  We study a higher dimensional cosmology with phantom field associated with a
negative kinetic term. Assuming that the universe possesses the phantom field
defined in $D$ dimensional spacetime, we investigate in detail the solutions
involved in the higher dimensional phantom cosmology, to explicitly predict
photon size and phantom field strength at present in nature. To be specific, we
find that the photon size decreases drastically at the early stage of the
universe after the Big Bang. Next we explicitly demonstrate the dependences of
the photon size, universe size and phantom field strength on the spacetime
dimensionality $D$. We observe that the size of the universe undergoes stiff
explosion with different types of slope depending on $D$. Moreover the scale
factor of the universe at present is shown to approach to a saturated value,
which is independent of $D$ and is the same as that in the $D=4$
Friedmann-Robertson-Walker cosmology. The photon size and phantom field
strength in the greater dimensionality are also shown to be larger and lower
than those in the smaller one, respectively. Next the photon size at present
$b_{*}$ in $D=5$ is numerically shown to be extremely small, namely
$b_{*}=6.08\times 10^{-216}$ cm, comparing to $b_{*}=1.56\times 10^{-63}$ cm in
$D=10$. In contrast, the phantom field strength at present $\sigma_{*}$ is
shown to be relatively large $\sigma_{*}=4.72\times 10^{24}$ (dyne$)^{1/2}$ in
$D=5$, comparing to $\sigma_{*}=1.39\times 10^{22}$ (dyne$)^{1/2}$ in $D=10$.
