# Limitations of magic as an energy conversion process

My world has magic and I would like to check a few things about it. Feel free to correct me if I'm way off-base.

My magic is basically an energy conversion process. You take energy from your environment and convert it into something else. For instance, fireball, light or other fun stuff. I should clarify that it only needs to look like a fireball, light or other fun stuff to the average medieval farm boy. It could actually be anything else as long as it has the same effects and visuals.

Anyway, to enable that process, you need a sentient caster with a body. The universe will not have it any other way (actually, it will, but it's not relevant here).

However, in order to convert energy, from what I understand, you need some more energy. This problem is dealt with the introduction of the Unbestanum effect. Said effect allows transdimensional particles to dump energy into our own dimension. It is as if you had an unlimited magical energy tank somewhere that you could tap into. The energy from the Unbestanum effect is what powers the energy conversion.

Consider the caster plus the Unbestanum effect as your conversion system. You still need to input something if you want a fireball, and that input is likely going to be air. Because air is just full of the heat and it's also right there. So, in principle, you take air, input it in the conversion system, and voilĂ , fireball. The conversion system is sufficiently powered to produce the desired amount of output because it's magic.

About how many rules of physics and thermodynamics am I breaking with that principle?

Taking that principle (and possibly adjusting for fewer broken rules), is there a limit to how many forms of energy I could output if all I had was air, unlimited power supply and maybe some ground (though I can't see why that would be helpful)? If there is, what forms of energy would I be able to output?

• Fire (oxidation) needs fuel, oxygen, and a spark. In your system would magic create the spark and you consume oxygen from the air and fuel from another source? Or would magic just heat up the air to 'make' a fireball? Also, how are you enforcing magic as a 'conversion process' but still having an unlimited well to tap into? – Lacklub Apr 8 '16 at 17:17
• @Lacklub I've edit my post to answer your question regarding fire. It has to look somewhat like fire, but it could actually be anything hot and flame-y. As for your other question, I think the answer is in my notion of the "conversion system". The unlimited well can only be used by the caster to allow the conversion to happen. The energy you convert however comes from the regular environment. – AmiralPatate Apr 8 '16 at 17:49
• No, that works. If you don't consider your power source, you're violating entropy. But with it, you have energy flowing into the system somehow, so it's fine. (It's a little odd that the power source can't directly be used for power though. Because energy flowing into the system should be at least deposited as thermal energy) If this is magic, then you could take energy from chemical bonds (like fire), nuclear bonds (fusion/fission), and having things fall (gravity). Is this the sort of behaviour that you want? – Lacklub Apr 8 '16 at 18:46
• @Schwern It only powers the conversion yes. Otherwise it's be too OP, and we don't want that. Or at least I don't. Truth be told, it's not unlimited really but there's about enough of it for practical purposes. – AmiralPatate Apr 9 '16 at 18:55
• @AmiralPatate Your wizards are already pretty OP. ;) – Schwern Apr 9 '16 at 18:59

It depends on just what sort of energy conversion you want to allow. Let's go straight to the crazy end... I mean... let's find the upper limit to what's allowed by thermodynamics.

The mass-energy of the surrounding air is the famous E = mc2. If you divide by the mass you get E/m = c2 which is the mass-energy per unit of mass. c is the speed of light at 3x108 m/s so c2 is 9x1016 m2/s2. A Joule is kg m2/s2. That works out to 9x1016 Joules per kg or 9x1013 Joules per gram.

1 liter of air has a mass of about 1.275 grams, so a caster easily has at least 1014 Joules available.

How much energy is that? Looking at the handy List Of Energies By Orders Of Magnitude we find 1 gram of air can power a small nuclear bomb, or a hurricane for a bit less than a second. That is a lot of energy.

Yes, if you allow wizards to convert mass into energy they can produce quite a large fireball.

• That's way more than I was expecting to be honest. Or more than I need, which is... something. – AmiralPatate Apr 9 '16 at 19:18
• @AmiralPatate It is 1 gram of something. – Schwern Apr 9 '16 at 19:23
• So besides fireballs and nuclear explosions, would that process allow for lightning, light sources or freeze cones? – AmiralPatate Apr 9 '16 at 19:35
• @AmiralPatate Thermodynamics has no problem with this, it's energy transfer. But from an engineering standpoint, shaping and direcrting that much energy is the trick. That's why we have fusion ("hydrogen") bombs, but not fusion reactors. How you manipulate, convert, and aim that much energy is normally done with high tech engineering, but you can use magic. For example, we don't use "lightning guns" because lightning wants to ground itself, not move in a straight line, but magic can fix that. – Schwern Apr 9 '16 at 19:43
• @Schwern Lightning guns are so much funnier when you add a little bit of laser to it. – Xandar The Zenon Apr 10 '16 at 1:13

The only really limiting factor amount of air have available to you since you technically are using air every time you make fire. Of course you always add another Limiting element, perhaps something related to the caster, maybe there's some sort of limit of trans-dimensional energy one magic user can use at a time.

Also is theoretically possible to convert matter to energy so maybe you could use the ground in your casting.