Time

I believe that time on earth originated from the beginning of the rotation of the earth on its axis and it depends on the mass and speed of rotation of the earth.

Albert Einstein, through his theory of special relativity held that time was relative based on an observer meanwhile Isaac Newton held that time was absolute for it didn't depend on an observer.

I believe that on earth, time is accelerating as it goes by, since the mass of the earth is decreasing (due to human activities and other natural disasters) and the speed of rotation of the earth is increasing. This change of time, makes time to be relative with reference to it's origin and not with reference to an observer on earth, for time experienced everywhere on earth at a particular instance is the same but it the time zone which changes.

The effect of time acceleration can be seen in the process of aging in humans where in the ancient times, the aging process was slow and humans had a long life expectancy compared to the present times where humans age faster with shorter life expectancy.

NB: there are other factors that can contribute to accelerated aging.

I believe that time is linear for it only moves forward and can not go backward. That's why we can't change any occurrence of the past.