Projection is an alien ability on WB sci-fi series Roswell.
Projection is the ability to produce something through the mere power of ones mind. This ability is unique to Isabel Evans, and has been demonstrated on a number of occasions when she has projected the music from CD's, she has also been able to manipulate the music similar to that of a DJ's equipment.
Advanced Projection is demonstrated by Isabel, who, whilst still holding onto the death of Alex, sub-consciously projects what seemed like Alex. This projection could only be seen, heard and touched by Isabel, as it was her who created the projection.
It should be known that this was not a true projection of Alex, as the projected Alex stated himself that he is from Isabel's sub-consious. It is highly possible that given enough time and practice that Isabel would have achieved in creating/projecting a person i.e. Alex, whom could be seen,heard and touched by others.