theoretical physicist, works with the science of black holes, despite having ALS which has decreased his ability to move his body over the years. When diagnosed at age 21, this genius was given two years to live, yet he overcame all odds, and is still alive today. He manages to communicate with the aid of a computer which vocalizes for him, and even gives speeches at scientific conferences.
http://www.timephysics.com/ discusses time in a thought provoking manner. Only "now" exists, yet "now" passes into the past, which only exists in memory while future only exists in imagination. Actually, time may be simply a way to measure motion.
The problem of time may be easy to solve if we go back to the original concept of sun moving across the sky. When we measure the speed of a car, we are just comparing its motion to the motion of the hands of the clock and also indirectly to the fractional motion of sun across the sky.We are not measuring speed with something abstract called time we are just comparing a known motion (of the sun) with an unknown motion of the car.
Time becomes evident through motion and is measured by comparison with other motions. Sunrise, sunsets, night and day, the changing seasons, the movement of the celestial bodies are all indicative of continuous change. The aging process is a reminder that molecular motion and interactions are also at work and are a part of time.