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).
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...
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...
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...
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...
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...
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...
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
I have considered the possibility that dark matter is so hard to find because it exists in extra dimensions. Before posting here I googled this, and found that some scientists postulate this exact possibility, while others consider that extra dimensions themselves cause the effects that are...
I am a bit frustrated with my current job search and I was wondering if people at PF could give some guidance. I am a doctoral graduate in Electrical Engineering from a low ranked university (~ 180 US News overall ranking). Although a EE doctorate most of my work was in materials...
So I'm looking to find the distance light has traveled since matter - dark energy equivalence. Assume dark energy dominance from equivalence.
Space-time has flat geometry and Ω0m = 0.315 , Ω0 = 1
Thus: Ω0Λ will equal Ω0 - Ω0m= 0.685
ρ0m (1 + zeq)3 = ρ0Λ
where: ρ0m = ρ0c * Ω0m
and: ρ0Λ =...
I have been wondering about how the universe created itself from nothing and it seems in spacetime, the time dimension must have come first followed by multidimensional space. Following this, matter and dark matter must have been created. While matter and dark matter both underwent timelike...
Ok, silly question. Lexx is a sci-fi TV show that ran from 1997-2002. In one episode they used 'approximately 14.2 Quadrillion Quadrillion drones" to basically suck matter away from the star slowly using gravity.
Ive always wondered: Do you think this is possible? Or would such a large mass...