Why Doesn't the Universe Explode Because of an Antimatter Reaction?

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Discussion Overview

The discussion revolves around the existence and capture of antimatter, particularly addressing why the universe does not explode due to antimatter reactions with matter. Participants explore the mechanisms of antimatter storage, the nature of annihilation, and the implications of using positrons in medical applications such as PET scans.

Discussion Character

  • Exploratory
  • Debate/contested
  • Technical explanation
  • Conceptual clarification

Main Points Raised

  • Some participants express confusion about how antimatter can exist without causing explosions upon contact with matter, suggesting the need for a concept of "neutral matter."
  • Others clarify that the "explosion" is actually annihilation, which releases gamma radiation, and that space is mostly empty, reducing the likelihood of contact.
  • It is mentioned that scientists use magnetic bottles to store antimatter, preventing it from coming into contact with matter.
  • Some participants question the effectiveness of magnetic fields, arguing that annihilation requires physical contact, while others assert that annihilation does indeed require such contact.
  • One participant expresses skepticism about the capture of antimatter, citing the energy produced during particle collisions and questioning how antimatter can be created in such processes.
  • Another participant states that antimatter has been created and captured multiple times, although typically for short durations.
  • Questions arise regarding the use of positrons in medical treatments, specifically how they do not cause explosions in the brain despite being emitted during procedures like PET scans.
  • Participants explain that the positrons emitted during PET scans quickly annihilate with electrons in the brain, producing gamma rays that are detected, and that the energy involved is minimal, preventing any harmful effects.

Areas of Agreement / Disagreement

Participants express a mix of agreement and disagreement regarding the mechanisms of antimatter storage and annihilation. While some clarify and support certain points, others remain skeptical or propose alternative views, indicating that the discussion is unresolved and contains competing perspectives.

Contextual Notes

Some claims about the nature of antimatter capture and annihilation rely on specific definitions and assumptions that may not be universally accepted. The discussion also touches on the limitations of current antimatter storage techniques and the conditions under which positrons interact in medical applications.

AntiPhysics
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So, semi-simple antimatter physics state that when antimatter comes in contact with regular matter, an explosion occurs. If there is only antimatter and matter in the universe, how can antimatter even exist, since it will come in contact with matter at one point and explode? So how are scientists able to capture it? They store it in a container made out if matter, so why doesn't that explode?

This really doesn't make sense to me. Maybe there could be such a thing called neutral matter, whose atoms are solely composed of neutrons?
 
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AntiPhysics said:
since it will come in contact with matter at one point and explode?
And so it does. But space is big. And nearly empty.

The "explosion" is really annihilation, with release of gamma radiation. We see lots of radiation in the universe.

AntiPhysics said:
So how are scientists able to capture it? They store it in a container made out if matter, so why doesn't that explode?
They store it in a magnetic bottle. The antimatter is prevented from contacting the container via magnetic fields.
 
DaveC426913 said:
And so it does. But space is big. And nearly empty.

The "explosion" is really annihilation, with release of gamma radiation. We see lots of radiation in the universe.


They store it in a magnetic bottle. The antimatter is prevented from contacting the container via magnetic fields.

Hmm... But magnetism is created by charges the matter produces, and you don't need physical contact for the reaction to occur.
 
AntiPhysics said:
Hmm... But magnetism is created by charges the matter produces, and you don't need physical contact for the reaction to occur.

If you mean the reaction that results in annihilation, then yes, you DO need physical contact.
 
AntiPhysics said:
Hmm... But magnetism is created by charges the matter produces, and you don't need physical contact for the reaction to occur.

Magnetism is particle-agnostic, just like photons. Yes, you do need physical collision for particles and anti-articles to annihilate.
 
phinds said:
If you mean the reaction that results in annihilation, then yes, you DO need physical contact.

Oh, okay, thank you. I'm not be a physicist, (heck, I'm only a freshman in high school), so sometimes I get my facts screwed up.
 
I don't think Anti-matter can be captured. Of course, I strongly contradict myself. But, there is some kind of belief in my self, may be a superstition, that anti-matter can't be captured or held in control with us.

I support this by saying that energy is produced during collision of particles at particle accelerators. Collision means, we are colliding particles with other particles - not anti-particles. When such thing is done energy is produced. Energy is released when a particle and anti-particle combination takes place. Then how come anti-matter is produced all of a sudden, when matter is collided. We know, matter is formed only when matter and anti-matter combination already occurred and matter is more than anti-matter during those collisions.
 
sheshank said:
I don't think Anti-matter can be captured. Of course, I strongly contradict myself. But, there is some kind of belief in my self, may be a superstition, that anti-matter can't be captured or held in control with us.

I support this by saying that energy is produced during collision of particles at particle accelerators. Collision means, we are colliding particles with other particles - not anti-particles. When such thing is done energy is produced. Energy is released when a particle and anti-particle combination takes place. Then how come anti-matter is produced all of a sudden, when matter is collided. We know, matter is formed only when matter and anti-matter combination already occurred and matter is more than anti-matter during those collisions.

You should read some real science instead of just making things up in your head.

Antimatter has been created and captured numerous times, although it has never been held for more than about 15 minutes so far.
 
Antiprotons can stay in storage rings for days, no problem.
 
  • #10
i have been wondering this as well . I read somewhere that they have inveted a treatment against alzheimer that implys the use of a radiactive fluorine that emitts positrons and that are send into the brain so that they can attach to the affected areas , or somehting like that , and i wonder how this can be possible ? or have i understand this wrong ?
 
  • #11
castro94 said:
i have been wondering this as well . I read somewhere that they have inveted a treatment against alzheimer that implys the use of a radiactive fluorine that emitts positrons and that are send into the brain so that they can attach to the affected areas , or somehting like that , and i wonder how this can be possible ? or have i understand this wrong ?
I think you are thinking of radioactive tracers or perhaps treatments where radioactive particles are targetted to specific locations. Nuclear medicine does deal with antiparticles, a good example is a PET scanner that measures the gamma rays released by a radioactive tracer.
 
  • #12
how come this PET doesn't explode the brain , it says that it emittes positrons , how come this positrons does not annihilate with the brains matter ? i understand how antimatter can be stored in magnetic fields , but how can this aplly in the brain when nuclear medicine uses antiparticle emittion inside the brain ?
 
  • #13
castro94 said:
how come this PET doesn't explode the brain , it says that it emittes positrons , how come this positrons does not annihilate with the brains matter ? i understand how antimatter can be stored in magnetic fields , but how can this aplly in the brain when nuclear medicine uses antiparticle emittion inside the brain ?
Annihilation is what a PET scanner measures. Essentially a radioactive tracer is injected into the patient, this tracer is designed so that after a while it undergoes positive beta decay in which a proton is converted to a neutron realising a neutrino and positron in the process. The positron lasts very small fractions of a second before interacting with an electron in the brain, this causes the release of gamma rays that are then detected by the PET machinery. The reason the brain is not damaged is due to the fantastically small amounts of annihilation. In total a patient is exposed to less than 10 millisieverts of radiation.
 
  • #14
They quickly annihilate with electrons in the brain and emit gamma rays - that is they way these tracers work, the gamma rays get detected and tell the doctors something about the distribution of the tracer in the human. The energy released per volume is extremely low, so you don't get macroscopic effects like heat ("explosion").

Edit: Too slow
 
  • #15
and they are so "slow " so they don't produce enough energy to create other antiparticle particle pairs , now i get it , thank you
 

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