This question has been constantly changed, including the title.

For whatever reasons, say for the very material(s) the earth was made of, large parts of it were being harvested for another use.

What would be the eventual effect on the orbit and forces? How long would this have to occur to show significant signs of its effects in the weather and what are these possible signs? How great this effect would have on Earths tilt?

Would this move Earth towards the moon, or pull it closer? Or drift into the Sun?

EDIT: To explain, the pieces of Earth are not being propelled away but reused. If they are being teleported and/or transported in some way does an effect even exist? Thank you for all responses.

EDIT 2: I am sorry if it appears that I am now asking several questions. But as responses started to come in I realize I don't have the vocabulary to even ask my question in a simple and complete way. I also learned the answer is very broad and that I am actually asking "what would happen if . . . etc" so I am looking for a description of these effects by this cause as an answer. Thank you. 8/23/17


closed as too broad by James, Thucydides, sphennings, L.Dutch, Azuaron Aug 24 '17 at 13:15

Please edit the question to limit it to a specific problem with enough detail to identify an adequate answer. Avoid asking multiple distinct questions at once. See the How to Ask page for help clarifying this question. If this question can be reworded to fit the rules in the help center, please edit the question.

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    $\begingroup$ If you remove a piece of the Earth, commonly called a stone, and let it free, you will notice that it will naturally seek to reunite very quickly with the rest of the Earth; as unlearned people say, it will fall back down. Recently, an Englisman named Isaac Newton pretended to explain this natural tendency as a consequence of a so-called natural law of universal gravitation. $\endgroup$ – AlexP Aug 23 '17 at 2:17
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    $\begingroup$ Reused how? If they're being reused on Earth, there will be no effect, because the earth's mass isn't changing. If they're being used off Earth, unless you've got a special teleportation device that ignores Newtonian mechanics, they're being propelled away in one direction or another. $\endgroup$ – jdunlop Aug 23 '17 at 3:31
  • $\begingroup$ Would the nature of the use matter? So whether or not they are being transported (not propelled), would this mean nothing would happen? Excluding drastic weather and such. $\endgroup$ – samoholic Aug 23 '17 at 3:38
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    $\begingroup$ If mass is being removed from Earth via teleportation or some other magic transportation then the orbit could be affected, but you'd have to remove an insane amount of material. If you are just mining stuff out of one side of Earth and stacking it up on another side of Earth orbits aren't going to change since the Earth's overall mass isn't changing. $\endgroup$ – Erik Aug 23 '17 at 3:41
  • $\begingroup$ As I've added teleportation/transporting of the material to the question. What would that change? $\endgroup$ – samoholic Aug 23 '17 at 4:14

This depends somewhat on how the chunks of Earth are being taken away and where they are going. If they just get dropped back down onto Earth at a different location, then there will be no overall effect and the Earth and the Moon will continue their orbits unaffected.

If the chunks of Earth are thrown out into space and do not return to Earth, each one will take with it a bit of Earth's momentum, and due to the conservation of momentum, this will give the rest of Earth a small push in the opposite direction. If many chunks are propelled away from Earth in the same direction, these pushes will eventually add up to something noticeable. If each chunk is propelled in the same direction that Earth orbits the Sun, then each push will rob Earth of a little orbital speed, causing it to spiral in toward the Sun as long as pieces keep being removed. Conversely, if the pieces are propelled the other way (if they're being sent to Venus or Mercury, perhaps), Earth will be nudged into a larger orbit, farther from the Sun.

If the chunks are always sent away in the same direction relative to the Moon, rather than the Sun, the recoil pushes will have an effect on the Moon's orbit. Keep in mind that the Earth and the Moon technically orbit around their shared center of mass (which is somewhere inside the Earth, but not at the center of the Earth). If the recoil pushes the Earth in the same direction that it orbits that center of mass, it'll add kinetic energy to the Earth-Moon system and effectively put the Moon into a slightly larger orbit.

If the fragments of Earth are ejected in all different directions, so there is no net effect from the recoil, the Earth-Moon system's orbit around the Sun will not be affected at all. The only effect will be on the Earth-Moon system as the center of mass shifts toward the Moon. The distance between the Moon and what's left of the Earth will not change; however, as mass is removed from the system, the orbital period- that is, the time required for one to orbit the other- will increase. When Earth is reduced to an insignificant asteroid orbiting the Moon, it will make one orbit every 0.661 years. This means that the lunar "month" will actually last almost two full years, since the Earth and Moon orbit in the same direction that they orbit the Sun.

  • $\begingroup$ So sorry, I did say the pieces were being harvested not propelled away from it. And since this is the scenario on which I base my question (concerning the pieces of Earth) does your explanation still apply? What I mean to ask is, would this mean nothing happens to their orbits except for the time it will take for them to complete? $\endgroup$ – samoholic Aug 23 '17 at 3:33
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    $\begingroup$ @samoholic since mass isn't being removed from earth then the orbits shouldn't be affected. $\endgroup$ – Erik Aug 23 '17 at 3:36

So there have been a number of questions asked in comments, and I'll try to sum up the answer to the OP with those in mind.

What would the effect be on the orbit and forces?

I'm not sure what you mean by "forces" - if you mean the force of gravity, it would obviously be reduced in proportion to the mass removed. The effect on the orbit around the sun would be dependent on how this mass was being removed. Ordinarily, when you're moving stuff off Earth, you have to propel it in one direction or another. If you're doing that to a substantial fraction of the Earth's mass, you've got effectively a giant rocket engine, so the direction in which it is being propelled matters. If it's being ejected in the direction of Earth's orbit, then Earth will fall towards the sun. If it's being ejected orthogonal to the orbit, or parallel to the orbit, the Earth will move away from the sun. If it's effectively being shot off in random directions, there will be no change in the orbit due to propulsion. While technically this reduction of mass will change the orbit of the earth relative to the sun and moon in a small way, Kepler's third law indicates that the orbits will still remain effectively constant.

How long would this have to occur to show significant signs of its effects in the weather and what are these possible signs?

Depends on what's being removed. If you're reducing the mass of the earth by removing its atmosphere, I imagine the effects would be rather quick to start showing up. It would be an absence of weather, though, rather than any weather extremes, and weather would not be the problem. If you're just removing, say, all the iron, the effect would also be the gradual acceleration of the loss of the atmosphere to space, and reduced weather effects. This would likely take hundreds of thousands or millions of years, even if all the iron were (safely) removed at once; atmosphere loss is a gradual process, just ask Mars.

How great an effect would this have on Earth's axial inclination?

If the mass is being removed in a fashion that doesn't act as propulsion, zero. If the mass is being removed in a fashion that does act as propulsion, it depends on which angle it is being removed at, how much mass is being removed, how fast it is removed, etc.

Would this move Earth towards the moon, or pull it closer? Or drift into the Sun?

Answered above - it would not, unless the mass were being used (deliberately or inadvertently) as propulsion.

So, to sum up, you could chip away at Earth for millennia, even steal the core entirely, and it wouldn't have much effect on where the Earth lives in the solar system. It would probably have other potentially catastrophic effects, but that's outside the scope of the question.


The orbit of the earth around the sun is determined almost entirely by the mass of the sun. If the mass of the earth changed drastically, that orbit wouldn't change.

The orbit of the moon around the earth is determined mostly by the mass of the earth. If the mass of the earth decreased, then the moon would get farther away, potentially being freed from earth's orbit entirely.

That is assuming the process of removing mass from the earth doesn't exert additional forces on the pieces of earth that are left. It's hard to imagine significant chunks of the earth being removed without altering the velocity or rotation rates of the planet.

There is also the matter of hydrostatic equilibrium. The gravity of earth keeps it as a sphere. If you were to remove a chunk of the planet so large that it disrupted the overall spherical shape, then the rock would flow to fill in the hole. Such a huge earthquake would generate lots of heat and might immediately render the entire planet uninhabitable, with the possibility of rendering the whole earth molten. Also, the movement of matter inward would make it spin faster.


Both angular momentum of the moon-earth system and the angular momentum of the sun-all-planets system are conserved. Linear momentum must be conserved also. Finally, we must account for the changes in the magnitude of gravitational attraction.

Since the mass of earth is the same as before, the gravitational attraction from the earth to both the moon and the sun are the same. Nothing about reforming the earth inevitably changes the basic orbit with respect to both the sun and moon. It could still happen if humanity wasn't careful.

Different types of angular momentum are linked. If what you did stopped the earth from rotating, you would affect the other angular momentums.

In the sun-all-planets system, angular momentum would need computer modeling. The earth's rotation is a bit player though. Venus has almost stopped rotating and it is still there in a mostly circular orbit

However, the angular momentum of the earth-moon system would be affected if the earth stopped rotating. The angular momentum of the earth moon system ("L(total)") Lrot is the angular momentum of the earth's rotation. Lmo is the angular momentum of the moon's rotation. L(total)= Lrot + Lmo.

According to zipcon.net, Lmo is four times Lrot. If the moon got all of the angular momentum from a spinning earth, it would just orbit further away. http://www.zipcon.net/~swhite/docs/astronomy/Angular_Momentum.html

It is also possible such an extreme process might disrupt the earth's rotation around the sun by making the rotation more elliptical. This would make seasons more extreme. Angular momentum would be conserved because the earth would move faster when closer to the sun and slow down when further away. This is Kepler's second law of planetary motion. Earth would never "drift into" the sun.

Let's face it. More extreme seasons would be the least of the problems of the people still living there. If the earth is no longer spherical, the earth's core would cool. There would be no magnetic field protection from solar wind. We'd probably either lose the ocean and atmosphere or they would be spread too thin to be of any use.

EDIT: 08/23/2017 Your question keeps changing.

When I read the earth was being “reused,” I was picturing building a non-spherical shape using the material in the earth. Since the surface area versus volume would be greater for any other shape other than a sphere, the atmosphere and water in the oceans would end up spread out very thin just by geometry. I am guessing this was not your intent.

I also implicitly presumed that we had unknown technology that could cool the inside of the planet, letting it get ripped apart in the first place. However, the level of detail you are asking for seems to indicate you want the most realistic answer possible. The ultra realistic answer is as follows:

The earth is more like a deep fried cheese curd than a cold solid mass of rock. The Kola Superdeep Borehole in Russia got to between seven and eight miles deep before being abandoned due to temperature. See also: https://www.livescience.com/6959-hole-drilled-bottom-earth-crust-breakthrough-mantle-looms.html

Beneath the hard and thin crust, earth’s mantle is pliable molten rock and that every dense astronomical body above a certain size of large asteroid wants to be a sphere because of gravity. The force exerted on the crust at the earth’s equator creates a bulge around the equator. However, this bulge is 28 miles, which is tiny in comparison to the diameter of the earth. https://www.space.com/17638-how-big-is-earth.html

So, you would have to pull with a force much greater than the forces involved in earth’s rotation to have a shot at pulling out a significant piece of mantle. Obviously, that would take an immeasurable amount of energy. With that level of energy being inserted into the earth, it would be anyone’s guess as to what orbit or rotation would result or whether the moon would get flung out of orbit as a complication of that process. I do know that the heat lost due to that much friction would heat up the earth to a molten state.

What you could do is dredge the crust off of the earth. However, even if you took the entire crust off of the earth, it still wouldn’t be a “large” chunk of the planet’s overall mass. You’d only be able to strip the crust off earth once. The top of the mantle would take an extremely long time to cool. Earth’s crust changes really slowly. Parts of Scandinavia are still rebounding after the weight of glaciers was removed 19,000 years ago. http://www.antarcticglaciers.org/glaciers-and-climate/sea-level-rise-2/recovering-from-an-ice-age/ Likewise, earth would be a ball of molten mantle for the foreseeable future after you stripped off the crust.

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    $\begingroup$ If the earth suddenly had half its mass by miraculously shedding the pounds without them speeding away in a different direction, gravity would be halved but so would momentum. I believe all the relevant equations have earth's mass as a factor, so it would all be affected equally. Orbit around the sun would not be affected too much. The strength of gravity between the earth and the moon would be less. The moon would orbit much further away. The moon would cause the earth to wobble more because the center of mass of the Earth-Moon system would shift to be closer to the moon. $\endgroup$ – emawerna Aug 23 '17 at 4:38
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    $\begingroup$ Also I might be able to dunk the ball. $\endgroup$ – Willk Aug 23 '17 at 14:55
  • $\begingroup$ So then, I am wondering HOW MUCH of the Earth being removed in such a massive way would begin to drastically change weather or signs of an catastrophe? Especially if the process is not being halted in any way. For how long will this process would have gone on if done in comparably insignifucant amounts compared to the size of Earth and the forces?. $\endgroup$ – samoholic Aug 23 '17 at 15:15
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    $\begingroup$ You may wish to clarify your question (again) then, but the short answer is that people would notice that large chunks of the planet were missing well before anything major changed in the weather. The earth is losing 50 000 tonnes a year, and it hasn't affected us in any noticeable way. $\endgroup$ – jdunlop Aug 23 '17 at 19:37

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