Alright so I have come up with this idea for the primary weapon of a particular class of mages in my fantasy world: the Railgun. These mages are called starborn because, when they are born, they are magically connected to a star, planet, or other gravitationally distinct astronomical object. These mages can then, at any time, use the power within the star (or planet) for their purposes. They could just emit the light of the star, at full strength, or the gravity of the star, at full strength, or the magnetic field of a star, at full strength, or literally shoot out matter from the star, but this is clearly very dangerous alot of the time. Anyways, these starborns eventually realize that the best way to destroy these massive, magical, enemy fortifications they need to destroy is to create railguns, lots of them.

My question is simply how strong of a magnetic field do these mages need to produce to make a Railgun? Or, more fit to the context of this question, is the magnetic field of basically any star, particularly red dwarfs, strong enough to use in a Railgun? If this is so, what is the least magnetically active planet I could use to make a railgun for those poor planetborns I have? Could the concentrated power of the earths magnetic field be used to make a railgun?

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    $\begingroup$ I can't help but feel that you want to use the least destructive aspect of a star to do your dirty work. $\endgroup$
    – Daron
    Oct 3 at 6:58
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    $\begingroup$ (a) VTC:Needs More Focus. You are allowed to ask one and only one question per post. (b) You're trying to mix science and magic? People have been trying to do that forever, and it rarely works. (c) Why are the specifics important to you? A PhD in physics or astronomy might realize that you've created a scientifically implausible situation, but nobody else will. What's the difference between your "railgun" and a telekinetic throwing rocks? None. I'd focus on balancing your magic system and not science. Tightly focused stellar wind would win out over railguns every time. $\endgroup$
    – JBH
    Oct 3 at 15:31
  • $\begingroup$ you may want to look up a type of star called a magnetar. $\endgroup$
    – John
    Oct 3 at 23:24
  • $\begingroup$ @JBH a) I am asking one question, one that was already answered, essentially what kinds of astronomical objects are magnetically powerful enough to make a railgun. b)randon Sanderson. c) the specifics matter because it allows the world to write itself. If you can't answer a question just say that, don't VTC cause you have no answer $\endgroup$
    – skout
    Oct 4 at 2:01
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    $\begingroup$ (a) Second paragraph, four questions. Pick one. (c) I ran a publishing house for 10 years. The scientific specifics don't matter when you're writing fantasy. The consistency of your world does. (c) The rules exist for a reason, Skout. If you don't want VTCs, follow the rules. I'm happy to help you edit your question to conform with the rules, but it's fairly juvenile to complain about a speeding ticket when you've been caught speeding. $\endgroup$
    – JBH
    Oct 4 at 15:44

1 Answer 1

  • Harness the power of a Star
  • Nuclear Fusion
  • Intense Heat
  • Radiation
  • 28 times Gravity

Now let's compare the suns Magnetic strength - it's twice the earths, so about 0.0001 teslas. A Sunspot is much higher, 0.4 Teslas.

The ArcFlash, which is a commercially available Gauss Rifle - and can achieve Muzzle Energies on par with a .22lr has....

8 Teslas.

So - peak Sun magnetic strength is 20 times less than a modern handheld railgun that is the equivalent of a .22lr.

And this is going to be the best option for taking down a fortress wall, when compared to say a sudden bubble of gravity 20 times stronger than normal, or a beam of fusion or a pulse of radiation?

To answer your question directly - A Stars magnetic field (so far as we know) is nowhere near the intensity needed to be effective against fortifications.

  • $\begingroup$ Is it a fair comparison? The magnetic force might be small, but the size is extremely large. If you have access to all magnetic forces of a star, couldn't you condense all that magnetic power into a tiny package? A billion tiny magnets together still pack a punch. I read some pop articles and none answer this well. $\endgroup$
    – Trioxidane
    Oct 3 at 20:25
  • $\begingroup$ @Trioxidane - Is it a fair comparison? In some ways yes, in some ways no. I mean, if we are using magic, we can just handwaive it and make it work - but the author wants some link to reality - in which case trying to justify using Magnetism over the other far more destructive options is just... well - I'll leave you to finish that sentence. $\endgroup$ Oct 3 at 21:00
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    $\begingroup$ I took all your points into consideration and have decided you are absolutely right. Some of the powers are literally too destructive to use but a gravity sling or some other tactic may be usable. Anyways, it is good to know that effective railguns would be a rarity $\endgroup$
    – skout
    Oct 4 at 2:05

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