Does the Earth's size change over time?

[~HAVOC~]

I am not sure if this would be where i would post this but here goes a question i been wondering about


earth 3.6 or 3.7 billion years ago life emerges on our planet.. so we go from a rock that is not getting any bigger on its own with life that grow and grows when it dies there is leftovers in the billions of years that we have steadily changed and evolved we had to of impacted the Earth's size

i guess i am wondering if the Earth's little by little size changes could be a factor in natural events such as ice ages the Earth's does this to shift around weight and naturally adjusting itself to the slowly gathering weight


or effecting out position in space ... perhaps the moon helps in this aspect also

 

[Borek]

Live things grow at the expense of their surroundings - so the amount of matter doesn't change, it just gets transported from one place to another.

 

[Baluncore]

The mass grows very slowly as dust falls on Earth from space. Some upper atmosphere evaporates into space.

The physical size of the Earth is really a factor of density. Changes in density result in small changes in the Earth's radius. Those density changes could result from changes in the crystal structure of minerals, or by thermal expansion of the solid or liquid components. Radioactive decay of elements deep in the Earth generate more nuclei and so increases volume without significantly changing the mass.

Plants convert CO₂ gas in the atmosphere into more dense organic plant material. But the CO₂ comes from animals, fossil organic material or from volcanoes. So when you analyse it, there is no significant change over time due to the closed cycles.

 

[KL7AJ]

Live things grow at the expense of their surroundings - so the amount of matter doesn't change, it just gets transported from one place to another.

Though we do accumulate about 60 tons of micrometeor dust every day. :) But it probably just makes us denser, not fluffier. :)

Eric the Informative.

 

[Borek]

I have specifically ignored this information, as the OP is apparently confused enough about basics.

 

[~HAVOC~]

those where for sure not the answers i had thought to receive i do not fully understand how
Live things grow at the expense of their surroundings - so the amount of matter doesn't change, it just gets transported from one place to another. but whatever thanks for putting an end to a question that has had me wondering :)

 

[davenn]

i do not fully understand how live things grow at the expense of their surroundings -

OK ... think about ... when you eat food and grow, say some meat and veges.
where did it come from ? ... an animal and plants.
how did they grow ? ... by taking nutrition in the form of minerals etc from the ground

so the ground ( the earth) looses material as plants and organisms grow

Dave

 

[pixelpuffin]

technically dave most of the mass of a plant is from the atmosphere (that being some of the water (rain) and the almost all of the carbon (co2)

 

[Borek]

technically dave most of the mass of a plant is from the atmosphere (that being some of the water (rain) and the almost all of the carbon (co2)

It doesn't change the general picture - air classifies as "surroundings".

 

[CWatters]

Good article...

http://m.slashdot.org/story/164101

 

[Ryan_m_b]

how did they grow ? ... by taking nutrition in the form of minerals etc from the ground

Don't neglect the atmosphere. Removing carbon from the air is how plants get the majority of their mass (aside from water).

 

[dextercioby]

Earth's gravity picks up matter from outer space. Think of meteors and asteroids as something visible. Getting significantly larger is however a matter of millions of years.

 

[CWatters]

From that link I posted above..

Taking all the factors into account, Smith reckons the Earth is getting about 50,000 tonnes lighter a year..

Which raises the question.. Does the Earth get bigger if it gets lighter?

 

[D H]

Good article...

http://m.slashdot.org/story/164101

I beg to differ. That is a dubious article.

It states as fact the mass lost to atmospheric escape and mass gained by dust impinging on the Earth when in fact estimates of those vary widely, and worst of all, it states as fact that there is a nuclear reactor at the very center of the Earth when in fact that is highly disputed.

The correct answer is that the Earth's mass may be increasing by a tiny, tiny, tiny, tiny, tiny amount or it may be decreasing by a tiny, tiny, tiny, tiny amount. The key point: It is at most a tiny, tiny, tiny, tiny amount. Taken as a fraction of the total mass of the Earth, it is best to call it essentially zero.

 

[Sammah]

The metal ores found in Earth can only occur when certain chemicals fuse at massive temperatures. This suggests the Earth was subjected to incredible temperatures.

When a sun begins it life it starts with gases gathering in one location, at this time it is not burning. After sufficient time gravity causes the gases to compress this is cumulative and the more gases accumulated the heavier the suns gravity. At a point no more compression can occur and the sun explodes from compression and eventually becomes stable as we know it.

While the sun was very hot at the start of its lifespan it heated the whole solar system very hot. This unstable period could have lasted for millions of years.

Hot things are bigger than cold things. Technically the Earth must have become bigger and smaller over billions of years and still is under endothermic changes it will continue most probably without us getting smaller as the sun dies, all be it over the course of many billions of years or so.

The Earth may have been getting smaller recently, but equally it may well have been getting heavier due to many of the theories discussed previously. Of course this is theory and may not be enough of a size change based on other factors, however it is there.

 

[Baluncore]

Welcome to PF.

The metal ores found in Earth can only occur when certain chemicals fuse at massive temperatures. This suggests the Earth was subjected to incredible temperatures.

It still is. The Earth's crust is very thin, 30km below your feet the Earth is hot enough to flow like lava.

Hot things are bigger than cold things.

That is a gross generalisation and not always true. I am hotter than a glacier.
The density of ice is less than liquid water which is why it floats.

Technically the Earth must have become bigger and smaller over billions of years ...

Thermal expansion and contraction are only part of the story. Phase changes of minerals and in magma can lead to significant local changes in density. Loss of gasses to space reduces the Earth's mass, while the arrival of dust and meteorites increases the Earth's mass. Radioactive decay deep in the Earth also causes an increase in volume, so a reduction of density.

There are a few scientists who think for varying reasons that the Earth has doubled it's diameter and continues to expand today, but most scientists think it has remained about the same size over hundreds of millions of years.

The time scales are very long and the changes very small, so the error margins are quite large and the net result is indeterminate.