What is the weight of the Earth?

Question

Weight, not mass

Answer 1

Weight is a force between two masses. Your own weight is the force between the mass of your body and the mass of the Earth when separated by a distance of 4,000 miles. Why 4,000 miles? Because for gravity calculations it is the distance between the centers of the two masses. So it is the distance between the center of your body and the center of the Earth that counts, and the center of the Earth is about 4,000 miles below the surface.

So what does this make the weight of Earth? It depends. On what? On the mass with which the force is being calculated. If you pick your own body as the mass, then the Earth weighs the same as you do. That is because the force is equal and opposite. Earth pulls you toward its center with a force of 200 pounds and you pull Earth toward you with a force of 200 pounds.

So what is your mass? The unit of mass in the English system is a "slug". Using Newtons equation F=MA, where F=200 pounds and A=32 feet per second squared, M calculates out to be 6.25 slugs. In the metric system, weight is measured in "Newtons" and mass in "kilograms". Most people not trained in physics have never heard of Newtons or slugs and have the incorrect impression that kilograms are a measure of weight.

Answer 2

Others have discussed weight vs mass so I'll focus on coming up with a number.

Assumptions:
1. The earth is a sphere with a diameter of 8000 miles.
2. The average density of earth is the same as sea water. 64 lbs/ft^3

Volume = 4/3 π r^3

r = 8000 / 2 = 4000 miles

Volume = 4/3 π (4000)^3 = 2.68 x 10^11 cubic miles

1 cubic mile = 5280^3 = 1.47 x 10^11 cubic feet.

Weight of earth = (2.68 x 10^11) x (1.47 x 10^11) x 64 lbs =
2.52 x 10^24 lbs.

Answer 3

It would be more proper to ask, "What is the mass of planet Earth?" The quick answer to that is: approximately 6,000,000,000,000,000,000,000,000 (6E+24) kilograms.

The interesting sub-question is, "How did anyone figure that out?" It's not like the planet steps onto the scale each morning before it takes a shower. The measurement of the planet's weight is derived from the gravitational attraction that the Earth has for objects near it.

It turns out that any two masses have a gravitational attraction for one another. If you put two bowling balls near each other, they will attract one another gravitationally. The attraction is extremely slight, but if your instruments are sensitive enough you can measure the gravitational attraction that two bowling balls have on one another. From that measurement, you could determine the mass of the two objects. The same is true for two golf balls, but the attraction is even slighter because the amount of gravitational force depends on mass of the objects.


It is "more proper" to ask about mass rather than weight because weight is a force that requires a gravitational field to determine. You can take a bowling ball and weigh it on the Earth and on the moon. The weight on the moon will be one-sixth that on the Earth, but the amount of mass is the same in both places. To weigh the Earth, we would need to know in which object's gravitational field we want to calculate the weight. The mass of the Earth, on the other hand, is a constant.

"How much does planet Earth weigh?". April 01, 2000 http://science.howstuffworks.com/question30.htm (April 28, 2007)

Answer 4

Mass: 5.9742×10 KG weight is relative according to the action of gravity upon it so you can't have the weight of the earth because it is it's own source of gravity. although I have heard it said it weighs 6 with 21 zeros after it but that number changes so much depending on who you ask that I don't think we can weigh the earth. only mass it.

Answer 5

Weight equals mass times the gravitational acceleration of some other mass. (..w = m * g..) If you apply the sun's gravitational acceleration on Earth (3.324 minus 3 m/sec/sec) then Earth 'weighs' 2^22 kg.

Answer 6

In actually it is 0.
Everything is weightless in space. So to be real the Earth is weightless. But, for reasons of giving something weight we use a mathematical formula as mention above. Though it is erroneous, we can base scientific observations upon this formula to give specific weight values to planets, stars, and to some degree of debate; Asteroids and Comets.

Answer 7

6 + 21 zeros.
but weight is a relative value. Other planets or satellites effect, turning speed, mass ,...esc

Answer 8

The Earth weighs around 6,600,000,000,000,000,000,000 tons (5,940 billion billion metric tons)!

Answer 9

The Earth weighs around 6,600,000,000,000,000,000,000 tons (5,940 billion billion metric tons)!

Answer 10

Earth weighs about 13,170,000,000,000,000,000,000,000 pounds (or 5,974,000,000,000,000,000,000,000 kilograms).