How old do you think Earth is? Why?
Consensus among scientists from different fields of studies says that the age of the Earth is 4.54 ± 0.05 billion years.
But it's not that I "think", you cannot "guess" the age of the world. You need evidence. it's the result of measures done by hundreds of scientists, with hundreds of experiments. And they are all consistent with each other (minus the margin of error stated before).
The scientific model is based on the idea that certain things in the universe have been going on throughout all time, similarly as they are going on today. Take carbon dating, for example.
Carbon dating is based on the idea that the C-14 content on earth, in the atmosphere, has been relatively the same for at least hundreds of thousands of years. But nobody knows that this is the fact. If the amount of C-14 forming, has been increasing very slowly over the years - so slowly that nobody could see or measure the increase - there is the potential that there was little to no C-14 back beyond 5,000 years ago. This would mean that carbon dating numbers are extremely far off... by as much as millions or billions of years. And this kind of mistaken thinking is the same kind that permeates virtually all of the scientific thinking on the dating subject.
The furthest science can go back with any accuracy at all is about 4,500 years. And even this is shaky. It is based on dating pottery and buildings from the distant past. Comparing the writings of ancient peoples and nations from beyond 3,000 years ago shows discrepancies in the writings that indicate that we don't know how to read dead languages correctly, or else the people of those days wrote historical fiction like we write science fiction today.
On the other hand, Moses lived and wrote 3,500 to 3,600 years ago. He had been a prince of Egypt, with access to whatever writings this great nation had back then. We can trust his writings because of the stubbornness of ancient Israel. This stubbornness is born out in the writings of the scribes of Israel. Bible books from the Dead Sea scrolls of over 2,000 years ago, are essentially the same as they are in our modern Bibles.
This means that we can place faith in the things that Moses wrote for us in the first 5 books of the Bible, way more than we can place faith in the writings of today's scientists. In fact, today's scientists tell us right in their writings that they are actually guessing as to the age of things.
The point is, the earth and universe are less than 7,000 years old, and probably only 6,200 years old. See
http://www.albatrus.org/english/theology/creation/biblical_age_earth.htm for how this is calculated out in the Bible. If the universe is much older than 6,200 years, the age cannot be calculated, because time and the space-time continuum operated differently before that time.
