Reading all the threads about the Omega 'moon' watches got me wondering. Given that gravity is a major influence on the accuracy of any mechanical watch, would a watch keep time better in zero gravity? Of course, the moon does have some gravity, but would that Omega have kept better time in space than when back home on earth?
Not necessarily, but it would be less subject to positional variation. To test this theory, try dropping your watch from a high building.
Don't forget that it's a near vacuum too, so would be worth taking the back off and giving the balance a chance to work with reduced air resistance...
Also need to consider the *other* effects of gravity.
Probably.
Time is relative so there is initially some variation by just travelling to space (Not much, granted).
The only real effect would be on an Automatic watch, in so far as the rotor would not function at zero gravity, unless of course sufficient force was applied.
Not strictly true, an auto would work fine, through the movement of the wrist creating force, the rotor however wouldn't stop, or rather take much longer to stop as there wouldn't be an gravitational resistance / weight to stop it, only the friction created as it's rotating.Originally Posted by Layin_Cable
I think???
The laws of inertia still hold true in low/zero gravity so automatics do still function in space.
Also none relative to other clocks in the same frame of reference. The watch itself does not run slower or faster, it's time itself that distorts. There is a small time dilation effect between clocks in orbit and clocks on the ground. They have to account for this in GPS satellites, but its nothing compared to the variance of a mechanical watch.
Good point. I don't know why I never put 2 and 2 together before when thinking about why the Speedmaster Pro is hand wound. Kinda obvious when you think about it.
Autos would, and do, work just fine (many astronauts wore their own second watch - pictures seem to show Rolex GMTs). It was more about the timing; at the beginning of the Apollo programme there were no automatic chronographs!
It's more than you might think - you need to adjust the atomic clock when you send a GPS satellite up...
This is really interesting, because GPS satellites are affected by both special and general relativity—in different directions!
Special relativity says that if you travel fast (relative to someone else) your clock runs slow (relative to someone else's). Satellites are going a lot faster than we are, so this effect is detectable.
However, general relativity says that if you're in a lower gravity field than someone else, then your clock appears to run fast (relative to someone else's). Satellites are further away from the Earth than we are, so they experience less gravity.
So which of Einstein's theories wins? It turns out the speed-up effect of general relativity is about six times bigger than the slow-down effect of special relativity. So, as you say, the atomic clocks aboard GPS birds are adjusted to take account of this. If they weren't, the error in ground position would be very serious.
I think the movement would work just fine in near vacuum conditions, as long as the pressure in the watch wasn't released explosively but you may find that the watch runs slightly fast since it would have been originally regulated with the balance wheel and forks and wheels moving in an environment subject to drag from the gas within the watch. I would guess that the effects of friction on the bearings is way more significant but even so the missing effect of air drag should speed things up slightly I should think, perhaps of the order of a few seconds a day.
That sounds massively too much to me. A decent watch is accurate to a few seconds a day anyway, so suggesting that air resistance would make 100% difference must be overstating it. Don't forget drag is proportional to cross-sectional area, and these components are tiny, and air doesn't have much resistance anyway. If you could measure the difference at all (without an atomic clock) I'd be surprised.
While the absolute error may be 100% more than with gas present, of more relevance IMO is that for the watch to gain, say 10 seconds a day it would be a speed up of 10s/86400s= 0.01% increase. It strikes me that air resistance or the lack thereof is more than capable of effecting such a small change in rate.
Last edited by Padders; 13th May 2016 at 17:52.
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