We need to find the exponent to which 8 must be raised to get 2.
In other words, we are looking for the number $x$ such that $8^x=2$.
Rewriting in exponential form, we have $2=8^x$.
Since $8=2^3$, we can rewrite the equation as $2=2^{3x}$.
Therefore, $3x=1$ and $x=\frac{1}{3}$.
Thus, $\log_82=\boxed{\frac{1}{3}}$.The answer is: \frac{1}{3}
Below is a math problem. Provide a detailed, step-by-step solution.

### Problem:
Evaluate $\log_82$.

### Answer:
