Do I weigh less at noon, new moon?

[DavidOfBanff]

...because that's when the moon and sun are most directly overhead.

Just an idle ponder.

[Telrad]

You do not weigh less when the moon is over you. The gravity of the moon has virtually no effect on you. If your weight does change it would change only by about 1/10,000th of a gram.

[rfdesigner]

I would have thought so but only marginally

You will also weigh less at altitude... AND depth. (i.e. down a mine)

[WayBig]

I would guess not, as the gravity pull of the sun and the moon would also affect the earth that you are standing on, so relative to you and the earth there would be no change...perhaps

[steelfixer]

I would have thought so but only marginally

You will also weigh less at altitude... AND depth. (i.e. down a mine)

I am facinated how do you figure you weigh less at altitute unless you are in space ?

[JBadger]

I am facinated how do you figure you weigh less at altitute unless you are in space ?

Simple: because the gravitational pull between two objects is inversely proportional to the square of the distance between them.

[Telrad]

Simple: because the gravitational pull between two objects is inversely proportional to the square of the distance between them.

Weight is generally the force applied by gravity on a person which is the product of the universal gravitational constant, the mass of one object (Earth), and the mass of the other object (the person) divided by the distance between them squared. In higher altitudes a person is farther away from more of Earth's mass so they weigh less, but the difference is very, very negligible for us.

[Mr TamiyaCowboy]

I am facinated how do you figure you weigh less at altitute unless you are in space ?

In higher altitudes a person is farther away from more of Earth's mass so they weigh less, but the difference is very very slight.

lets say you weigh 100 lb and you make your way to the top of mount everest. once there you would then weigh 99.72 pounds. so you loose 0.28 pounds in weight.

also the air is more thinner so your more boyant

[DavidOfBanff]

also the air is more thinner so your more boyant

Fair enough, but what if you're a gurl ?

[Keiran]

I would guess not, as the gravity pull of the sun and the moon would also affect the earth that you are standing on, so relative to you and the earth there would be no change...perhaps

This is what i would think...

[steelfixer]

So then if your were down a deep mine you would weigh more??

[rfdesigner]

RE: So then if your were down a deep mine you would weigh more??

no.

Lets go to an extreme. Concider a mine that goes all the way to the centre of the earth. Now there's equal earth in all directions and all the gravity cancels out, you're weightless.

If you are 100m down a mine, then there is 100m less rock beneath you pulling you down and 100m more rock above you pulling you up, so you weigh less than at the surface. In fact the surface is where weight is a maximum.

Derek

[Ags]

It's a funny thought - stuck at the middle of the earth, crushed by millions of tons of radioactive nickel-iron, and you're weightless!

[JamesF]

If you think of your "weight" as the amount of force with which you are attracted towards the centre of mass of the earth, then when you're on the surface of the planet most of its mass has a "downwards" component to its gravitational effect on you and that's your weight. If the sun and moon are overhead they will exert a small attraction the other way, meaning the total force towards the centre of the planet is reduced compared with the times when they're at other positions in the sky. If you climb a high mountain or go up in an aeroplane then much (or all) of the earth's mass is further away from you, and since gravitational attraction works on the inverse square principle, there will be less force exterted on you towards the earth, so again you'll weigh less.

If you go down a deep mine, a chunk of the earth's mass is now exerting a gravitational force on you sideways and upwards rather than having a downwards component, so that will act in opposition to the forces giving you weight. Of course assuming you go down a mine in the UK, Australia will now be closer and exert a larger gravitational influence on you that it does when you're on the surface. I still reckon you'd weigh less than on the surface though.

It doesn't help that we commonly use the same units for measuring mass (how much "stuff" something is made of) and weight (how strongly that mass is attracted to the nearest planet/moon/other large celestial body, I guess).

James

[Earl]

Regardless of all of the above, you stand a good chance weighing more if your in a Maccy D's

[DavidOfBanff]

Regardless of all of the above, you stand a good chance weighing more if your in a Maccy D's

Mmmm, but mightn't the collective gravitational influence of the other customers ameliorate the occasional Whopper? (plus fries?).

[Ags]

Eyepieces weigh more when you drop them.

Telescopes weigh more AFTER you buy them.