It makes the miraculous seem mundane. It makes the impossible possible. It makes people spout quasi-Shakespearean dialogue. It is the power cosmic. But just what the hell is it?
It can't be gravity, because it helps people defy it. It can't be potential or kinetic energy, because it laughs at Newton's Laws of Motion. And it can't be electromagnetic, because the Silver Surfer doesn't stick to any fridges or woollen sweaters he happens to be passing.
Whatever it is, it's got kick. Beings infused with it can travel at super-luminal speeds and stop comets cold. They are also elevated beyond such frail mortal concepts as good, evil and fashion sense.
Maybe it's the 'superforce' conjectured by grand unified field theory, of which the four forces that act upon our universe (the strong and weak nuclear forces, electromagnetism and gravity) are believed to be mere facets of. Or perhaps the zero-point or vacuum energy said to arise from pure void. But somehow I doubt it. Galactus, an entity so powerful he probably bullied God at school, must subsist on energies that he syphons from Earth-like planets in order to survive - and this is very strange indeed. If he was taking almost any form of energy of which we are aware of, then practically anything BUT Earth-type planets would be the best sources. If it's thermal, why not the sun? If it's simply converting mass to energy, why not big fat Jupiter? And if it's psychic energy, why not whatever planet Yuri Gellar got thrown off of?
Whatever the power cosmic is, we're a mother-lode of it. And whatever it is, we're clearly not using it. So it can't be fossil fuels or internet pornography sites.
Let's observe Galactus again (presumably from a bunker within another bunker within an armour-plated planet on the other side of the universe from his present location) and see what more we can ascertain. He was created when the universe before our own went through its 'Big Crunch' and was compacted down to single point in which he just happened to be standing. This is very revealing because it makes him a naked singularity, and also because it suggests that the power cosmic is the essence of desolation, the distillation of decay.
That is, entropy.
And with our cars, our industries, our depletion of resources and our busy, busy lives we must be making tons of the stuff. That's what Earth's got that most other planet's haven't: a population of wasters.
This explains why the poor Silver Surfer is such a tortured soul. An angel of annihilation, he is his own antithesis. He wants peace and love, he wants to heal and build, but he runs on ruin. No wonder his comic keeps getting cancelled. And coming back again. And cancelled again.
So there you have it; the power cosmic is entropy. Which means that all of life's failures and fuck-ups, the nerds, the geeks, the losers, the people who mis-spend valuable time writing crap about comic book cosmology, are, in fact, power personified.