# ZPi

## Special Relativistic Time Dilation As A Cause Of Geriatric Southern Migrations In The Northern Hemisphere

### A Sociological Mystery

An unresolved question in sociology is why elderly Americans so often wish to spend the latter years of their lives in places such as Florida and the Southwest. Many theories have been put forth, including geriatric preference for hot temperatures and the increased availability of rubber for elastic waistbands in beltless pants, but all have been found lacking in evidence. An important fact that has either been down-played or gone unnoticed by researchers in this field is that there is a definite trend in the patterns of geriatric migration: retirement communities tend to concentrate more towards the Earth's equator than towards its poles. It is from this observation that I have discovered the answer to this pressing sociological mystery.

### As The World Turns, Or The Young And The Relativistic

Figure 1: Person B, standing at the Equator, is spinning at twice the speed of Person A, standing at 60° North latitude, and is therefore experiencing relative time dilation.

The Earth is spinning on an imaginary axis that runs through its center. Because of the (near) sphericity of the Earth, different latitudes on its surface experience different rates of rotative motion relative to the axis. This can be illustrated by analogy with an ancient device called a "record player." As a record spins on the player, an object placed near its edge will travel at a faster speed than an object placed nearer to its center. This is because, since a circle drawn around the record near the edge will have a greater circumference than one drawn near the center, it has to travel a greater distance in the same amount of time. Since speed is a measurment of distance over time, you can see that things nearer the edge of a spinning disc will have greater speed. This same principle holds true for a spinning sphere. The farther one travels either North or South from the equator, the nearer one gets to the central axis of the Earth's spin, and thus the slower one is traveling, relative to the Earth's axis, compared to people at or near the equator. (It is this same difference in speeds at different latitudes that causes the "Coriolis Effect.")

One of the consequences of Einstein's Special Relativity is time dilation. Time dilation is when an inertial frame experiences slowing of time relative to another inertial frame that it is moving faster than. The usual example of this is the "Twin Paradox" which goes something like this:

Imagine a set of twins, say in their 20-30's. One of them boards a rocketship and blasts off into space, traveling at very high speeds. When he returns, all the clocks on his rocketship, as well as his memory, tell him that he was only gone for a week or so. But upon landing and going to his brother's house, he is shocked to find that his brother is now an old, grey-haired, man. "What could have made you age so much in only a week?! Some sort of strange retro-virus, no doubt!" says the astronaut twin. "Huh? Wha' ya talking about, sonny?" says his decrepit sibling, "I ain't no more than a week more aged than I was last week. And wha' the gall durn is a 'red trove iris'? I ain't heard such nonsense since my fool twin brother done went off in his rocky ship more than half a century ago and never returned! He was always spouting off big fancy words like that. Say, ya look familiar. Do I know ya...?"

So, according to the concept of time dilation derived from Special Relativity, for people standing at the equator of the Earth, time will pass more slowly than for people standing at either pole. This clearly offers us an explanation to the geriatric migration enigma.

### Sensing Time

As was illustrated in the Twin Paradox, from the point of view of the elderly living in the South, time will pass at exactly the same speed as it would if they were in the North. So how does this solve the migration problem? The answer is relative, in both meanings of the word. One of the most important things to people when they get on in age is their network of family and friends. This network offers the Senior Citizen emotional support and a sense of purpose as he or she imparts his or her wisdom to the younger generations. Without this network, the Senior Citizen feels a sense of loneliness and worthlessness. Interactions with family and friends (many, if not most, of whom live more towards the North,) via telephone, letters, or modern video-conferencing, are what bind this network together. Also, taking part in political concerns via such organizations as AARP or writing a representative -- all of which are based in Northern cities like Washington D.C. -- is another way the Senior Citizen can pass on wisdom to the future.

Time is relative not only in the way that Einstein discovered, but also in a way that is expressed by the aphorisms "a watched pot never boils" and "time flys when you're having fun." Although a person living on the equator may not notice that time is moving more slowly for him than it is for someone in New York, it still is. If these two people are in contact with each other, the person at the equator will get more raw interaction over, to him, the same amount of time than he would have if he too lived in New York. This is like living more life in less time. And if his life was the same length of (local) time as it normally would be, then he would perceive it as a longer life. Plus, from the point of view of the person in New York, it was a longer life. What this means to our Senior Citizen is more relative time to pass on wisdom, enjoy family and friends, help better the future, and experience the satisfaction of seeing the future start to blossom. Time dilation becomes time compression, allowing our Senior Citizen to do more with what time he or she has left, to do the things that need to get done to insure his or her legacy.

### Limiting Factors On Equatorial Migration

Why, you may ask, if what I am saying is so, don't we see all our senior citizens moving to the equator, instead of stopping at Florida? Well, I would argue that in a perfect world, where all we have to consider is a spinning sphere and Relativity, that we would see just that. However, our world is not perfect. Physical factors such as geography, climate, and ecology; and socio-cultural factors such as politics, economics, tribalism, and xenophobia all act against total equatorial migration.

Most of the equator is underwater. Of the equatorial land mass, a lot is covered by tropical jungles or other inhospitable or sensitive environments (even AARP would have a hard time politically justifying the cutting down of rainforests to build golf courses or other retirement community necessities.) The equatorial regions are hot and heat stroke is a serious concern for the elderly. Although they put up with it to a degree in places like Florida because of the benefits of time dilation, there comes a point of diminishing returns where the costs of the heat out weigh the temporal gains.

Furthermore, equatorial areas that are hospitable are, more often then not, in some sort of political or social turmoil. Witness the civil war in the former Zaire and the continuing drug-related criminal activity and police corruption in places like Columbia and Ecuador. Even Kenya, a relatively peaceful nation whose economy is based on ecotourism, has been having problems recently. Couple this with linguistic and/or cultural differences, not to mention immigration concerns on the part of the locals, and the idea of mass equatorial migration from nations North and South of the equator seems unlikely. In the end what we have is a balance between the desire for pseudo-longevity driving the elderly to the equator and various factors pushing them away.

### Other Implications Of Socio-Relativistic Thinking

Yet another mystery of sociological geriatrics is serendipitously answered by the above application of Special Relativity, namely the "RV Syndrome." Why do a large subset of senior citizens feel the need to buy what amounts to houses on wheels and then wander around the continent aimlessly? The answer to this is now evident: they are constantly on the move and, therefore, time is slower for them.