Matter/Anti-Matter: Explaining Space Travel Applications

[DarkStar707]

Please explain the process of matter anti matter and how it could be used in space travel

 

[S.Vasojevic]

When matter and antimatter annihilate all the mass is converted to energy. This makes antimatter the most efficient fuel possible. Mass of the fuel is critical for space travel, so it also makes antimatter ideal fuel for space travel.

Just to give you some idea of numbers: you can match entire output of three space shuttle main engines during entire liftoff sequence with just 0.134 grams of antimatter - matter combination. Scary, isn't it?

 

[DarkStar707]

Well It's the kind of stuff That makes us a phase 2 society.
Are there current work in progress to make this happen?

 

[Matterwave]

They are creating anti-matter in labs, but the costs are prohibitive at this point. (~Several tens of trillions of dollars per gram)

Here's a paper on it:
http://www.engr.psu.edu/antimatter/Papers/NASA_anti.pdf

 

[DarkStar707]

Thanks for filling me in on this matter heh Pun completely intended

 

[Phyisab****]

As someone studying physics, it is very easy to get bogged down in the difficulties and mathematics and lose sight of the grand ideas which fascinated me as a child. Thanks for that link, I found it to be a very interesting examination of something at the intersection of physics and science fiction.

 

[Phyisab****]

Of course, storage of >~1g of antimatter in one place would present, I would have to assume, essentially insurmountable risks.

 

[DaveC426913]

Of course, storage of >~1g of antimatter in one place would present, I would have to assume, essentially insurmountable risks.

Puh-leeze. It can be stored in a cannister the size of a tennis ball can and contained with some dry cell batteries. I saw it in Angels & Demons.

 

[Phyisab****]

But I am assuming that But any failure would be so spectacular the entire device would have to be legally regulated

 

[jweie29nh]

I have questions about this too. Has anyone ever seen what antimatter looks like and what triggers antimatter to travel back in time? If antimatter does travel back in time then, where is the proof? Are there equations that explain how it goes back in time or has someone actually seen antimatter disappear in front of them to say that the antimatter opened a new dimension?

 

[DaveC426913]

I have questions about this too. Has anyone ever seen what antimatter looks like

It looks the same as matter. Photons are their own antiparticle, so when an antimatter atom emits a photon it gives no indication that it came from antimatter.

and what triggers antimatter to travel back in time?

It doesn't. where did you read this?

 

[Anti-Meson]

Firstly anti-matter does not exist in nature. Secondly when created, in lab, it takes more energy to create it than what can be yielded from it (thermodynamics). SO it is not viable means of powering anything.

 

[Phyisab****]

You are completely missing the point. It is useful as a storage mechanism.

 

[MotoH]

We need an anti-matter container to store this anti-matter. The container would explode if we touched it, so we need some anti-matter gloves. The gloves would explode if they touched our hands so we need anti-matter skin. We would then explode because we touched the earth, therefor we need an anti-matter earth.

Now how are we going to use anti-matter when anti-matter has become matter?

 

[Anti-Meson]

The answer is no because of the very fact that currently only a few atoms of anti-matter can be produced and that transporting such anti-matter is mind boggling. Any contact with normal baryonic matter and it will simply annihilate itself.

 

[DaveC426913]

What is going on here? :grumpy:

Firstly anti-matter does not exist in nature.

Of course it does. :grumpy:

Secondly when created, in lab, it takes more energy to create it than what can be yielded from it (thermodynamics). SO it is not viable means of powering anything.

Neither do Ni-CAD cells or Liquid Hydrogen, but they are an excellent way to power something.


As Phyisab**** points out, most of our propulsion systems are really storage devices. Producing the potential energy that is stored in this those batteries is always energy-intensive.

We need an anti-matter container to store this anti-matter.

All we need is a magnetic bottle.:grumpy:

 

[MotoH]

Thanks for ruining my whole theory Dave.

 

[Anti-Meson]

Of course it does. :grumpy:

Provide your evidence that anti-matter DOES exist in nature.

 

[DaveC426913]

Provide your evidence that anti-matter DOES exist in nature.

Feel free to start http://en.wikipedia.org/wiki/Antimatter#Origin_and_asymmetry".

Antiparticles are created everywhere in the universe where high-energy particle collisions take place. High-energy cosmic rays impacting Earth's atmosphere (or any other matter in the solar system) produce minute quantities of antimatter in the resulting particle jets, which are immediately annihilated by contact with nearby matter. It may similarly be produced in regions like the center of the Milky Way Galaxy and other galaxies, where very energetic celestial events occur (principally the interaction of relativistic jets with the interstellar medium). The presence of the resulting antimatter is detectable by the gamma rays produced when positrons annihilate with nearby matter. The gamma rays' frequency and wavelength indicate that each carries 511 keV of energy (i.e. the rest mass of an electron or positron multiplied by c2).

 

[Anti-Meson]

For Dave, may I point out this article produced by CERN - http://public.web.cern.ch/Public/en/Spotlight/SpotlightAandD-en.html

Admittedly, it is primarily focused on angels and demons but you will understand why anti-matter does not exist , exist being the key word, in nature.

There is no possibility to use antimatter as energy ‘source’. Unlike solar energy, coal or oil, antimatter does not occur in nature; we first have to make every single antiparticle, and we have to invest (much) more energy than we get back during annihilation.

EDIT: Dave, you are a PF contributor and supposed science advisor. I thought PF was a serious site promoting education. If you believe this you should stop referencing unregulated WIKIPEDIA and start referencing papers from scientific authority.

 

[Phyisab****]

EDIT: Dave, you are a PF contributor and supposed science advisor. I thought PF was a serious site promoting education. If you believe this you should stop referencing unregulated WIKIPEDIA and start referencing papers from scientific authority.

http://www.esa.int/esaCP/SEMKTX2MDAF_index_0.html

I followed the wikipedia citatation. The statement that antimatter does not exist is an enormous generalization. Of course it exists.

 

[DaveC426913]

For Dave, may I point out this article produced by CERN - http://public.web.cern.ch/Public/en/Spotlight/SpotlightAandD-en.html

Admittedly, it is primarily focused on angels and demons but you will understand why anti-matter does not exist , exist being the key word, in nature.




EDIT: Dave, you are a PF contributor and supposed science advisor. I thought PF was a serious site promoting education. If you believe this you should stop referencing unregulated WIKIPEDIA and start referencing papers from scientific authority.

I referenced Wiki for your benefit. It is a good place for you to start reading up on the subject if you're going to discuss it.

If someone comes on the board and says "F=ma is wrong", I'd do the same thing: "start here with your learning".

Your unilateral statement that it does not occur in nature is wrong. You can certainly modify it to say that it doesn't exist in great enough quantities and doesn't exist for long enough to be useful, but that would be a different claim.

For Dave, may I point out this article produced by CERN - http://public.web.cern.ch/Public/en/...tAandD-en.html

Admittedly, it is primarily focused on angels and demons but you will understand why anti-matter does not exist , exist being the key word, in nature.

Yes, an FAQ aimed at the uneducated who want simple answers about a film. Here at PF, it is not good enough to be so general.

 

[Anti-Meson]

http://www.esa.int/esaCP/SEMKTX2MDAF_index_0.html

I followed the wikipedia citatation. The statement that antimatter does not exist is an enormous generalization. Of course it exists.

Interesting, however, if you read the article it is not definitive if anti-matter exists in nature or not. There is some debate as to whether the detected 511 keV transmission spectra is caused by a positron-electron collision. Though thank-you for providing something not from wikipedia.

Other astronomers wondered whether more exotic processes were at work... so it was suggested that dark matter was annihilating or decaying into pairs of electrons and positrons, which then annihilated to produce the gamma rays.
The trouble with this idea, however, was that the dark matter particles needed to be much less massive than most theories were predicting.

 

[Phyisab****]

Please read that paragraph again. 511keV is the rest mass of an electron or positron. There is very little doubt the line is caused by electron positron annihilation.

 

[Anti-Meson]

You are misinterpreting that paragraph.

Elaborate if you wish to win me over.

 

[twofish-quant]

Anti-matter is something that people see all over the place. There's something near the center of the milky way that's creating lots of positrons. If you are trying to argue that antimatter doesn't exist in nature, that's more or less like trying to argue with someone that thinks the moon doesn't exist. If someone really insists that the moon does not really exist, it's hard to figure out where to begin to convince them otherwise. If you really, really want to argue that anti-matter does not exist in nature, most people in astrophysics will just think you are loony.

Also I think the wikipedia is a perfectly good source of information for general overviews of a topic. It has it's flaws, but the fact that anyone can edit strong encourages people with expertise on a topic to participate in a discussion. You can point to some of the flaws in wikipedia, but it's much, much better than any other source of information that I can think of.

 

[Phyisab****]

I really don't have any further argument. You are completely misinterpreting that paragraph. This thread "run its course" as they like to say here.

 

[twofish-quant]

Elaborate if you wish to win me over.

If you read the paragraph, you'll see that the open question is on what causes the positrons rather than that there are positrons. Anytime you have a 511 Kev spike, that's a positron annihilation line, there are no known physical processes that produce a 511 Kev spike other than anti-matter annihilation. You can go into http://adswww.harvard.edu/ for more details. (Search for pair production)

 

[Anti-Meson]

If you are trying to argue that antimatter doesn't exist in nature, that's more or less like trying to argue with someone that thinks the moon doesn't exist. If someone really insists that the moon does not really exist, it's hard to figure out where to begin to convince them otherwise. If you really, really want to argue that anti-matter does not exist in nature, most people in astrophysics will just think you are loony.

Please keep your fallacious arguments off PF.

 

[Phyisab****]

ugh i forgot to unsubcribe

 

[Anti-Meson]

If you read the paragraph, you'll see that the open question is on what causes the positrons rather than that there are positrons. Anytime you have a 511 Kev spike, that's a positron annihilation line, there are no known physical processes that produce a 511 Kev spike other than anti-matter annihilation. You can go into http://adswww.harvard.edu/ for more details. (Search for pair production)

I think the majority of people here is misinterpreting my position, in that case I shall clarify, if I haven't done so already.

I do not deny the whether of antimatter is real or not, laboratories have shown that anti-matter is real and pair production is such an experiment. What I do deny is that antimatter exists in nature. By exists I mean it can it exist without be unaffected, similar to baryonic matter. However, this is not the case since it will simple annihilate with any baryonic matter and the end result is either pure energy, in form photons or more baryonic matter - not antimatter.

 

[S.Vasojevic]

As Phyisab pointed, it is about how much energy you can 'carry' on a space ship, not about mining the antimatter from nature. With antimatter you will get engines with highest specific impulse possible. Problem of puting that energy to use remains, because it comes as gamma rays, but nevertheless concept seems plausible.

 

[DaveC426913]

I think the majority of people here is misinterpreting my position, in that case I shall clarify, if I haven't done so already.

I do not deny the whether of antimatter is real or not, laboratories have shown that anti-matter is real and pair production is such an experiment. What I do deny is that antimatter exists in nature.

No, your position is very clear and unambiguous. You are arguing that antimatter does not exist in nature. That's not true.

By exists I mean...

Trying to change the meaning of the words you used after-the-fact does not make your original argument any less wrong.

Rather than try to backpedal, just concede that you made a claim you should not have made. Nor is there any need to redirect what you meant to say, we've got that covered: anti-matter does not exist in nature in any large enough quantity or for any length of time to be of use in the way we've been discussing it here. This we can agree on.

 

[DaveC426913]

Point of order: the OP asked about antimatter travellnig backward in time. I said 'no' but the OP provided a link to some article about it. That link seems to have gone missing. Was it deleted? I never had a chance to read it.

 

[Phyisab****]

yep seems to have been deleted