Earth Mass: 5.9x10^24 kg - Last Measurement & Why?

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Discussion Overview

The discussion revolves around the mass of the Earth, specifically the value of 5.9 x 10^24 kg, and inquiries into why this mass appears unchanged despite increases in population and biodiversity. Participants also explore the implications of mass gain from space debris and the conservation of mass in relation to living organisms.

Discussion Character

  • Exploratory
  • Debate/contested
  • Conceptual clarification

Main Points Raised

  • Some participants question how the Earth's mass remains constant despite population growth and the emergence of new flora and fauna.
  • Others propose that the mass of Earth increases slightly due to space debris, although the extent of this increase is uncertain.
  • It is suggested that the mass of Earth is effectively unchanged by human population increases, as matter is not created during birth.
  • Some argue that even significant additions, such as 7 billion aliens, would not measurably alter the Earth's mass.
  • Participants note that Earth loses more mass than it gains due to atmospheric loss from solar wind.
  • There is a discussion about the determination of the gravitational constant G and its stability over time, with some questioning whether changes in Earth's population would necessitate a reevaluation of G.
  • Several participants emphasize the conservation of mass, stating that new flora and fauna are merely rearrangements of existing atoms, not additional mass.
  • One participant humorously compares the movement of mass on Earth to moving coins between pockets, illustrating that such movements do not affect total mass.
  • There is a mention of energy not being conserved on cosmological scales, introducing complexity to the discussion of mass and energy conservation.

Areas of Agreement / Disagreement

Participants generally agree on the principle of conservation of mass, but there are multiple competing views regarding the implications of population growth, the effects of space debris, and the stability of the gravitational constant G. The discussion remains unresolved on several points, particularly regarding the impact of these factors on the Earth's total mass.

Contextual Notes

Some claims depend on assumptions about the nature of mass and energy conservation, and there are unresolved questions about the extent of mass gain from space debris and the implications of changes in the gravitational constant.

VASUbhagwat
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Mass of the Earth is 5.9 x 10^24 kg . How long has it been at this value and why does it not change even when the population of the word has gone up by many folds , there have been new flora and fauna . when was this last measurement taken?
 
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Hi,

I have heard that the mass of Earth is increased a bit because of the debris coming from space (do not know exactly the extent of the increase).

The increase of population does not change the mass of the earth/biosphere, because the matter of a person is not generated during birth.
 
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Even if 7 billion aliens each with 100kg mass arrived from outer space, it wouldn't change the mass of the Earth to any significant degree.
 
VASUbhagwat said:
why does it not change even when the population of the word has gone up by many folds , there have been new flora and fauna
Where does the matter making up living organism come from?

DoItForYourself said:
I have heard that the mass of Earth is increased a bit because of the debris coming from space (do not know exactly the extent of the increase).
Nasa said:
Every day, Earth is bombarded with more than 100 tons of dust and sand-sized particles.
Source: https://www.nasa.gov/mission_pages/asteroids/overview/fastfacts.html
 
Actually the Earth looses more mass than it gains because a bit of Atmosphere is blown away by the solar wind.

Anyways, the mass of the Earth is determined in a funny way. What you actually need to know is the constant of Gravitation G. It must be determined with test masses in a laboratory and it is only known to about four significant digits. The first one who did it was Henry Cavendish in 1798. The radius of the Earth was already known in ancient times. Once you have done all that, the gravitational acceleration on the ground g is given by g=G/r² m_E, which gives you the mass of the Earth.
 
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yes g=GM/(r^2), does give the relation to determine the mass of the earth. But why does not the value of G change with times with so much of activities happening in the universe?? and when cavendish determined the value of G( i thought he was the one who determined the mass of the earth, stay my ignorance) in 1798...the entire population of the Earth was surely much less than what it is now...so does it lead us to a new determination of the value of G ?
 
As other people already pointed out, there is generally a conservation of mass and the change of the Earth's mass over time is tiny compared to the total mass. And because G is not very well known you would have to crash a very large asteroid into Earth to make a change which is actually measurable as a change in Earths total mass.
 
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http://geodesy.curtin.edu.au/research/resolution/
Edit: change G to g - thanks phyzguy
Check out the image on the first page. A really cool map of very local g values (short scale gravity field), demonstrating that g is not a constant value over Earth's surface. For example, it varies by latitude. The changes are small, BTW.

The first image shows the effect of mountain ranges in Asia, another image further down shows Ayers Rock.
 
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jim mcnamara said:
http://geodesy.curtin.edu.au/research/resolution/

Check out the image on the first page. A really cool map of very local G values (short scale gravity field), demonstrating that G is not a constant value over Earth's surface. For example, it varies by latitude. The changes are small, BTW.

The first image shows the effect of mountain ranges in Asia, another image further down shows Ayers Rock.

G, the universal constant of gravitation, does not change. It is the acceleration of gravity g = GM/r^2 that is changing locally.
 
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  • #10
You are correct. Thanks.
 
  • #11
VASUbhagwat said:
Mass of the Earth is 5.9 x 10^24 kg . How long has it been at this value and why does it not change even when the population of the word has gone up by many folds , there have been new flora and fauna . when was this last measurement taken?
The new flora and fauna are not additional mass.
They are just new arrangements of existing atoms, most of which are in organic molecules.
Those molecules are there as byproducts of previous flora and fauna which died.
No new atoms are being created, matter is being recycled
 
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  • #12
You are what you eat!
 
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  • #13
rootone said:
The new flora and fauna are not additional mass.
They are just new arrangements of existing atoms, most of which are in organic molecules.
Those molecules are there as byproducts of previous flora and fauna which died.
No new atoms are being created, matter is being recycled
Well I suppose everything is a rearrangement of existing atoms, and the mass of the Universe now is the same as at the moment of the Big Bang. [Sorry for being difficult].
 
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  • #14
How about this for an answer:

We are all a portion of the Earth's total mass. Every person, every lifeform. Every breath we take, every drop of water. Just moving this planet's material about, from this continent to that one. Will have no measurable effect. You take four quarters from your pocket and move it to another pocket. You still have one dollar.

Even the space station. in such a close, protective orbit around the Earth, still contributes it's mass to the grand total of planetary mass.

It would take a stellar level cataclysmic effort to reduce the total mass of the Earth in any measurably substantial way.
 
  • #15
Ernest S Walton said:
Well I suppose everything is a rearrangement of existing atoms, and the mass of the Universe now is the same as at the moment of the Big Bang. [Sorry for being difficult].
Sure, conservation of mass=energy is generally considered to be true.
No new stuff appears from nowhere, and nothing mysteriously disappears.
 
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  • #16
Ernest S Walton said:
Well I suppose everything is a rearrangement of existing atoms, and the mass of the Universe now is the same as at the moment of the Big Bang. [Sorry for being difficult].

rootone said:
Sure, conservation of mass=energy is generally considered to be true.
No new stuff appears from nowhere, and nothing mysteriously disappears.
Actually energy is NOT conserved on cosmological scales and it does in fact disappear as EM waves lose energy due to the expansion of the universe.
 
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  • #17
phinds said:
EM waves lose energy due to the expansion of the universe.
Well granted, but apart from that, what has the universe ever done for us?
 
  • #18
rootone said:
Well granted, but apart from that, what has the universe ever done for us?
In the grand scheme of things ... well ... chocolate.
 
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  • #19
rootone said:
The new flora and fauna are not additional mass.
They are just new arrangements of existing atoms, most of which are in organic molecules.
Those molecules are there as byproducts of previous flora and fauna which died.
No new atoms are being created, matter is being recycled
Never trust atoms. They make up everything.
 
  • #20
we are now in the Comedy Show. While the jokes are fun and probably deserved, this thread longs for an ending. So here it is: locked.
 

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