For the same reason Dwarves live 500 years, Elves are "immortal", and humans live 100 years or so in D&D.
Because it's all made up.
Why do you think Adam and other ancient prophets and people mentioned in the Bible (such as Noah) lived so long? Source or link provided would be great too:)
I absolutely do not give any credibility whatsoever to the tales of Adam, or any other biblical characters, living for multiple centuries.
They are myths (see Tom's answer).
Adam, Noah, Enoch, Methuselah and all of those other OT uber-centenarians more than likely never existed at all.
It is generally believed that the ages described in the bible were created "to fill the time". I.e. If you believe that events took place over a period of 2000 years but you have only 3 generations to fill that time, then you have to make each generation 666 years long.
Whatever you perceive the bible to be, it was still put together by humans, and humans are fallible.
It seems highly likely that people lived much shorter lives in "biblical times" than they do now.
A few comments:
The books of the old testament were written over a large number of years. Job: Considered earliest, but date unknown: Genesis: 1445-1405 BC ( www.biblegateway.com/blog/2016/02/when-was-each-book-of-the- )
There are myths included in the bible---a myth is a traditional story, especially one concerning the early history of a people or explaining some natural or social phenomenon, and typically involving supernatural beings or events. A myth is NOT automatically a false idea. ( Internet )
I am unaware of any general acceptance of a theory that the "ages of the Patriarchs" were for the purpose of "filling the time."
And while human beings are infallible, human beings while being used as instrumental causes by the Abrahamic God to write the bible are not fallible regarding what they write.
Here's an article that may be of interest to you:
https://www.biblegateway.com/blog/2016/02/when-was-each-book-of-the-bible-written/
In the future there will be no need to use a restroom.
Natural foods produce no waist.
How many other religious stories will you need clarity on?
Many believed that before the "Fall of Man" ("Bad ADAM! Bad Boy! <Smacks Adam on the nose with a newspaper>), there was no such thing as death . . . Hence the eating of the tree of Good and Evil brought about the decay and eventual death of all living things . . .
Decay and death slowly grew quicker . . . I mean Noah live pretty long . . . Right?
So, if you believe that, why haven't we bumped into Poseidon yet when we explore the ocean? . . . . Whoops, wrong God belief.
Adam wasn't a prophet. They didn't have the same diseases and processed food/junk food and took care of their "temple" (body) and God also intervined
There are a number of ideas one being that the prophets had whole souls where as we don't as there are so many of us hence we don't live as long see link..
Or that calculation was different and numbers were symbolic (see Jewish mysticism)...
http://jandyongenesis.blogspot.co.uk/2007/07/what-about-those-really-old-dudes.html?m=1
Of course there is also the idea that sin and death are linked, hence sin and wickedness entered the world when Adam was able to choose good from evil, he could choose evil, he became Godlike because he gained a sense of SELF but lost his oneness with God the spirit, also the sons of God married the daughters of men and gave birth to the Giants, and men of old, where the Titans and Olympian stories come from.
Hence why God sent the flood, men had turned to strange flesh, pride, greed, gluttony, sloth, envy, lust, and wrath and nothing good comes from this, men turned to the flesh and worldy and outcast the need for food for the spirit and guidance of God. God reduced mans lifespan.
Adam and others lived for so long because they are closer to perfection than we are today. It was God's original purpose that all humans would live forever in peaceful conditions in paradise on earth. When Adam and Eve decided that they no longer wanted to follow God's right to rule and became disobedient, in that very day they began to die. Since we are ther children we inherited sin and death from them. But this did not stop God from keeping his promise, that the earth will be a paradise and Humans will be able to live forever.
Probably because they were careful with how frequently they ordered Fast Food, tried not to get hooked onto Iced Tea, did not eat tons of Tilefish, did not fall for the convenience of Microwave Popcorn, resisted the temptation to have Chicken Nuggets, kept a count on their spoons of White Sugar and cut down on their Sugary Cereal.
Source:
The Bible record reveals that humans were made to live much longer than animals. The early offspring of Adam, being near to perfection, lived as long as 969 years. This illustrates the fact that cell-replacement continued for all those years, and the cells of the central nervous system (which scientists say can be repaired but not replaced) were maintained in healthy repair during centuries of living. (Genesis 5:27; see also verses 5-31; 9:29.) The short-lived generations of today are, of course, far removed from that time, with sin and imperfection multiplying during the thousands of years since.