to current students of the school. One such prospective undergraduate claimed that he crossed one school off his list because that school only did condensed...

I have to choose between U of T and UBC for my physics graduate school. QS ranking places UBC(46th) much higher than U of T (100th), but two of my professors told me the other way around. any ideas about the discrepancy? thanks~

The standard example of the Missing Mass Problem comes from the rotational profiles of galaxies. By counting up the visible matter, we extrapolate a mass profile for a galaxy. We then apply Kepler's laws (the enclosed mass of a stable orbit can be modeled as a point mass) to calculate the...

I thought this was an interesting article on dark matter, what might this kind of DM be made from? I also wondered could DM help explain in some way where all the anti matter ended up? http://www.space.com/27794-dark-matter-destroying-neutron-stars.html

i just read something that said they are through the mass-energy equivalence formula. The original quote was now i wouldn't think matter and energy are interchangeable because energy doesn't take up space and i believe that's how matter is defined. Granted this quote was from Yahoo answers so...

hello! is there a book or something, to have an overview of the possible interactions between waves and matter? for example ultrasound can ignite flammable liquids for example lasers can ionize materials what are the possible material transformations that can take place? ionization...

Hi, According to Newton, F= (GM¹M₂)/r² Einstein proved that light bends around massive bodies, due to gravity. (because space bends around these bodies) Mass of light = zero, but its being affected by gravity. So, is Newton's equation not universal?

If we could observe a piece of dark matter with naked eye would it appear dark or invisible? Dark matter doesn't emit photons at all but it neither absorbs photons (it doesn't interact at all with photons right?) so it would appear invisible?

Homework Statement A power plant burns oil that is 4% ash and 3% Sulfur. At 50% excess air, what particulate (mg/m^3) emissions would you expect? Homework Equations PM in grams = 2.8*.04=.112 grams of PM per 1000 kg of oil Start with 1000 g of oil oil = 4% ash, 3%sulfur, and 93% carbon...

I had a small question regarding water slides. Imagine 2 identical water slides, let the slides be a fun one as in with all the ups and downs, of course not going higher than the initial height! If two people have a race: would their weights matter? If so who would win? Also if they were of...

Homework Statement Estimate the resistivity of an amorphous metal whose mean free path is of the order of an atomic spacing. Compare your answer to crystalline copper.Homework Equations VF = h(bar) KF / m VF = l / τ ρ = m / n e2 τ The Attempt at a Solution I think my real issue with this...

Hello! Could someone tell me what they are studying in the first three years (undergradute) in condensed matter physics.

https://www.physicsforums.com/threads/is-matter-still-being-created.424456/ I don't think anyone truly understood what this person was saying. He is asking several things. Is the big bang done or is it still exploding; the universe is expanding after all? How do we know the expanding universe...

is a dark matter black hole possible, and what would it be like ?

If there is a big crunch will space collapse with the matter?

Homework Statement A two component gaseous system has a fundamental equation of the form $$S=AU^{1/3} V^{1/3} N^{1/3} + \frac{BN_1N_2}{N}$$ where $$N=N_1+N_2$$ and A and B are positive constants. A closed cylinder of total volume 2V_0 is separated into two equal subvolumes by a rigid diathermal...

Hey, I've a short question. Is there any research attempting to constrain models of dark matter by assuming stable solution for the universe? I'm interested in knowing whether this gives any sensible constraints on the dark matter models. I'm still fairly new to studying dark matter but as I...

Why did Dark Matter have less of an Impact on the Universe than Dark Energy? Under a different set of universal laws, do you think it would be possible for Dark Matter to have more of an impact than Dark Energy during an alternate big bang to create a infinitely dense point as a universe?

Homework Statement I figured out this homework problem, after many tries, but I'm confused about the correct final answer. Here's the question: The rebounding ball, mass of 0.06 kg, traveling horizontally at 7.6 m/s, is caught by a player who brings it to rest. During the process, her hand...

Why did dark energy overcome dark matter to create the expanding universe we live in today?

When we observe galaxy lensing of background objects taking place, is it possible to estimate the total mass of the galaxy carrying out the lensing and from that confirm that dark matter is needed to be present to provide sufficient mass to bend the light by the amount observed? Is there...

If the energy or matter can't be created nor destroyed but can only be converted from one form to another, does it mean everything including us, used to be stardust or chemicals or whatever that existed right after the big bang? Is everything that we use now, are made from the stuff that...

is 'matter' mind-dependent? I see many philosophers talking that, there is some science on this ?

Homework Statement Calculate the Fermi energy, EF at 0K for potassium (atomic weight = 39, density = 860 kgm3). Homework Equations KF3 = 3π2n Fermi Momentum ρ = h(bar)KF The Attempt at a Solution :[/B] For the first part: Using: E = ρ2/ 2m Can substitute Fermi momentum into that to get: EF...

Hello everyone this is my first post here. I'm sorry if my spelling is terrible. I am no physicists so I would like to ask if my thinking was going in the right direction. When I say energy I really mean electromagnetic radiation. The Earth receives it constantly from the sun but there is no...

Hi all. i am new in quantum mechanics and i am having difficulties in understanding wave nature of matter. what is exactly mean of it when we say wave nature of matter. Does it mean matter also move in waveform, oscillating or something else. How matter waves move? And please don't give examples...

I was wondering if matter stays at a constant amount. You cannot really destroy anything really because crushing it just turns it into smaller pieces of itself, decomposition turns matter int separate elements, vaporizing just turns matter into gas and burning is a combination of all of the...

What is the evidence for dark matter being new particles as opposed to some modified form of gravity?

It is said, that in the beginning the universe was a singularity and then it exploded. A picoseconds or so after the explosion it was a fiery ball trillions of degrees in temperature and containing pure radiation. as it expanded it cooled down until quarks and then barons and other particles...

Hi! It is stated in V. Mukhanov's book "Physical foundations of Cosmology" the following (page 44, after equation 2.25): "In contrast, for the dust dominated universe, where ηmax=2π, the event horizon exists only during the contraction phase when η>π." could someone please explain why is this...

I am not sure if this would deem another thread but I wanted to ask if school and/or degree level (BS, MS,PhD) has meaningful bearing on starting salary with electrical engineering. I know that there are people who can make 100k with BS and people who make 50k with MS. However there is a...

Homework Statement What thickness of copper is required to stop a 500 MeV/c proton? Homework Equations E=(m^2+p^2)^1/2 The Attempt at a Solution So I have been to some websites and trying to google this- and everyone is using charts and looking of the value of the range in a material...

Hello everybody! I'm currently in the third semester of my Masters' and still haven't decided which direction to specialize in. So far, I have been doing almost exclusively theoretical courses (particle physics and QFT, GR, advanced stat. mech) with a computational physics lab class being the...

I have been curious about something concerning universities for a while. I originally got a my BS in Physics at Louisiana Tech University. And right now I am doing Graduate study in Electrical Engineering at Southern University and AM. I am posting to ask if the type of public school really...

Let me give you an example of a reasoning I made in a simple case. Afterwards comes the question: Start of reasoning. Consider two standard ideal capacitor plates with a dielectric material in between them. Let's call the external field caused by the plates ##\vec{E_{ext}}## and the average...

How massive would the neutrinos have to be so that relic neutrino from the big bang would account for all dark matter?

I recently viewed a video with Richard Carrier, who apparently was using information he derived from Lee Smolin. He said that 99.9999% of the matter in the universe goes to making black holes. Is this true? What percentage of matter does go to the making of black holes, is it even something we...

how do I calculate the time when matter pressure and vacuum pressure add to 0 in the evolution of the universe. I have an exam of gravitation and cosmology coming Monday but have no clue where to start from. I can find nothing on weinberg and kolb and Turner textbooks

Dark Matter, Dark Energy. Is it possible that dark matter and dark energy are illusions caused by the fact that the equations of physics are only approximations? For example, in the falling body equation, F = mg, F (the initial weight of an object) is assumed to be constant, but in fact the...

This is probably a stupid question, but is there an equivalence between matter, energy and space time? Like for instance if you had a ball of 1 kilogram, could you convert it into volumetric space and have everything around it be further away? When two or more objects are going further away from...

I was thinking about the properties of dark matter - how it doesn't seem to interact with any of the forces of the universe except gravity and I was thinking about how neutrinos also don't have any charge and they don't interact with any other forces except the weak force and gravity. I thought...

In my university lecture notes, maxwell's equations in matter are written in the following format: \oint \vec E d \vec L = 0 \oint \vec D \vec dS = \int_V P_f (\vec r)dV \oint_S \vec B d \vec S = 0 \oint_L \vec H \vec dL = \int_S P_f \vec J_f d\vec S I am new to electromagnetism...

Hi.. I was reading some papers on continuum dynamics and its application to various material dynamics. The determination of macroscopic behavior is being studied , considering phononic interactions. As a material consists of phonons of various wavelengths, it is necessary to account for various...

Hello all, I was talking to a friend of mine earlier explaining why a force acts as if all the mass is concentrated at the center of mass. I know of no other proof than taking the time derivatives of the center of mass. Seeing as this was long before definitive proof of the atomic structure of...

How do we know that out of 100 percent, 4.96% is Matter, 0.42% is Neutrinos, approx 25% Dark matter and rest 70% is dark energy. How do we know about these percentages if we don't know how large the universe is? Or are these calculations based on the spaces of the VISIBLE universe? Are Dark...

I don't know if this question should be in the quantum physics section, so I'm just posting it here. So I have doubts regarding matter wave and electromagnetic waves associated with electron or just any particle. 1. So I understand when an electron is accelerated, it produces electromagnetic...

Information that is ordered can be compacted down to a single repeating unit i,e; 110055110055110055110055 down to just 110055 and this meant that it must have been highly ordered to be compacted down this far. So could it be that matter is also highly ordered somehow and it can be compacted...

This is a video by the two of the researchers who found anomalous xray emissions. These emissions may be related to dark mater, needs further verification. Edit 12/14/14 : preprint http://arxiv.org/abs/1402.4119