Question: how much does the sky weigh

Leigh Kesler answered on 3 Mar 2019:

That’s a really hard question to answer, because the “sky” can mean a lot of different things. If you mean all the things in the sky that we can see, the answer would be almost infinite, since we can see (with a lot of special equipment) see a huge chunk of the universe. If you want the mass (which is sort of like weight) of the visible universe, it comes to 1 x 10^50 tonnes, or a hundred thousand billion billion billion billion billion tonnes (that’s a lot!). We can also measure the mass of the things we can see in the sky; for example, the sun has a mass of about 1 x 10^27 metric tonnes, or 1 billion billion billion tonnes.

The “sky” could also mean all the gases that make up the atmosphere, which is the air we breathe. If you look at all the air in the atmosphere (for the whole world) that has a mass of around 5 x 10^15 tonnes, or 5 million billion tonnes.