A googol-to-one gear ratio [video] • Hacker News Board

Re: A googol-to-one gear ratio [video]

#41

Post by numpad0 » Sat, Mar 07, 2020, 1:13 AM UTC

Benjammer wrote: post #31

noncoml wrote: post #27

Earlier quoted context omitted.

Impressive but imho he could take it one step further and instead of concrete on the other end, he could rotate the gear in the opposite way.

It would take more energy than the total energy of the known universe to turn the last gear.

*the gear in the middle

Re: A googol-to-one gear ratio [video]

#42

Post by owenmarshall » Sat, Mar 07, 2020, 1:14 AM UTC

chrisseaton wrote: post #38

owenmarshall wrote: post #35

Earlier quoted context omitted.

There are 10^80 electrons in the universe, Eddington thinks. Even if you managed to make a contraption that turned one electron into one rotation of the first wheel, and you fed the entire universe to your contraption... you’re coming up a few dozens order of magnitude short to make that full turn :^)

That's what I already said > where are you going to get that much energy to turn them so fast?

I guess you just have to make a machine that manages two turns per electron.

(I know you did - but any chance to introduce Eddington’s number is fun)

Re: A googol-to-one gear ratio [video]

#43

Post by bilekas » Sat, Mar 07, 2020, 1:19 AM UTC

This is insane. My OCD is tempered and my love for all things mechanical has been re-ignited.

I am curious how this ratio is calculated though, I didn't drill into the relative ratios.. If anyone has a link I would love to see!

Re: A googol-to-one gear ratio [video]

#44

Post by jxcole » Sat, Mar 07, 2020, 1:21 AM UTC

Now if on the slow end you connected an exactly reversed series of gears you could configure it such that the final gear moves at exactly the same speed as the first gear, but the middle gear moves at 1/googol the speed. Of course this is likely to break down at some point but it would be interesting to see exactly what the maximum recoverable ratio is for gear movement and what the limiting factors are.

Re: A googol-to-one gear ratio [video]

#45

Post by noncoml » Sat, Mar 07, 2020, 1:22 AM UTC

NegativeLatency wrote: post #34

jagged-chisel wrote: post #30

Earlier quoted context omitted.

When all the slack has been rotated out, it would require a tremendous amount of force to rotate that last gear in reverse. After all, the system wants to amplify the gear speed from that end.

I think parent’s idea would work if the system was mirrored and duplicated. Then you could attach the two the them together with the stationary gears in the middle

Yes, thanks for clarifying it :)

Re: A googol-to-one gear ratio [video]

#46

Post by chrisseaton » Sat, Mar 07, 2020, 1:25 AM UTC

owenmarshall wrote: post #42

chrisseaton wrote: post #38

Earlier quoted context omitted.

That's what I already said > where are you going to get that much energy to turn them so fast?

I guess you just have to make a machine that manages two turns per electron. (I know you did - but any chance to introduce Eddington’s number is fun)

> I guess you just have to make a machine that manages two turns per electron.

But that just isn't going to be tractable.

Re: A googol-to-one gear ratio [video]

#47

Post by Benjammer » Sat, Mar 07, 2020, 1:30 AM UTC

numpad0 wrote: post #41

Benjammer wrote: post #31

Earlier quoted context omitted.

It would take more energy than the total energy of the known universe to turn the last gear.

*the gear in the middle

Sure, if you are inverting the gear ratios half way through...

Re: A googol-to-one gear ratio [video]

#48

Post by banana_giraffe » Sat, Mar 07, 2020, 1:33 AM UTC

xwdv wrote: post #26

If you made this in a physics engine could you get the last gear to spin in a reasonable time and not break the simulation?

Nope. Even if your physics engine could deal with the rotation of the first gear in one "unit", and batch the rotation of that gear a million times in a "super unit", then calculate a million "super units" each second, it would still take longer than the universe has been around, by 10^70 times, to complete one rotation of the final gear.

Re: A googol-to-one gear ratio [video]

#49

Post by samstave » Sat, Mar 07, 2020, 1:33 AM UTC

tunesmith wrote: post #20

hnuser123456 wrote: post #14

Earlier quoted context omitted.

In the hour-long video, from the start to the end, only the first seven gears move visibly, and the 8th moves maybe a pixel. You probably couldn't move anything past the 3rd or 4th gear with your hand, depending on how low-friction the bearings are, how strong you are, and how little you care about hurting your hand. You could attach a long lever to one, but that'll only get you one, maybe two gears further.

Yeah, but that's just an engineering problem.

Your arm is poorly engineered for this particular problem, so you are correct.

Re: A googol-to-one gear ratio [video]

#50

Post by kibwen » Sat, Mar 07, 2020, 1:34 AM UTC

xwdv wrote: post #26

If you made this in a physics engine could you get the last gear to spin in a reasonable time and not break the simulation?

Only if you're okay with some sort of extreme fast-forward mechanism (which seems like cheating), since even if you turned the first gear once per CPU cycle you'd still be spending about 10^90 seconds to turn the last gear once. There's otherwise no problem with representing the state of the simulation itself; a googol only takes 333 bits to represent.