The incompatibilities between the standard theory of interstellar extinction and observations

In this paper I review a series of observations which do not agree with the standard interpretation of the extinction curve. The consequence is that light we receive from a reddened star must be contaminated by starlight scattered at very small angular distances from the star. The true extinction curve is a straight line from the near infrared to the far-UV. If so, all interstellar grains models must be questionned. Another conclusion concerns the average properties of interstellar grains which seem much more uniform than previously thought.