 If you look at the reflection from silk, it's brilliantly white, lustrous, sparkling, vibrant, so you can use all the terms to describe the uniqueness of reflection from silk. Based on the Anderson Light Localization Invisible Light, it reflects all solar energy, basically sunlight, and high emissivity of silk molecules dissipate heat from one space to the other. As a result, we can have a self-cooling effect because we don't use any external energy. It is called passive radiative cooling. It's well known in Asian countries that if we wear silk underwear, it's warm during winter time and it's quite cool in the summertime, but now we have physical mechanism why it works. To test the capability of the radiative cooling of native silk, we have compared with common rooftop materials such as aluminum and black painted coated aluminum. The temperature of the silk cooling panel is 10 degrees lower than the temperature of the aluminum panel. So in this respect, we could confirm the idea of passive radiative cooling in native silk. So our study has several implications and direct applications. From an imaging standpoint, we can take advantage of Anderson Light Localization in silk fibers so that we can use silk fibers as optical imaging fibers that can be implemented in human body without having any side effect. From a nanomanufacturing standpoint, the idea of insect factory and bioreactor of silkworms can provide a new strategy for green nanomanufacturing. So we might have some nanomaterials and nanostructures in a scalable, sustainable and eco-friendly manner.