Does the Earth have the same mass today as it did billions of years ago?

1. 59

   davidwpaposted 14 years ago

   Does the Earth have the same mass today as it did billions of years ago?
   
   If mass is constant but changes form, does the Earth with 6 billion people on it now have the...same mass as it did a billion years ago when there was very few or no humans here?  In other words does the population explosion create more mass or just reallocate mass already on the planet (including its atmosphere)?

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2. 62

   mintinfoposted 14 years ago

   matter cannot be created or destroyed, it only changes form. matter only appears to be heavier in solid form like asking, which is heavier, A pound of feathers or a pound of steel? Therefore the earth is the same mass now as it was a billion yrs ago.

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3. 60

   dabeanerposted 14 years ago

   Assuming mass has not accreted from elsewhere, why would you think that there would be a mass change just because at different times it is in different forms (mineral --> plant --> animal --> mineral)?
   
   Now, here is something to chew on:  Perhaps the earth (and other planets and stars) IS increasing in mass.  That it has increased substantially over millions of years.  This has been posited because of zero point energy conversion to matter at the cores (centers) of celestial bodies.
   
   Consider that the largest land animals today are elephants.  They cannot run or jump.  (But they can shuffle faster than humans can run.)  How, millions of years ago, was it possible for dinosaurs to be much larger than elephants and other land animals today?  Today, it is not be possible for animals of that size to exist because their bones and musculature would not be able to support them against the larger gravity (due to larger earth mass) of today.
   
   Woo-hoo!

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4. 0

   Will Bensonposted 14 years ago

   Every year about 200,000 tons of extraterrestrial material hits Earth. (Meteors, etc.). Nothing leaves except the occasional rocket.
   It sounds like a lot but it's really infinitesimal compared with the mass of earth. So we're gaining mass, but ever so slowly.

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5. 83

   Doc Snowposted 14 years ago

   Will Benson is right about the slow accretion of mass due to micrometeors coming to Earth.  I think, though, that there's a competing effect--the slow loss of atmospheric gases to space.
   
   I'm not sure which is larger, but I think the accretion may be--in which case Will's answer would stand, although the rate mass increase would be even slower.
   
   As to the population explosion (of humans!) that adds no mass whatever; it's just reallocation.

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