So i was reading this things' dex entry, and it's stated to be sending signals to space. Now that got me thinking, what could it possibly want to contact there? Well, Magnezone requires a powerful electromagnetic field to evolve from Magneton, and what in space would generate a strong magnetic field? That's right, the fucking sun.
Now, Magnemites are made of iron. How is iron created? Supernovae.
In the pokemon universe neutron stars become gigantic star gods when they blow, and the lesser planetside Magnezone are evoking their unborn lord with their signals, hastening its eruption and thus awakening. This theory has no holes and you can't convince me otherwise.