Naked Science Forum
Non Life Sciences => Physics, Astronomy & Cosmology => Topic started by: Lee Wood on 22/03/2009 22:30:03
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Lee Wood asked the Naked Scientists:
hey, science dudes (http://www.thenakedscientists.com/HTML/podcasts/), I have a question for you:
If Time were accelerating, would we be able to detect it?
Keep up the good work.
Lee Wood
Portland, Oregon, USA
What do you think?
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Wocha,
I think if the time that was changing speed was in our own locality, then we would not detect it because we would not perceive the change.
I think !
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I agree; there would be no way to measure. I think too [:)]
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If time is relative, and the time of the entire universe accelerates, it's not accelerating relative to anything, so is it really accelerating?
If it were more localized, like within our solar system or galaxy, we would start to notice the light from stars red-shifting I think.
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I'll go with Maddidus :)
And I'll even go one step longer..
If it was only time and all other 'constants' stayed the same I think we would notice that lights speed, for example, no longer would be a 'constant'. Measuring it we would find it to decelerate. Say that light moved one meter per clocktick before, now when measuring it, that speed would be down to 0.9 meters per clocktick , and the moment after 0.85 meter/klocktick in infinitum . And somewhere down the line I think you would be able to see that photon cheerily wave at you as it passed in that syrupy motion towards its goal:)
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But your clocktick would slow down as well as the light
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We define time in terms of the vibrations of (http://tycho.usno.navy.mil/cesium.html) the cesium atom. So the only way we would notice a change is if the cesium atom changed its frequency of vibration. If we noticed this, we would probably first suspect the thing that seemed to have a different time than the cesium atom. The link is to an article that explains more about the cesium time standard.
A "cesium(-beam) atomic clock" (or "cesium-beam frequency standard") is a device that uses as a reference the exact frequency of the microwave spectral line emitted by atoms of the metallic element cesium, in particular its isotope of atomic weight 133 ("Cs-133"). The integral of frequency is time, so this frequency, 9,192,631,770 hertz (Hz = cycles/second), provides the fundamental unit of time, which may thus be measured by cesium clocks.
In 1967, the 13th General Conference on Weights and Measures first defined the International System (SI) unit of time, the second, in terms of atomic time rather than the motion of the Earth. Specifically, a second was defined as the duration of 9,192,631,770 cycles of microwave light absorbed or emitted by the hyperfine transition of cesium-133 atoms in their ground state undisturbed by external fields.
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But how could we notice a change in frequency of the cesium atom
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Madidus you are correct when it comes to light:)
But you could measure time mechanically too and that wouldn't involve any photons, ah, I think? Or maybe not thinking about it again, would that too be regulated by photons, awh, We can't can we? As long as the smallest process in any system is transfered by photons. And everything is, so we wouldn't notice anything as long as the times 'slowdown' was universal? Vern and Neil is right I think..
And you too Madidus under your 'restrictions'.
But the brain and our sense of motion should notice it as it became really 'syrupy' for us, or would all our processes slow down too. This one was tricky
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Yeah, everything would slow down, light, vibrations, a clock, an hourglass, the processes of your brain, to the effect that relatively, nothing has slowed down at all
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But how could we notice a change in frequency of the cesium atom
We would notice that our solar days no longer match our clocks.
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Yep, the 'relative' velocities in space shouldn't change Vern :)
And then I wonder about if thoughts would 'slow down'?
What would happen to that core Earth has?
It's a metallic liquid and electromagnetic, isn't it?
And wouldn't the the deceleration change the mass of the particles as they vibrate less.
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But how could we notice a change in frequency of the cesium atom
We would notice that our solar days no longer match our clocks.
That would take a while. But rubidium, mercury and hydrogen are used as well (and other elements), so certain changes would show up as difference in these clocks — this is one way of checking for changes in the fine structure constant. If time itself were changing, they would all show the same result — this is exactly what happens in relativity, where the clock type is not important.