Does the Fine-Structure Constant Vary with Cosmic Time?

The fine structure constant at red shifts $\frac{\Delta \lambda }{\lambda }\approx 0.2$, corresponding to an epoch around two billion years ago, has been determined using the wavelengths of a pair of O III emission lines measured in the spectra of five radio galaxies. We find $\frac{\alpha \mathrm{}(z=0.2\mathrm{})\mathrm{}}{\alpha \left(\mathrm{lab}\right)}=1.001\mathrm{}\pm 0.002$ probable error.