The Earth's diameter is given as \(8.0 \times 10^3\) miles. This notation means:
\[ 8.0 \times 10^3 = 8.0 \times 1000 = 8000 \text{ miles} \]
As a result, \(8.0 \times 10^3\) miles is equivalent to 8 thousand miles.
Thus, the answer is: 8 thousand miles.