A large comet is quickly approaching my fantasy world. Its impact will spell doom for all life on the planet. Fortunately, there are mages on this fantasy planet who possess a magic capable of shattering the comet. But, magic isn't free, energy has a cost....
At first blush you may think I am asking a question about magic. I am not. I'll take care of the magic when I write my story. What I hope to discover is the most efficient means of shattering the comet. From this perspective, I'm looking for a science-based answer.
- Use the Swift-Tuttle comet as the basis of your analysis.
- Do not worry about how the effect takes place or is delivered.
- The best answer will explain the lowest energy method of shattering the comet.
- Do not worry about the physics of what-happens-next to the comet. I'll take care of that, too.
- The comet must be shattered, not deflected or stopped (I have plans for the remnants).
- The remnants of the comet must still be headed for or already orbiting the planet.
- Please consider the orientation of the comet to the world as unimportant.
- Vaporize the liquids in the comet.
- Create a temporary wall the comet impacts, thereby shattering the comet.
If the answerer can demonstrate that vaporizing the liquid would require less energy than absorbing the impact of the comet using brute force, it would be selected as the best answer.
Once again, it does not matter (and is irrelevant to this question) how these effects are delivered to the comet. since the delivery mechanism is magic you need not worry about rockets or any other delivery consideration. The magic can be thought of as "bringing the energy needed for the effect to bear."
Question: Given the conditions and examples above, what is the lowest-energy method for shattering the comet?
For future viewers, while I've marked the answer, the answer supplied by Shadowzee provides several viable options (as well as several less viable, but still funny, ones).