To face our impending ending is the beginning of maturity. The truth is we are dying every day. I remember listening to a scientist who said that that the cells of our body change completely every 7 years. Where did the old ones go? They died. To die every day is the secret of youth! We need to go to bed every night having let go of the day's events then fall asleep without carrying any emotional baggage into our sleep state. If we can do this we will have successfully died to that day and we will awaken afresh the next morning, eager and ready for the day's events.
Asking questions about our impending ending is an important and vital step in our maturity but it is even more important to ask - why was I born? Hardly anyone asks this question. Each of us was born because in our previous life we left the earth with lessons to learn. We were carrying baggage into our death. It is this unresolved baggage that kept us from attaining perfection in our last life and which caused our soul to choose to reincarnate once more on earth to face the lessons and challenges we need to progress spiritually.
Material life is formed out of the creative void we call Spirit, Soul or God. A good way of understanding this is to recall a time when you had an original idea or solved a problem in an innovative way and then moved to put the idea or innovation into action by creating something. People who are highly creative, well motivated and have high ideals are close to God. It is our values that reach into the void and determine the quality of our creative expression. I think it was Edison who, motivated by a desire to serve and uplift human society, used to lie back and enter a state of meditation between sleep and wakefulness, assisted by keeping a ball held lightly in his fingers, as an aid to receiving his innovative ideas from the timeless, creative void.
Science is not in conflict with spirituality they are like two wings of a bird - both are needed for the health of the individual and the society of which he is an integral part. The difference between science and spirituality is in the direction of focus. Science looks outward into the material world and seeks to understand its laws and mechanisms. Spirituality looks inward to the mind and heart in order to unite with the Soul. Since the outer and inner worlds are interdependent (like the two wings of a bird) then by looking inward to understand ourselves we can come to understand Mankind and the Universe.
Science seeks to understand the material world by experimentation and the formulation of theories. The spiritual aspirant seeks to understand himself, by raising the quality of his consciousness and by reducing the veil cast between him and the world by the ego. This journey of consciousness is what personal development is all about.
To start raising your consciousness the first step is to dwell on your own faults (which come from the ego) rather than the faults of others. The quality of our consciousness grows as we become open and eager to receive criticism about our behavior, and then show an equal enthusiasm for addressing our faults by making persistent efforts to change ourselves. This is the purpose of life. This is why we incarnate.
If, throughout your life, you give proper attention to your spiritual quest and use the trials and challenges of your life to that end, your consciousness will grow and your life will become increasingly meaningful. Then, as the corrupting influence of your ego fades, so too will the questions you pose about death, because you will be giving birth to the timeless. Eternity lives like an unhatched egg within. Eventually, along with the rest of humanity, you will fully enter the timeless state - by living completely in the present moment - and in so doing attain perfection. Earthly existence will then having nothing further to teach you. You will have been reborn into pure Spirit.
Eventually all must go through this narrow gate - and if you are wise you will use this lifetime to begin and end that journey.
Further Help and Resources
My own book Unfold Your Wings and Watch Life Take is an excellent introduction to the spiritual life. At its core is the story of how one can use one's experience to develop one's consciousness by learning to live a life guided from within. If you are interested in learning more about living a spiritual life then you will find it most helpful.
Personal development has, as one of its aims, to transcend the human condition. If one's consciousness survives death, then the motivation to achieve this becomes far stronger. Frederick Myers recognized this as a critical question for all intelligent people and worked relentlessly to provide us with a solid proof of life after death. As someone who enjoys a scientific perspective, you will be interested in this.