[ExI] Physicist proposes using magnetic fields to produce gravitational fields?

[Anders Sandberg]

On 2016-01-09 02:10, Will Steinberg wrote:
>
> Can it be arbitrarily scaled up, though?  Because even if it would be 
> practically impossible, that would still be an interesting result.  
> And maybe something to hold on to for when we figure out fusion or 
> make Dyson spheres.  If it can't scale though then it does kinda suck.
>

Gravity fields tend to suck :-)

But, yes, the effect is small:
> The precision achieved by optical lattice clocks in the measurement of 
> a transition
> frequency is of the order 10^-15 [12]. Achieving such a gravitational 
> redshift with single-layered solenoids would require CI = 10^-15, 
> i.e. for an electric current of
> 1kA, n = 100 it would require a solenoid length of about 10^11 m.
Now, CI scales with the square of the current and widning length. The 
length is already on Dyson lengthscales, but you could of course amp up 
the current by a mere factor of a few million to get order of unity 
gravity effects. GigaAmpere currents doesn't sound that impossible if 
you are using enormous superconductors.

In the end this is likely the wrong way of making gravity. You could use 
the energy to spin stuff up or move masses around. Electrical fields get 
their energy divided by a c^2 factor when calculating their gravity 
effect, so mass is way more effective in making gravity.

-- 
Dr Anders Sandberg
Future of Humanity Institute
Oxford Martin School
Oxford University

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