# How fast would we age without movement?

1. Oct 24, 2014

### iDimension

Assuming the duration of a second didn't change, how fast would we age and die if the Earth wasn't moving, the sun wasn't moving, the galaxy wasn't moving etc etc?

All this speed allows us to live the duration that we do right? So if it all stopped, how fast would we be born, age and then die?

2. Oct 24, 2014

### Matterwave

If the Earth and Sun weren't moving, we'd all die from being cooked by the Sun's rays 24/7 on one side of the Earth, and the other side of the Earth would freeze to death. So...I'd say we'd live a lot shorter.

3. Oct 24, 2014

### Staff: Mentor

I think that what you are actually trying to ask is "What is the time dilation of a clock on earth relative to one at rest with respect to the CMBR?"

Our velocity relative to the CMBR is 627 km/s which translates to a time dilation of 1.000002 or a difference of about 1 hour and 20 minutes over the course of a 70 year lifespan.

4. Oct 24, 2014

### Matterwave

5. Oct 24, 2014

### Staff: Mentor

Just to make sure it gets said: since you aren't moving with respect to your clock, the movements of the earth don't affect how long you live according to your clock.

6. Oct 24, 2014

### Staff: Mentor

I'm not sure that I understand your question. Are you starting from the idea that time slows down as you move faster and wondering how that affects a normal lifetime?

7. Oct 25, 2014

### iDimension

While I appreciate you taking the time to reply to my question I'd prefer it if you could actually answer my question and not drive off onto something with no reference to my question. Thanks.

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. 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?

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?

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

8. Oct 25, 2014

### Staff: Mentor

Dalespam provided the answer -- not sure if you saw it.

But I want to make sure this is clear: "relative to an object which isn't moving" implies you think that there is some absolute rest frame. There isn't. What you are really referring to is an object moving or not moving relative to an arbitrary (but nevertheless useful) choice of reference frame: the CMB. But we could just as easily decide we like our frame better and declare them to be moving relative to us!

9. Oct 25, 2014

### ghwellsjr

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.

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-v2/c2))

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/(1-500,0002/669,600,0002)) = √(1/(1-0.000752)) = √(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.

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.

You can apply the Time Dilation factor for 0.99c:

√(1/(1-0.992)) = √(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.

10. Oct 25, 2014

### DrStupid

This is in principle correct, but it works in both directions. The clocks of the rest system of the CMBR are delayed by the same factor compared to the clocks of our rest system. The resulting difference has no physical meaning.

11. Oct 25, 2014

### iDimension

Perfect thanks!

Sorry I didn't see your post. Thanks for taking the time to answer :)

12. Oct 25, 2014

### Matterwave

That's why I linked you to the FAQ in my next post. :) But your question said "How fast would we be born, age, then die", and my answer was "probably we wouldn't be born in the first place under such considerations". I don't see that as highly off topic.