Observations in the [[visible light|optical]] regions of the [[electromagnetic spectrum]] have revealed where the shockwave hits high [[density]] regions of gas.<ref name=spitzer/> After the shock wave passes, these denser regions form bright knots and filaments. [[Infrared]] images of the nebula have shown microscopic [[dust]] particles that have been heated by the shockwave and brightest where in the knots and filaments. | Observations in the [[visible light|optical]] regions of the [[electromagnetic spectrum]] have revealed where the shockwave hits high [[density]] regions of gas.<ref name=spitzer/> After the shock wave passes, these denser regions form bright knots and filaments. [[Infrared]] images of the nebula have shown microscopic [[dust]] particles that have been heated by the shockwave and brightest where in the knots and filaments. |