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Posted

To eliminate all energy losses, you would need to build it in a good vacuum too. If you're using magnetic fields as a lubricant, you also need to watch for conductors moving in them as this would give Foucault currents.

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Posted

Also known as eddy currents. Induced in conductors when magnetic field varies, explainable by Maxwell's equations, just like the current that can be induced in a coiled wire. They cause dissipation due to the resistivity of the conductor and they also have applications, such as in induction AC motors and EM braking.

 

Unfortunately, it's hard to totally eliminate all dissipation. Take an atom in it's ground state and you have a perpetual motion. Consider the Earth orbiting around the Sun and you have an almost perpetual motion. Consider the Earth turning daily on it's axis and that's a not quite perpetual motion... why? Why, also, does the Moon show us the same face? Pure coincidence?

Posted
Take an atom in it's ground state and you have a perpetual motion. Consider the Earth orbiting around the Sun and you have an almost perpetual motion. Consider the Earth turning daily on it's axis and that's a not quite perpetual motion... why? Why, also, does the Moon show us the same face? Pure coincidence?

 

Yes, the atomic structure was a mystery for a long time, until the whole thing with the De Broglie wavelengths and Planck's Constant got worked out. Before that, no-one could work out why the negative charges didn't just spiral into the positive, and destroy each other. Turns out it is due to energy quanta - you can't lose less than a full quanta, so at those scales you lose nothing.

 

As for the earth round the sun, it is a fairly good vaccuum and two hugely massive bodies with lots of energy. The earth does slow down a little with every impact, and from the drag of the molecules it hits as it runs round the sun, but the actual effect is negligible, due to the massive inertia of the earth.

 

Not sure why the moon always shows the one face. It's probably so the aliens hiding up there don't have to hide everything twice a day. :naughty:

Posted
Why twice a day??????

It depends how fast it was spinning relative to the rate of rotation of the earth.

 

Spinning it slightly out of phase would be bad. Eventually you would have to leave the base and move, since it would take another 400 years to get back to being the dark side, unless you tweaked it, and we would notice that these days.

 

Spinning it too fast would mean you would have a very short time to do anything, and the aliens would get dizzy.

 

But I just picked twice a day out of the air.

Posted
Thanks for the explanation Qfwfq, I see you were up late last night :hihi: (12:08 am).
Q lives in Italy. He had just gotten to work!

 

We need a thread on how to deal with time zones around here! :naughty:

 

Temporaly fluid,

Buffy

Posted

There's lots of wierd ones. My favorite is China, which should span about 6 time zones, but the entire country works on Peking time... You can step over the border into India and travel 3 hours into the past....

 

Tachyon junkie,

Buffy

  • 2 months later...
Posted

In response to the (US & UK) Patent Office not taking screwy PM patents any more:

 

They will with a working model...

 

No, they won't. There was a PM bell that ran for 300 years. It was in a near vacuum, and fooled everyone for a long time. Turns out it was owered by a cunning battery inside it, which used the tiny charge transfer as it's power supply.

 

If some tries to sell you a working PM machine, and you can't find the power supply, look harder...

Posted
In response to the (US & UK) Patent Office not taking screwy PM patents any more:

 

 

 

No, they won't. There was a PM bell that ran for 300 years. It was in a near vacuum, and fooled everyone for a long time. Turns out it was owered by a cunning battery inside it, which used the tiny charge transfer as it's power supply.

 

If some tries to sell you a working PM machine, and you can't find the power supply, look harder...

Hmmm?...

 

What was the power supply exactly? And where is it?

Posted

I know the US patent office has made a rule explicitly about PM machines, because there are simply too many crackpots trying to patent them. However, don't forget the distinction between PM of first and second species.

 

There was a PM bell that ran for 300 years. It was in a near vacuum, and fooled everyone for a long time. Turns out it was owered by a cunning battery inside it, which used the tiny charge transfer as it's power supply.
Sure it was 300 years??? From what year to what year??? :) I suppose battery means a voltaic cell.

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