Weight of Earth

[vollerbo]

My 7 year old son would like to know how much the earth weighs, anyone know?

[squarebear]

6,000,000,000,000,000,000,000,000 kilograms

http://science.howstuffworks.com/question30.ht m

[Tichfield]

Apparently it is

approximately 6,000,000,000,000,000,000,000,000 (6E+24) kilograms.

according to

http://science.howstuffworks.com/question30.ht m

[squarebear]

Looks like we use the same search engine Tich?
Given the speed at which we found the answer, perhaps the original question setter could have spent 10 seconds doing the same?

[Tichfield]

But, because the planet exists in a vacuum it could be said to weigh nothing at all.

[markysngc]

The weight of the earth is 0 (weight is dependent on gravity) if you put a huge weigh scale under the earth it would read 0 as it's floating in space.

The mass is approx

5,972,000,000,000,000,000,000 metric tons

or

5.972 sextillion metric tons

Give or take a couple of Kg's I should reckon

[vollerbo]

thanks, squarebear I could have but you are quicker and am breastfeeding baby at mo while looking after sick elder child who just asked question and knew would get quicker answer here and you know what they say about women when they have children (brain fried!) cheers though

[squarebear]

No problem at all.

[Marg0]

just put your scales upside down on the floor. Pffffff. Am I the only one who can work these things out??? So obvious...

[crazy legs]

The Earth might have some weight as it is affected by the sun's gravity.

[markysngc]

but to measure that you would have to counteract centrifugal force by stopping the orbit of the earth, you would then get a weight of the earth, as long as the scales are held in place else it's a plummet to the sun:)

[crazy legs]

"centrifugal force" my physics lecturer flips when someone says that phrase.

[gen2]

My physics teacher used to flip whenever anyone said 'weight' when they meant 'mass' (as well as for centrifugal force).

[markysngc]

hi knobby

Happy birthday, hope ya having a good one

To weigh the earth wouldn't you also have to first determine what is considered up and down on a universal level

[Peter Pedant]

Wasnt the first person to estimate the Gravitational constant, G, a fella called Boyes ?

and plugged into the usual formula

F = G . m1 . m2 / r squared, you get the mass of the earth

and if you know the radius of the earth, you can get the volume and therefore the density

wh I recollect to be 5.5 gm/cm3 - yeah CGS units , it was some time ago.

[mibn2cweus]

Pete, In reference to your question, you are perhaps thinking of Robert Boyle, the gas man . . . Boyle�s Law ~ the inverse relationship between volume and pressure (once the original temperature has been restored)?

What Henry Cavendish (coincidently another �gas man�) actually did was measure the density of the Earth by comparing the attraction between one mass and another to that of Earth, (or something like that), from which G was later derived). Interestingly he described it as 'weighing the world'.

Oh, and your recollection is correct!

Mean radius 6,371.0 km
Volume 1.0832073�1012 km�
Mass 5.9736�1024 kg
Mean density 5.5153 g/cm�

I hope you were a teacher because you are a good one. I just learned a lot, (not that I�ll remember any of it tomorrow).