Mortality of Men even without Infection
There is a key element called a telomere in human cells or on the DNA that decides the life span of each human being, since the human body is made of cells.
"A telomere is a region of repetitive nucleotide sequences at each end of a chromosome, which protects the end of the chromosome from deterioration or from fusion with neighboring chromosomes...
For vertebrates, the sequence of nucleotides in telomeres is AGGGTT, with the complementary DNA strand being TCCCAA, with a single-stranded TTAGGG overhang. This sequence of TTAGGG is repeated approximately 2,500 times in humans. In humans, average telomere length declines from about 11 kilobases at birt to fewer than 4 kilobases in old age, with the average rate of decline being greater in men than in women." (https://en.wikipedia.org/wiki/Telomere)
https://www.news-medical.net/life-sciences/What-are-Telomeres.aspx
But how do telomeres decide the length of our life?
Recent research also points to what deterrmines our lifespan. At birth, we have 10,000 base pairs of telomeres on the DNA in our cells. By death we have around 5,000. Hence we lose 50 base pairs a year. (https://books.google.co.jp/books?id=B4i1mSFCZn8C&pg=PT153&lpg=PT153&dq=telomere%E3%80%80%E3%80%80bases%E3%80%8010000%E3%80%80pairs&source=bl&ots=FlGKIFwrAQ&sig=ACfU3U3mWj99pr9LkWayfdBjiHbgVRi38g&hl=en&sa=X&ved=2ahUKEwiRnM3zg7XpAhUwxosBHdotCFIQ6AEwDHoECAoQAQ#v=onepage&q=telomere%E3%80%80%E3%80%80bases%E3%80%8010000%E3%80%80pairs&f=false)So, as a man lives, his cells undergo cell division. But at each cell division, its telomere becomes shorter, shortening remained lifespan. And cell division can occur 50 times for each cell of a newborn baby. Finally at age around 100 of a man, telomeres reach their limit, and accordingly human cells stop division, causing his death. That is why there has been nobody who has ever lived more than 120 years or so.
But if there is no limit in telomeres, cells will be divided forever in uncounted times regardless defects caused in cells as time goes by. Then, human beings with full of defectives cells, such as cancer cells, emerge. It cannot be accepted for the nature. A man should die before its cells start to totally malfunction.
As long as a man is made of cells, he cannot live forever even if advanced science can modify this mechanism based on telomeres. So, men will finally adopt artificial and robotic bodies. They may even transfer brain functions to electronics. Then, we may say that the mankind has obtained eternal life. In a million year before the lifespan as the human species comes to the end, human science may achieve this goal. But, from the beginning, this universe itself has its fate; it cannot forever exist as it is today. In the far future, it is thought that all the materials in this universe are disintegrated in the ever expanding universe to be nothing. So, artificial and robotic men will also be disintegrated to nothing as long as they are made of materials.
So, to obtain eternal life, we have to enter the spiritual world, namely the Heaven ruled by the God who set the limit of lifespan of the mankind. And, it is truly encouraging that Christ Jesus told that we could be allowed to enter Heaven and obtain eternal life through Him.
As for viruses, it seems that there is no sch a mechanism based on telomeres. But, there must be another one to exterminate them, for example, by modifying some characteristics and functions of human cells. If we can find it, there will be even no need, in a extreme case, for human beings to do away with biological bodies and adopt artificial and robotic bodies in order to avoid deadly damage from future more fatal viruses.
Anyway, this corona-pandemic reminds us of mortality of human beings, even without infection by corona-viruses, and should accelerate our faith in the God.
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Matthew 5 King James Version (KJV)
14 Ye are the light of the world. A city that is set on an hill cannot be hid.
15 Neither do men light a candle, and put it under a bushel, but on a candlestick; and it giveth light unto all that are in the house.
16 Let your light so shine before men, that they may see your good works, and glorify your Father which is in heaven.