(86:11) Tells us of the 20th century scientific fact known as "Ionosphere". People of the 7th century used to think that these ayaat talked about rain, but modern science also affirms that this verse is describing everything that bounces back of the atmosphere to Earth.

Pikthall [at-Tariq 86:11] By the heaven which giveth the returning rain,
Yusufali [at-Tariq 86:11] By the Firmament which returns (in its round),
Shakir [at-Tariq 86:11] I swear by the raingiving heavens,

We see that 2 translator, understand this verse as raingiving heavens, Yusufali translate the verse more closer to the original. Let us have a look on these three words.

and the heaven

such

the return

So we do not see any rain here, but the early interpretation for it, is the rain. Why?! Because of the next verse.

Pickthall [at-Tariq 86:12] And the earth which splitteth (with the growth of trees and plants)
Yusufali [at-Tariq 86:12] And by the Earth which opens out (for the gushing of springs or the sprouting of vegetation),-
Shakir [at-Tariq 86:12] And the earth splitting (with plants);

We see all the translator agree to translate sadaa' to splitting with plants, opens out (for the gushing of springs or the sprouting of vegetation), splitteth (with the growth of trees and plants).

This is the earlier interpretation for it, and nobody could argue that it had another meaning. Lets have the two verses next to each other.

I swear by the raingiving heavens,
And the earth splitting (with plants);

We see a link between the heavens (which gave the rain) and earth (which splitting with plants). Since there is no plants without water. We could see that Quran talking about the earth which arrogated by the heaven rain. We shall not forget that the word ragaa' mean return. This return is from heaven. Since the next verse talk about the earth, it mean that this return is to the earth, not to the out space.