What I’ve Got – Glow in the Dark StarsI had glow in the dark start on my walls as a kid, and recently put some up in my room, and I’m really enjoying them. They add just a little bit of flair to my walls, and are pretty unobtrusive in the daytime. They can essentially be adhered to any surface, and don’t leave residue on the walls, making them pretty functional. Glow in the dark stars glow because they contain phosphors, or photoluminescent compounds, which slowly release electromagnetic energy absorbed at a previous time. Photoluminescence has been observed in natural contexts (like the glow of fireflies) for thousands of years, but phosphorus was isolated in 1669 by Hennig Brand. Since then, many other phosphorescent compounds have been discovered, and the stars on my walls likely contain zinc sulfide or strontium aluminate. These compounds can absorb visible light and then release it slowly over a long time span, which means that these stars are slowly losing their glow, and eventually will cease to do so. Source:http://inventors.about.com/od/gstartinventions/a/glow