View Full Version here: : Another question - Antimatter

12-10-2010, 04:54 PM
So one theory is that all matter has an antimatter mirror and because the universe is not symetrical they don't destroy each other....

We also have a BB theory that says the universe started as extremely hot energy, it cooled a little and particles formed. Well this supposedly means matter and antimatter was created. So when they formed why didn't they destroy each other? I'm basing this on the experiment I saw where a photon collided with a particle to create an electron and positron, ie they were created in the same space and kept apart by electric charge. What would keep them apart during the BB particle formation process?

So is antimatter natural or just the result of artificial experiments?


12-10-2010, 06:32 PM
I was watching Planet Science recently, talking about this exact issue, they were saying that a slight inbalance was resulted that stopped the destruction of all matter. I am not sure how much of this is true or whether it is based of fact, or math or whatever. There is a hole in science that is completely unknown straight after this part of the big bang which is hope that the LHC will discover. The discovery of higgs Bosan energy/particle (whatever)

It was an interesting program and only recently aired, wondering why it is not on IView though.

12-10-2010, 11:26 PM
To answer your questions may I suggest you read up on the Standard Model Have a look at this

13-10-2010, 08:15 AM
The asymmetry of the Universe is one of the unsolved mysteries.

Unlike the popular science fiction notion that matter and antimatter annihilate each other at the drop of a hat, the reality paints a different picture.

The proton/antiproton and electron/positron colliders we have at our disposal indicates there is only certain probability that a reaction will occur.
This probability is defined by the particle physicist as the cross section.
In terms of classical physics the cross section is how big the target is for a collision to occur.

While antimatter was mathematically predicted, it is "natural".
Antimatter in the form of antineutrinos are created through the B decay of neutrons.



13-10-2010, 10:03 AM

Thanks for that info re matter and anti-matter not necessarily annihilating each other spontaneously. My thought was that if spontaneous mutual annihilation was the only outcome of a positron and an electron coming together, then how could there be any antimatter left. Surely by now the very small amount of antimatter (relative to matter) left after the BB would have had plenty of time to be annihilated by matter. But now I see why we still have antimatter.


13-10-2010, 11:55 AM
Unless Antimatter can be destroyed in another way.

13-10-2010, 12:17 PM
This thread raises a question I've pondered on occasion. If a positron were accellerated enough to overcome the repulsion from a proton, would the positron annihilate part of the proton and what would happen with the remains? What would the remains break down to? Or will the process only work with particles of the same type/mass?

13-10-2010, 12:30 PM
i believe i read somewhere (can't remember were) that in the initial stages of the BB there was a slight imbalance in the matter to anti-matter ratio something along the lines of one extra part of matter to every 10 billion parts of anti-matter. If i am remembering correctly within the first few seconds after the big bang the universe was consumed in matter and antimatter effectively destroying each other until matter won (due to its slightly larger numbers lol). why this imbalance happened well that is not entirely known lol but i am happy for it ... means i exist lol.

13-10-2010, 12:53 PM
Begs the question what would happen if it went the other way. Would we be anti humans :)

I would think it we would have reversed the physics and terminology.

13-10-2010, 01:21 PM
I also read something along those lines in a book by Nigel Henbest called "The Mysterious Universe", which would be close to 20 years old now :)

13-10-2010, 04:02 PM
No it wouldnt annihilate part of the proton. Annihilation occurs through reaction with a particles own anti-particle. Anti-particles have opposite electric charges to their corresponding particles. As far has been observed electric charge is a conserved quantity - similar to energy or matter except that charge has a negative of itself (so you can create or annihilate opposite charges without creating or destroying charge eg 1-1=0 or 0=1-1).

13-10-2010, 05:46 PM
They did this at 318 GeV at HERA (http://en.wikipedia.org/wiki/HERA), (Hadron Electron Ring Anlage), in Hamburg from 1992 to 2007.

The HERA website (http://zms.desy.de/research/particle_physics/particle_physics_at_hera/index_eng.html) also tells the story.