# 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:** 5\ **Page:** 2
**Author:** ![Irishman](https://avatars.discourse-cdn.com/v4/letter/i/b487fb/32.png) [@Irishman](https://boards.straightdope.com/u/Irishman)\ **Post date:** [September 6, 2012, 7:34pm UTC](https://boards.straightdope.com/t/is-the-earth-getting-heavier-or-lighter/630951/21 "2012-09-06T19:34:47Z")
> [@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 =) Sure, adults weigh more than (and are larger than) eggs and sperm. Where does that growth come from? Answer - food. Where does the food come from? Animals and plants. Where to animals get it? Plants. So it boils down to plants. Where do plants get the matter that eventually gets turned into people? They get carbon from the air, water from the environment, some nitrogen and such from the soil. So, whether it is people, or cows, or trees, or grass, or corn, all living matter grows by taking mass that is already on the planet Earth and recombining it into a new arrangement. More people, fatter people, etc are all still just rearranging the mass that the Earth already has. The only way that changes is when the aliens show up and start migrating here. ---
**Author:** ![ukdave](https://avatars.discourse-cdn.com/v4/letter/u/f19dbf/32.png) [@ukdave](https://boards.straightdope.com/u/ukdave)\ **Post date:** [September 14, 2012, 7:49am UTC](https://boards.straightdope.com/t/is-the-earth-getting-heavier-or-lighter/630951/22 "2012-09-14T07:49:23Z")
> [@Irishman](#): > > Answer to which question? Short term memory loss! The question was "Is the earth getting heavier or lighter? " (See OP) ---
**Author:** ![ukdave](https://avatars.discourse-cdn.com/v4/letter/u/f19dbf/32.png) [@ukdave](https://boards.straightdope.com/u/ukdave)\ **Post date:** [September 14, 2012, 7:59am UTC](https://boards.straightdope.com/t/is-the-earth-getting-heavier-or-lighter/630951/23 "2012-09-14T07:59:00Z")
I know it’s difficult, but try to see it this way. There is no such thing as weight; there is only gravity. If things had weight, everything would fall to the bottom of space! ---
**Author:** ![ZenBeam](https://avatars.discourse-cdn.com/v4/letter/z/3ab097/32.png) [@ZenBeam](https://boards.straightdope.com/u/ZenBeam)\ **Post date:** [September 14, 2012, 4:11pm UTC](https://boards.straightdope.com/t/is-the-earth-getting-heavier-or-lighter/630951/24 "2012-09-14T16:11:32Z")
A smart-ass answer to a question asked colloquially. Color me unimpressed. You old enough to drive yet? You could try answering the interesting question: Is the Earth getting more or less massive? ---
**Author:** ![Quercus](https://avatars.discourse-cdn.com/v4/letter/q/7ab992/32.png) [@Quercus](https://boards.straightdope.com/u/Quercus)\ **Post date:** [September 14, 2012, 5:56pm UTC](https://boards.straightdope.com/t/is-the-earth-getting-heavier-or-lighter/630951/25 "2012-09-14T17:56:09Z")
> [@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) Anyway, for the sake of the question, assuming there is a net mass gain, then, yes this would slow the rotation. But of course by an immeasurably tiny amount, as the gain is immeasurably tiny compared to the amount of mass already rotatiing. And this assumes that angular momentum around the Earth’s axis of the incoming mass sums out to zero. There may well be something about the Solar System that means this isn’t true, so you’d have to account for this as well. Though again, ‘immeasurably tiny’ is the applicable description. [Previous page](https://boards.straightdope.com/t/is-the-earth-getting-heavier-or-lighter/630951.md?page=1)