Theoretical models according to Black-Scholes have no skew or smile. However, because vega decreases as time to expiration decreases, I initially thought that the skew or smile would flatten. On a second thought, the value of vega bears no linear relation to volatility, vega <=> d(price)/d(vol). Therefore, I finally concluded that time has no effect on skew or smile. I.e., implied (or historical) volatility is a stochastic variable independent of time; and therefore skew or smile is not affected by time. Any comments?