That means the sky and the Earth. The word "Universe" is not in the sentence. BTW, the notion of a "big bang" is every bit as much dead as evolutionism, being based on an interpretation of cosmic redshift phenomena which has essentially been disproven. The universe is not expanding and, in all likelihood, has simply always been around.
That means the sky and the Earth.
But you conveniently ignore the part that says In the beginning. You seem to think there was an earlier beginning, a kind of pre-beginning, when God created the stars and stuff, before "the beginning" began.
And what entitles you to declare that "the heaven" just means "the sky"? Genesis doesn't even have God creating Light until verse 3... so were all the stars of the universe emanating darkness for eons before God got around to creating the earth and then light?