What would happen to a person at -450 degrees ferenheight and what would happen to the earth if it?

ab·so·lute ze·ro
noun
the lowest temperature that is theoretically possible, at which the motion of particles that constitutes heat would be minimal. It is zero on the Kelvin scale, equivalent to –273.15°C or –459.67°F.

Ok, so you are writing a science fiction story. You are the story teller. We just have to wait and see what you do with it.