An astrophysical finding recently placed a galactic nebula directly between the earth and a distant quasar. Studies of emission from the quasar put an upper limit on the average gas (hydrogen) number density of 10m, and an electron temperature of 2 eV. The radio emission from the distant quasar is found to drop off dramatically in intensity at frequencies less than 10 kHz. Assuming that the nebula can be treated as a weakly ionized collisionless plasma, estimate the average electron density. Briefly comment on the validity of the collisionless plasma approximation.