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How can increasing the radius of earth may cause an impact on the solar system ? Like, would earth may start making a bigger orbit (due to increase in size and wait) or vice versa ? or else ?

PS: The base of my question arises from the point of view of "Growing Population", and managing it by "artificially increasing the size of earth" (Instead of say, finding possibilities to live on other planets like Mars). So, if the radius increases, naturally the circumference of the sphere, and hence surface to live on will increase.

I understand however that probably exploring newer planets might be more feasible solution. But just for curiosity I shared my query. :)

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It's somewhat unclear. Or maybe, I didn't understand it right..! Did you mean that increasing the radius also increase the volume. I doubt that size matters and I think mass is that matters :-) – Ϛѓăʑɏ βµԂԃϔ Nov 17 '12 at 11:23
ya.. increasing radius would be just like adding hundreds of more layer of earth on the present surface. – Vishwas Gagrani Nov 17 '12 at 11:50

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Radius has little to do with an object's orbital properties. Instead, consider its mass.

The mass of a satellite (in this case the Earth) does not affect any properties of its orbit. This makes sense, since the force of gravity is proportional to mass, and acceleration is proportional to force divided by mass. Therefore, the Earth's orbit would not change.

The moon's orbit, however, might. If one were to double the central mass of a body being orbited, the velocity of the orbit would increase by a factor of sqrt(2), causing the period of the moon's orbit to reduce to around 20 days. Also, the moon's orbital radius would decrease, thereby increasing tides slightly.

All and all, there would be few notable changes.

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added some more information as a base of my question. Does it make sense ? If i really go on increasing the size of earth ( and hence the mass) this way.. 2 times.. 5 times 10 times.. would it really have no impact on the people living on earth ? – Vishwas Gagrani Nov 18 '12 at 7:02
There would come a point where the moon's orbit would intersect the edge of the Earth. This, obviously, would lead to the moon colliding with the Earth and causing quite a mass extinction. Furthermore, as Anna said in the other answer, there may be some climate changes as well. However, meteorology is beyond the scope of my knowledge. – Draksis Nov 18 '12 at 21:59

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