# Antimatter - could it ever be utilized as poss. energy source?

1. Aug 20, 2004

### Simfish

I'm guessing that the amount of energy taken to generate an antimatter particle would always be more than what you would get back by colliding the antimatter generated with a matter particle.

But if we ever find a source of antimatter in the universe, then do you suppose that in the far future, we could utilize antimatter for power?

-T_Simfish

2. Aug 20, 2004

Im not an expert and dont quote me, but I think that the law of conservation of energy plays a part. I think the energy neede to convert a particle into a particle-antiparticle pair is the same as when the pair reunite to form energy.
To answer your second question, the problem with antiparticles is containig them, it is soo hard to contain them, you must use strong magnetic fields. To utalize it for use, I'd say it would take us another meillenium to get there.

3. Aug 20, 2004

### Simfish

Ah, ok. I forgot about the conservation of energy! Thanks for the response! :)

4. Aug 20, 2004

### Entropy

Maybe for spacecrafts but thats about it. You need to create the actual anti-matter first which raises the question, where do you get the energy to create the anti-matter?

5. Aug 20, 2004

### Simfish

6. Aug 20, 2004

### daveed

hmm... this sounds rather like somerthing from dan brown's Angels and Demons

7. Aug 20, 2004

### futb0l

It will cost a lot of money to produce antimatter... so if there is a new and more efficient way of producing - then maybe we can use it for spacecrafts.

8. Aug 21, 2004

### Deeviant

Anti matter is already created in small quantities in large particle accelerators today, albeit very small quantities. Anti matter would most likely not be used for power generation, but power storage, as its energy density is about as high as possible.

And we already have the ability to store it, at least for relatively small periods of time.

9. Aug 21, 2004

Anti matter is most commonly produced through pair production. When a photon of light has enough energy, it will produce an electron/positron pair. The equation for this is:
$$E_{photon} = mc^2 + mc^2 + E_k$$

the two m's are for the masses of the electron/positron, which are the same. And the $$E_k$$ is the left over kinetic energy as the electron/positron fly apart.

The energy of the photon can be wrotten as:
$$E = hf = \frac{hc}{\lambda}$$
making out final equatin for pair production or antimatter/matter production:

$$\frac{hc}{\lambda} = mc^2 + mc^2 + E_k$$

10. Aug 22, 2004

### ArmoSkater87

The rest mass energy of the electron is .511MeV, in order for electron-positron pair production to be possible, the photon must have an energy of 2(.511) = 1.022MeV. That is the threashhold for creating the pair, and if the energy of the photon is greater than the threashhold, then it adds on to the kinetic energy of the electron and positron after the transformation.

This website should clear everything up for you
http://hyperphysics.phy-astr.gsu.edu/hbase/particles/lepton.html

11. Aug 22, 2004

### ArmoSkater87

You are guessing very right, in fact, if you combined ALL the antimatter ever made at CERN, and if you used that antimatter by anihhilating it with matter, it would give off enough energy to light a light bulb for 3 seconds.

We probably wont ever use antimatter as a source of energy, I agree with Nenad about how its very hard to contain since it will want to annihilate with its counterpart. The conservation of energy would mean that the energy of the particles when they collide will equal the energy of the annihilation of the antiparticles and particles produced - this is what Nenad was implying. BUT!! it also takes a lot energy to create strong magnetic fields in order to accelerate those particles to have such high energy. So...in the long run, you are losing much much more energy than gaining. It is theorised that there are still consentrations of antimatter in the universe left over from the Big Bang, which would give a very sufficial amount of antimatter, but once again, it would be a problem containing it. Although the biggest problem would be geting to it since it will be somewhere very far away from us.

12. Aug 22, 2004

we cannot tell where antimatter is. It will look exackly like matter, not difference but the only diff will be charge. And by the time we find this charge, we will be long gone in a fantastic explosion. For all we know, the Andrometa galaxy could be antimatter.

13. Aug 22, 2004

### expscv

using anitmatter as energy, isnt simmliar to nuclear power which we already have?

14. Aug 22, 2004

### Staff: Mentor

Somewhat, yes - and using it to generate power would be trivially simple (simpler even than nuclear power). Collecting it (if we ever found a source) and containing it would be the tough part.

15. Aug 22, 2004

### Zeteg

Are you saying that the speed in which matter and anti-matter collide, would affect the energy given?

I don't know much about this, so this may seem like a really really stupid question... but: So, you're saying when a matter particle and an anti-matter particle collide, they can create a very small amount of energy? I mean, just as much as a photon in the same direction?

16. Aug 22, 2004

### ArmoSkater87

Thats very true, which is why scientists are trying to detect heavy anti-atoms coming from deep space, possibly left over after the death of anti-stars in anti-galaxies. The Andromeda is probabaly not made from antimatter since its so close, we would expect anti-galaxies to be much much further, but your right it is possible.

No, in particle accelerators, particles (proton, neutrons, electrons) are accelerated to almost the speed of light, and then smashed into a target. That smash gives off so much energy that a particle-antiparticle pair are spontaneously produced. I was saying that the energy released from the smash would equal the energy that would be released if the particle and antiparticle were to annihilate each other after creation. They dont have to collide at high speed in order to annihilate, they just have to "touch". Although if they annihilated after colliding at some speed, that adds on to the energy released afterward.

Last edited: Aug 22, 2004
17. Aug 23, 2004

### Zeteg

Ahh, I see. Thanks =)

18. Aug 23, 2004

### Vern

I think there must be something else involved, otherwise we would never see photons with more energy than that required to produce an electron-positron pair. Not to mention that if something else were not involved it would falsify a pet theory of mine

Keep on chuggin !!

Vern

19. Aug 23, 2004

Yes there is something else involved. Pair production depends on temperatude. If the temperature is <$$10^{9} K$$, then no pair production occurs. If the temp is between $$6*10^{9} K\ to\ 10^{13} K$$ then an electron/positron pair is produced, and if temp is greater than the upper limit, a proton and a antiproton is produced.