Everyone is familiar with the use of magic in stories, movies and video games. While it seems that it is possible for anything to happen in such environments, usually it is implicit that this is not so. It may even been touched on explicitly in the narrative.
What exactly is magic, though? Arthur C Clarke said that “Any sufficiently advanced technology is indistinguishable from magic” and that’s an excellent angle to approach magic from. An obvious example from the “magic is technology and technology is magic” approach is the introduction of guns to people who only knew spears and bows and arrows.
There are many laws of physics but the major ones comprise “classical physics”. I don’t propose to touch on quantum physics here – though magical devices might need to use such physics to account for the huge energy densities involved.
One of the cornerstones of classical physics is that you don’t get something for nothing. Energy is conserved and not created, though Einstein has shown that energy and mass are much the same thing.
When Harry Potter waves his wand and his enemies are thrown backwards, the energy must come from somewhere, and that is from or through the wand. If the energy is stored in the wand, it would have to be stored very densely, and the densest form of energy is matter.
Does Harry’s wand transform mass to energy in a controlled way? Perhaps it does. Scientists talk about “cold fusion” and while it has not been demonstrated for real, perhaps it will be possible with future technologies.
Another possibility is that Harry’s wand is merely a channel for magical energies. Well, anything is possible, but I doubt it. The energies used in magic, for example, when used to repel attackers, are so large that the slightest inefficiencies in the process would probably melt the wand and destroy it and Harry with it.
Magic has been used to suspend people in the air, to overcome gravity. It usually requires the use of energy, so that the suspended person will eventually succumb to gravity eventually. Scientists have suspended small animals using magnetic fields, so it is definitely possible to achieve levitation with current scientific knowledge, this gives a hint about how magic might achieve the feat.
Wands are often controlled by voice. This again is not a huge step beyond current technologies. Our wands, I mean cell phones, can already be controlled by voice.
That actually brings up an interesting point. Wands are used for all sorts of things, to battle enemies, gain access to secure places, to travel in time, but they are rarely, if at all used for communications. Harry Potter does not talk into his wand to communicate with Ron Weasley and Hermione Granger, so maybe modern technology has something that is one up over magic.
When Harry throws a fireball from his wand, there is no recoil. This would appear to violate a number of physical laws. Energy appears to be created from nothing and the Law of Equal and Opposite Reaction (Newton’s Third Law) does not seem to apply.
The energy necessary to create the fireball can be attributed to a mass to energy conversion process as above. Such a process would, as described above, use very little mass to create the fireball and to send it towards Harry’s opponent. It’s possible that the reaction to the throwing of the fireball is absorbed by the wand or harmlessly directed in the opposite direction, much as the recoil of a “recoiless gun or rifle” absorbs or redirects any recoil.
Interestingly Harry’s opponents don’t usually appear to be seriously injured by his fireballs. They are thrown backwards and are usually discomforted by the fireball, but there is no sign of any wounds or other injury. Evidently they are cushioned in some way.
However several people were killed by the wands during battles, so it is evident that as weapon, the wands could be controlled by the users.
Magic is able to transform things. Sometimes this is permanent, sometimes temporary. Sometimes people have the ability to change form, like the werewolves in many stories. Science does not have the ability to do things like this, but it occurs in nature, when a caterpillar metamorphoses into a butterfly.
Maybe science will be able to perform such feats, when we have mastered the genetic code. The body shows remarkable abilities to recover from trauma, to repair itself. Maybe we will some day learn how to use these abilities to modify our bodies in a similar way to the way that magic does.
It is unlikely that we will achieve the instant transformations of magic in the near future, but we may be able to regrow damaged arms, to change our heights and bodily appearance. For most people the first priority will be to gain the ability to control obesity!
Invisibility is a theme of magic. The hero uses the ability to become invisible to sneak past the guards and to rescue the maiden, recover the lost valuable, or defeat the evil overlord. Science has been trying to perform this trick for a long time, and has achieved some success. At the very least you can use an “Invisible Fence” to contain your pets!
Things can be made invisible by the use of mirrors, but that’s not quite the same as an Invisibility Cloak. Things can be made invisible by camouflage too, though that again can be considered as cheating, I suppose. Real invisibility, which amounts to complete transparency, is currently unachievable by science. I would not bet against science being able to bend light around objects to make them properly invisible in the long term though.
A disadvantage to becoming invisible, apart from people tending to walk into you of course, is that you would not be able to see where you are going without disrupting the very fact of your invisibility. This is because you need to capture photons to be able to see. You may not need a lot of photons, but it would mean that there would be a slightly dim patch where you are standing with your Invisibility Cloak and you would not be able to see what is around you.
Arthur C Clarke’s dictum implies that everything achievable by magic would eventually be achievable by science. It may be that some things achievable by magic in stories are actually physically impossible, so we will never be able to achieve them. But it is interesting to think of ways that they might be achieved by science.