Answer:
Because of the immensity and the mysteries that the two environments have.
Explanation:
The deep sea has an unimaginable immensity, in addition to countless mysteries that are inaccessible to human beings, but that stimulate curiosity about this place. The deep sea is a place of difficult access to human beings and that is why it is so mysterious. Outer space has these same characteristics and that is why the author of the article compared these two environments so directly.
