It's a laser. Also there are many characters who could survive, Hulk, Iron Man, Galactus, silver surfer, Asura and so on and so forth.
English
-
There is no way light, pure light which is what a laser is, could do that much damage. A laser weapon would simply burn a hole through the planet. Causing volcanic activity yes, but none the less it would not destroy the planet. A beam of plasma fired with enough force, and containing enough mass would shatter the planet's crust on impact, it would certainly look like a laser beam. The same goes for a directed antimatter explosion.
-
If it put a hole in the planet, it would destabilize the core of the planet, which could cause massive problems.
-
It would cause problems, but it wouldn't blow up the planet.
-
But it has always been described as a laser, it's fiction, it doesn't have to follow our physics to the letter.