  Over the last few years, many close orbiting ($\sim 0.05$ A.U.) large mass
planets ($\sim M_{J}$) of nearby stars have been discovered. Their existence
has been inferred from tiny Doppler shifts in the light from the star and in
one case a transit has been observed. Because ordinary planets are not expected
to be able to form this close to ordinary stars due to the high temperatures,
it has been speculated that the close-in large planets are in fact exotic
heavenly bodies made of mirror matter. We show that the accretion of ordinary
matter onto the mirror planet (from e.g.the solar wind from the host star)
should make the mirror planet opaque to ordinary radiation with an effective
radius ($R_p$) large enough to explain the measured size of the transiting
close-in extrasolar planet, HD209458b. Furthermore we obtain the rough
prediction that $R_{p} \propto \sqrt{{T_s\over M_p}}$ (where $T_s$, is the
surface temperature of the ordinary matter in the mirror planet and $M_p$ is
the mass of the mirror planet) which will be tested in the near future as more
transiting planets are found. We also show that the mirror world interpretation
of the close-in extra solar planets explains the low albedo of $\tau$ Boo b
because the large estimated mass of $\tau$ Boo b ($\sim 7M_J$) implies a small
effective radius of $R_p \approx 0.5R_J$ for $\tau$ Boo.
