Anti-matter .....why?

[mrcurious]

Why is there antimatter? Why does normal matter and antimatter particles annilate each other when the come into contact, but matter always wins over anti matter? Reading a book called 'Origins" in the book they describe how the universe began......normal particles & anto particles would collide and annihilate one another, but in the end a normal particle would still be created after the annihilation....whats going on? And why doesn't anti matter have anti properties? If something is the opposite I would figure that these anti particles would have opposite properties.....anti-gravitons for anti gravity.... darkness for the anti photon....yet I don't think anti matter works that way....why?

 

[derekmcd]

I'll take a shot at answering some of your questions, though I hope some much smarter than me will elaborate.<br /><br />"<i>Why is there antimatter?</i>"<br /><br />Not sure I can answer why, but i'll try with 'how'. Antimatter is created naturally in the universe when high-energy particles collide. Cosmic rays from the sun hitting the Earth's atmosphere can create anitmatter particles. It's likely produced in the same way at the center of the Milky Way or any other region of space where incredibly energetic event occur.<br /><br />"<i>Why does normal matter and antimatter particles annilate each other when the come into contact, but matter always wins over anti matter? </i>"<br /><br />First, matter does not win. Matter and it's Anitmatter couterpart mutually annihilate each other producing a gamma ray. I believe this happens because they have opposite charge. An electron has a negative charge and an anti-electron (positron) has a positive charge.<br /><br />"<i>Reading a book called 'Origins" in the book they describe how the universe began......normal particles & anto particles would collide and annihilate one another, but in the end a normal particle would still be created after the annihilation....whats going on?</i><br /><br />I wouldn't be one to argue with Dr. Tyson, but I don't recall the mutual annihilation still producing a particle. I haven't read that book and am curious if they are discussing matter/antimatter during the first second of the Universe. My understanding is that there was not quite an equal amount. For some, yet still unexplainable, reason, there was a very tiny fraction more matter than antimatter.<br /><br />"<i>And why doesn't anti matter have anti properties? If something is the opposite I would figure that these anti particles would have opposite properties.....anti-gravitons for anti gravity.... darkness for the anti photon....yet I don't think anti matter works that way....why?</i>"<br /><br />An antimatter particle is, in fact, a 'no <div class="Discussion_UserSignature"> <div> </div><br /><div><span style="color:#0000ff" class="Apple-style-span">"If something's hard to do, then it's not worth doing." - Homer Simpson</span></div> </div>

 

[yevaud]

This is due to what's known as Symmetry - each particle has an anti-particle (the Photon is the lone exception).<br /><br />It's accepted (so far) that there was a slightly more matter than anti-matter when the Big Bang occurred, meaning that we see only "normal" matter wherever we look today. <div class="Discussion_UserSignature"> <p><em>Differential Diagnosis:  </em>"<strong><em>I am both amused and annoyed that you think I should be less stubborn than you are</em></strong>."<br /> </p> </div>

 

[alokmohan]

Yebahood,thats correct as far I know. In antimatter world ,all elements are of same spectra as ours.We cant distinguish between star and antistar ,galaxy and antigalaxy unless they come in contact. In the same star we may not have both,they must have destroyed each other.

 

[Saiph]

One of the reasons "why" anti-matter exists is due to laws of conservation. When energy turns to matter, or particles split into two other particles (like muon decay) charge, mass, and spin have to be conserved.<br /><br />When a high-energy photon decays into an electron, in order to preserve spin, and charge another particle must also be created, that spin in the opposite way the electron does (no big deal really) but also of the opposite charge: a positive charge.<br /><br />As for why there was slightly more matter than anti-matter at the BB, or why matter wins out "slightly" in the annihilation...nobody's really sure. There are theories of course, I don't know of any "definitive" ones. <div class="Discussion_UserSignature"> <p align="center"><font color="#c0c0c0"><br /></font></p><p align="center"><font color="#999999"><em><font size="1">--------</font></em></font><font color="#999999"><em><font size="1">--------</font></em></font><font color="#999999"><em><font size="1">----</font></em></font><font color="#666699">SaiphMOD@gmail.com </font><font color="#999999"><em><font size="1">-------------------</font></em></font></p><p><font color="#999999"><em><font size="1">"This is my Timey Wimey Detector.  Goes "bing" when there's stuff.  It also fries eggs at 30 paces, wether you want it to or not actually.  I've learned to stay away from hens: It's not pretty when they blow" -- </font></em></font><font size="1" color="#999999">The Tenth Doctor, "Blink"</font></p> </div>

 

[why06]

<i>And why doesn't anti matter have anti properties? If something is the opposite I would figure that these anti particles would have opposite properties.....anti-gravitons for anti gravity.... darkness for the anti photon....yet I don't think anti matter works that way....why? </i><br /><br />As for anti properties I can tell you what your talking about is negative mass. ("Yes I said it again Yevaud")<br /><br />Negative mass particles would have antigravity... Behav opposite to newtons laws. In other words accelerate away from you the faster you approached them. You would have equal, but not opposite effects... weird.<br /><br />All these guy are right about the antimatter. Heck who knows perhaps antimatter did win out and we call normaal matter antimatter. Really it doesn't matter. You know the whole "Rose by any other name.." thing. <br /><br />I figured it my duty to at least comment on your question since you did call my name: "why?" <img src="/images/icons/wink.gif" /> <div class="Discussion_UserSignature"> <div>________________________________________ <br /></div><div><ul><li><font color="#008000"><em>your move...</em></font></li></ul></div> </div>

 

[kelvinzero]

Ive heard somewhere that a positron can be regarded as an electron moving backwards in time.<br /><br />This makes me wonder if an electron and a positron anihiating to create a gamma ray as in this diagram http://en.wikipedia.org/wiki/Feynman_diagram is actually equivalent to the collision of an electron and a gamma ray causing the electron to bounce off in a new direction, but just viewed through different axes.<br /><br />(I cant explain why that diagram doesnt show the electron and positron creating two gamma rays to conserve momentum.. apparently it is some weird quantum mechanics thing that only works over minute periods of time)<br />

 

[why06]

back in time? this goes way over my head. that is really wierd. why would a particle ever go back in time from being annihilated? <div class="Discussion_UserSignature"> <div>________________________________________ <br /></div><div><ul><li><font color="#008000"><em>your move...</em></font></li></ul></div> </div>