# Mass Of Earth

1. Jan 3, 2006

### Mr.Socrates

All Of Us Know Most Of The Constants In Physics Have A Constant Mass Of Earth Used...

Is It True That Mass Of Earth The Same Or Approximately The Same ....

My Prediction Is It Will Be Twice The Mass Calculated And All The Nearby Quantities Will Be 1/2 The Orginal Value....

The Reason Y I Say This Very Simple ..... Assume The Mass Of Earth Is X Billion Kilos... The No Of Humans In Earth Be X Billion.... Let The Mass Of A Human Be The Least 1 Kg Then The Mass Of Earth Is = Mass Of Earth + Mass Of Human Beings.

If U Start To Reply As Approximation ...... The Word Approximately Means It Should Be Any Were Near By...
Not The Difference This Big....

2. Jan 3, 2006

### Integral

Staff Emeritus
So some how, as I gain weight, that weight was not part of the earths mass before I gained it... Tell me where did it come from? Mars? The Moon?

The mass of the inhabitants of the earth do not change the mass of the earth. All of the matter which is incorporated into your body as you grow was part of, and always will be part of the earths mass. Unless of course you die in deep space.

3. Jan 3, 2006

### BobG

A couple of misconceptions.

As Integral mentioned, any mass in the human body came from the planet Earth, so there is no net change due to the number of humans.

The mass of the Earth is 6 x 10^24. There are about 6.6 billion humans with an average mass of about 75 kg. This totals up to about 5 x 10^11 kg. To find the percentage of the Earth's mass that is made up of humans, just divide the total human mass by the Earth's mass and multiply by 100. It's virtually zero.

4. Jan 3, 2006

### Mk

I think we're overpopulating.

Anybody ever drive through Oklahoma? Or the midwest? EMPTY, GOOD land. NO BODY there.

5. Jan 4, 2006

### daveb

Although it makes you wonder...is the total mass of the earth increasing or decreasing (since the planet absorbs energy from the sun and reradiates some into space). I wonder what the net loss/gain is?

6. Jan 4, 2006

### Chi Meson

Mass of earth is X billion kilos, sure, if "X" = 6,000,000,000,000,000.

7. Jan 4, 2006

### Janus

Staff Emeritus
To put it in even more perspective:
Even if you imagined that the whole Earth, oceans included, was covered with people at a population density equal to that of Tokyo, the total mass of humanity would still only be about $2x10^{16}$ kg. Compare that to the mass of the Earth, $6x10^{24}$ kg ,and the mass of the people would still only be 0.000000328% that of the Earth.

8. Jan 5, 2006

### arildno

The following conclusion seems warranted:
The Earth is big, really, really
BIG!!!!!

9. Jan 5, 2006

### matthyaouw

I've seen bigger... :tongue:

10. Jan 5, 2006

### zoobyshoe

I have just read the extremely interesting story of how the mass of the earth was first determined in 1798 by Henry Cavendish, and I must say I am extremely impressed. It would not have occured to me to figure it out this way, or any way, in a thousand years.