# The Naked Scientists Forum

### Author Topic: Is the Earth gaining or losing mass ?  (Read 27555 times)

#### ROBERT

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##### Is the Earth gaining or losing mass ?
« on: 19/12/2005 14:01:15 »
Is planet Earth, including its atmosphere, currently gaining or losing mass ?.

Mass is gained from space by meteors, (mostly tiny ones), falling to Earth or burning up in the atmosphere.

Mass is lost into space by gases at the outermost limits of the atmosphere escaping Earth's gravitational pull, (only a small minority of gas molecules will exceed Earth's escape velocity).

So currently is there a net gain or a net loss in Earth's mass INCLUDING its atmosphere ?.

If Earth was losing mass then this would explain why the moon is slowly moving away from Earth.
Earth's gravitational pull on the moon would be reduced and the Earth-moon distance would increase,
if Earth was losing mass.

#### DoctorBeaver

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##### Re: Is the Earth gaining or losing mass ?
« Reply #1 on: 19/12/2005 14:12:49 »
http://www.mcasco.com/qa_lomfe.html

Although this doesn't address the question of loss of gases, I think you'll see from the figures that any such loss would be almost negligible. Then apply the inverse square law of gravity and the figure you'd get for the difference in gravitational attraction reaching the moon would be almost zero

#### ROBERT

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##### Re: Is the Earth gaining or losing mass ?
« Reply #2 on: 19/12/2005 14:37:20 »
however, as you said, it does not address the lost gas question.
The moon is moving away VERY slowly (3.8cm/year) so the loss in Earth's mass to cause this would be VERY small and could possibly be accounted for by the loss in atmospheric gas.

« Last Edit: 19/12/2005 15:13:14 by ROBERT »

#### DoctorBeaver

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##### Re: Is the Earth gaining or losing mass ?
« Reply #3 on: 19/12/2005 15:13:31 »
I can't find anything about the earth losing gases

#### ROBERT

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##### Re: Is the Earth gaining or losing mass ?
« Reply #4 on: 19/12/2005 15:28:30 »

"" Earth has lost 18% of its oxygen in the last 3 billion years.

http://thayer.dartmouth.edu/spacescience/wl/misc/Outflow/Seki%2001.pdf ""
« Last Edit: 19/12/2005 16:32:31 by ROBERT »

#### DoctorBeaver

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##### Re: Is the Earth gaining or losing mass ?
« Reply #5 on: 19/12/2005 15:33:35 »
I was obviously using the wrong search criteria.

Interesting links. I'll work through them more thoroughly later
« Last Edit: 20/12/2005 00:33:39 by DoctorBeaver »

#### ROBERT

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##### Re: Is the Earth gaining or losing mass ?
« Reply #6 on: 21/12/2005 15:46:07 »
If the "18% loss of oxygen over 3 billion years" is correct,
then this approximates to a loss of one billionth of one percent of all atmospheric gases per year.

This is approximately 50 million kilogrammes per year,
i.e. 50,000 tonnes of gas lost into space per year.

(here billion = thousand million, NOT million million).

This article estimates the mass gained from meteors is 105,000Kg per year:-

However this article says 100,000,000Kg per DAY (sic) of meteors fall on Earth:-

« Last Edit: 21/12/2005 16:47:50 by ROBERT »

#### Andrew K Fletcher

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##### Re: Is the Earth gaining or losing mass ?
« Reply #7 on: 28/12/2005 09:59:51 »
The Earth is not losing gas, it is being converted into water. The Earth is growing, which common sense tells us when we see the continents drifting apart.

"The explanation requiring the fewest assumptions is most likely to be correct."
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#### another_someone

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##### Re: Is the Earth gaining or losing mass ?
« Reply #8 on: 28/12/2005 10:40:22 »
quote:
Originally posted by Andrew K Fletcher

The Earth is not losing gas, it is being converted into water. The Earth is growing, which common sense tells us when we see the continents drifting apart.

"The explanation requiring the fewest assumptions is most likely to be correct."
K.I.S. "Keep it simple!"

I believe the notion of a growing Earth to accommodate continental drift was a common theory some decades ago, but has now been superseded by the understanding that subduction faults can recycle the Earth's crust, and thus there is no need to consider the Earth to be anything but of a fixed size.

Nor is any gas being converted to water – excepting that water vapour itself might condense.  Water itself may well be being consumed by photosynthesis (in conjunction with the consumption of CO2) to create oxygen and carbohydrates, but ofcourse animals (such as humans) are busily trying to reverse that process by converting carbohydrates and oxygen back into water and CO2.

#### Andrew K Fletcher

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##### Re: Is the Earth gaining or losing mass ?
« Reply #9 on: 28/12/2005 11:53:02 »
I beg to disagree on this one. maybe the thought of the Earth growing in mass is too much for the people responsible for ignoring common sense to admit. To believe that stability is achieved in a planets mass is nonsense. All planets are ever evolving and will one day reach their ultimate goal and become too big for their own boots. this will indeed produce the predicted armageddon when the mass reaches its critical point and becomes either a sun or part of another larger mass.

"The explanation requiring the fewest assumptions is most likely to be correct."
K.I.S. "Keep it simple!"

#### DoctorBeaver

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##### Re: Is the Earth gaining or losing mass ?
« Reply #10 on: 28/12/2005 12:45:03 »
If the continents are moving apart, how come Africa is pushing northwards into Europe? Ditto India into Asia?
If the Earth is gaining mass, why is the moon moving away? The opposite should be true.
The minimum mass for a body to start nuclear fusion is 75 times that of Jupiter. Jupiter's mass is 318 times that of the Earth. That means the Earth would need to be 75*318=23850 times its current mass before it had the chance to become a star. Considering the Earth is estimated to be 4.5 billion years old, I doubt that much mass could be gained before our sun turns into a red giant in about 4 billion years from now. Yes, you are right in saying that the Earth will become part of a larger mass - the sun. But the reason for that lies in the evolution of stars and has nothing to do with the Earth gaining mass.

#### Andrew K Fletcher

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##### Re: Is the Earth gaining or losing mass ?
« Reply #11 on: 28/12/2005 13:01:20 »
magnets can attract and repel, depending on the way the polarity lines up. Could the Earths growth and its inevitable increase in gravitational pull as it grows, coupled together with the moons growth have something to do with the alleged increase in distance between them?

"The explanation requiring the fewest assumptions is most likely to be correct."
K.I.S. "Keep it simple!"

#### another_someone

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##### Re: Is the Earth gaining or losing mass ?
« Reply #12 on: 28/12/2005 13:12:33 »
Andrew,

One thing one has to be careful of here, even if one wishes to entertain the possibility of growth in size or mass of objects, is that a growth (or reduction) in size is not necessarily accompanied by a similar growth (or reduction) in mass, nor visa versa.

Are you sure you wish to speculate upon both, or are you really looking merely to speculate on a growth in size (which would be easier to explain than a growth in mass)?
« Last Edit: 28/12/2005 13:13:14 by another_someone »

#### daveshorts

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##### Re: Is the Earth gaining or losing mass ?
« Reply #13 on: 29/12/2005 12:28:09 »
The increase in distance to the moon is all to with the tides. Because the moon creates tides on the earth which have a net effect of slowing it's rotation, due to one of newton's laws this means that the moon must be dragged in the opposite direction - in the direction of it's orbit, hence increasing the height of it's orbit.

#### daveshorts

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##### Re: Is the Earth gaining or losing mass ?
« Reply #14 on: 29/12/2005 12:32:34 »
Andrew, if you use GPS to measure the movements of the plates you find that the amount of subduction is the same as the amount of plate that is created so the earth is staying the same size.

If the earth was increasing in mass that mass would have to come from somewhere outside of the earth. since plates move at the order of a few cm a year that would mean there would have to be a few cm of cosmic dust and meterites faling every year. if this was the case meteorites would be a hell of a lot easier to find.

#### DoctorBeaver

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##### Re: Is the Earth gaining or losing mass ?
« Reply #15 on: 29/12/2005 13:18:40 »
http://sunearth.gsfc.nasa.gov/eclipse/SEhelp/ApolloLaser.html

From the above site:-

quote:
Measurements show that the Moon is receding from Earth at a rate of about 3.8 centimeters per year

#### rikuk

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##### Re: Is the Earth gaining or losing mass ?
« Reply #16 on: 01/01/2006 14:23:35 »
A quick one, from someone who doesn't know much........

If the earth isn't growing, why are most fossils (including fossil fuels) buried? any time you look at a deep hole/land mass movement, its in layers, sugesting that it has been built up. if the earth was staying the same size, wouldn't every thing just be on the surface?

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#### ukmicky

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##### Re: Is the Earth gaining or losing mass ?
« Reply #17 on: 01/01/2006 16:23:10 »
quote:
A quick one, from someone who doesn't know much........

If the earth isn't growing, why are most fossils (including fossil fuels) buried? any time you look at a deep hole/land mass movement, its in layers, suggesting that it has been built up. if the earth was staying the same size, wouldn't every thing just be on the surface?

Like you I'm no expertbut thinking about your reply i feel Apart from volcanic eruptions there are two other processes going on.

The first one is the natural cycle of the earth where something is converted from one form into another.
In other words something dies and rots and becomes food/ energy for something else which then  dies and becomes food and energy for the growth of something else . This doesnt increase the mass of the earth.

The second one is the energy from sun.(The Equivalence of Mass and Energy }
Just by shinning on the earth the sun passes on some of its energy and therefore increases the rest mass of the earth.
Its like how a charged battery weighs more than an uncharged one,or a hot metal bar   will weigh more than when it was cold.
However going by Einsteins e=mc2 and the part of the equation c2 its not going to be much.
(I definitely stepped into areas their that i should leave to the experts)

Plants also us the suns energy (electromagnetic radiation) which is converted through Photosynthesis into mass. It may only be a tiny amount but mass is being added to the earth so yes i would say your right.

DISCLAIMER I may be wrong,but i'm sure someone will say if i am or explain it better

Michael
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« Last Edit: 01/01/2006 18:04:54 by ukmicky »

#### another_someone

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##### Re: Is the Earth gaining or losing mass ?
« Reply #18 on: 01/01/2006 21:19:23 »
Like UKMicky, I think (as a non-expert) that part of it is detritus – food is absorbed from beneath the surface through the roots of plants, which are then eaten and recycled through faeces, or simply rot on the surface.  Beyond that, there are animals that simply turn over the surface, anything from earth worms, to moles.  Finally, one has sediment movement, where soil high up on a mountain side comes down into the valleys and covers whatever was in the valley.

Ofcourse, sometimes that which was deep down in the Earth sometimes comes to the surface, so it isn't all just going down.

#### Bass

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##### Re: Is the Earth gaining or losing mass ?
« Reply #19 on: 02/01/2006 01:15:31 »
quote:
Originally posted by rikuk

If the earth isn't growing, why are most fossils (including fossil fuels) buried? any time you look at a deep hole/land mass movement, its in layers, sugesting that it has been built up. if the earth was staying the same size, wouldn't every thing just be on the surface?

It's not the size that matters, what's important is how you move it!

The surface of the Earth is dynamic due to the motion of the plates.  Because of plate tectonics, we have a rock cycle- ocean basins form, collect sediments (including fossils and fossil fuels), get uplifted, squeezed into mountains, erode, dump sediments into new ocean basins...

A static surface, whether growing or not, would result in "Waterworld"- no land masses, no sediments (other than organic material) and we'd all have to grow gills in order to survive.

Subduction causes orogeny.

#### another_someone

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##### Re: Is the Earth gaining or losing mass ?
« Reply #20 on: 02/01/2006 01:41:31 »
quote:
Originally posted by Bass

The surface of the Earth is dynamic due to the motion of the plates.  Because of plate tectonics, we have a rock cycle- ocean basins form, collect sediments (including fossils and fossil fuels), get uplifted, squeezed into mountains, erode, dump sediments into new ocean basins...

A static surface, whether growing or not, would result in "Waterworld"- no land masses, no sediments (other than organic material) and we'd all have to grow gills in order to survive.

Not sure this is totally true.

Certainly, mountain ranges are caused by plate tectonics, but volcanic mountains would be there even if there were no plate tectonics, as would depressions caused by meteor strikes, featured carved by weathering, etc.

Mars, which (as far as I am aware) no longer has any active plate tectonics, nonetheless has uplands and lowlands.

#### daveshorts

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##### Re: Is the Earth gaining or losing mass ?
« Reply #21 on: 02/01/2006 11:48:26 »
Most volcanism on the earth is related to plate tectonics, if you have a look at it's distribution it is all along the edges of the plates, there is some that is not, Hawaii for example, but that is definitely in the minority.

Mars does have highlands, but it also doesn't have water, so errosion is far less active, hence mountains are fossilized for far longer.

If the world was just getting bigger with no plate tectonics the rocks may be in layers, but you would never see them as you wouldn't get uplift so the layers would allways be under your feet.

#### another_someone

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##### Re: Is the Earth gaining or losing mass ?
« Reply #22 on: 02/01/2006 16:27:54 »
quote:
Originally posted by daveshorts

Most volcanism on the earth is related to plate tectonics, if you have a look at it's distribution it is all along the edges of the plates, there is some that is not, Hawaii for example, but that is definitely in the minority.

Mars does have highlands, but it also doesn't have water, so errosion is far less active, hence mountains are fossilized for far longer.

If the world was just getting bigger with no plate tectonics the rocks may be in layers, but you would never see them as you wouldn't get uplift so the layers would allways be under your feet.

I am not questioning that many of the land features we see would be absent, only that this would not make the world featureless.

Yes, the east coast of Britain is falling into the sea, but as it does so, the north-west of the country continues to rise out of the sea – and this, despite their being no plate boundaries near Britain.  There have been arguments that part of this is a rebound from the weight of ice that sat atop of Britain in the last ice age, another theory is that it is due to hot magma beneath the crust.  Whatever the reason, it is happening.

Mars does still have considerable erosion because of the high winds and sandstorms.  There is still much we do not know about the processes that shape the Martian environment, so I will not make claims about those processes that I certainly would not know of there, only to say that wind blown sand can be a highly corrosive force.

Ofcourse, the other question is that in the absence of volcanism (or the substantial proportion of it), how much water would be on the surface of this planet either, or would we have an environment much more similar to Mars?

There is the other issue as to whether the speculation is about a world without any plate tectonics, or merely a world without subduction faults.

#### Bass

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##### Re: Is the Earth gaining or losing mass ?
« Reply #23 on: 02/01/2006 20:03:57 »
quote:
Originally posted by another_someone
I am not questioning that many of the land features we see would be absent, only that this would not make the world featureless.

Let's see- open my mouth, insert foot, wiggle toes....

Absolutely correct, Another Someone- the planet would not be featureless.  I made the huge assumption that, without plate tectonics, water would still be present and would quickly erode any wayward topographic features above sea level.  But as to the original question of finding layers- they would either be non-existent or extremely thin (no detrital material) if the earth's surface were static.  The exception would be organic sedimentary rocks.

Subduction causes orogeny.

#### ROBERT

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##### Re: Is the Earth gaining or losing mass ?
« Reply #24 on: 07/01/2006 11:51:41 »
IF the recession of the moon was entirely due to earth (including atmosphere) losing mass, i.e. ignoring tidal drag, (humour me Daveshorts), then it is possible to calculate the annual mass loss (m) if you have software which can cope with an astronomical number of significant figures.

Where:-
D = mean moon-earth distance = 384,400,000 metres,
d = mean annual increase in moon-earth distance = 0.038 metres,
r = ratio,
E = mass of earth (crust+interior) = 5.98x10^24 Kg,
A = mass of earth's atmosphere (gas) = 5.11x10^18 Kg,
m = net annual loss of mass = (gas lost to space - meteors gained).

If your calculator gives r=1 , then it doesn't store enough significant figures to perform this calculation,
(no mine doesn't either).

If my assumptions are correct, (probably not [B)]), then "m" cannot exceed the mass of atmospheric gas lost to space which I estimated (above) at approximately 50 million kg (per year).

« Last Edit: 26/01/2006 11:22:24 by ROBERT »

#### The Naked Scientists Forum

##### Re: Is the Earth gaining or losing mass ?
« Reply #24 on: 07/01/2006 11:51:41 »