Let's assume we were on a Rogue planet

wondering through the universe, not belonging to a solar system or orbiting any star.

How would we measure time? Our whole time measurement is based on the Earth's orbit around the sun.

1 full orbit around the sun = 365 days = 1 year
1 full rotation of the earth = 1 day.

if we were on a rogue planet, we wouldn't have a sun, and we wouldn't have anything on which to base our time measurement.

This makes me think that time is not a property of the universe but only a human invention

reply to post by muse7


Just like I do here on earth. Turn to the critter standing next to me, ask them what time it it....

Des

The night sky(which, if rogue, would be 24/7. so to relativity speak) would always be changing. The changes in the star alignment would be noticed, just as it was on earth, and soon enough, bright minds would use it to set a standard of time.

reply to post by muse7


You're right, it is a human invention in a sense. But if you're on another world... You either keep using Earth time, create a new measurement of time, or learn to live without it. It's a simple matter really.

The proper motion of stars would only mean that we are moving through space, but that would not be a good thing to use for time measurement

Also considering it would take stars hundreds of thousands of years to just move a couple of degrees in the sky.

time is inconsequential
as its a human thing on earth

if not on earth time don't matter
do it

Originally posted by spoonbender
time is inconsequential
as its a human thing on earth

if not on earth time don't matter
do it

Well, firstly, I thought you were suggesting if we were on a rogue planet, we being humans. So as humans demand defination on literally everything, we'd define the passage of time.

Originally posted by muse7
The proper motion of stars would only mean that we are moving through space, but that would not be a good thing to use for time measurement

Also considering it would take stars hundreds of thousands of years to just move a couple of degrees in the sky.

edit on 5/6/2012 by muse7 because: (no reason given)

edit on 5/6/2012 by muse7 because: (no reason given)

On this rogue planet, other things could be used to indicate passage of *time*. Say a fungus only multiplies during a certain phase of planetary conditions. This fungus has a vile odor during it's growing phase....then the sense of smell might very well be used to establish time frames, based on the cycle of growth of the fungus.

Des

Originally posted by muse7
How would we measure time? Our whole time measurement is based on the Earth's orbit around the sun.

No, actually our time system used to be based on the rotation of the planet (which you could still use from a rogue planet).
But for the last few decades its based on the vibration of caesium atoms.

Since 1967, the second has been defined to be: the duration of 9,192,631,770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of the caesium 133 atom.

reply to post by Destinyone


Exactly. I was thinking of things such as the length of pregnancy or how long it took a plant to sprout from a seed and then how long it took to flower.

There is no time, its a program in orbit. Would they need to mark time or would they mark sequence of events? And when they're working with probabilities and timelines too, that is not linear.

reply to post by muse7


Well first we should ask how life could evolve on a rogue planet without a star for heat/small levels of radiation to encourage evolution

You would probably still measure time as we do on earth since there would be no other way to measure it. Night time and day time would be irrelevant, and we would still have to live on our 24 hour cycle. Seconds, minutes and hours are a human invention, the rest are based on the Earth's rotation, the Moon's orbit, and the Earth's orbit.

Technically it's not a planet, a planet has to be in orbit.

reply to post by muse7


What a fascinating question. It really is. As much as a quick answer came, I kept stopping at the obvious. Every simple solution thinks of the Deep Ocean labs or underground ones. ISS guys have similar issues...and it's all by using the clock as the clock and no relation to light levels out the window....

Then.. HECK! Ya got me. Where did the clock come from? To measure a 24hr day in a consistent way. ..and where the 24 hours come from? Yeah. You get circular on that in a hurry huh?

It seems to me that we'd still have chosen some block of time to measure the passage, but I suppose the basis of choosing it would be arbitrary in thinking of it, compared to the rock solid nature of our Sun. Hmmmm..

Now that is sure taking a moment to think about something!

The fact that you age proves time.

reply to post by Wrabbit2000


One word...sundial.

Des

Without a star for a heat source, a rogue planet would likely be lifeless and extremely cold.

If there were a steady heat source, such as a persistent volcanic heat source, then life might evolve.

As far as measuring time goes, we Earthlings would probably use whatever unit of time makes most sense and convert it for anyone interested. If we lived in a different star system not on a rogue planet, then we would likely use that planet's solar revolution cycle as a year. Proxima Centauri star system years might be years faster or slower than Earth years. If there were no star to use as a measurement of time, then we might use moon months or so many moon months to make a year. In this case the moon might be whatever satellite might be in orbit around the rogue planet. If we traveled to a rogue planet with constant darkness, then we humans might just bring our own clocks and stay with Earth time based clocks as a time measurement system.

If a rogue planet had rotation, the stars in the sky would keep shifting like they do here on Earth. Therefore you could use an arbitary system designating day time stars and then the other group of stars would be night time stars. Of course since the rogue planet was not in orbit around a star, the sky would be constantly dark. Stars in the distance are so far away, the star constellation patterns stay the same within our lifetimes. It would be the same on whatever rogue planet we visit unless that planet was moving almost light speed.
I'm talking about star constellation patterns for a given location wherever the rogue planet is located. If you visit a different rogue planet thousands of light years away in a different location, of course the constellations are going to be different.

Originally posted by orionthehunter
Without a star for a heat source, a rogue planet would likely be lifeless and extremely cold.

If there were a steady heat source, such as a persistent volcanic heat source, then life might evolve.

As far as measuring time goes, we Earthlings would probably use whatever unit of time makes most sense and convert it for anyone interested. If we lived in a different star system not on a rogue planet, then we would likely use that planet's solar revolution cycle as a year. Proxima Centauri star system years might be years faster or slower than Earth years. If there were no star to use as a measurement of time, then we might use moon months or so many moon months to make a year. In this case the moon might be whatever satellite might be in orbit around the rogue planet. If we traveled to a rogue planet with constant darkness, then we humans might just bring our own clocks and stay with Earth time based clocks as a time measurement system.

How do you know there isn't a life form that doesn't require heat? You only understand life on this planet. Life elsewhere could have evolved in any environment. They could be made of completely different materials, and work completely different to what we know and understand. Anything is possible.

reply to post by SpearMint


Anything may be possible but in my experience of what I have seen, life is based on molecular activity and if that activity is extremely small, the chances for life should be extremely small as well. I believe the vast majority of life will need some amount of heat to evolve or even to develop. I'm not saying heat sources are not present. I'm just saying I believe the chances of life developing on a planet with no heat sources near absolute zero are slim to none.

Home time experiment.

1)Sniff your finger.

2)Scratch your ar$e.

3)Sniff your finger again.

If time didn't exist.....your finger will smell like ar$e at #1.

If time does exist.....you've just wasted 30 seconds reading this and you can not get that time back.

Oh....and....go wash your finger.