|December 19, 2005||Posted by Staff under Progress Report, The Progress Report|
The Economics of Gravity
by Fred E. Foldvary, Senior Editor
by Fred E. Foldvary, Senior Editor
Gravity is a natural public good. If you ask students for examples of free goods, they will often answer air. But air is not universally free, nor is it a universal common resource. If you rent an apartment or flat, you have exclusive possession of the air inside, and the air is not free, because you must pay rent to breath it at that location.
The same concept applies to gravity. Locations are scarce if when they are free of charge, the quantity demanded of such sites is greater than the quantity supplied. Physics does not charge us for the use of gravity, but we are impacted by gravity in specific locations, and if that location is scarce, it has an economic rent, and people who wish to be located there can be required to pay that rent. So gravity at those locations is not a free good.
Gravity does not increase the rent of land, because all areas of the earth have gravity. If some locations had gravity and others not, then those locations with gravity would have a higher differential rent, the extra rent due to gravity. Gravity has a rent in scarce locations because like the air, it is tied to the location, not because it adds to rent.
Economically, gravity is land, a natural resource. Gravity is also a collective good; the use of gravity by one person does not diminish the use by another person. So gravity is a natural public good. Gravity is an excludable good, since its impact is territorial, and people can be excluded from locations. We could also potentially exclude somebody from utilizing the earths gravity by putting him in a rocket and sending him into outer space.
The law of gravity states that the gravitational attraction between the earth, with mass m1, and an object with mass m2 on the surface of the earth, equals the gravitational constant times m1 times m2, divided by the square of the radius of the earth. The gravitational potential at a point in space is the work performed by gravity as mass is brought to that point from infinity.
According to the theory of relativity, time and space create a four-dimensional framework in which gravity is created due to the curvature of space around a massive object. The rotation of the earth also affects gravity. The distortion of space-time caused by a large mass such as a planet is called a gravity well. You can get screen savers of fictional gravity wells.
If the earth were a perfect sphere with uniform density and without rotation, and with no moon, then gravity would be the same on all locations on the sea level of the earth. But the earth is not a perfect sphere, has varying densities, rotates, and has a moon whose gravity affects the tides on the earth, so gravity is not identical in all sea-level locations. Gravity is stronger at the poles than at the equator, and of course the gravitational attraction is reduced at higher elevations. If you weigh too much and live by the sea in Alaska, you can lose weight by moving to Hawaii.
Geologists have measured the gravity on and below the surface of the earth with a high degree of accuracy. Gravity surveys have discovered anomalies (differences) due to varying densities of solid and liquid matter. Gravity data and maps of gravity surveys are available, such as this one for Canada, this one for the oceans, and these maps for the Hayward fault in California.
In recent years, patents have been awarded for rights to gains from living organism, even if the organism accidentally comes into someones territory. Suppose that similarly the scientists employed by a company made a scientific discovery about gravity for which the firm was granted a patent which required everybody using gravity to pay the patent holder. The owners of the gravity company would be able to charge everybody on earth for the use of gravity, superceding the rights of possession and rent held by the holder of the title to territory. The gravity company would be able to collect the economic surplus of all locations, which equals the locational rent of all sites on earth, leaving the holders of title to territory with no rent.
Most folks would think it absurd for there to be a gravity company that can charge everybody for gravity. Actually, there are companies that use the name gravity, including a Zero Gravity Corporation that sells the feeling of not having gravity, i.e. weightless flights, and a game called Gravity Corporation. But there is no company that has rights to all the gravity on earth.
But wait a minute! All the landlords of the earth in effect own the gravity in their locations, and they do charge for using gravity along with the other services of the locations. So every landlord, including owner-occupants, are gravity-owning companies. If we dont think it just to charge others for the gravity provided by physics rather than produced by the landowner, the remedy is the public collection of the natural rent of land, which includes gravity.
Copyright 2005 by Fred E. Foldvary. All rights reserved. No part of this material may be reproduced or transmitted in any form or by any means, electronic or mechanical, which includes but is not limited to facsimile transmission, photocopying, recording, rekeying, or using any information storage or retrieval system, without giving full credit to Fred Foldvary and The Progress Report. Also see:
Foldvary: Paying for Gravity
Foldvary: String Theory and Land Rent
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