# The earth's weight. **URL:** \ **Category:** Cecil's Columns/Staff Reports\ **Created:** [March 25, 2000, 3:56am UTC](https://boards.straightdope.com/t/the-earths-weight/1014 "2000-03-25T03:56:00Z")\ **Posts on this page:** 16\ **Page:** 1
**Author:** ![chrisooya](https://avatars.discourse-cdn.com/v4/letter/c/85e7bf/32.png) [@chrisooya](https://boards.straightdope.com/u/chrisooya)\ **Post date:** [March 25, 2000, 3:56am UTC](https://boards.straightdope.com/t/the-earths-weight/1014/1 "2000-03-25T03:56:00Z")
OK, in cecil’s thing about whether the earth was getting heavier or lighter, he gave some estimates of the earth’s weight, but how can the earth have a weight. We know that “weight” is really just the gravitational force between two objects, so if that’s the weight of the earth, reletive to what? If you talk about weight, its usually assumed that you’re talking about weight on earth, so you can’t just give a weight of the earth itself without specifying what you’re talking about. -Rev. Chrisooya ---
**Author:** ![RM\_Mentock](https://avatars.discourse-cdn.com/v4/letter/r/e274bd/32.png) [@RM\_Mentock](https://boards.straightdope.com/u/RM_Mentock)\ **Post date:** [March 25, 2000, 4:46am UTC](https://boards.straightdope.com/t/the-earths-weight/1014/2 "2000-03-25T04:46:00Z")
Welcome to Straight Dope Which column are you talking about? * * * rocks ---
**Author:** ![JillGat](https://avatars.discourse-cdn.com/v4/letter/j/9fc29f/32.png) [@JillGat](https://boards.straightdope.com/u/JillGat)\ **Post date:** [March 25, 2000, 5:46am UTC](https://boards.straightdope.com/t/the-earths-weight/1014/3 "2000-03-25T05:46:00Z")
[http://www.straightdope.com/classics/a3\_355.html](http://www.straightdope.com/classics/a3_355.html) Always good to post the link to the column, Chris. And welcome to the board! Jill ---
**Author:** ![Billdo](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/billdo/32/315_2.png) [@Billdo](https://boards.straightdope.com/u/Billdo)\ **Post date:** [March 25, 2000, 6:06am UTC](https://boards.straightdope.com/t/the-earths-weight/1014/4 "2000-03-25T06:06:00Z")
Howdy Rev. Glad to have you here. You gotta read carefully, Cecil got the weight of the earth by putting it on a scale. > [@](#): > > Puny humanoid, you think the pitiful efforts of mankind have appreciably altered the mass of the earth, reliably estimated at 6 sextillion, 588 quintillion tons? (And man, if you don’t think it was a bitch getting that puppy on the scale…) Actually, I assume that he got the “weight” of the earth by determining how much an object with the mass of the earth would weigh if it were in normal earth gravity. (But I really shouldn’t presume to speak for His Cecilness). To review, boys and girls, mass is a measure of how much “stuff” an object has, while weight is a measure of how much force of gravity is acting on an object. The English unit pounds is a measure of weight, while the metric kilogram is a unit of mass. Imagine a one kilogram hammer (takes a lot of imagination, doesn’t it.) Here on earth it weighs about 2.2 pounds, because that’s the force of the earth’s gravity acting on it. Now let’s take it up to the moon. On the moon, it would still have a mass of one kilo. However, since the moon’s gravity (more properly, the force of the moon’s gravity on a given mass on the surface of the moon) is about 1/6 of earth’s gravity (on a given mass on the surface of the earth), it would have a weight of about 0.37 pounds (1/6 of 2.2). Anyway, Chrisooya, I think that you’ve caught the Master in an inclarity, to say the least. Good job. ---
**Author:** ![RM\_Mentock](https://avatars.discourse-cdn.com/v4/letter/r/e274bd/32.png) [@RM\_Mentock](https://boards.straightdope.com/u/RM_Mentock)\ **Post date:** [March 25, 2000, 1:06pm UTC](https://boards.straightdope.com/t/the-earths-weight/1014/5 "2000-03-25T13:06:00Z")
> [@](#): > > Originally posted by Billdo: > \*\*You gotta read carefully, Cecil got the weight of the earth by putting it on a scale. > \*\* I dunno. I read it as saying “mass,” not weight, even though the original question clearly says weight–but means mass. * * * rocks ---
**Author:** ![Arnold\_Winkelried](https://avatars.discourse-cdn.com/v4/letter/a/3d9bf3/32.png) [@Arnold\_Winkelried](https://boards.straightdope.com/u/Arnold_Winkelried)\ **Post date:** [March 25, 2000, 7:15pm UTC](https://boards.straightdope.com/t/the-earths-weight/1014/6 "2000-03-25T19:15:00Z")
The metric unit of weight (for a physicist) would, of course, be a Newton, though in common parlance people usually describe weight with kilograms, assuming earth gravity. Is there an English standards unit for mass then? ---
**Author:** ![SouthernXYL](https://avatars.discourse-cdn.com/v4/letter/s/a698b9/32.png) [@SouthernXYL](https://boards.straightdope.com/u/SouthernXYL)\ **Post date:** [March 25, 2000, 7:28pm UTC](https://boards.straightdope.com/t/the-earths-weight/1014/7 "2000-03-25T19:28:00Z")
Slug, I think, but we don’t use it. ---
**Author:** ![BobT](https://avatars.discourse-cdn.com/v4/letter/b/8e8cbc/32.png) [@BobT](https://boards.straightdope.com/u/BobT)\ **Post date:** [March 25, 2000, 8:15pm UTC](https://boards.straightdope.com/t/the-earths-weight/1014/8 "2000-03-25T20:15:00Z")
Yes, it is the noble slug. It is the force required to push one pound at an acceleration of one foot per second per second. ---
**Author:** ![RM\_Mentock](https://avatars.discourse-cdn.com/v4/letter/r/e274bd/32.png) [@RM\_Mentock](https://boards.straightdope.com/u/RM_Mentock)\ **Post date:** [March 25, 2000, 10:47pm UTC](https://boards.straightdope.com/t/the-earths-weight/1014/9 "2000-03-25T22:47:00Z")
> [@](#): > > Originally posted by BobT: > **Yes, it is the noble slug. It is the force required to push one pound at an acceleration of one foot per second per second.** Ahem. Slug is not a force. It is the _mass_ that would be accelerated at one foot per second per second when acted upon by a force of one pound. Well, this _is_ a pendant thread. * * * rocks ---
**Author:** ![Dystopos](https://avatars.discourse-cdn.com/v4/letter/d/e79b87/32.png) [@Dystopos](https://boards.straightdope.com/u/Dystopos)\ **Post date:** [March 26, 2000, 1:43am UTC](https://boards.straightdope.com/t/the-earths-weight/1014/10 "2000-03-26T01:43:00Z")
A pendant thread, or a pedant’s thread? presumably, since every mass associated with the Earth has a weight, it would be possible to calculate a total for the Earth’s mass, even though the net effect of this weight would be more or less negated by the distribution around the center of gravity. Then again, defining a discrete set of matter as being associated with Earth gets fuzzy. The weight of any one object being the net force acting upon it by all the rest of that mass, including, to some infinitessimally small degree, the gravitational forces acting throughout the entire cosmos. Precision is such a fickle quality. ---
**Author:** ![waterj2](https://avatars.discourse-cdn.com/v4/letter/w/858c86/32.png) [@waterj2](https://boards.straightdope.com/u/waterj2)\ **Post date:** [March 26, 2000, 2:05am UTC](https://boards.straightdope.com/t/the-earths-weight/1014/11 "2000-03-26T02:05:00Z")
The slug is still in use. As a matter of fact I used it often in a few fluids courses as recently as 1998. The sea level density of air will forever be engraved in my mind as 0.002377 slugs per cubic foot. ---
**Author:** ![BobT](https://avatars.discourse-cdn.com/v4/letter/b/8e8cbc/32.png) [@BobT](https://boards.straightdope.com/u/BobT)\ **Post date:** [March 26, 2000, 10:35pm UTC](https://boards.straightdope.com/t/the-earths-weight/1014/12 "2000-03-26T22:35:00Z")
> [@](#): > > Originally posted by RM Mentock: > \*\* Ahem. Slug is not a force. It is the _mass_ that would be accelerated at one foot per second per second when acted upon by a force of one pound. > > Well, this _is_ a pendant thread. > \*\* It’s helps to type the whole definition from the dictionary. That… and proofreading. ---
**Author:** ![SouthernXYL](https://avatars.discourse-cdn.com/v4/letter/s/a698b9/32.png) [@SouthernXYL](https://boards.straightdope.com/u/SouthernXYL)\ **Post date:** [March 26, 2000, 10:55pm UTC](https://boards.straightdope.com/t/the-earths-weight/1014/13 "2000-03-26T22:55:00Z")
Hey, measurements and units are funny things. I remember the double take the kid gave me when I told her that temperature is not a measure of heat. WELL WHAT IS IT THEN? I had to get an old college textbook and look it up before I could tell her. (Basically, it’s a measure of whether heat will flow between two bodies. You can put 80 calories of heat into a gram of ice at 0 degrees C and the temp will not change; the ice will only melt.) ---
**Author:** ![Arnold\_Winkelried](https://avatars.discourse-cdn.com/v4/letter/a/3d9bf3/32.png) [@Arnold\_Winkelried](https://boards.straightdope.com/u/Arnold_Winkelried)\ **Post date:** [March 26, 2000, 10:56pm UTC](https://boards.straightdope.com/t/the-earths-weight/1014/14 "2000-03-26T22:56:00Z")
Thank you for teaching me a new word today! Newton is to pound as kilogram is to slug. That should be good for winning a few bar bets. ---
**Author:** ![waterj2](https://avatars.discourse-cdn.com/v4/letter/w/858c86/32.png) [@waterj2](https://boards.straightdope.com/u/waterj2)\ **Post date:** [March 27, 2000, 12:57am UTC](https://boards.straightdope.com/t/the-earths-weight/1014/15 "2000-03-27T00:57:00Z")
Unless they insist on measuring mass in those god-awful pound-mass things. A pound-mass is the mass of an object with a weight of one pound at sea-level. But if you want a real stumper for them, try a degree Celsius is to a Kelvin ( **not** a degree Kelvin) as a degree Fahrenheit is to a ???. Answer: degree Rankine. ---
**Author:** ![Arnold\_Winkelried](https://avatars.discourse-cdn.com/v4/letter/a/3d9bf3/32.png) [@Arnold\_Winkelried](https://boards.straightdope.com/u/Arnold_Winkelried)\ **Post date:** [March 27, 2000, 7:04pm UTC](https://boards.straightdope.com/t/the-earths-weight/1014/16 "2000-03-27T19:04:00Z")
Another good piece of information, waterj2! K (kelvin) is to °C (degree centigrade, aka celsius) as °R (degree Rankine) is to °F (degree Fahrenheit). Here’s a puzzler though: What is the absolute temperature equivalent for °r (degree Réaumur)? 🙂 I’m guessing there isn’t one. They don’t list one on this page. [How Many? A Dictionary of Units of Measurement](http://www.unc.edu/~rowlett/units/dictD.html)