This Kilogram Has A Weight-Loss Problem

NPR ^ | 20 Aug 2009 | Geoff Brumfiel

[BGHater]

FR-Kilogram

[dirtboy]

Originally the meter was equal to the length of a piece of metal kept alongside the kilogram, but in 1983 it was redefined as the distance light travels in a vacuum over 299,792,458ths of a second.

Now define a second.

[frogjerk]

In 1889, the copies and the kilogram weighed the same, but by 1989, they had drifted apart. Based on the data, the kilogram appears to weigh slightly less than the copies.

Then use the copies.

[BGHater]

[frogjerk]

Now define a second.

The amount of time the government needs to decide it should infringe upon your rights.

[discostu]

I like how they pretend that if the cylinder went away suddenly the scale in my bathroom would be wrong. Some times scientists get a little to addicted to linear thinking. How do you fix the kilogram? How’d you guys decide that was a kilogram, that’s the real definition.

[iceskater]

That would be nanosecond.

[GonzoGOP]

Perhaps the copies are gaining weight. I know I have put on a few kilos since 1989. Perhaps the copies have been sitting in front of the tube watching Oprah and eating bon bons.

[DuncanWaring]

1. Time required for light to travel 299,792,458 meters.

Alternatively:

2. The duration of 9,192,631,770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of the caesium 133 atom.

[dirtboy]

2. The duration of 9,192,631,770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of the caesium 133 atom.

At what temperature?

[MosesKnows]

Then use the copies

You miss the problem. When they differ how would you know which to use, the original or the copy? Did the copy become heavier or did the original become lighter?

Therein resides the dilemma and that is why they seek a solution.

[DuncanWaring]

0 Kelvin.

Don’t forget to correct for gravitational time dilation.

[frogjerk]

OK. So if they use the sensative scale they are speaking about aren’t they assuming gravity is constant when it might not be?

[randog]

Robinson admits that when he started working on watt balances in the 1970s, he thought it would take just five or six years to redefine the kilogram. Today, after decades of work, scientists believe they are still five or six years away from setting a new standard.

Sure they are. It will be done when their full retirement is vested.

[tgusa]

NERDS!!!

[dirtboy]

And neutrinos.

[frogjerk]

Ignore my last post.

[GeronL]

Then use the copies

*stupid french accent*. "Oh, dat iz eazy for you to zay. But ve are ruled by zee bureaucrats and zee treatiez. It izn't so zimple az dat. Dis iz zee law. Ve listen to zee law"

[DuncanWaring]

I clean forgot about those stupid neutrinos ... they’re always screwing everything up.

[Old Professer]

I assume the triple-nested real one is kept in a rareified atmosphere while the others are exposed to air to account for the gain in the copies.