# Thread: how much mass does the earth gain on any given day?

1. ## how much mass does the earth gain on any given day?

i assume that space debris contact earth every day, how much mass is the earth accumulating every day from cosmic dust, debris and meteor impact?

does sunlight add to the mass of the planet due to photosynthesis?

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I would think that the mass gain from dust, debris and meteors would not be very significant. Most of the meteors that come towards the earth are very small and burn up quickly in the upper atmosphere, we experience these as shooting stars and we don't see them very often... and those are obviously bigger than dust particles or other small space debris.

On photosynthesis... no, that would not add mass to the planet. Photons do not have mass, plants simply use the energy from photons to combine nutrients from the soil with carbon from atmospheric carbon dioxide, therefore transforming those raw materials into something needed by the plant for growth, and releasing oxygen as a by-product into the atmosphere. There is no net gain or loss of atoms taking place here, only a conversion of energy from light to stored chemical potential energy, which is then passed down the food chain when plants are eaten by animals.

3. Not sure on the figure for cosmic dust etc. The Earth does loose mass from atmosphere bleeding off too. (net result is Earth gaining mass but it isn't much)
As far as gaining mass do to photosynthesis. Thinking about the process the photon is used to break the chemical bond of C02. It isn't actually absorbed. Perhaps a better biogeek can explain the process better.

4. Originally Posted by sabianq
i assume that space debris contact earth every day, how much mass is the earth accumulating every day from cosmic dust, debris and meteor impact?
See here:

http://www.talkorigins.org/faqs/moon-dust.html

Quoting:

Dohnanyi also quotes a value from Barker & Anders, 1968, based on isotopic abundance ratios in sea floor sediments that estimated 6.12 × 1010 g/year, with an upper limit of 1.48 × 1011 g/year, which turns out to nicely match Ceplecha's 1996 correction of his own 1992 results.
Using 6 × 1010 grams per year, I get about 164,000 kg per day (60,000,000/365) , or about 360,000 pounds per day. At the upper limit, a bit more than twice that.

does sunlight add to the mass of the planet due to photosynthesis?
Not significantly. The equivalent mass is insignificant, and most of the energy that goes into plants gets reradiated fairly quickly.
Last edited by Van Rijn; 2010-Jun-12 at 11:21 PM. Reason: spelling

5. Originally Posted by WayneFrancis
Not sure on the figure for cosmic dust etc. The Earth does loose mass from atmosphere bleeding off too. (net result is Earth gaining mass but it isn't much)
As far as gaining mass do to photosynthesis. Thinking about the process the photon is used to break the chemical bond of C02. It isn't actually absorbed. Perhaps a better biogeek can explain the process better.
hmmm. is there a figure on the atmospheric loss?
would it be close to what value from Barker & Anders, 1968, of an estimated 6.12 × 1010 g/year, with an upper limit of 1.48 × 1011 g/year as sited by Van Rijn?

otherwise, not adding the atmospheric loss value, over a period of a million years, the earth could accumulate 164,000 kg per day at 365 days that comes to what 59 million kilograms per year. in one million years, the earth takes on 59 million million kilograms or 59 trillion kilograms? is that right? do i need to add 1 million / 4 leap days to that figure? (i wont, i think the figgure is more conservative with out the leap year days)

so every one million years the earths increases by 59 x 10^12kg
mass of Earth = 5.9742 × 10^24 kilograms
that is only a difference of 101 trillion kilograms?

wait wait..
my math is wrong.. is it?
that says that the earth has grown by 50% over the past million years.
what?
no.no..
where did i screw up?

6. is the name of this phenoma called "accretion"

apparently
wiki:
The first and most common is the growth of a massive object by gravitationally attracting more matter.
so would it be safe to say that the earths accretion rate was higher in the past?
if it was, is there data from ice cores? i wonder if the acreation curve over time is linear or log.. or reverse exponential. (is that log?) sry, im not a math guy..

7. Originally Posted by sabianq
so every one million years the earths increases by 59 x 10^12kg
mass of Earth = 5.9742 × 10^24 kilograms
that is only a difference of 101 trillion kilograms?

wait wait..
my math is wrong.. is it?
that says that the earth has grown by 50% over the past million years.
what?
no.no..
where did i screw up?
You can't subtract the exponents. 5x10^24 minus 5x10^12 is about 4.999999999995x10^24.

8. Originally Posted by sabianq
that says that the earth has grown by 50% over the past million years.
No . . . read the page I linked to. The mass increase currently is trivial as a percentage of the Earth's mass (in the very early history it was different, of course).

9. Originally Posted by sabianq
otherwise, not adding the atmospheric loss value, over a period of a million years, the earth could accumulate 164,000 kg per day at 365 days that comes to what 59 million kilograms per year. in one million years, the earth takes on 59 million million kilograms or 59 trillion kilograms? is that right? do i need to add 1 million / 4 leap days to that figure? (i wont, i think the figgure is more conservative with out the leap year days)
The estimates on the page are per year. The range in the estimates is large enough that there isn't any point in worrying about being too specific (which is why I said "about" 164,000 kilograms per day, and that you could more than double it for the high end estimate). No need to worry about leap days.

10. Originally Posted by baric
You can't subtract the exponents. 5x10^24 minus 5x10^12 is about 4.999999999995x10^24.
YES, YES, YES...
YOU ARE CORRECT.

the ratio over a million years is a 1 billionth the mass of the earth for the past 1 million years...

if the earth is 4.5 billion years old then it took 4.5 billion years to get from 0kg to 5.9e24 kgs

11. Originally Posted by Van Rijn
No . . . read the page I linked to. The mass increase currently is trivial as a percentage of the Earth's mass (in the very early history it was different, of course).
my math was wrong..
it was i think corrected below to be 1 billionth the mass of the earth over the past 1 million years..
is that right?

and as you go further back in time, that ratio goes up
i just wonder what that curve would look like..

12. Originally Posted by Van Rijn
The estimates on the page are per year. The range in the estimates is large enough that there isn't any point in worrying about being too specific (which is why I said "about" 164,000 kilograms per day, and that you could more than double it for the high end estimate). No need to worry about leap days.
and if i were to double that number as above, then the ratio would be 1 /500 millionth of the total mass of the earth over the past 1 million years that the earth has gained in kilograms..

rounding the numbers here...

13. does this seem right? ^^^^^^^^^^^^^^^^^

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Originally Posted by HelenofBorg
I would think that the mass gain from dust, debris and meteors would not be very significant. Most of the meteors that come towards the earth are very small and burn up quickly in the upper atmosphere
So what if they burn up? Combustion obeys conservation of mass. It wouldn't eliminate their mass from the system of the Earth just because its burnt up.
Originally Posted by HelenofBorg
On photosynthesis... no, that would not add mass to the planet.
Yes, it would. Energy is mass * c2 and the light from the sun began as mass of the sun, and when it strikes a chlorophyll it sends an electron into a higher energy state, increasing that electron's mass-energy. The Earth is also expelling mass through infrared black-body radiation resulting from collisions of atoms at its temperature. These may be tiny factors in terms of mass, but let's not spread misinformation all the same, HelenofBorg.

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Originally Posted by CaptainToonces
So what if they burn up? Combustion obeys conservation of mass. It wouldn't eliminate their mass from the system of the Earth just because its burnt up.

Yes, it would. Energy is mass * c2 and the light from the sun began as mass of the sun, and when it strikes a chlorophyll it sends an electron into a higher energy state, increasing that electron's mass-energy. The Earth is also expelling mass through infrared black-body radiation resulting from collisions of atoms at its temperature. These may be tiny factors in terms of mass, but let's not spread misinformation all the same, HelenofBorg.
I thought that photons (light) did not have mass, and that mass cannot travel at the speed of light. I thought that energy from light gave electrons more energy thereby facilitating the chemical reaction necessary to create food for the plant, but that there was no gain or loss of mass in the process. My intent was not to spread misinformation, I am only going off what I was taught in school about photosynthesis. I'm not at all saying that I'm definitely right, just that I was saying what I was taught about light in high school. Perhaps we only got simplified information.

I guess the most obvious question now is how much mass do photons have?

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Direct measurement will likely remain inaccurate very long term. Calculations involve assumptions of possible significant error. The consensus seems to be that the input of meteor and comets is a few parts per trillion, over the past billion years or so. The solar wind = subatomic particles is a smaller addition. Loss of atmosphere is still smaller, photon gain still smaller and mostly offset by infrared photons that Earth sends into space, because Earth and our upper atmosphere are warm. Neil

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How about including radioactive decay as well thats happening all the time in the earth with the heat generated being eventually radiated into space this will lower the earths mass over time. But like all the other reasons for mass gain/loss its negligable compared to rest of the earths mass.

18. Originally Posted by HelenofBorg
I thought that photons (light) did not have mass, and that mass cannot travel at the speed of light. I thought that energy from light gave electrons more energy thereby facilitating the chemical reaction necessary to create food for the plant, but that there was no gain or loss of mass in the process. My intent was not to spread misinformation, I am only going off what I was taught in school about photosynthesis. I'm not at all saying that I'm definitely right, just that I was saying what I was taught about light in high school. Perhaps we only got simplified information.

I guess the most obvious question now is how much mass do photons have?
mass–energy equivalence.. energy is equal to mass times the speed of light squared, and mass is equal to energy divided by the speed of light squared.
while a photon is "massless" it still has energy and that energy is transfered to the plant, and that energy transfer adds mass. albiet a very very very very tiny amount..

i think that is right.. (what we were taught in high school anyway circa~1988)

19. Originally Posted by neilzero
Direct measurement will likely remain inaccurate very long term. ...
Yes. If you could hold your own mass constant enough, you could measure the Earth's mass-gain/loss with an accurate enough bathroom scale. Be sure to hold your breath and not sweat or anything. Perhaps a more sensible way to track it would be launch a corner-reflector and put it in Geo-synchronous orbit, and use lasers to keep track of the true orbital period and distance. Many factors will need to be accounted for, but I think it would be within the theoretical limits of measurability.

20. Originally Posted by sabianq
hmmm. is there a figure on the atmospheric loss?
would it be close to what value from Barker & Anders, 1968, of an estimated 6.12 × 1010 g/year, with an upper limit of 1.48 × 1011 g/year as sited by Van Rijn?

otherwise, not adding the atmospheric loss value, over a period of a million years, the earth could accumulate 164,000 kg per day at 365 days that comes to what 59 million kilograms per year. in one million years, the earth takes on 59 million million kilograms or 59 trillion kilograms? is that right? do i need to add 1 million / 4 leap days to that figure? (i wont, i think the figgure is more conservative with out the leap year days)

so every one million years the earths increases by 59 x 10^12kg
mass of Earth = 5.9742 × 10^24 kilograms
that is only a difference of 101 trillion kilograms?

wait wait..
my math is wrong.. is it?
that says that the earth has grown by 50% over the past million years.
what?
no.no..
where did i screw up?
The joy of exponents. 1x1024 - 1x1012 is like 1x1023.999999999976 not 1x12
What it does show you is the difference is 1x10-12 of 1x1024

So going off your numbers....lets change the 59x1012kg to 5.9x1013kg
that means over that time period there was a net gain of about 1x10-11 or .000000001%

21. Originally Posted by sabianq
my math was wrong..
it was i think corrected below to be 1 billionth the mass of the earth over the past 1 million years..
is that right?

and as you go further back in time, that ratio goes up
i just wonder what that curve would look like..
I'm not sure that it would go up significantly until you got to about 4.5 billion years ago. Then there is that issue of the Mars size object hitting us and all.

22. Originally Posted by HelenofBorg
I thought that photons (light) did not have mass, and that mass cannot travel at the speed of light. I thought that energy from light gave electrons more energy thereby facilitating the chemical reaction necessary to create food for the plant, but that there was no gain or loss of mass in the process. My intent was not to spread misinformation, I am only going off what I was taught in school about photosynthesis. I'm not at all saying that I'm definitely right, just that I was saying what I was taught about light in high school. Perhaps we only got simplified information.

I guess the most obvious question now is how much mass do photons have?
If I'm reading you right that is my understanding too. Sunlight doesn't add to the mass of the planet but just provided energy to break the bonds in CO2 thus allowing the plant to use the C in building itself up.

23. Originally Posted by sabianq
mass–energy equivalence.. energy is equal to mass times the speed of light squared, and mass is equal to energy divided by the speed of light squared.
while a photon is "massless" it still has energy and that energy is transfered to the plant, and that energy transfer adds mass. albiet a very very very very tiny amount..

i think that is right.. (what we were taught in high school anyway circa~1988)
but the plant isn't gaining any mass from the photons. That energy is just being used to break a chemical bond. Any "mass" gained by a photon kicking an electron into a higher orbit will be quickly lost when that electron drops back down to the ground state and releasing 1 or more photons with a combine total energy of the original photon.

24. Originally Posted by WayneFrancis
but the plant isn't gaining any mass from the photons. That energy is just being used to break a chemical bond. Any "mass" gained by a photon kicking an electron into a higher orbit will be quickly lost when that electron drops back down to the ground state and releasing 1 or more photons with a combine total energy of the original photon.
But, surely, some of that energy will have been used in driving the chemical reaction (unless it is exothermic overall) and so the photon emitted later will have less energy. Which just means that the mass contibuted by the photon is a very very very very tiny fraction of the origianl very very very very tiny amount...

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The energy emitted by the sun comes from converting rest mass in the core's fusion cycle. The sun loses mass, produces electromagnetic energy in the form of photons out of that lost mass. When the photons reach Earth and are absorbed by anything, and NOT re-emitted to space, the Earth gains a corresponding increase in mass (whether it is a plant absorbing a photon, your skin at the beach, or the leather seat inside your car absorbing it). What complicates the issue is the subtleties....Earth radiates away more heat in infrared on the dark side than it absorbs in sunlight on the bright side....which means it's still cooling. We also absorb tiny traces of neutrino energy from the sun and all other actively-fusing stars, and emit some from radioactive decays.
The photon energy is E=hv...the Planck-Einstein equation from the photoelectric effect, and E=mc2 is rearranged as E/c2 = m to solve for the mass, letting the E's equal each other.

SEE:http://hyperphysics.phy-astr.gsu.edu/hbase/hframe.html

and you might like a few other points on it...listen here:http://www.pbs.org/wgbh/nova/einstein/experts.html
Last edited by trinitree88; 2010-Jun-12 at 05:00 PM. Reason: typos. link

26. Originally Posted by WayneFrancis
but the plant isn't gaining any mass from the photons. That energy is just being used to break a chemical bond. Any "mass" gained by a photon kicking an electron into a higher orbit will be quickly lost when that electron drops back down to the ground state and releasing 1 or more photons with a combine total energy of the original photon.
Originally Posted by Strange
But, surely, some of that energy will have been used in driving the chemical reaction (unless it is exothermic overall) and so the photon emitted later will have less energy. Which just means that the mass contibuted by the photon is a very very very very tiny fraction of the origianl very very very very tiny amount...
Strange appears to me to be on the right track. I am as sure as I can be that the forming of carbohydrates and free oxygen from carbon dioxide and water is endothermic, meaning that the end combination has more energy than the raw materials. Otherwise this combination would not be combustible.

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Originally Posted by Hornblower
Strange appears to me to be on the right track. I am as sure as I can be that the forming of carbohydrates and free oxygen from carbon dioxide and water is endothermic, meaning that the end combination has more energy than the raw materials. Otherwise this combination would not be combustible.
Just thinking that if photosynthesis did not add energy to the plant then the plant would die ... but they do not die so therefore the energy is increased by photosynthesis.

As far as mass goes - it is miniscule compared to meteors.

Is there a substance that if a meteor were composed of that substance then it could poison the earth/atmosphere when it burned up? And is that substance readily present in space?

28. Photosynthesis does (insignificantly) increase the Earth's mass, but so does any other absorption of solar radiation. Warm rocks are (very slightly) heavier than cold rocks, for a given composition.

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Which planets (and moons) actually gain mass instead of losing it? Where is that boundary?