Perhaps the greatest mystery in the universe is the very existence and origin of the universe. Why is there something rather than nothing? How can something come from nothing?
Think of the universe like a grown child whose parents have long since passed away. She lives alone on a farm, completely self-sustainable. An alien could arrive on the planet, observe this human, then wonder how she came to be? There’s no evidence of where she came from—no mother or father anywhere in sight—she appears to have come from nothing.
But the aliens would be wrong. She came from something—two somethings, in fact—a mother and father. But those somethings no longer exist.
The universe likewise came from something that we cannot discern today because it no longer exists. Something didn’t come from nothing—something came from something, but we may never know what that something is.
Where did the something we came from come from? Impossible to say unless we know what the first something is, which may be impossible to know.