Now before anyone starts to interject bias, based on personal belief, lets look at the facts, in order to back this up. As was mentioned before, we all have a birth date. That date, as well as any date in history, is referenced to the birth of Jesus Christ. This is a fact. This article is being written on December 16th, 2011. This date, along with any other date that takes place after Jesus Christ's birth, is referenced as AD. So the date is December 16th, 2011 AD. AD stands for "anno domini", which means 'in the year of the Lord'. BC stands for "Before Christ". This time reference system is global, and is used by everyone on the planet. This fact that the birth of Jesus Christ is a time reference for all dates that are written, suggests that Jesus Christ is the most well-known person in all of human history. To suggest anything else, goes against common logic, and is probably suggested due to a bias, or personal belief.
So because the birth of Jesus Christ is the most well-known birth of all time, we should now ask the question "why was his birth so significant?" What contribution did he make that is so important that it causes us to reference all time to his birth? In order to investigate this, we have to continue to look at history.
It's a fact that the most complete account of the life of Jesus, is recorded in the Bible. The Bible tells us that Jesus performed many miracles that were witnessed by tons of people. It says that, on the day that Jesus was crucified, many people rose from the dead. These previously-dead people, walked around a city, and were witnessed by many. The Bible also claims that Jesus, himself, came back from the dead, three days after his death, and then ascended from this earth. It's a fact that this is what the Bible says. It's also a fact that the body of Jesus has never been found. Though this is true, we also have to remember that there are many people who have died, and we can't find their bodies. So even though this is a fact, it gives mild support to the resurrection of Jesus. What's much more compelling, is the account of countless miracles that were consistently witnessed by tons of people, of that day. All of these fantastic facts gives a logical explanation for why the birth of Jesus is considered such a big deal. So we know that his birth was a big deal because we reference all of time to his birth. And the Bible gives a very strong explanation as to why his birth was a big deal.
Not everyone believes that the Bible is true. But it's a fact that Jesus believed that it is. The New Testament of the Bible, gives an account of the life of Jesus, and it tells us that Jesus believed that the Old Testament is completely true.
So if the most significant man that ever lived believes that the Bible is true, what does the Bible say about the meaning of life? In the Old Testament, there's the book of Ecclesiastes. This book was written by King Solomon, a man who was given supernatural wisdom by God. In this book, Solomon sought the answer to our important question, "What is the meaning of Life?". At the end of the book, after tons of deep thought and pondering, he gives an answer. He says, "After all of this, there is only one thing to say. Have reverence for God and obey his commandments, because this is all that man was created for." Also, Jesus, himself, says the same thing. More than once, he talks about obeying God.
So there's the answer to our question. The meaning of life can be summed up in two words, "obey God". So why do people still consider the meaning of life to be a mystery? All that's left to counter logic is preconceived bias, and personal belief.