After watching Harry Potter the other day, I wondered whether it would be possible to make a working invisibility cloak. If so, any suggestions on how it woild work would be useful.

Obviously we can all see full spectrum light when it's pointed directly at us or when it's reflected/refracted off of an object. However if a light (a torch say) was shined horizontally across our field of vision, from an angle where we could not observe the light directly. Across a vaccum where the beam of light would not be interfered with or interrupted whatsoever. Would we be able to observe the beam of light. If so, how? And if so, wouldn't space be light instead of black?