Question

HOW MUCH DOES THE SKY WEIGH.???

Answer 1

space that is visible from earth is known as sky.so it does not have any weight

Answer 2

The weight of an object on Earth is nothing but the reaction force applied by the Earth on that body.

And sky is nothing but the atmosphere surrounding us.

Pressure exerted by atmosphere on earth surface= Atmospheric pressure at Earth's surface = 101.325 KPa = 101.325x1000N/m2= 101325N/m2

Surface area of Earth=510.1 million km²

So, force exerted by atmosphere on earth surface = PressurexArea
=101325x1000x1000x510.1 N
516,868,958x10^6 N

This is the weight of the sky on Earth.
and it will vary from planet to planet.