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istillhaveanameitsrick · 56-60, M
ElwoodBlues · M
@istillhaveanameitsrick Relativistic Rolling Stones!
[media=https://youtu.be/sEj8lUx0gwY?t=15]
[media=https://youtu.be/T8o8oHIG_3I]
[media=https://youtu.be/sEj8lUx0gwY?t=15]
[media=https://youtu.be/T8o8oHIG_3I]
ElwoodBlues · M
The measured length of an interval of time, even using the same clocks, depends on the relative velocity of reference frames; that's part of what Einstein's special relativity is all about (it also depends on how deep you are in a gravity well, or how much acceleration you are undergoing; that's general relativity).
In short, time is not invariant, nor is length. However, there is a relativistic invariant, usually represented with an s:
s² = x² + y² + z² - C²t²
So if you and your aliens can both observe two events out there in the universe, and you can measure the time and distance between them, you have a universal ruler. Maybe there are two pulsars not too far apart you both can observe.
You can also both build identical clocks, say hydrogen masers, and measure the pulsar timings in your local frames of reference, and this will give you time correction factors. But be careful, as the Earth orbits the sun it's velocity relative to your aliens will change and thus the time correction factors will change.
In short, time is not invariant, nor is length. However, there is a relativistic invariant, usually represented with an s:
s² = x² + y² + z² - C²t²
So if you and your aliens can both observe two events out there in the universe, and you can measure the time and distance between them, you have a universal ruler. Maybe there are two pulsars not too far apart you both can observe.
You can also both build identical clocks, say hydrogen masers, and measure the pulsar timings in your local frames of reference, and this will give you time correction factors. But be careful, as the Earth orbits the sun it's velocity relative to your aliens will change and thus the time correction factors will change.
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Tastyfrzz · 61-69, M
@ElwoodBlues now I'm curious. Might there be more factors to that equation for other dimensions that we don't account for?
ElwoodBlues · M
@Tastyfrzz It's possible. There are "superstring" theories that posit 10 or 11 dimensions, but the others outside the familiar four are tightly curled, so not a possible direction of travel. General relativity says that gravity fields curve our four dimensional space-time continuum; do we need to posit another dimension in which to embed the curved 4D?? It's all above my pay grade!!
Thodsis · 51-55, M
Seeing as there is communication, all that's needed is a simple procedure.
One group says 'start' then some time later says 'stop'. Both use their time measurement devices to see how long that takes. They then make sure that the measurements synchronise with each other.
And they have a unit of time.
One group says 'start' then some time later says 'stop'. Both use their time measurement devices to see how long that takes. They then make sure that the measurements synchronise with each other.
And they have a unit of time.
Zaphod42 · 46-50, M
@Thodsis That’s fair, and more or less my original idea for the story I’m writing, but I was just wondering it’s there’s a universal basis for a ‘Star date’ kinda system. Maybe a measurement of how far light can travel in a vacuum in the time it takes for a hydrogen atom to flip orientations a given number of times or something… 🤷♂️
WaryWitchWandering · 36-40, F
WaryWitchWandering · 36-40, F
@Sojournersoul not all that bright either haha… it’s ok
Sojournersoul · M
@WaryWitchWandering you seem smart and bright
GeistInTheMachine · 31-35, M
Mamapolo2016 · F
Sojournersoul · M
Starcrossed · 41-45, F
Measuring the passage of time itself can be done with atomic clock.
Determining what constitutes as a "day" cycle is another matter.
https://www.nasa.gov/missions/tech-demonstration/deep-space-atomic-clock/what-is-an-atomic-clock/
Determining what constitutes as a "day" cycle is another matter.
https://www.nasa.gov/missions/tech-demonstration/deep-space-atomic-clock/what-is-an-atomic-clock/
Zaphod42 · 46-50, M
@Starcrossed true, but atomic time is set by the vibrations of a cesium atom irradiated by a very specific microwave frequency. What if the aliens don’t have easy access to cesium, or for whatever reason are unable to use microwaves to make it vibrate at the exact frequency needed?
MrBrownstone · 46-50, M
Light years
Zaphod42 · 46-50, M
@MrBrownstone That’s a measurement of distance, and still depends on the exact orbital experience of this planet
MrBrownstone · 46-50, M
@Zaphod42 Using TIME to see how far light travels.
Zaphod42 · 46-50, M
@MrBrownstone Yes, but what is a universal way of telling time? Someone from a different planet would have a different definition of a year, and therefore how far light can travel in that time. It’s a specific measurement that wouldn’t mean much outside of this world.
Human1000 · M
@Zaphod42 Each civilization creates a clock using the same quasar, then adjusts universal time based on their relative location from each other to account for distances and movement.
Time dilation is the difference in elapsed time as measured by two clocks, either due to a relative velocity between them (special relativity), or a difference in gravitational potential between their locations (general relativity). When unspecified, "time dilation" usually refers to the effect due to velocity.
Time dilation is the difference in elapsed time as measured by two clocks, either due to a relative velocity between them (special relativity), or a difference in gravitational potential between their locations (general relativity). When unspecified, "time dilation" usually refers to the effect due to velocity.