Emission nebulae
					� The red glow is Hydrogen Balmer �� (H ) emission � Could be from hot gas but � � relative strength of emission lines not always right � Can also get fluorescence: � UV photon from bright star boosts electron to high level (or ionizes it) � Emission lines created as electron cascades back down through H energy levels � The �horse� is a dark cloud in front of the glowing gas.