# Matter combined with Antimater question

1. Apr 28, 2006

### scott1

I herd if you took 1 gram of matter and 1 gram of Antimatter and took them to center of Chiago and mixed toghter Chiago will be gone.

Why does the mixture of Antimatter and matter create so much energy?

2. Apr 28, 2006

### kmarinas86

When the matter and antimatter contact each other, they annihilate each other spewing radiation all over leaving no mass behind.

And it's true:

http://www.1728.com/convert2.htm

2 Gram of Mass (Energy Equivalent)
42.962 Kilotons of TNT
2.1471 Hiroshima A-Bombs

3. Apr 29, 2006

### scott1

Can you be more specfic? I know what happens when you mix toghter I dont understand why?

4. Apr 29, 2006

### SpaceTiger

Staff Emeritus
From the QED perspective, it's simply because one can draw a low-order diagram for the interaction process. You can think of this in terms of conservation laws. If you take an electron and positron in the initial state, would any conservation laws be violated if they changed into two photons? They have opposite charge, so the net charge is zero, just as with the photons. The net lepton number in the initial state is zero as well (+1 for the electron, -1 for the positron). For comparison, try considering two electrons or an electron and a proton. The former annihilation would violate conservation of charge and lepton number and the latter would violate lepton number and baryon number conservation.

The conservation of energy is what makes the event so energetic. Since electrons and positrons each have 511 keV of mass energy, at least twice this amount of energy must be dumped into the final state photons. Each of these photons will be 100-1000 times more energetic than the typical photon emitted from the sun, so you don't want to be around when a lot of this stuff annihilates.

5. Apr 30, 2006

### Euric

I think you could have described it a little easier by just noting that E=mc^2 applies. You have 0.002 kg of mass and c=299 792 458 m/s. The result is approximately 180 TJ.

Now you can tell us in what forms 180 TJ manifests itself. What percentage of that energy has the form of heat? light? radiation?

I don't think they leave no form of mass behind? What about atomic and sub-atomic particles? Don't these have mass? Aren't they forms of matter? What is radiation? Isn't it atomic and sub-atomic particles moving at high speeds?

So how can you say that the encounter of matter with anti-matter leaves no mass behind?

6. Apr 30, 2006

### kmarinas86

In matter-antimatter annihilation, 100% light. Light is electromagnetic radiation that contains energy which can used to heat matter.

They leave energy behind, but since the byproducts travel at the speed of light, there's no mass.

They do.

They are of course, why wouldn't they be?

Anything that was emitted or absorbed by a particle. It may or may not have mass. Not all radiation is light. All light is radiation.

It can be.

Because the byproducts of an matter-antimatter collision do not have mass, they are just photons. The byproduct of a photon with the same energy as two electrons may form an electron and a positron (which is the opposite of matter-antimatter annihilation).

http://en.wikipedia.org/wiki/Annihilation

7. Apr 30, 2006

### SpaceTiger

Staff Emeritus
You ought to get both. The annihilation of an electron and positron at low energy should produce only photons, but proton and anti-proton annihilation (the particles being more massive) can produce other particles as well. Perhaps someone more experienced in particle physics can give an idea as to the relative ratios.

8. Oct 22, 2007

### keinve

to put it simply, matter and anti-matter have a rather high matter to energy ratio. the heat loss will help kill off any people who survive the explosion.

9. Oct 22, 2007

### mattex

Is it possible to point a TV picture tube (ie electron gun) from an old TV set at the tungsten filiment of a light globe & produce antimatter in your home? Obviously some magnets are necessary (= hi-fi speakers??)...

10. Oct 23, 2007

### Chronos

There are no pure matter/antimatter collisions [between massive bodies]. Some of each will be expelled as highly energetic particles - like cosmic rays.