Theories about time

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USING THEORIES OF PHYSICS TO PROVIDE A HYPOTHETICAL ANSWER

WHAT IS TIME?


THE DEFINITION OF TIME Time can be defined from many perspectives. From a perception view point, time is an emergent (developing) concept which our mind creates. The present is the consciousness or awareness of recording of memory into the brain. The past is just a record while the future does not exist. From a point of view of physics, time is presence of motion and forces in the universe. Imagine two objects, one moving in orbit around the other, in space. Now suppose from our distant observation point of a fixed time, we observe time to get slower in the area where these two objects are moving. We expect to see slower motion? We also should observe proportionally weaker gravitational force; otherwise the objects will get pulled together. If we observed faster time, we expect to see faster motion and stronger gravity to keep the objects from flying apart. While with zero time, motion will freeze and gravity will become zero. The increase or decrease in strength of gravity is only in relation to our fixed time from where we are making the observation. From the point of view (time) of the orbiting objects neither motion nor gravity has changed. As this thought experiment also can be extended to particles held together by electromagnetic forces we can

say that time involves both motion and forces. Time is a real phenomenon, a continuous change through which we live. To understand time we have to understand the mechanism which brings about this continuous change which forms the illusion of the flow of time in our minds. 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. Another very important aspect of time is the presence of motion of particles such as photons (packets of light) and motion at an atomic level. Time involves all kinds of motion. The spin of particles and the motion of photons are dependent on time. Gravitational force and electromagnetic forces are all part of time as well, as is the motion of celestial bodies the atoms and all other motion.



CAN TIME BECOME OBSELETE?


The Speed of Light

In an article of the magazine Scientific American, Craig Callender compared time with units of motion. Time is a way to compare or describe different kinds of motions like speed of light, how fast heart beats or how frequently earth spins around its axis. But these processes could be compared directly without making reference to time. These graphs illustrate the difference between using seconds and heart-

beats to measure the speed of light and the Earth’s rotation. Time may just be a common unit of motion against which all other motions are measured, making the world easier to explain but having no independent existences from these other motions. This suggests the underlying mechanism that time is just the presence of motion.

The Earth’s Rotation


Entropy is a term usually associated with thermodynamics, but can also be used in conjunction with time. Entropy is commonly associated with the amount of order, disorder and/ or chaos in a given system; the higher the entropy, the greater the disorder. This disorder usually refers to the number of different microscopic states a system can be in (the exact states of all of the molecules making up the system). The idea here is that even knowing the composition of a space (volume, energy pressure and temperature) doesn’t tell us much about the exact state of each molecule in the system. Even a small piece of matter can have an infinite number of combinations of microscopic states. Due to the fact that we cannot see what state a system is in, people often like to say that entropy is a descriptive measure of how uncertain or ignorant one is about the exact, detailed, microscopic state of a system. Or, another popular way of saying this is that entropy measures the microscopic disorder of a system. As an example, suppose that you put a marble in a large box, and shook the box around, and you didn’t look inside afterwards. The marble could be anywhere in the box, so the marble in the box has a high entropy. Now suppose you put the marble in a tiny box and shook up the box. Now, even though you shook the box, you pretty much know where the marble is, because the box is small. In this case we say that the marble in the box has low entropy. Later, Boltzmann, in efforts to develop a kinetic theory for the behavior of a gas, applied the laws of probability to the molecular interpretation of entropy so to begin to interpret entropy in terms of order and disorder. Similarly, in 1882 Hermann von Helmholtz used the word “Unordnung” (disorder) to describe entropy.

DISORDER IS INCREASING



CONSIDER A SOLID OBJECT...

COMPOSED OF MILLIONS OF MOLECULES AND ATOMS HELD TIGHTLY TOGETHER AND HIGHLY ORDERED


...IF A PART OF THIS OBJECT IS DESTROYED ON A MOLECULAR LEVEL, THE SPACE THE OBJECT OCCUPIED WOULD BE MUCH EMPTIER AND SIMPLER...


BUT THE MOLECULES WOULD


D BE IN COMPLETE DISARRAY


So the length of a lifetime... 1 billion heartbeats. Not a human life alone, apparently the lifespan of all amphibians, birds, fish, mammals and reptiles can be counted in number of heartbeats, and that number is about 1 billion. How can that be, you say? Humans live in average 65 years, hamsters in average 3 years and Artic whales as many as 150 years, but the number of heartbeats stay the same. Because whales can have as few as 10 heartbeats a minute and hamsters as many as 450, during a lifespan the number of beats averages, still, at about 1 billion. At the rate of 70 beats per minute, humans shouldn’t be living past young adulthood, and that what true for most of our history and is still the case for many parts of the world, like Swaziland, Botswana and Lesotho in Africa, with life spans between 33 and 35 years. Developments in health treatments and sanitation have expended that to about twice as much, but the natural connection remains intact. These measurements started in the 1930s, work of Swiss-born chemist Max Kleiber. The Kleiber Ratio determines that for every creature, the amount of energy burned per unit of weight is proportional to that animals mass raised to the three-quarters power. Symbolically: if q0 is the animal’s metabolic rate, and M the animal’s mass, then Kleiber’s law states that q0 ~ M3/4. Thus a cat, having a mass 100 times that of a mouse, will have a metabolism roughly 31 times greater than that of a mouse. Kleiber Ratio’s is universal: “There’s this exquisite interconnectivity. All the structures have different forms and functions, but all of them adhere to the same scaling pattern.”

IS A LIFESPAN A BILL


Capillaries grow into veins and arteries according to the same three-quarter-power scale. So also do neural fibers by becoming whole nerves then becoming nerve bindles. From the mitochondria to the cell to the blue whale, the rule holds through twenty-seven orders of magnitude. Now, if the numbers are right, then by increasing our exercise and consequently our heart rate, we would be reducing our life span, but we know that the opposite is true. Why is that? Let’s say you ran a marathon with a heart rate of probably around 150 bpm for the 6 hours it takes to run 26 miles, so in a quarter of a day you’d have used up just over a half a day’s worth of heartbeats! Then why exercise? Let’s say you started running three years ago with an average heartrate of 72 bpm. Let’s assume that you lived your first 28 years at that heart rate, which means you’ve used up 1.06 billion of your life’s heartbeats in that span. Now let’s assume that you keep exercising for the rest of your life and that being in good shape you bring your heart rate to 56 bpm, so if you keep that up for the remaining 1.94 billion heart beats you would live another 69 years to the age of 94 which is an increase in lifespan of about 15 years. Each year exercising 3 to 4 times a week costs you one week of heartbeats, but the improved fitness adds about 13 weeks to you life expectancy. Now, your heart rate can also be increased by stress, without any of the benefits of exercise and meditation can dramatically decrease the number of used beats per minute. What does this connection mean? The answer might lie in the creation and purpose of life itself...

LION HEARTBEATS?



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