Our Simple World: The Theory of Relativity
02-19-2015
Author: Blog Editor in The Distance Formula
Albert Einstein believed that “everything should be made as simple as possible, but not simpler.” Unfortunately the world is not that convenient. This famous aphorism seems more cynical than humble when considering Einstein asserted the Theory of Relativity which challenged the completeness of Newtonian physics (the basic principles we still learn in grade school). Of course these principles are still accurate for our everyday purposes, but for objects moving relative to the speed of light they fall short. For the majority of our time we measure objects moving much slower than the speed of light, but our observations of them depend on light reaching our eyes. This irony questions any objectivity in measurement, and is a major factor in one of our most relevant technologies, GPS.
The Global Positioning System, dependent on many conclusions of the Theory of Relativity, has become an everyday tool with its overwhelming presence in cars, phones and many more technologies such as ATMs and wrist watches. Originally it was held exclusively for military purposes. Considering the usefulness of GPS today, it seems a simple solution to release it to the public. However, it was only deemed necessary that the US government release GPS to the public after an incident where a commercial airliner entered restricted soviet airspace due to navigational errors, and was shot down. Seventeen years later, in May 2000, selective availability was removed, giving the public equally accurate access to GPS.
Now a single surveyor can accomplish in one day what once took an entire team weeks to do. Power outages can be fixed more readily by engineers by tracing the location of a power line break using the exact time measurements that GPS provides. Also Emergency services can locate callers through GPS. GPS is indeed used for much more than locating the nearest store. Precise timing and synchronization is crucial to a variety of economic activities around the world such as communication systems, electrical power grids, and financial networks. The free availability of GPS time has enabled cost savings for companies that depend on precise time and has led to significant advances in capability.
GPS provides this information with the atomic clocks on board their satellites. The position of a receiver can be calculated by determining the distance between the receiver (the phone, car, etc.) and at least three different satellites. The distances are calculated by measuring the time difference between the moments of emitted and received radio signals. However, time passes differently for these satellites. According to the Theory of Relativity, time dilation is caused by differences in either gravity or relative velocity, each slowing down time as they increase. Einstein explains relativity through an analogy of a train track. If two observers, one on a moving train and one on foot are equally distant from two simultaneously striking lightning bolts, the one on the ground should see both bolts occur at the same time while the one on the train should see the bolt they are heading toward first (see figure). Simply put, the time it takes both lights to reach the observers will allow the moving observer time to approach one of them, though very slightly.
In the case of orbiting satellites, their high velocity slows down time, but their distance from earth (and resulting low pull of gravity from it) increases time. If the earlier ambiguity of the observation of light wasn’t enough, now we are accepting time measurements from machines which experience time differently than us. Of course these systems are highly organized and monitored to ensure their reliability, but we still share the same concern as Einstein when he specifies the need for two clocks of the same exact design for his thought experiment. The world requires unity to communicate effectively, but there are so many factors complicating that process such as language and distance. Even in Einstein’s analogy of the train, the issue of social inequality creates a difference in perception between one person who is on the train and one who is off of it (if the one not on the train could not afford to be on it). It won’t be simple, but we’re working on it.
About the Blogger: Brian Dean is an editor and critic who studied Literature at Florida State University. “The Distance Formula” is an exploration of the equally expansive landscapes of the world and the mind.
The Global Positioning System, dependent on many conclusions of the Theory of Relativity, has become an everyday tool with its overwhelming presence in cars, phones and many more technologies such as ATMs and wrist watches. Originally it was held exclusively for military purposes. Considering the usefulness of GPS today, it seems a simple solution to release it to the public. However, it was only deemed necessary that the US government release GPS to the public after an incident where a commercial airliner entered restricted soviet airspace due to navigational errors, and was shot down. Seventeen years later, in May 2000, selective availability was removed, giving the public equally accurate access to GPS.
Now a single surveyor can accomplish in one day what once took an entire team weeks to do. Power outages can be fixed more readily by engineers by tracing the location of a power line break using the exact time measurements that GPS provides. Also Emergency services can locate callers through GPS. GPS is indeed used for much more than locating the nearest store. Precise timing and synchronization is crucial to a variety of economic activities around the world such as communication systems, electrical power grids, and financial networks. The free availability of GPS time has enabled cost savings for companies that depend on precise time and has led to significant advances in capability.
GPS provides this information with the atomic clocks on board their satellites. The position of a receiver can be calculated by determining the distance between the receiver (the phone, car, etc.) and at least three different satellites. The distances are calculated by measuring the time difference between the moments of emitted and received radio signals. However, time passes differently for these satellites. According to the Theory of Relativity, time dilation is caused by differences in either gravity or relative velocity, each slowing down time as they increase. Einstein explains relativity through an analogy of a train track. If two observers, one on a moving train and one on foot are equally distant from two simultaneously striking lightning bolts, the one on the ground should see both bolts occur at the same time while the one on the train should see the bolt they are heading toward first (see figure). Simply put, the time it takes both lights to reach the observers will allow the moving observer time to approach one of them, though very slightly.
In the case of orbiting satellites, their high velocity slows down time, but their distance from earth (and resulting low pull of gravity from it) increases time. If the earlier ambiguity of the observation of light wasn’t enough, now we are accepting time measurements from machines which experience time differently than us. Of course these systems are highly organized and monitored to ensure their reliability, but we still share the same concern as Einstein when he specifies the need for two clocks of the same exact design for his thought experiment. The world requires unity to communicate effectively, but there are so many factors complicating that process such as language and distance. Even in Einstein’s analogy of the train, the issue of social inequality creates a difference in perception between one person who is on the train and one who is off of it (if the one not on the train could not afford to be on it). It won’t be simple, but we’re working on it.
About the Blogger: Brian Dean is an editor and critic who studied Literature at Florida State University. “The Distance Formula” is an exploration of the equally expansive landscapes of the world and the mind.
Comment
Final ProofFebruary 20, 2015 | 03:41 PM
Einstein summarized his theory to a reporter once, saying “When you sit with a nice girl for two hours you think it’s only a minute, but when you sit on a hot stove for a minute you think it’s two hours. That’s relativity.” ~Brian Dean
February 20, 2015 | 11:41 AM
Interesting connection. I use GPS quite often when travelling, but when I look at it like this, I see that there's a lot more to it. As a natural consequence of what you're talking about here, could it be said that because my RV has a higher mass than I do, time moves more quickly when I'm outside of it than when I'm inside? Perhaps this is why driving seems to take so long - but attending a BBQ outside seems to go by so soon.
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