# [time-nuts] Einstein Special on PBS

Didier Juges shalimr9 at gmail.com
Sun Nov 29 14:19:51 EST 2015

```Wow. So elegantly simple explanation, thanks John!

On November 27, 2015 2:54:51 PM CST, John Miles <john at miles.io> wrote:
>So, here's how I finally grokked this stuff.  c, the speed of light in
>a vacuum, is often spoken of as a "speed limit" that nothing can ever
>exceed.  That's a bad way to put it, and people who have expressed it
>that way in popular science writing for 100 years should feel bad.
>
>Instead, the way to visualize relativity is to realize that c is the
>*only* speed at which anything can travel.  You are always moving at
>300,000,000 meters per second, whether you want to or not.  But you're
>doing it through all four dimensions including time.  If you choose to
>remain stationary in (x,y,z), then all of your velocity is in the t
>direction.  If you move through space at 100,000,000 meters per second
>in space, then your velocity in the t direction is 283,000,000 meters
>per second (because sqrt(100E6^2 + 283E6^2) = 300E6.)
>
>It doesn't make sense to speak of moving a certain number of "meters"
>through time, so your location in time itself is what has to change.
>You won't perceive any drift in your personal timebase when you move in
>space, any more than you will perceive a change in your location
>relative to yourself.  ("No matter where you go, there you are.")  But
>an independent observer will see a person who's moving at 100,000,000
>meters per second in x,y,z and 283,000,000 meters per second in t.
>They see you moving in space, in the form of a location change, and
>they also see you moving in time, in the form of a disagreement between
>their perception of elapsed time and your own.
>
>Likewise, if you spend all of your velocity allowance in (x,y,z), your
>t component is necessarily zero.  Among other inconvenient effects that
>occur at dt/dt=0, you won't get any closer to your destination, even
>though your own watch is still ticking normally.  Particles moving near
>c experience this effect from their point of view, even while we watch
>them smash into their targets at unimaginable speeds.
>
>This is special relativity in action.  The insight behind general
>relativity is twofold:  1) movement caused by the acceleration of
>gravity is indistinguishable from movement caused by anything else; and
>2) you don't even have to move, just feel the acceleration.  That
>second part was what really baked peoples' noodles.  It is what's
>responsible for the disagreement between the two 5071As.
>
>-- john, KE5FX
>Miles Design LLC
>
>> Hi Mike,
>>
>> The time rate does remain the same - at the device.  The problem is
>the idea
>> that it is the hyperfine transitions that determine the time...
>
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