if man starts to live on different planets, how would we tell eachother's ages???

Originally posted by cmdrkeenkid
I think the usage of years could go through a series of stages...

1.) The crews and colonists use Earth years during the trip and beginnings of the colony; when the colony is still most dependant on Earth.

2.) The colony, still depending on Earth but also creating its own industry, will have this intermediate step. The year could be measured in how long it take for Earth to be in reasonable position to send supplies/people back and forth.

3.) Once the colony is no longer dependant on Earth it would go to what others have already said; Having its own time scale, but also using Earth's in order to keep some things in order.

thats cool...

i cannot wait until the future...

Originally posted by they see ALL
i cannot wait until the future...

dont worry, itll be here soon enough

*checks watch*
there ya go! future's here! get yer future!

Originally posted by they see ALL

Originally posted by Amorymeltzer

yup. think of it as gravity bending space. the more mass, the more gravity, the more bending. the more bending, the slower time goes. and so, since earth weighs more than mars, those on earth will, in fact, age slower.

however, it wont make a bloody difference. the amount of time 'gained' by mars relative to us is going to be insignificant. besides, the times we all use are estimated anyway, everynow and then we have to adjust things to be proper. we can easily factor this in every 400 years or so (coincide with the leap year).

man, i thought i was good in physics

this is crazy stuff...

As Intelearthling stated the only difference involves the observer but it also effects the people living on the different worlds. So we would have people who live on earth living longer than those on mars. People on Mars would live longer than those who live on the moon. And another thing to think about is people who live on asteroids and very small objects would age extremely fast relative to their planetary breathern.

Originally posted by BlackJackal
As Intelearthling stated the only difference involves the observer but it also effects the people living on the different worlds. So we would have people who live on earth living longer than those on mars. People on Mars would live longer than those who live on the moon. And another thing to think about is people who live on asteroids and very small objects would age extremely fast relative to their planetary breathern.

theyre only older if you use a single reference point. a martian is alive for 80 martian years, and a terran is alive for 80 terran years. theyre both 80. if you decide to pick the terran second as the standard, then the martian is older (not by much). but if, as i suspect will be the case, mars adopts its own time system, then theyre equal in age.

Amorymeltzer....

I think you have the reason for the clocks being different times wrong. It's not about the bending of space/time. It's because the clock on the top of the tower has a higher absolute speed from a fixed, external, reference point, because it's further off the surface of the planet, in much the same way that the outside of a CD/LP is actually moving faster than the inner porition (even though the whole thing is moving at a certain RPM):

Assume a 24" disc (diameter). Now draw a block (ba) on the inside of the disc, near the center hole (let's say 3" from dead center). Now draw another block (bb) 12" from dead center.

Spin the disc at 33RPM.

BA will travel:
3" radius * 2 * pi: 18.84" per revolution, or 622" per minute or .58MPH

BB will travel:
12" radius * 2 * pi: 75.39" per revolution, or 2487" per minute or 2.35MPH

Thus BB will be travelling closer to the speed of light, thus it's mass is higher greater and time moves more slowly.

Now in you example the top of the water tower is BB, the clock on the ground is BA, since the earth is spinning at a pseudo-fixed rate, and the clock at the top of the tower is further from the center of the earth and travelling a greater distance in the same amount of time.

Osiris

PS: The harddrives in my computer have 3" platters and spin at 10,000 RPM, they are moving at 89MPH!!! at the outer most edge, reading data that is stored in magnetic blocks that are mere microns in size.