The beginning of the universe in time is the single biggest bug-bear for the secular cosmologists. They must eliminate the need for the beginning in order that they can eliminate the need for the Creator Himself. If you have an origin in time, you can argue that anything that exists, and had a beginning in time, also had to have a Creator.
This is the Cosmological Argument. And if the big bang cosmologist agrees the universe exists and began to exist at some moment in time past, then it also had to have had a cause–a first cause. That first cause can only have been an infinite Creator, who is greater than the universe itself.
Some long age/old earth Christian apologists use this argument starting with the assumption that the big bang was a real historical event. That also is a flawed approach even though they use valid logic after the fact. Their initial assumption–their starting premise–is not a fact (or cannot be proven to be a fact) and hence the rest of their argument fails.
But what would these apologists, like W.L. Craig or H. Ross, say when the secular big bang theorists continue to push towards the elimination of the origin in time, even the big bang beginning itself?
Astrophysicist Ethan Siegel is quoted (September 21, 2017) in an article in Forbes titled “The Big Bang Wasn’t The Beginning, After All”:
The conclusion was inescapable: the hot Big Bang definitely happened, but doesn’t extend to go all the way back to an arbitrarily hot and dense state. Instead, the very early Universe underwent a period of time where all of the energy that would go into the matter and radiation present today was instead bound up in the fabric of space itself. That period, known as cosmic inflation, came to an end and gave rise to the hot Big Bang, but never created an arbitrarily hot, dense state, nor did it create a singularity. What happened prior to inflation — or whether inflation was eternal to the past — is still an open question, but one thing is for certain: the Big Bang is not the beginning of the Universe! [my emphases added]
He states his belief as if fact, i.e. that the big bang definitely happened, even though cosmology is not actually science. See Cosmology is Not Science! His theory has no super-dense initial singularity. But he assumes, as fact, an early period of cosmic inflation (which is a best speculative), which eventually finished and gave rise to the hot big bang fireball that the rest of this universe allegedly evolved from. He leaves open the question whether the universe was eternally inflating in the past, but the one thing he is certain of is that the big bang was not the beginning of the universe. Others have proposed an eternal universe that eventually explodes in a big bang.
Eliminate the need for the big bang to be the beginning in time and eventually they hope they can eliminate any need for the Creator Himself. After all didn’t the universe create itself?
Quite obviously not. For, in the beginning God created the universe (Genesis 1:1).