Answer

Hello A.,
As I told you today, there are several ways to explain this, and I have no way to decide among them. The question could have been important if it had no answer (because then it would prove that the Torah is not divine), or if it had only one answer, because then we could know the true answer. But since there are several answers and there is no way to decide among them, nothing can be proven from this regarding the divinity of the Torah, nor can we reach a conclusion about what really happened. So this question does not seem especially important to me, and it does not occupy me much.
I will briefly explain the various possibilities here:
1. The description in the Torah is mythical rather than historical. Its purpose is educational, not academic-factual. The description may, for example, be intended to teach about the moral hierarchy between the inanimate, plants, animals, and human beings (according to the order of creation). By the way, Nachmanides wrote this in the 13th century, long before there was any need to come up with answers to challenges from modern science.
2. The chronology of the creation story is metaphorical. The description is factual, but one day in creation describes a stage, not a 24-hour day. At least in the first days there was not yet a sun, so it is clear that there were no days in the current sense. Thus each day in the biblical creation narrative describes a stage in historical creation, which could also take a billion years.
3. According to general relativity, the rate at which time flows changes depending on the density of mass in the universe. In the first moments of creation (the Big Bang), the mass was very dense, and therefore, in terms of present-day time, it comes out to six thousand years, but in objective terms it is billions of years.
4. The world was not created in an explosion from a singular point, but in its present form (in Bereishit Rabbah it says: “The works of creation were created in their full stature”). Think of a baby that is born. It is not born the size of a point, but already at a fairly large size. It is already a complete, formed human being. Its primordial stage was in the womb. So too with the world. The Bible describes the six thousand years that have passed since creation. For example, if when the world was created you had checked the carbon-14 age of trees, you would have found that they were thousands of years old, just like the trees of our own day. And the same would apply to rocks, etc.
5. The Bible describes the last six thousand years of the process, from the formation of humanity onward. The earlier stages are not described (in kabbalistic terms, this is the “world of chaos”).
6. The rate at which time flows changed over the course of history, and therefore today it appears to us that the world is billions of years old. Think of a baby who is born and then begins to grow. Suppose it gains about ten centimeters each year. At age two, we ask ourselves what its height will be in another thirty years, and the answer would be about four meters. We assume the processes will continue at the same rate as until now, but that is not always correct. So too when looking backward: think of an adult who is no longer growing. Now we ask at what height he was born, and the answer would be 1.80 meters. Again, we are projecting the present backward, not necessarily justifiably. So too with the world. We see processes (the decay of carbon and the like) that take place at a given rate and assume that this is how it has always been. But there is no proof of that whatsoever. It is possible that in the past decay was much faster (like the baby’s growth), and therefore it is possible that the age of the world and the objects in it is much smaller. By the way, there is a lecture by Rupert Sheldrake that was removed from the TED website, in which a very interesting person speaks about changes in the constants of physics over the last hundred years (that is, not even over a time period with evolutionary or cosmological significance). See here: https://www.lifehacks.co.il/2-%D7%94%D7%A8%D7%A6%D7%90%D7%95%D7%AA-%D7%A9%D7%9C-%D7%98%D7%93-ted-%D7%A9%D7%94%D7%95%D7%97%D7%A8%D7%9E%D7%95/