# Time dilation and death

1. Jun 15, 2011

### alphali

lets say that there is a triplet at the age of exactly 60 years old.one of them A is in space far away from any gravitational field and not moving , B is on planet earth,and C is near a black hole.
C looks at A and see that for every 10 min passes according to his clock(hand and biological) A ages 10 years .
B looks at A and see that for every 10 min passes according to his clock(hand and biological)A ages 10 days .
so after 10 min C see's that B aged 10 years and died while b see's that A aged 10 days and still alive. and to A's clock he aged only 10 min.
so A now is dead ,and 10 days past 6o,AND 10 MIN PAST 6O IN THE SAME TIME????!!!

COULD ANY ONE CLEAR THIS FOR ME. was i wrong in something or is it true?

2. Jun 15, 2011

### harrylin

Above I numbered your claims. Let's pretend that they are all at rest wrt each other (or nearly so). Then there is no reciprocal aging like in the Twin paradox.

1. OK, C's clock is very slow near the black hole.

2. Exaggerated but in principle OK: B's clock is a little slow compared to A's clock.
In view of what follows, let's make your example simpler as follows:

1 year on C's clock = 5 years on B's clock = 10 years on A's clock.

3. You forgot the time it takes for light to reach an observer. However that's not the main issue. Neglecting the propagation time of light and using my simpler numbers:

After 1 year on C's clock, C sees that B aged 5 years (according to B's clock) and died; B sees nothing anymore. If he/she were still alive, B would see that A aged 10 years (according to a clock of A; perhaps A died).

Does that help?

3. Jun 15, 2011

### yuiop

First the time dilation factor on the Earth is 0.99999999999999989096 which is almost insignificant ( See http://www.wolframalpha.com/input/?i=sqrt%281-2*6.673E-11*5.9742E24%2F%286378000*299792458%29^2%29 ) but let us ignore that for now and also ignore the light travel times involved which could be significant. Sticking with your original figures we have:

(1) From C's point of view, for every 10 min on his clock, A ages 10 years.
(2) From B's point of view, for every 10 min on his clock, A ages 10 days.

We can conclude from that information that:

(3) From C's point of view, for every 10 min on his clock, B ages 3650 minutes.
(4) From B's point of view, for every 10 min on his clock, C ages 0.0274 minutes.

(5) From A's point of view, for every 10 min on his clock, B ages 0.00694 minutes.
(6) From A's point of view, for every 10 min on his clock, C ages 0.000019 minutes.

Now lets look at your final statements:

That should be:

So after 10 min (on C's clock), C see's that B aged about 2.5 days and B is probably not dead. See (3).

Now you switched to 10 minutes by B's clock, but not made that clear.

If 10 minutes have passed on A's clock, then according to A, then only 0.00694 minutes have passed on B's clock or 0.000019 minutes have passed on C's clock. See (4) and (5).

Are you sure?

Hopelessly confused and imprecise. Statements like "IN THE SAME TIME" have to clarified in relativity due to different observers having different ideas about simultaneity.

You start the claim with "so after 10 min" without specifying according to whose clock that 10 minutes is measured by and I suspect you think there is some sort of universal absolute time, which there is not in relativity.

Either way, if A has a large clock attached to him clearly displaying his age, then both B and C will see A die when his proper age is 70. The first person to see A die will be an observer standing right next to him. The events of B and C seeing A die, are in the future light cone of the event of A dying and so the temporal sequence of events is preserved for all these observers.

4. Jun 16, 2011

### alphali

that's true the problem was here thanks

5. Jun 16, 2011

### sicarius

Ok. You are not grasping the full meaning of time being relative. Lets forget for the moment that B's position is impossible (not moving relative to what? The earth, which would have to have it following our orbit? The black hole? Both, which means that the black hole and point b have to be following our orbit?)

So according to what you have laid out 1 minute of c = 36.5 days of a = 1 day of B. So 10 minutes for c occurs at 10 days for b and 1 year for a. Lets say each one of them has 10 years to live at the start of the experiment. A's death would occur at 100 days for b and 100 minutes for c. b's death would occur at 365 years for a and 25.35 days (roughly) for c. C's death occurs at 525600 years for a and 1440 years for b.

hope this helps.