# Is the earth getting heavier or lighter? **URL:** \ **Category:** Cecil's Columns/Staff Reports\ **Created:** [August 9, 2012, 1:52pm UTC](https://boards.straightdope.com/t/is-the-earth-getting-heavier-or-lighter/630951 "2012-08-09T13:52:30Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![Bakhesh](https://avatars.discourse-cdn.com/v4/letter/b/3da27b/32.png) [@Bakhesh](https://boards.straightdope.com/u/Bakhesh)\ **Post date:** [August 9, 2012, 1:52pm UTC](https://boards.straightdope.com/t/is-the-earth-getting-heavier-or-lighter/630951/1 "2012-08-09T13:52:30Z")
Ok, so Earth is getting heavier by up to 100,000 tonnes per year. My follow up question is, does this affect the rotation of the planet? I seem to remember from high school physics that linear momentum is worked out by multiplying mass and velocity, so as the mass of the planet increases, wouldn’t the speed of rotation decrease? (I also remember that rotational dynamics were a lot more complicated than linear dynamics, but the same principals should apply) ---
**Author:** ![C\_K\_Dexter\_Haven](https://avatars.discourse-cdn.com/v4/letter/c/b2d939/32.png) [@C\_K\_Dexter\_Haven](https://boards.straightdope.com/u/C_K_Dexter_Haven)\ **Post date:** [August 9, 2012, 10:40pm UTC](https://boards.straightdope.com/t/is-the-earth-getting-heavier-or-lighter/630951/2 "2012-08-09T22:40:53Z")
Link to Column: [Is the earth getting heavier or lighter? - The Straight Dope](http://www.straightdope.com/columns/read/815/is-the-earth-getting-heavier-or-lighter) ---
**Author:** ![Powers](https://avatars.discourse-cdn.com/v4/letter/p/edb3f5/32.png) [@Powers](https://boards.straightdope.com/u/Powers)\ **Post date:** [August 10, 2012, 5:57pm UTC](https://boards.straightdope.com/t/is-the-earth-getting-heavier-or-lighter/630951/3 "2012-08-10T17:57:26Z")
> [@Bakhesh](#): > > Ok, so Earth is getting heavier by up to 100,000 tonnes per year. My follow up question is, does this affect the rotation of the planet? > > I seem to remember from high school physics that linear momentum is worked out by multiplying mass and velocity, so as the mass of the planet increases, wouldn’t the speed of rotation decrease? (I also remember that rotational dynamics were a lot more complicated than linear dynamics, but the same principals should apply) The Earth’s speed of rotation is already decreasing thanks to the tidal effect of the moon. I suspect any further effect from accumulated mass is negligible. Powers &8^] ---
**Author:** ![MarvinKitFox](https://avatars.discourse-cdn.com/v4/letter/m/7ba0ec/32.png) [@MarvinKitFox](https://boards.straightdope.com/u/MarvinKitFox)\ **Post date:** [August 15, 2012, 4:06pm UTC](https://boards.straightdope.com/t/is-the-earth-getting-heavier-or-lighter/630951/4 "2012-08-15T16:06:37Z")
Slight correction, as in “You are totally off your gourd, next time check your facts” The Great Cecil’s post states “It’s believed the earth gains anywhere from several dozen to several hundred tons per day due to meteorites and meteoritic dust — 10,000 to 100,000 tons a year. (Sorry, but estimates vary widely.) This far exceeds any losses” Try this for losses: In Hydrogen only: 18 to 40 Kilogram per second. That is roughly 568 000 tons to 1 260 000 tons per year of mass loss. This quite handily exceeds any estimate of mass gain from meteoric origins. There are other losses/gains to look at, but yes they are quite a bit less. gain: Accretion from solar wind. (about 10% as much as the H2 loss) loss: Radioactive decay in the core a) subsequent heat loss through surface: 20TW= about 7 tons per year b) Energy loss as neutrino’s from the decay: about 15 tons per year. loss: Tidal slowing of earth, generates heat, loss of about 3 tons per year. loss: Energy from human consumption, lost as heat: about 500 exajoule, a mere 6 tons. loss: Stuff rocketed into space: considering that almost all rocket fuel burnt at orbital height exceeds escape velocity: several hundred tons per year! Shall we look for more? I’m sure I missed a few dozen sources 🙂 ---
**Author:** ![ZenBeam](https://avatars.discourse-cdn.com/v4/letter/z/3ab097/32.png) [@ZenBeam](https://boards.straightdope.com/u/ZenBeam)\ **Post date:** [August 15, 2012, 11:28pm UTC](https://boards.straightdope.com/t/is-the-earth-getting-heavier-or-lighter/630951/5 "2012-08-15T23:28:03Z")
Where did you get the “18 to 40 Kilogram per second” figure? Looking around, I see 3 kg per second, e.g. [here](http://www.bbc.co.uk/news/magazine-16787636) and [here](http://www.scientificamerican.com/article.cfm?id=how-planets-lose-their-atmospheres). That first link claims that overall the Earth is getting lighter by about 50,000 kg per year, so your overall remains, though. In **Cecil** ’s defense, I’ll note the column is from 1989. In [this paper from 1969 (PDF)](http://www.annalsofgeophysics.eu/index.php/annals/article/download/5083/5152), the author writes (Note: you have to select the text to read it. The scan is illegible otherwise): > [@](#): > > T h e rate at which h y d r o g e n is supplied t o the Earth > by the solar w i n d , and the rate at which h y d r o g e n escapes f r o m the E a r t h > by diffusion into space are compared 011 the basis of recent estimates. > It is f o u n d that the hydrogen supplied by the solar w i n d is roughly compar- > able to or m a y even be larger than present h y d r o g e n losses. Hard to say what the scientific opinion was when the column was written. ---
**Author:** ![cynyc](https://avatars.discourse-cdn.com/v4/letter/c/f05b48/32.png) [@cynyc](https://boards.straightdope.com/u/cynyc)\ **Post date:** [August 22, 2012, 11:45pm UTC](https://boards.straightdope.com/t/is-the-earth-getting-heavier-or-lighter/630951/6 "2012-08-22T23:45:49Z")
I don’t know if the mass of the earth is increasing in a significant degree, unless mass also applies to weight. Now the weight of the earth is changing because we have billions of people who won’t stop procreating, adding even more weight, and then those obese American kids. At best the droughts and subsequent lack of food, particularly McDonalds, or beef if you will, will make the fat kids skinny, unless, of course, the gov hands out tons of processed cheese food. I don’t know about the earth’s rotation. Had it been impacted when the Great Meteor hit? Support Planned Parenthood. ---
**Author:** ![Powers](https://avatars.discourse-cdn.com/v4/letter/p/edb3f5/32.png) [@Powers](https://boards.straightdope.com/u/Powers)\ **Post date:** [August 23, 2012, 1:34am UTC](https://boards.straightdope.com/t/is-the-earth-getting-heavier-or-lighter/630951/7 "2012-08-23T01:34:46Z")
I’m not sure you have any idea what you’re talking about. Powers &8^] ---
**Author:** ![gamerunknown](https://avatars.discourse-cdn.com/v4/letter/g/6bbea6/32.png) [@gamerunknown](https://boards.straightdope.com/u/gamerunknown)\ **Post date:** [August 23, 2012, 8:45am UTC](https://boards.straightdope.com/t/is-the-earth-getting-heavier-or-lighter/630951/8 "2012-08-23T08:45:13Z")
It’s simple, we can avoid this fragile globe collapsing if we cure obesity with abortions. ---
**Author:** ![Bozuit](https://avatars.discourse-cdn.com/v4/letter/b/edb3f5/32.png) [@Bozuit](https://boards.straightdope.com/u/Bozuit)\ **Post date:** [August 23, 2012, 11:31am UTC](https://boards.straightdope.com/t/is-the-earth-getting-heavier-or-lighter/630951/9 "2012-08-23T11:31:38Z")
Surely the Earth must be lighter by now. We keep dumping all our metal on Mars. ---
**Author:** ![gnoitall](https://avatars.discourse-cdn.com/v4/letter/g/bb73d2/32.png) [@gnoitall](https://boards.straightdope.com/u/gnoitall)\ **Post date:** [August 23, 2012, 2:45pm UTC](https://boards.straightdope.com/t/is-the-earth-getting-heavier-or-lighter/630951/10 "2012-08-23T14:45:03Z")
> [@Bozuit](#): > > Surely the Earth must be lighter by now. We keep dumping all our metal on Mars. Mars manages to land [some of its rock on Earth](http://www2.jpl.nasa.gov/snc/) from time to time, too. Hard to know if this is a continuing process or just geological-historical. My calculations from that page show that we know of about 91 kg of Mars rock on Earth. Of course, we totally tipped that balance into an Earth weight deficit when Viking 1 landed, since its lander masses 572 kg by itself. (Assuming there’s not some mountain-sized Martian-stone meteorite buried someplace we haven’t looked.) ---
**Author:** ![Irishman](https://avatars.discourse-cdn.com/v4/letter/i/b487fb/32.png) [@Irishman](https://boards.straightdope.com/u/Irishman)\ **Post date:** [August 23, 2012, 9:04pm UTC](https://boards.straightdope.com/t/is-the-earth-getting-heavier-or-lighter/630951/11 "2012-08-23T21:04:41Z")
> [@cynyc](#): > > Now the weight of the earth is changing because we have billions of people who won’t stop procreating, adding even more weight, and then those obese American kids. At best the droughts and subsequent lack of food, particularly McDonalds, or beef if you will, will make the fat kids skinny, unless, of course, the gov hands out tons of processed cheese food. This is complete gibberish. Increase in human population, and feeding people to be fat instead of skinny, only redistributes the existing mass from one location and form to another. It does not increase the mass of the planet. Weight in this context is just a stand in for mass. Fat people weigh more, because they have more mass in one location for gravity to act on all at once. The gravity field is determined by the amount of matter collected together. Weight is a function of the distribution of that matter. Move matter from pile of dirt over here to belly over there through the process of growing plant matter, or perhaps feeding said plant matter to animal and then processing animal into food source. ---
**Author:** ![ukdave](https://avatars.discourse-cdn.com/v4/letter/u/f19dbf/32.png) [@ukdave](https://boards.straightdope.com/u/ukdave)\ **Post date:** [September 3, 2012, 9:15am UTC](https://boards.straightdope.com/t/is-the-earth-getting-heavier-or-lighter/630951/12 "2012-09-03T09:15:08Z")
The weight of an object is merely the measurement of the effect gravity has on that object. In space the same object would have no weight. Since gravity is a force generated by the mass of the earth, the weight of the earth cannot be measured in this way.The earth cannot “weigh” itself! The earth is an object in space and therefore is weightless. The answer to the question is “no”. ---
**Author:** ![Irishman](https://avatars.discourse-cdn.com/v4/letter/i/b487fb/32.png) [@Irishman](https://boards.straightdope.com/u/Irishman)\ **Post date:** [September 5, 2012, 9:34pm UTC](https://boards.straightdope.com/t/is-the-earth-getting-heavier-or-lighter/630951/13 "2012-09-05T21:34:10Z")
Answer to which question? ---
**Author:** ![HippieMagic](https://avatars.discourse-cdn.com/v4/letter/h/2bfe46/32.png) [@HippieMagic](https://boards.straightdope.com/u/HippieMagic)\ **Post date:** [September 5, 2012, 11:39pm UTC](https://boards.straightdope.com/t/is-the-earth-getting-heavier-or-lighter/630951/14 "2012-09-05T23:39:57Z")
I’m still confused how more people aren’t more weight. I mean I get how everyone comes from what’s already here, our sperm and eggs… And that babies only grow up and get bigger from what they eat which is already here… But don’t all our bones, organs, and even our bag of skin weigh more than sperm and eggs? I guess I just don’t know where it all comes from =) ~Appreciate feedback ---
**Author:** ![HippieMagic](https://avatars.discourse-cdn.com/v4/letter/h/2bfe46/32.png) [@HippieMagic](https://boards.straightdope.com/u/HippieMagic)\ **Post date:** [September 5, 2012, 11:43pm UTC](https://boards.straightdope.com/t/is-the-earth-getting-heavier-or-lighter/630951/15 "2012-09-05T23:43:55Z")
@ukdave Okay, so the Earth can’t actually weigh anything since we only judge our weight based on our gravitational pull to the Earth itself in the first place. But if the Earth is gaining mass, then gravity should be getting stronger right? ---
**Author:** ![John\_W.Kennedy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/john_w.kennedy/32/1031_2.png) [@John\_W.Kennedy](https://boards.straightdope.com/u/John_W.Kennedy)\ **Post date:** [September 6, 2012, 1:21am UTC](https://boards.straightdope.com/t/is-the-earth-getting-heavier-or-lighter/630951/16 "2012-09-06T01:21:29Z")
> [@HippieMagic](#): > > @ukdave > Okay, so the Earth can’t actually weigh anything since we only judge our weight based on our gravitational pull to the Earth itself in the first place. > But if the Earth is gaining mass, then gravity should be getting stronger right? Yes, though it’s partly canceled out by the surface of the Earth getting further from the center. But both effects are much too small to measure. ---
**Author:** ![ZenBeam](https://avatars.discourse-cdn.com/v4/letter/z/3ab097/32.png) [@ZenBeam](https://boards.straightdope.com/u/ZenBeam)\ **Post date:** [September 6, 2012, 2:17am UTC](https://boards.straightdope.com/t/is-the-earth-getting-heavier-or-lighter/630951/17 "2012-09-06T02:17:30Z")
> [@HippieMagic](#): > > I’m still confused how more people aren’t more weight. > I mean I get how everyone comes from what’s already here, our sperm and eggs.. And that babies only grow up and get bigger from what they eat which is already here… > But don’t all our bones, organs, and even our bag of skin weigh more than sperm and eggs? I guess I just don’t know where it all comes from =) > > ~Appreciate feedback It all comes from food. How much food have you eaten over your lifetime? Tens of tons of it, at a guess. The real mystery is, why do you weigh so little? ---
**Author:** ![HippieMagic](https://avatars.discourse-cdn.com/v4/letter/h/2bfe46/32.png) [@HippieMagic](https://boards.straightdope.com/u/HippieMagic)\ **Post date:** [September 6, 2012, 4:16am UTC](https://boards.straightdope.com/t/is-the-earth-getting-heavier-or-lighter/630951/18 "2012-09-06T04:16:32Z")
Poop Zen. . poop. ---
**Author:** ![HippieMagic](https://avatars.discourse-cdn.com/v4/letter/h/2bfe46/32.png) [@HippieMagic](https://boards.straightdope.com/u/HippieMagic)\ **Post date:** [September 6, 2012, 4:17am UTC](https://boards.straightdope.com/t/is-the-earth-getting-heavier-or-lighter/630951/19 "2012-09-06T04:17:32Z")
Thanks for the explanations guys 🙂 ---
**Author:** ![eschereal](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/eschereal/32/18939_2.png) [@eschereal](https://boards.straightdope.com/u/eschereal)\ **Post date:** [September 6, 2012, 5:20am UTC](https://boards.straightdope.com/t/is-the-earth-getting-heavier-or-lighter/630951/20 "2012-09-06T05:20:19Z")
> [@MarvinKitFox](#): > > Slight correction, as in “You are totally off your gourd, next time check your facts” Your figures pertaining to heat are absurd. The earth’s total energy budget is around 174PW from the sun alone, which pretty much dwarfs all the other heat sources combined. I am not clear on whether the energy budget is actually in balance, but the numbers you put forth for heat (mass) loss have not been adjusted for incoming solar radiation, which is a lot – even the solar variation is greater than all the other heat. The earth does not seem to be getting significantly colder, it appears to be very close to a balanced energy budget, so the mass loss you ascribe to heat radiation strikes me as highly unlikely. Then there is all the junk we have shot into space: how much of it leaves the earth? Booster stages fall back and burn up, returning to earth. Many other parts float around for a while, maybe even staying in orbit for a very long time. And tens of thousands of satellites remain in earth orbit for years or longer. Really, just because a thing is not on the ground does not mean it is no longer part of the planet, anything that is in the gravity well is not net “lost mass”. So before you go cussing out Cecil, consider that the situation might not be as simple as you think. [Next page](https://boards.straightdope.com/t/is-the-earth-getting-heavier-or-lighter/630951.md?page=2)