LinkBack URL
About LinkBacksafter reading Dan Brown's "Angles and Demons", i was wondering that does antimatter really exists....
What r your views?
December 1st, 2007, 01:44 PM
after reading Dan Brown's "Angles and Demons", i was wondering that does antimatter really exists....
What r your views?
Yes, antimatter exists. Antimatter is matter that has some opposite properties from "normal" matter. For instance, the antimatter companion of the negatively charged electron is the postively charged positron.
We know that positrons exist because they are emitted during the beta+ decay of some radioactive materials. Also electron-positron pairs can be created from a energetic enough photon in a process known as pair production.
The antiparticle of a particle always has the same mass but the opposite charge. In the case of particles without charge, the antiparticle will have opposite helicity (see the thread "Neutrinos and antineutrinos"). And it's good to remember than antiparticles are no different from any other particles, they're just not as common and aren't the norm we're used to. They're nothing special, really.
December 2nd, 2007, 01:19 AM
Oh God NO! That book has so many errors.Originally Posted by emon
Don't believe everything he says about antimatter. Some of those things are pure bullshit.
December 2nd, 2007, 06:04 AM
Relative to the observor.Oh God NO! That book has so many errors.
Don't believe everything he says about antimatter. Some of those things are pure bullshit.
December 2nd, 2007, 01:17 PM
Ok.....and what about that the fuel made from antimatter yields no pollution and is 100% eco-friendly?
December 2nd, 2007, 01:51 PM
What fuel? The Fermi National Accelerator Laboratory makes one billionth of a gram a year at a cost of $80 million.
So what kind of mileage can you get from one billionth of a gram?
December 2nd, 2007, 03:46 PM
Well i think the amount of energy you would get by using antimatter is
E=mc^2 , where m is the amount of energy destroyed in the process.
It wouldn't leave any matter residue, just energy behind. So yes it is clean but I wouldn't say its environmentally friendly because you still have to make the stuff in the first place. So its only as clean as the original source of energy is minus the loss due to inefficiency. Actually i wouldn't say its really a fuel because we don't find the stuff in nature, i.e we cant "mine" it. So its really more like a battery, energy storage mechanisim.
Which brings up another question. Where is all the antimatter in nature ? Did the big bang discriminate when it made matter and anti matter ?
December 2nd, 2007, 04:13 PM
Exactly. You'd have to manufacture the equipment to make it, and all the equipment to make use of it.
On a similar note... Making antiprotons "requires 10 billion times more energy than it produces." So sure, antimatter itself may be a (hypothetically) energy efficient fuel, but factor in the energy expended to make it...
December 2nd, 2007, 06:23 PM
As far as I'm aware, the belief is that matter and antimatter were created in equal amounts, but then something happened to the antimatter. What that something is is still a matter of debate.
What would your assumption be on the temperature of antimatter?
My personal belief is that the temperature antimatter is below absolute zero. I have my own reasons to believe that but what are some of your theories?
And opposite spin.
That's impossible. Why would antimatter have an opposite temperature? To have a temperature of below absolute zero would require negative motion. Try moving, but oppositely.
Its anti matter, it may not be below zero but it has to have anti-temperature as it has to have opposite qualities of all its makeup not just the things we want it to have.And opposite spin.
That's impossible. Why would antimatter have an opposite temperature? To have a temperature of below absolute zero would require negative motion. Try moving, but oppositely.
I blindly said that heat is proportional to gravity. We know heat has nothing to do with gravity, but "what if". It almost makes sense. Sun's total heat is really high right, thus its gravity is really high. In outer space where theres low gravity, its very cold (low heat). Black holes suck everything in, creates friction, creates heat, creates gravity. so higher the heat, higher the gravity. So I just assumed that below 0 degree kevlin would be negative gravity. Below 0 K is impossible for any entity, but what if dark matter was not a physical entity but something rather different and was infact 0 k or below.
Just a thought.
Thats really a good idea! :-D
You serious? So there would be no gravity on Pluto? HogwashThats really a good idea!
What xactly did u mean by DARK MATTER? Is that something linked with what is called ANTIUNIVERSE?
Dark matter.
Not dark matter.
Absolute zero is called absolute zero because it's absolute. There is no such thing as negative temperature. Absolute zero is the absolute lowest temperauure possible and even it can't be reached. Antimatter is the same exact thing as matter, it's just oppositely charged from what we decide to call matter. If we had decided to assign a positive charge to electrons and a negative charge to positrons and switch their names around, the world wouldn't be any different. A positron is just as much matter as antimatter. It's just that it has a positive charge.
No pluto does have gravity because (according to my previous thought) pluto has a positive kelvin temperature. I said if heat was proportional to gravity, negative temperature in kelvin would yield anti matter.
Being a bit more open mindedAbsolute zero is called absolute zero because it's absolute. There is no such thing as negative temperature. Absolute zero is the absolute lowest temperauure possible and even it can't be reached. Antimatter is the same exact thing as matter, it's just oppositely charged from what we decide to call matter. If we had decided to assign a positive charge to electrons and a negative charge to positrons and switch their names around, the world wouldn't be any different. A positron is just as much matter as antimatter. It's just that it has a positive charge., all we know about dark/anti matter is that it exists. We have no proof that is a physical entity or something tangible. So there is still a decent possibility that antimatter could potentially have an impossible (well impossible relative to us) temperature of negative or 0 degree Kelvin.
dark matter and anitmatter are two separate things. Dark matter is matter that does not interact with electromagnetic radiation.Being a bit more open minded
Antimatter is matter that has an opposite charge and spin of "normal" matter.
At present we already know of one type of dark matter, it is called the neutrino. It is what the the majority of the "missing mass" is made up of that we don't know yet.
We know quite a bit about antimatter. As I already mentioned, positrons, the antimatter equivalent of the electron, are produced naturally by radioactive decay. We have also artificially produced small amounts of antimatter.
From the observed behavior of these known particles, we can say for a fact that antimatter does not have negative temperture.
Temperature" is a measure of the average kinetic energy of a sample of particles. For antimatter to have a negative temperature, the particles of antimatter would have to have negative kinetic energy.
If antimatter particles had negative kinetic energy, then when a radioactive isotope produces a positron, it would lose negative energy. IOW it would gain postive energy. But that does not happen, the positron carries energy away from the isotope leaving it with less energy.
So it is not a matter of being "open-minded", its a matter of actual observation disproving the idea that antimatter has neagtive temperature.
No, think of a toaster, how small it is, and how hot it is. Compare it to the Earth, who's average temperature is much lower. Heat affects the movement of mass on the atomic/molecular scale, and mass affects gravity (via spacetime curvature), but there is no direct relationship between heat and gravity.I blindly said that heat is proportional to gravity. We know heat has nothing to do with gravity, but "what if". It almost makes sense. Sun's total heat is really high right, thus its gravity is really high. In outer space where theres low gravity, its very cold (low heat). Black holes suck everything in, creates friction, creates heat, creates gravity. so higher the heat, higher the gravity. So I just assumed that below 0 degree kevlin would be negative gravity. Below 0 K is impossible for any entity, but what if dark matter was not a physical entity but something rather different and was infact 0 k or below.
Just a thought.
Wikipedia isn't always correct, but in the "Antiparticle" article it actually states that antiparticles must have the same spin.And opposite spin.
After checking the discussion related to the article I saw this:Wikipedia isn't always correct, but in the "Antiparticle" article it actually states that antiparticles must have the same spin.And opposite spin.
The spin of an antiparticle is equal to the spin of the corresponding particle, not its negative. In fact, the spin is never negative, only its projection can be nagative. I corrected the first paragraph accordingly.
Elad Tsur May 25 08:08:56 UTC 2005
yeah what if because of antimatter and antiparticles there is anti-temperature!?
below 0 degrees K
because if the anti-world is a mirror image of the real world then it must have anti-temperature!
If Albert Einstein said that, then indeed that is the last nail in his coffin for me. Do you have any place I can locate that Albert Einstein said that?
There being a God, and eternal life, as an individual spirit, is taught and believed wholesomely through youth, and through life in good times, by most religions and individuals.
This belief is often shunned, when a real crisis, that needs a show of their conviction, to what they know is true, arises.
You do not have to be a martyr to do good things. Usually a whole community dips into the dark underworld. You will rarely see just the people in jail, doing most of the wrong things. They often rather openly mimic evil leaders. And usually want to be caught.
Einstein turned his back on reality for a payoff. He would simply explain things, incorrectly.
Sincerely,
William McCormick
I totally agree. But ... Paul Dirac predicted the positron by interpreting Einsteins equation of the total energy of a particle. He noticed that a negative total energy is allowed and he attributed this to the existence of antimatter.
http://en.wikipedia.org/wiki/Dirac_sea
October 5th, 2008, 07:14 PM
No, I don't think it does exist.
I think antimatter is one of reality's mistakes that it quickly and effectively eliminates.
For something to exist, it stays around. It says, "hey, I am a force to be reckoned with". Antimatter is some type short-lived excuse for a by-product of some type of "decay" process. It does not exist. Reality's watchmen make sure anti-matter "does not exist".
I believe, in saying this, I am saying that space-time allows itself to make mistakes, but to correct those mistakes, that holes exist for problematic particles to come into being, which of course are quickly erased given the constitution, the existing constitution, of reality.
October 6th, 2008, 02:30 AM
It is not a matter of belief. It s a fact - and a definition. If a particle has properties inverse to another - simply speaking - it is its antiparticle. And if they encounter each other, they both annihilate to form pure energy. This theoretically expected and empirically observed. By the way, every radioactive decay that involves electrons or positrons also produces neutrinos to account for the conservation of particles and leptons. For every electron, there must be an anti-neutrino, and for every positron produced, there must also be a neutrino.
Particles appear and disappear all the time. The only constant thing in the quantum regime is change. Reality is not as lasting as it appears.
October 9th, 2008, 07:37 PM
It is not a matter of belief. It s a fact - and a definition. If a particle has properties inverse to another - simply speaking - it is its antiparticle. And if they encounter each other, they both annihilate to form pure energy. This theoretically expected and empirically observed. By the way, every radioactive decay that involves electrons or positrons also produces neutrinos to account for the conservation of particles and leptons. For every electron, there must be an anti-neutrino, and for every positron produced, there must also be a neutrino.
Particles appear and disappear all the time. The only constant thing in the quantum regime is change. Reality is not as lasting as it appears.
What we actually and mistakenly call energy, are particles. Electrons.
Sincerely,
William McCormick
October 19th, 2008, 11:21 PM
My last antimatter containment vessel met with distast, blowing my best friend to atoms. Needless to say, the enviroment was faily unfriendly, in a practical sort of way.
Excellent explanation, most concise. It may be said that the devices used to produce antimatter are not optimized to do so in bulk and that it is very possible that significant reductions in cost may be realized if improvements are made accordingly. For spacecraft propulsion antimatter has obvious advantages and dribbling a bit of antihydrogen into reaction chamber with plenty of regular hydrogen would create best rocket imaginable except for maybe photon rocket, which antimatter could also power.
Absolute zero is called absolute zero because it's absolute. There is no such thing as negative temperature. Absolute zero is the absolute lowest temperauure possible and even it can't be reached. Antimatter is the same exact thing as matter, it's just oppositely charged from what we decide to call matter. If we had decided to assign a positive charge to electrons and a negative charge to positrons and switch their names around, the world wouldn't be any different. A positron is just as much matter as antimatter. It's just that it has a positive charge.
Why is one replying to a 3 year old dead thread?
To explain what antimatter is in it's fullest, one needs to write out the Dirac Equation and explain what it means. Be back soon.
I need to find out whether this place uses latex.
The equation of interest should be a wave equation:
If we pull the derivative down in respect to x in our function Ψ = e^i(kx-ωt) gives ik, and if we pull down our derivative in respect to t gives us iω, and if we take the two from each other we have:
which means k=ω. We become to realize that we have a concept known as right moving and left moving particles. What are right moving and left moving particles? Physically, all we need to know is that it represents a physical system. What this physical system is will become clear eventually. Right moving particles are expressed as:
and left movers are:
These two physical quantities now have a specific meaning in our equations, which take the form of particles moving off to the left and particles moving off to the right.
They physically represent particles and antiparticles.Represented as column vectors, we have:
This is just a neat mathematical way to express right and left movers.Usually we would place a dot above the expressions φ_R and φ_L to express that we are taking the time derivative of the quantities.Such an equation would be read as:
We have a newcomer, and his name is alpha α and he is a matrix. The importance of alpha will become clear as we proceed.
Now turn out attentions toand it's relativistic representation:
so
What we would like to do now, is rewrite this equation (∂/∂dt) ψ = α (∂ψ/∂x) in a more compact form. When you take a wave and hit it with ∂/∂dt it may be remembered that this pulls down -iω. We then look at ∂ψ/∂x and this pulls down a -ik. The equation now has the more simplified form of:
which simplifies to
The alpha here acts like an instruction to express k either positively or negatively. Because of our relativistic relationship ω=√m2+k2 we would like to consider a mass and a new matrix which is called beta:
A requirement on our matrices is that whatever α and β are, they must satisfy that the square of ω is equal to m^2+k^2. So let's square it:
Decomposing this equation, we find a usual notation:
we are now going to expand our terms - we get
we can rewrite the superlfuous quantities αβKm+βαkm here, knowing that k is simply momentum and m is the mass as ( αβ+βα)km.Whatever alpha is (we know its a matrix) but whatever it would have been to the imagination before this, we would know that through matrix calculations, α2=1. Likewise, whatever beta would be also requires β2=1. Because (αβ+βα)km has no place in our formula, this means that we need α and β to satisfy an algebraic property called anticommutation in that (αβ+βα)=0. This is actually a clifford algebra.
Our two wave equations, expressed in these equations with beta and alpha are:
both these equations describe right moving wavesand left moving wave
and they physically represent particles and antiparticles. The mass term is strictly positive, and because of the mass term, it can describe a new type of particle, the majorana particle which is a particle which is it's own antiparticle. The majorana mass term couples left and right movers together.
This is what a mass term does - so there you have it. The Dirac Equation which was able to predict the existence of a negatively charged particle and a postive charged particle, the latter being the antiparticle in the electron case.
(testing something [latex]a[/latex])
Last edited by Goldstone; September 28th, 2011 at 10:23 AM.
| « plasma ionisation | Can anyone explain to me Einstein's theory » |
| Bookmarks |
Bookmarks |
