TIME

What is Time? ‘Time’ is defined by the Webster’s New World College Dictionary (4^th Edition) as: A period or interval; the period between two events or during which something exists, happens or acts; measured or measurable interval

Time is passing and we follow it with clocks and calendars, yet we cannot study it with a microscope or experiment with it. You cannot see it or touch it, but its effects are clearly visible

Time is represented through change, such as the circular motion of the moon around the earth. Time is elusive and we measure it with clocks and calendars in an effort to manage our lives within it. A day is measured by the amount of time it takes the earth to rotate one time on its axis; but no-one really knows why there are 24 hours in a day? This goes back to the Babylonian days (working on link)

The passing of time is closely connected to the concept of space. The relationship of space and time is called the space-time continuum, which means that any event that occurs in the universe has to involve both time and space.

The Einstein Theory of Relativity relates to our physical universe. It notes that time is relative with the speed of the object while moving through space. According to this theory, time passes differently for celestial bodies that move at different velocities. To measure the speed of time, you need at least two objects that travel at different speeds. When they reunite time has past differently for each object. The closer an object gets to the speed of light, the slower the time passes compared to another object that remains stationary. The concept here is that time is not linear, but relative. It indicates that our day-to-day perception of Time is different than its real nature.

Albert Einstein concluded in his later years that the past, present, and future all exist simultaneously. His most descriptive testimony to this faith came when his lifelong friend Besso died. Einstein wrote a letter to Besso's family, saying that although Besso had preceded him in death it was of no consequence, "...for us physicists believe the separation between past, present, and future is only an illusion, although a convincing one."

Despite tremendous advancement in science and technology and the precision with which time can be measured, there is very little known about the true nature of time.

These are a few of the memorable time spans throughout history:

-1 picosecond (one-trillionth of a second) - This is about the shortest period of time we can currently measure accurately.

-1 nanosecond (one-billionth of a second) - 2 to 4 nanoseconds is the length of time that a typical home computer spends executing one software instruction

-1 microsecond (one-millionth of a second)
-1 millisecond (one-thousandth of a second) - This is the typical fastest time for the exposure of film in a normal camera. A picture taken in 1/1,000th of a second will usually stop all human motion.
-1 centisecond (one-hundredth of a second) - The length of time it takes for a stroke of lightening to strike
-1 decisecond (one-tenth of a second) - A blink of an eye
-1 second - An average person's hear beats once each second.
-60 seconds - One minute
-60 minutes - An hour
-8 hours - The typical amount of sleep a person needs every night
-24 hours - One day; the amount of time it takes for the planet Earth to rotate one time on its axis
-7 days - One week
-365.24 days - One year; the amount of time it takes for the planet Earth to complete one orbit around the sun
-10 years - One decade
-75 years - The typical life span for a human being
-5,000 years - The span of recorded history
-50,000 years - The length of time Homo sapiens has existed as a species
-65 million years - The length of time dinosaurs have been extinct
-200 million years - The length of time mammals have existed
-3.5 to 4 billion years - The length of time that life has existed on Earth
-4.5 billion years - The age of planet Earth
-10 to 15 billion years - The suspected age of the universe since the big bang

(source for time spans-how stuff works)