The energy of the sun feeds life on Earth and is harvested by molecules of chlorophylls and carotenoids. In case of certain photosynthetic bacteria thousands of these molecules are fitted into spheres smaller than 1/10000 of a millimeter (see the October 2007 highlight on Life's Solar Battery). Naturally, it is crowded in these spheres! Researchers now established the composition and arrangement of the light harvesting system, the chlorophylls and carotenoids being held by hundreds of ring-shaped proteins. Utilizing the sun light's energy optimally is a difficult balancing act in molecular engineering: on the one hand the proteins need to pack closely to share light energy absorbed by any chlorophyll or carotenoid, on the other hand, roadways need to be kept open for passing chemical substances that capture the light energy in chemical form and deliver it to the remainder of the bacterial cell. Researchers now report how the bacterial cell manages the balance through ingenious utilization of quantum electronics. More on light-harvesting in purple bacteria can be found here.