Electrostatic suspension/Laboratory

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The image is an artist concept of Gravity Probe B spacecraft in orbit around the Earth. Credit: NASA/MSFC.

A laboratory is a specialized activity where a student, teacher, or researcher can have hands-on, or as close to hands-on as possible, experience actively analyzing a situation.

Here, the subject is electrostatic suspension. Consider an object of some shape. Configure either the object or the environment around the object so that it is suspended against an outside force.

Usually, the research and development (R&D) follows someone else's ideas of how to do something. But, in this laboratory you can create these.

This laboratory is structured along the lines of electrostatically suspending an object of some shape and mass.

I will provide an example of such a suspension. The rest is up to you.

Questions, if any, are best placed on the discuss page.



evaluation activity


  1. Using the approximate charge separation between the Earth's ionosphere and ground it should be possible to calculate how much charge or voltage is necessary to raise a 5,000 kg object above the ground between 70 m and 7000 m.

Vertical suspension[edit]

This diagram describes the mechanical core of a torsion pendulum. Credit: E. Willemenot and P. Touboul.

"The upper electrodes are used to apply control voltages (228 V in nominal conditions). The lower electrode voltages are controlled to Vp [a dc voltage of about 10 V], so that no force attracts the mass toward the bottom."[1]

For a gap of 0.00206 m, a proof mass of 5.40 g is successfully suspended against 1 G (of gravity) with a field of 7.7 x 106 V/m. The voltage on the proof mass is nominally 10 V.[1]

A thin gold wire is attached at the bottom of the proof mass to allow charge or voltage to be added of removed from the proof mass. The mechanical core apparently including the proof mass is made of gold coated fused silica.[1]

Natural electric field of the Earth[edit]

The natural electric field of the Earth refers to the planet Earth having a natural direct current (DC) electric field or potential gradient from the ground upwards to the ionosphere. The static fair-weather electric field in the atmosphere is ~150 volts per meter (V/m) near the Earth's surface, but it drops exponentially with height to under 1 V/m at 30 km altitude, as the conductivity of the atmosphere increases.

The Earth is negatively charged, carrying 500,000 Coulombs (C) of electric charge (500 kC),[2] and is at 300,000 volts (V), 300 kV,[3] relative to the positively charged ionosphere. There is a constant flow of electricity, at around 1350 amperes (A) [approximately 1100 A].[3]

"The magnitude of [the natural electric] field decreases with altitude; at 10 km it has a value of about 3% of that at the surface, whereas at 30 km it is about 300 mV/m and 1 μV/m at about 85 km (Rakov and Uman, 2003)."[2]

The "value of the electrical field intensity, 3×106 V/m, [is] for electrical breakdown between two parallel plane electrodes at sea level in dry air (Rakov and Uman, 2003)."[2]

"It is known that the earth is negatively charged and that there is a difference of potential between the earth's surface and a layer of the upper atmosphere of the order of 3 x 105 volts in fine weather; therefore any body rising from the earth's surface to this upper layer of the atmosphere will carry a negative charge at a potential of approximately 3 x 105 volts to the surrounding air, assuming of course that it has lost no charge by dissipation."[4]

"The electric field at the ground is an easily measurable quantity that has been measured at various locations. During fair weather the variation is small and the strength is ~ 100 V/m. However, the electric field on the ground can vary from -200 to 400 V/m if fog and haze [are present.] In fair weather the ground electric field variations are due to changes in columnar resistance, ionospheric potential, and local conductivity".[5]


In the vertical suspension device described above a voltage in supplied to the lower plate to keep the proof mass at a fixed distance from the lower plate. The proof mass is 5.40 gm and the electric field is 7.7 x 106 V/m. The proof mass has an inductive voltage of 10 V nominal, which can be adjusted through the gold wire suspended from the lower part of the proof mass.

An increase in mass from 5.40 gm to 5000 kg suggests that an increase in field strength from 7.7 x 106 V/m to 7.1 x 1012 V/m is required.

As the Earth's natural electric field is around 150 to 200 V/m, an increase in voltage on the 5000 kg proof mass must induce a field of 4.8 x 1010 V/m greater.

A nominal 10 V potential on the 5.40 gm proof mass suggests that the voltage should be at least 4.8 x 109 V/m greater.

This would be way beyond the breakdown voltage of the atmosphere.

There "are several reasons to believe that gravity is actually of electrical and magnetic origin."[6]

  1. "It is possible to take a large sample of the matter on the earth, namely that comprising the atmosphere, or 5.27 x 1021 grams, and show that it contains, within experimental error, the required electrical charge, namely about 1.36 x 1018 e.s.u. [We may] treat the atmosphere as a concentric-sphere condensor [capacitor] with the base of the atmosphere or the lithosphere as the inner sphere [and the approximate base of the ionosphere as the outer sphere. This] amounts to about 0.6 to 3.17 volts/cm (positive vertically upward so that q is positive) near the earth's surface. The average value is required to be 3.1 volts/cm in order that G½ M = q which is in excellent accord with the observed atmospheric potential gradient."[6]

If "gravity is actually of electrical and magnetic origin",[6] then increasing the negative potential on the proof mass should cause the proof mass to be repelled by the ground and attracted to the ionosphere such that no where near 7.1 x 1012 V/m is required. All that may be required is to raise the negative charge on the proof mass until the field through the proof mass is less than ~ 150 V/m.

Using the charge to mass ratio of about 1.36 x 1018 e.s.u. over 5.27 x 1021 grams, a 5000 kg proof mass needs about 1290 e.s.u. to be about 150 V/m. Any increase in negative charge above this should cause the proof mass to rise.


Title: Vertical suspension of a proof mass between the surface of the Earth and its ionosphere.



A device aboard Gravity Probe B allowed minute measurements of gravity or changes in it using an electrostatically suspended proof mass. By extending the field proportionately it should be possible to outline the suspension of a 5,000 kg mass between the surface of the Earth and its ionosphere. Appropriate back-of-the-envelope calculations and estimates are presented in support of this idea.


The electrostatic conditions inside the Gravity Probe B electrostatic suspension device have been described in the Vertical suspension section above. Proportional changes to match the natural electric field of the Earth may present the necessary conditions for suspension of the proof mass.





To assess your method of heating the solar corona, including your justification, analysis and discussion, I will provide such an assessment of my example for comparison.

If you chose another star, even of a different spectral type, be sure to include likely scale factors or other adjustable parameters.


Unless the influx is significantly higher at lower energies it seems that 10 to 700 MeV is way too high. The corona of the Sun would be producing gamma-rays not X-rays. No justification is given for the 104th increase in the influx estimate. Actual data on interstellar electrons does suggest MeV levels.

See also[edit]


  1. 1.0 1.1 1.2 E. Willemenot and P. Touboul (January 2000). "Electrostatically suspended torsion pendulum". Review of Scientific Instruments 71 (1): 310-4. http://www.mtl.mit.edu/researchgroups/mems-salon/sriram_torsion-pendulum.pdf. Retrieved 2015-01-12. 
  2. 2.0 2.1 2.2 Lorenzo Labrador (April 5, 2005). "Sensitivity of Tropospheric Chemistry to the Source of NOx from Lightning: Simulations with the Global 3D Chemistry-Transport Model MATCH-MPIC". Heidelberg, Germany: University of Heidelberg. Retrieved 2014-12-20.
  3. 3.0 3.1 C Polk (1969). Samuel C. Coroniti, J. Hughes, ed. Relation of ELF Noise and Schumann Resonances to Thunderstorm Activity, In: Planetary Electrodynamics. 150 Fifth Avenue, New York, NY USA: Gordon and Breach Science Publishers. pp. 55–83. ISBN 0677136005, 9780677136004 Check |isbn= value: invalid character (help). Retrieved 2014-12-13.
  4. B.L. Goodlet (February 1938). "The author's reply to the discussions on Lightning at Glasgow, Newcastle, Belfast, Manchester, Birmingham, Loughborough, Bristol and Middlesbrough". Journal of the Institution of Electrical Engineers 82 (494): 211-3. doi:10.1049/jiee-1.1938.0030. http://ieeexplore.ieee.org/xpls/abs_all.jsp?arnumber=5317467. Retrieved 2014-12-13. 
  5. Eileen K. Stansbery (March 1989). A global model of thunderstorm electricity and the prediction of whistler duct formation (PDF). Houston, Texas USA: Rice University. p. 174. Retrieved 2015-01-03.
  6. 6.0 6.1 6.2 Melvin Alonzo Cook (1958). Apendix III Plasma and Universal Gravitation, In: The Science of High Explosives. American Chemical Society Monograph Series. New York: Reinhold Publishing Corporation. p. 440. Retrieved 2014-09-03.

Further reading[edit]

External links[edit]

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