Big Bang Theory The Universe

The Big Bang theory doesn’t state that the universe came from nothing, we don’t know what was there before the Big Bang nor does any reputable scientist claim too. What it does state is the universe began in a dense state. It underwent rapid expansion, cooled off and finally the first light was produced. This light is called the CMB. We can see it in the static on TV. It’s literal proof of the Big Bang
And not sure what the moon has to do with the Big Bang, but it is thought the moon originated from an impact on earth. The ejected material coalesced into the moon due to gravity.