Shrinking Kilogram Bewilders Physicists

Originally posted by bourbon2nite
Just a shot in the dark here. Its been along time since high school for me , but is not gravity the result of the spinning of the earth. If the earths rotation has slowed ever so slightly, would not the gravitational pull also decrease ever so slightly? Any merit to this thought?

edit on 1/28/2011 by bourbon2nite because: (no reason given)

No not in the slightest.

Where on earth did you come up with this?

Gravity is the mutual attraction of one object to another caused by mass, or in relativity a warp in the stress energy tensor.

Thank you for your reply, Im sorry it wasnt even a slightly intelligent guess.

Why is this shocking?

Gravity is neither consistent or constant across the Earth.

The gravity in your location can change over time...118 years (although short geologically) is more than enough time for a locale to have minute changes.

Maybe they should wheigh everything in the room to make sure it is not an area effect before claiming that the individual piece has changed.

Edit to add:

If you wish to see a visualisation of the Earth's gravity, check out NASA's model, produced by the GRACE mission.

GRACE

Originally posted by bourbon2nite
Thank you for your reply, Im sorry it wasnt even a slightly intelligent guess.

No, you just probably forgot some stuff man.

It's all right, we all forget things from time to time!

Explanation: S&F!

We ALREADY do have a scientific constant for 1 kilogram of mass [which has a weight of 1kg in earths 1G environment]...

It's called 1 LITER of water at sea level at 4 degree's centigrade/celsius and at 760 millimetres of mercury pressure.!

Re-inventing the wheel too much me thinks!

Liter Definition [wiki]

wiki.answers.com...

These scientists are so desparate to hold on to their jobs!

Personal Disclosure:

reply to post by peck420


According to the article..

Due to an uneven distribution of mass inside the Earth, the Earth's gravity field is not uniform

and I would think the mass inside the Earth underneath the place where the kilogram is kept and weighed would not have changed measurably at all in those years so there would be no reason for the gravity there to have changed either.

reply to post by MissSmartypants


Both latitude and altitude also effect gravity.

As well as density of substructures, geological topology (upper crust - where people are capable of building.)

Any of these could have changed more than enough for a 50 microgram change.

Hell, the building it is stored in could have elevated enough to cause that.

It could even just be as simple as a much more sensitive measuring device.

We are talking 50/1000 of a milligram.

If it had lost a gram I would be ....but really?

Edit to add:

Let's assume the 9.81m/s2 of gravity.

Gravity would have had to shift by .000005%.

We are talking about an absolutely infintismal amount of movement.

To give an example, the measured gravity at the top of Mount Everest (8,850m) is .28% less than sea level. For this 1 kg to weigh 50 micrograms less, the building would have to move approx. .16m (16cm) up in lattitude over 118 years.

Interesting... I thought about radioactive decay, but given the information on Wikipedia that would still take a really really long time given the known half-life of the metal involved. (Even the "stable" isotope does undergo alpha decay.)

Earth's variation in gravity does seem like a more likely explanation. Even if you didn't move the sample all it would take is a bit of geological activity somewhere deep underground, and all of a sudden the weight measured for a given mass would shift by a very small amount. (Provided you have the degree of precision needed to see it.)

Reminds me of the observation made in this comic.

reply to post by IntastellaBurst


Or more likely....in my not so humble opinion. Being organized in a manner that is subject to manipulation. The problem is they are trying to find out what is manipulating it.....I guess we'll have to wait until they figure it out.

The object never changed since it was made in the 1800's.

Gravity changed.

Paris, France has moved with Continental drift and is no longer at the same location it was at in the 1800's. Also the planet is NOT a perfect sphere and changes it's imperfect spherical shape over time.

As the planet changes, gravity will change at location X as the piece of ground you stand on moved with the Continental Drift and the planet itself changed it's spherical shape. Our planet is not a perfect ball, it's always changing.

Those Physicists should have realized gravity changes and is not constant during school.

There is no place on Earth that will ever, ever, ever have a constant gravity where weight of objects will be constant over long periods of time.

No place on Earth! There's is more than 1 Gravity on Earth as well:

en.wikipedia.org...

reply to post by dominicus


Hmm. I wish I could remember where I saw it, but I read a very similar article the other day about just this, bearing a similar title.
The title turned out to be designed to catch ones eye, as there was no actual mystery.
It was a change to a system of measurement apparently, resulting in the literal translation that this universal weight they use, 'lost' a little weight as a result, when in reality it lost nothing but its old associated method of weighing it.

I could be wrong, but it may have been one of the UK news websites I saw it on.


Aha - here it is: www.guardian.co.uk...

reply to post by OptimisticPessimist


I'm not familiar with 'www.physorg.com' - are they in the habit of making up blatantly fake stories?

reply to post by OptimisticPessimist


Ok, before anyone else points it out, I made a mistake with my information! The 50 micrograms isn't a loss due to a change in measurment, that was all my misreading of the article when I first read it.
It pays me to read things twice - I should remember that.

I also retract my initial implication that psyorg were putting up anything fake - they were simply over dramatising the facts.

Here's what the Guardian article said:

One problem with using a lump of metal to define such a basic quantity as the kilogram is that it is liable to change over time. Measurements over the past century have shown that the international prototype has lost around 50 micrograms, around the weight of a grain of sand.

"Why should it [the current standard] be stable? It's a piece of platinum cast in London 130 years ago, full of holes, full of hydrogen," said Quinn. "What's on the surface, it's impossible to know. There are all sorts of surface layers of hydrocarbons."

No mystery, apparently.

reply to post by BellaMente


Your thought on energy increasing is interesting. I wonder if the constant bombardment of increasing external energies are stripping off mass/atoms of the matter they interact with in increasing frequency?