For one, the region is smack dab on top of the world's magnetic North Pole, where the violently charged particles released by sunspots and solar flares are inevitably drawn. This solar interference makes it hard enough to separate important radio signals from background noise — and when you're trying to detect a stealth missile specifically designed to repel radio waves, your job gets even harder.

That's why Canadian scientists want to up their country's spy-spotting game in the arctic by replacing their traditional radar stations with powerful "quantum radars," powered by one of the enduring puzzles of quantum physics. [Supersonic! The 11 Fastest Military Planes]

The phenomenon known as "quantum entanglement," which involves creating pairs or groups of particles whose fates are forever tied, might hold to key to seeing through stealth aircraft's radio-repelling shields.