No not the sci-fi series on Syfy and Amazon Prime Video that is based on the books by James S.A. Corey. But the matter created on day 2 in the Genesis account.

In Genesis 1:6 (NASB20) we read:

Then God said, “Let there be an expanse in the midst of the waters, and let it separate the waters from the waters.”

Depending on your translation the Hebrew word rāqîa may be translated as “expanse” (NASB, NET, ESV, Holman), “firmament” (KJV, NKJV) or “vault” (NIV). The NLT translates the word as “space”.

In order to understand what the expanse is we will read through the rest of the Genesis account. Examining the account and listing out what the text says about the entity that was created on day two. We will focus on both its description and function.