http://what-if.xkcd.com/67/

Kilograms are a measurement of mass, not weight. Mass does not vary depending upon gravity.

(Needed to get that out of my system)

-Fooglmog
Guy with no clue.

seems to also be defined as a measure of force, which probably has neither mass or weight.

Well, true, he should have gone with Newtons... but who measures their weight in Newtons anyway! lol

Anyone needing to account for changes in gravitational force.

-Fooglmog
Guy with no clue.

Eh I think they use it properly, given the context. If a person steps on a scale before the Earth expands, it'll read 70kg. If they step on a scale after the Earth expands, it'll read 70.01kg. They didn't gain any mass, but mass and weight are interchangeable in everyday circumstances when it comes to a person standing on the (normal-sized) Earth, so nearly all of our "mass" measuring equipment measures weight, not mass.

Of course, the logical thing would have been to use the English system here and there'd be no confusion :-P

When measuring kgs, you must either use a balance scale with a known mass on the opposing side, or you must zero your scale using a known mass. Either way, the measurement will remain the same regardless of changes in gravitational forces.

The fact that you can make a scale give an incorrect answer by mis-using it does not alter reality. Your measurement is simply wrong.

-Fooglmog
Guy with no clue.

Ack this sent me on a 2 day spree of catching up on every what-if I'd missed... lol...

it sends me back to the question of the Big Bang. why do we have gravity if it went boom and everything is supposed to be expanding away from everything? tiny little dot containing the entire known universe goes boom and starts expanding, why does some of it stop and decide to start clumping together?