iDimension said:
Yes. Earth is moving through space, the sun is moving through space, the galaxy is moving through space so all that speed is affecting our time relative to an object which isn't moving.
It's not useful to talk about objects "moving through space" as if you could tell the difference between one that is "moving through space" and another one that "isn't moving". You could just as legitimately say that the first object "isn't moving" and the other one is "moving through space". This is kind of like the first rule of relativity so for you to ask your question in a way that violates that first rule will only cause confusion.
iDimension said:
So let's say as an example all the speed added up is 500,000mph. Relative to an observer who isn't moving, how much time dilation is there between us and them? How much slower is time for us than for the observer?
What you should do is talk about in Inertial Reference Frame (IRF) in which one observer "isn't moving" and "we" are moving at 500,000mph. Then you can apply the Time Dilation factor which is called gamma and is equal to:
√(1/(1-v
2/c
2))
Since c = 186,000mps and since there are 3600 seconds in an hour, we can calculate c in terms of mph which would be 186,000 times 3600 or 669,600,000 mph. Now we plug those numbers into the formula;
√(1/(1-500,000
2/669,600,000
2)) = √(1/(1-0.00075
2)) = √(1/(1-0.00000056)) = √(1/.99999944) = √(1/.99999944) = √(1.00000056) = 1.00000028
I hope I've done that right. In any case, it means that our seconds take 0.28 microseconds longer in this IRF than they do for the observer.
However, we can turn this around and transform to the IRF in which we are stationary and the observer is moving at 500,000 mph in the opposite direction and he will be the one whose seconds take longer.
iDimension said:
Now I ask if for us 1 year is 1 year, what would it be for the observer who isn't moving? 1 week? 1 day?
Since there are 31 million seconds in a year, it comes out to 0.28 seconds longer than 1 year. You can figure out the other ones, I hope.
iDimension said:
Another example is imagine a particle has a half-life of 1 year while moving at 99% c, if you slowed that particle down to a complete stop, it's half-life would only be 1 second for example
You can apply the Time Dilation factor for 0.99c:
√(1/(1-0.99
2)) = √(1/(1-0.9801)) = √(1/0.0199) = √(50.25) = 7.09
So 1 year or 12 months divided by 7.09 would be 1.7 months.