Say your digging straight down on earth ( North to South )how do you define when up is down and down is up.?

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answers:
Atarah Derek say: "Up" is away from the earth's gravitational center. So until you reach the core, you're digging down. Once you pass the core, you're digging up.
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lenpol7 say: 'When you reach the centre of the Earth.
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busterwasmycat say: which way does gravity pull the strongest? That direction will be down. There will be a zone where the difference is slight and you wouldn't be able to say without careful measurement (and even with careful measurement), and while you were traveling through that region, you wouldn't really have an up or down.

Of course, it depends on what exactly you mean by the relative term that is the word "down". I have chosen gravitational force to define it, since that is the practical meaning to us surface-dwellers (down is the direction things drop).
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roger say: plumb bob will work 'til you get to the center. From there just follow on with the direction that you were going
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CarolOklaNola say: When you are at the center of the Earth and you are weightless, EVERYWHERE is "up" relative to YOU, hypothetically.
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Eddie say: Excluding the huge molten core of the Earth for this hypothetical situation.
Once you got to the halfway point, or close to it, it should be low or zero gravity, with only the mass around you creating any sort of pull. There would technically be no up or down, except relative to where your entry point was to the core.
Think of it as like youre on a playground roundabout. The feeling you get close to the edge is stronger than that in the middle.
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Acetek say: the sameway you define it now
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