Forums → The Tavern → Physics, Why Do They Exist?

@Reton8: What you said sounds and look UBER smart, but its just grade 11 physics :P Oh and is it universal to bold vector quantities, cause ive seen multiple people/books do that

Lol, I know. It wasn't anything beyond a few entry level college course (which are basically the same as high school courses) ha ha.

Except for F= dp/dt which is the net vector sum of the force equals the derivative of momentum with respect to time I think. That equation might not be high school, unless the advanced High school classes have calculus based physics.

But, I got most this from wikipedia. Lol.

Why isn't the world made of antimatter instead of regular matter?

Because antiparticles are, by and large, very unstable. A universe made entirely of antimatter would either expand far too rapidly, or collapse upon itself. Furthermore, when quantum fluctuations led to the rapid expansion and cooling of our universe, and there were both matter and antimatter in abundance, antimatter particles collided with their corresponding matter particles and were destroyed. However as antimatter is more unstable it is widely held that more antimatter was destroyed than was matter, leaving us a universe made up essentially of leftovers.

Physics is a field of study that is all about disproving a theory.

Actually it's a field that's based on mathematics which covers the action and interaction of matter. And, since it's based in maths, we get our proof from equations. We know that E=MC^2 because the math has been checked and double checked countless times. We know how strong gravitational forces are because, again, we have a mathematical equation which explains it, and this equation has been tested and verified.

Furthermore, advanced physics is based on simpler physics which have not only been verified mathematically, but also through real life applications and testing. Such as with E=MC^2, we know what the speed of light is in a vacuum, so we know that part of the equation not only through math, but observation. Then we tested and measured a reaction which converted mass into energy. The mass used, and the energy resulting from the reaction matched perfectly with Einstein's equation. Now we can base more abstract, and solely mathematical models off of this.

I don't believe that fire is considered a force in physics.

Correct. Fire is a chemical reaction, not a force.

Because antiparticles are, by and large, very unstable. A universe made entirely of antimatter would either expand far too rapidly, or collapse upon itself. Furthermore, when quantum fluctuations led to the rapid expansion and cooling of our universe, and there were both matter and antimatter in abundance, antimatter particles collided with their corresponding matter particles and were destroyed. However as antimatter is more unstable it is widely held that more antimatter was destroyed than was matter, leaving us a universe made up essentially of leftovers.

Baryon asymmetry

"The baryon asymmetry problem in physics refers to the apparent fact that there is an imbalance in baryonic matter and antibaryonic matter in the universe. Neither the standard model of particle physics, nor the theory of general relativity provide an obvious explanation for why this should be so; and it is a natural assumption that the universe be neutral with all conserved charges." (Source Wikipedia)

The question I posed doesn't yet seem to have a direct answer. I was just saying, in other words, when both matter and antimatter were initially created, antimatter could have been the predominant form of matter or,

"'The Big Bang' should have produced equal amounts of matter and antimatter; as such, there should have been total cancellation of both. In other words, protons should have cancelled with antiprotons, electrons with antielectrons (positrons), neutrons with antineutrons, and so on for all elementary particles. This would have resulted in a sea of photons in the universe with no matter." (Source Wikipedia)

So why not a universe of predominately antimatter or a universe of that's a photon sea?

Do you see what I'm saying? Electrons are have a negative charge, but why? What if they had a positive charge and the antimatter positrons had a negative charge? Wouldn't everything be relatively the same.

(What if apples had been given the name strawberries and strawberries the name apples? A rose by any other name would smell as sweet.)

So why not a universe of predominately antimatter or a universe of that's a photon sea?

Again, to the best of my understanding, antimatter particles are less stable, hence even if there is never any binding or transmutation of particles, antimatter would degenerate faster, eventually leaving more matter than antimatter. Furthermore, they would not necessarily cancel eachother out 1:1 as an antimatter particle only causes destruction when it collides with it's corresponding matter particle. (e.g. antihydrogen only causes a destructive reaction when it collides with hydrogen)

Because of the shear size and distance it is illogical to assume that every antimatter particle in existence would find it's corresponding matter particle. Had this occurred then there would be nothing left at all and we wouldn't be here to ask such questions anyway.

Do you see what I'm saying? Electrons are have a negative charge, but why? What if they had a positive charge and the antimatter positrons had a negative charge? Wouldn't everything be relatively the same.

No, not really, again because of the instability of antimatter molecules.

(What if apples had been given the name strawberries and strawberries the name apples? A rose by any other name would smell as sweet.)

Exactly. You can call a proton whatever you like, but it is still a positively charged atomic particle.

Because of the shear size and distance it is illogical to assume that every antimatter particle in existence would find it's corresponding matter particle. Had this occurred then there would be nothing left at all and we wouldn't be here to ask such questions anyway.

I get what your saying, but I can't find (yet) anywhere on the internet that says antimatter is less stable than matter. I understand that, "In antimatter-matter collisions resulting in photon emission, the entire rest mass of the particles is converted to kinetic energy." (Source Wikipedia).

So,matter - antimatter collision produce a 100% conversion of rest mass to energy, which means a complete conversioin from matter - antimatter to energy.

Why is the Universe composed of matter and not antimatter?

But, even the yahoo answer may not be true.

http://en.wikipedia.org/wiki/Baryon_asymmetry

"Most explanations involve modifying the standard model of particle physics, to allow for some reactions (specifically involving the weak nuclear force) to proceed more easily than their opposite. This is called " violating CP symmetry" in weak interactions. Such a violation could allow matter to be produced more commonly than antimatter in conditions immediately after the Big Bang. However, as of yet, no theoretical consensus has been reached regarding this, and there is no experimental evidence of an imbalance in the creation rates of matter and antimatter.

Another possible explanation of the apparent baryon asymmetry is that there are regions of the universe in which matter is dominant, and other regions of the universe in which antimatter is dominant, and these are widely separated. The problem therefore becomes a matter/antimatter separation problem, rather than a creation imbalance problem. Antimatter atoms would appear from a distance indistinguishable from matter atoms, as both matter and antimatter atoms would produce light (photons) in the same way. Only in the border between a matter dominated region and an antimatter dominated region would the antimatter's presence be detectable, as only there would matter/antimatter annihilation (and the subsequent production of gamma radiation) occur. How easy such a boundary would be to detect would depend on its distance and what the density of matter and antimatter is along it. Presumably such a boundary would lie (almost by necessity) in deep intergalactic space, and the density of matter in intergalactic space is reasonably well established at about one atom per cubic metre.[2][3] Assuming this is the typical density of both matter and antimatter near a boundary, the gamma ray luminosity of the boundary interaction zone is easily calculated. Approximately 30 years of scientific research have placed boundaries on how far away, at a minimum, any such boundary interaction zone would have to be, as no such zones have been detected. Hence, it is now considered unlikely that any region within the observable universe is antimatter dominated.

At least one more major scientific study, called the Alpha Magnetic Spectrometer, is planned that would, among other things, advance our capability of detecting very distant antimatter dominated regions[4].

Another possibility is that antimatter dominated regions exist within the universe, but outside our observable universe. Inflationary cosmology models suggest that the there may be more to the universe than can be seen from the Earth, if only for the simple reason that the universe isn't old enough for light from the most distant parts of the universe to have reached us yet. If so, radiation from the boundary of matter and antimatter dominated regions may simply still "be on its way" to Earth, and so cannot be observed."

I don't see anywhere in the wikipedia article that states antimatter is less stable than matter in a region where antimatter is colliding with other antimatter (not regular matter).

I understand it's only wikipedia and yahoo answers, but I would they would have mentioned somewhere that antimatter is not as stable as matter. I'm not seeing it.

I'm going one degree back from just the creation of the matter antimatter itself. I'm saying what governed the fact that electrons are negative and and protons are positive and neutrons neutral? Why are positively charge particles attracted to negatively charged particles?

physics exists to teach students that sometimes, even if you pay attention for the whole class every class and read the book, you still don't understand the subject.

That's math. Physics is intuitive, i.e. it makes sense after somebody else figured it out.

That's math. Physics is intuitive, i.e. it makes sense after somebody else figured it out.

physics does not make sense to me. i just see it as a way to explain why stuff happens.