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question about anti-matter colliding with matter

find_the_fun

Active member
Feb 1, 2012
166
I was watching this YouTube video regarding the formation of our universe (around 20:09 minutes) and they were talking about antimatter and matter. When anti matter comes into contact with normal matter they obliterate each other and a large amount of energy is released. When our universe was created there were initially equal amounts of antimatter and normal matter but somehow we are lop sided towards the matter. In the checkers analogy used in the video they say it's like our entire universe is like the one checker that is remaining at the end of the game.


What I don't understand is, when antimatter and matter destroy each other a large amount of energy is released. According to Einstein's equation E=mc^2 energy can be converted into matter. So even if all matter and antimatter collide and everything becomes energy, it's not like anything's "lost" and all that energy could be converted back into matter right?

If the answer is "no" and something is permanently lost, than does this disprove the law of conservation in a closed system (i.e. the universe)?
 

CaptainBlack

Well-known member
Jan 26, 2012
890
Re: question about anti matter coliding with matter

I was watching this YouTube video regarding the formation of our universe (around 20:09 minutes) and they were talking about antimatter and matter. When anti matter comes into contact with normal matter they obliterate each other and a large amount of energy is released. When our universe was created there were initially equal amounts of antimatter and normal matter but somehow we are lop sided towards the matter. In the checkers analogy used in the video they say it's like our entire universe is like the one checker that is remaining at the end of the game.


What I don't understand is, when antimatter and matter destroy each other a large amount of energy is released. According to Einstein's equation E=mc^2 energy can be converted into matter. So even if all matter and antimatter collide and everything becomes energy, it's not like anything's "lost" and all that energy could be converted back into matter right?
That is right, nothing is lost. In fact energy is being turned back into particle/anti-particle pairs all of the time.



CB
 

topsquark

Well-known member
MHB Math Helper
Aug 30, 2012
1,140
Re: question about anti matter coliding with matter

I was watching this YouTube video regarding the formation of our universe (around 20:09 minutes) and they were talking about antimatter and matter. When anti matter comes into contact with normal matter they obliterate each other and a large amount of energy is released. When our universe was created there were initially equal amounts of antimatter and normal matter but somehow we are lop sided towards the matter. In the checkers analogy used in the video they say it's like our entire universe is like the one checker that is remaining at the end of the game.


What I don't understand is, when antimatter and matter destroy each other a large amount of energy is released. According to Einstein's equation E=mc^2 energy can be converted into matter. So even if all matter and antimatter collide and everything becomes energy, it's not like anything's "lost" and all that energy could be converted back into matter right?

If the answer is "no" and something is permanently lost, than does this disprove the law of conservation in a closed system (i.e. the universe)?
This goes kindof deep in particle physics.

There is a particle called a kaon made of a strange quark and an up quark. It is the K+ and K- is its anti-particle. (We can do this with bottom quarks just as well.)

The neat thing about particle is that the way it decays violates something called "parity." Simply speaking parity conservation means you could replace a function f(x) to be the same as the function f(-x). (Of course you need this to happen in three D.)

Why do we care? Well you can combine the K+ and K- states and create what are called the long and short Kaons and both have a charge of 0.

The short (lived) kaons decay into into two pions and the long (lived) kaons decay into three pions. One would expect that these particles are completely distinct...sort of like two orthogonal vectors. But it isn't that simple. With parity violation some weird things happen. For example, the short kaons will occasionally decay into three pions. Which should not happen...but it does.

So where does that lead us? Well, looking at the pion decay states we note that the short kaons can produce a small amount of matter over antimatter. "Summing" this up over the whole of the early Universe we get that there were 1 billion particle-antiparticle states creating nothing but a radiation field, along with one lonely particle of matter. Matter over antimatter. Voila!

-Dan